diagonal planking

[Boston]

of all the many types of planking I could go with for my wood build, diagonal seems to be the lightest and strongest of my options. Its glue intensive, which in my book is a strike against it, but, the stiffness it so obviously imparts is a strong consideration in its favor. The main issue I have with it is Ive not any experience in a cold molded technique and so far nothing about this build is outside of my experience in building. Im not adverse to learning something, its just learning it the hard way, I prefer to avoid.

most of you know the boat Im working out the preliminary design for, but since the size and hull configuration is so critical to sheathing considerations Ill picture her again

http://maggiesfarm.anotherdotcom.com/uploads/elco57.jpg

57' of easy radii
no problem to get a bend around with one small area of compound curve
the hardest turn in the hull being about a 5'8" diameter radius at station #7

so far I'm going with a laminated keel out of Black Locust under a white oak skeleton
( turned out to be a pain in the ass to acquire BL in timber sizes )
with a BL keelson and bellow wl stringers the rest being WO

frames are steam bent solid and Im upping the scantlings from 1 5/8 x 1 5/8 each 9" to 1 7/8 x 3 tapering to 1 7/8 x 1 7/8 each 9"
midway through the turn Im about 1 7/8 x 2 3/8 on edge and I think thats about what I can expect to safely bend out of WO without risking eventual damage to the frame over time

Ill make a few and see how they survive
I may have to laminate the frames to get the bend and the size I want
maybe as I think Im in the ball park on that bend limit
this vessel was not originally designed to be a open water voyager so Im thinking it needs some stiffening ( storm shutters and stiffening in the superstructure as well but thats no big deal )

reason I start this thread is that if I went with diagonal planking I might gain sufficient strength to pair down the frames some considering that true cold molded hulls generally dont even have frames in em just bulk heads and stringers.

I want a frame ( for me its half the fun of building ) but the sheathing, laminated keel, and stringers on a diagonal planked hull do most of the work

so
question is
how much strength does a monolithic skin impart to the structure as a whole
for each four layers ( two diagonal two linear ) of what wood do I gain what over the same thickness of the same wood

Im guessing its significant but Im guessing and thats not good enough
someone of you builders have got a chart somewhere
so if you could post it
Ild sure appreciate it

cheers
B

[nero]

Strength is only part of the compromise. Weight is another.

If you take the surface areas and add up the hull thickness as weight-per area then is becomes amazing how fast things get too heavy.

You would be much stronger, faster, fuel efficent to make the plan as a constant radius and use pannels construction. Or simply redue the plan in something like TouchCad and let it spit out the unrolled shapes.

Regards

[Boston]

of all the many types of planking I could go with for my wood build, diagonal seems to be the lightest and strongest of my options.

so whats its strength to weight ratio as compared to other planking styles in a given wood

I can calculate weight and get this boat to its original displacement and be stronger in the long run

once I get this thing further along Ill post the strength to weight ratios of each member and then on the whole structure to derive the strength gain over original
assuming someone has the numbers on diagonal planking

cad is not necessary friend
I prefer to do things by hand

best
B

[jehardiman]

so
question is
how much strength does a monolithic skin impart to the structure as a whole
for each four layers ( two diagonal two linear ) of what wood do I gain what over the same thickness of the same wood

Im guessing its significant but Im guessing and thats not good enough
someone of you builders have got a chart somewhere
so if you could post it
Ild sure appreciate it

cheers
B

Actualy, I doubt that you will find a chart comparing like thickness. Double diagonal cold molding is so superior in strength to conventional caravel construction that you usualy end up with a much thinner skin.

For conventional construction, the plank thickness is selected to support buckling and shear load between frames with each plank acting as an individual. The frames (actualy the plank fastenings) attempt to hold all the planks in relation to one another, but are relatively ineffective in this (i.e. racking and working) and at distributing load between planks.

In cold molding, the monolithic structure of the shell allows for load to be distributed throughout many planks with the diagonal layers locking the inner and outer layers together athawartships. These diagonal layers are far more effective than frames (with modern glues) in maintaining the geometry of the shell and the relationship between planks.

FWIW, conventional hull design have been trying to solve the individual plank flexture problem for hundreds of years. The Diagonal riders in the Humphries frigates, the iron or bronze strapping in the clippers and 1870's yachts, the iron framing and diagonal strapping of the composite tea clippers, right up to the Ashcroft system, have all be trying to make a monolithic wooden hull.

[Tad]

Boston,

I see you've morphed a traditionally built pilot schooner into a cold-molded power boat? There's a leap....

Wood is "anisotropic", it's strength is unequal in all directions. Strength is dependent on grain direction and orientation to the loads imposed. Trying to mix traditional and modern construction techniques, or even compare them, is a complex exercise needing precise input.

What's the load? Powerboats are subjected to various major loads, the big one is speed dependent, but there's also bending in waves. And what "strength" do you want to compare? Compression, Tension, Shear, or Static Bending? Parallel to the grain or perpendicular to the grain? Or someplace in between as with most boatbuilding problems? Understanding Wood, by Bruce Hoadley, is a good primer on wood engineering.

You cannot address one part of the structure and ignore the rest, it must be designed as a system, otherwise there will be problems. A cold molded hull will take many more man hours, will need more clamps, you'll need to learn about vacuum bagging and get rigged up with plastic nails and gun.

A properly designed and built cold-molded hull will be far superior to a traditional one, in stiffness, puncture resistance, insulation value, and more valuable in the marketplace, also long term maintenance will be far lower. Initial cost is far higher, and you have to deal with nasty goop.

The boat in my avatar is 80', cold-molded of all diagonal skins on big plywood and laminated stringers, There was no benefit in running any of the planking longitudinally.

[peter radclyffe]

of all the many types of planking I could go with for my wood build, diagonal seems to be the lightest and strongest of my options. Its glue intensive, which in my book is a strike against it, but, the stiffness it so obviously imparts is a strong consideration in its favor. The main issue I have with it is Ive not any experience in a cold molded technique and so far nothing about this build is outside of my experience in building. Im not adverse to learning something, its just learning it the hard way, I prefer to avoid.

most of you know the boat Im working out the preliminary design for, but since the size and hull configuration is so critical to sheathing considerations Ill picture her again

http://maggiesfarm.anotherdotcom.com/uploads/elco57.jpg

57' of easy radii
no problem to get a bend around with one small area of compound curve
the hardest turn in the hull being about a 5'8" diameter radius at station #7

so far I'm going with a laminated keel out of Black Locust under a white oak skeleton
( turned out to be a pain in the ass to acquire BL in timber sizes )
with a BL keelson and bellow wl stringers the rest being WO

frames are steam bent solid and Im upping the scantlings from 1 5/8 x 1 5/8 each 9" to 1 7/8 x 3 tapering to 1 7/8 x 1 7/8 each 9"
midway through the turn Im about 1 7/8 x 2 3/8 on edge and I think thats about what I can expect to safely bend out of WO without risking eventual damage to the frame over time

Ill make a few and see how they survive
I may have to laminate the frames to get the bend and the size I want
maybe as I think Im in the ball park on that bend limit
this vessel was not originally designed to be a open water voyager so Im thinking it needs some stiffening ( storm shutters and stiffening in the superstructure as well but thats no big deal )

reason I start this thread is that if I went with diagonal planking I might gain sufficient strength to pair down the frames some considering that true cold molded hulls generally dont even have frames in em just bulk heads and stringers.

I want a frame ( for me its half the fun of building ) but the sheathing, laminated keel, and stringers on a diagonal planked hull do most of the work

so
question is
how much strength does a monolithic skin impart to the structure as a whole
for each four layers ( two diagonal two linear ) of what wood do I gain what over the same thickness of the same wood

Im guessing its significant but Im guessing and thats not good enough
someone of you builders have got a chart somewhere
so if you could post it
Ild sure appreciate it

cheers
B
lloyds scantling rules allow, a reduction of 10% of planking thickness for oiled calico, double diag, if you dont want to use glue, & as you know, 1'000s of wonderful american boats have been built this way, & a reduction of up to 25% for cold moulded, but check your frame spacing, i repeat , up to 25%, so for safety 15-20%, as you wish, i am not a cold moulded specialist, i am sure there are many with far more exp than I.

[Boston]

I see you've morphed a traditionally built pilot schooner into a cold-molded power boat? There's a leap....

just seemed a lot more livable
and then I started considering the upkeep on all that rigging and the sails and bla bla bla. The old Elco ended up being a way bigger bang for the buck with a far more habitable design, so, I jumped ship.

glad someone noticed
I was beginning to think no body cared :-(

Wood is "anisotropic", it's strength is unequal in all directions. Strength is dependent on grain direction and orientation to the loads imposed. Trying to mix traditional and modern construction techniques, or even compare them, is a complex exercise needing precise input.

precise input being exactly what Im after mate ( thanks Tad for the numbers )

What's the load? Powerboats are subjected to various major loads, the big one is speed dependent, but there's also bending in waves. And what "strength" do you want to compare? Compression, Tension, Shear, or Static Bending? Parallel to the grain or perpendicular to the grain? Or someplace in between as with most boatbuilding problems? Understanding Wood, by Bruce Hoadley, is a good primer on wood engineering.

you forgot stability across the grain transition, moisture content, fiber stress at proportional limit, both rupture and elasticity, and the all important impact bending.

I will undoubtedly be considering the entire structure in the one part of this build that will be computer generated, a flex analysis.

You cannot address one part of the structure and ignore the rest, it must be designed as a system, otherwise there will be problems.

am working my way through that system now which is why I was after the numbers on diagonal planking vs other forms of planking

Pete my frame spacing is per original specs and my sheathing will probably be tulip wood set in epoxy with either the inner and outer layers longitudinal or just the outer
need feed back on that and how it relates to the overall stiffness of the structure

c mon people
I know someones got a comparison somewhere
although that 25% from Lloyd's is pretty telling, I need to also consider wood species, thickness, number of lamination's and all that jive.

basically I could alter species of the original specifications from ceder to tulip wood, go with the same thickness for a slight weight gain, go with diagonal planking for significantly greater strength "over all".
also the take up would be nearly eliminated so in the end the weight gain in the species switch would balance itself out
and Ild be dryer inside

any flaws in that logic Ild love to hear it

[thudpucker]

I keep thinking about the WWII Sub Chaser I had some time on.
It was double planked. 4" for (I think) a total of 8".

It was probably necessary for the WWII sea Duty, but I doubt if you need it now. It had two 16 Cylinder, Radial GM 71 Inch cylinders. Awsome power.

I also had a Chris Craft of the 50's, single planked and it worked fine. Just that maint problem if you ever had to pull it out of the water.
It had two little Izuzu four cylinder diesels.

I'd stick with single planking and smaller engines.

[Boston]

that was closer to the mark than you may know
I found lines and some details for the old elco ML's or Movies that were the sub chasers in WW1 for the English Navy. I detrended them and scaled that down to fit the dimensions of the 57. It worked perfectly and looks exactly like the 29 Elco flat top.

The original elco 57 had 1 1/4 inch ceder carvel planking on the hull
and 1 1/4 white pine on the deck all over white oak framing

I think it was Par that mentioned having a 40 wooden fishing boat that lost a full ton in take up once out of the water for a few weeks.
if that ratio of length to weight is scaled up to the 57' boat Im thinking of then thats about 1.5 tons of weight that I can play with in strengthening
through strategic design.

B

[rasorinc]

My 2 bits. Bottom 2 layers 1st 1/2" 2nd 1/2" marine ply max 9" wide which should give you max usage out of a 4 x 8 Final layer 3/16" to 1/4" black locust.
Sides 2 layers 1st 3/8" 2nd 3/8" marine ply. Final layer 3/16" black locust. I sent you that link for Black Locust a guy in Washington state has whole dry logs. Increase diameter depending on frame spacing. The Black Locust provides shock and dent resistance. The double ply laid diagonally gives fantastic strength and it is never seen. I'm assuming frames at 24" OC to 30" OC. Best, Stan PS this is a Minimum, not a maximum Use these composite nails, brads, staples to attach the plywood layers. Use bronze screws for the final layer and you can pre drill through the composites for the bronze. Raptor are used thoughout in boat building but they will not go through black locust
http://www.raptornails.com/english/firstframe.html

[Boston]

Hmmmmmm

that was the magic last bit I needed Ras

ply strips are week perpendicular to the surface grain so I was going to avoid using it in the sheathing of the hull, (at least 5 ply is, 9 is the bomb but I wont be finding it in 1/2"). Black Locust is great for structural members of the frame exactly as you previously stated but heavy, might add to much weight but would sure be worth using. Please send that link again as I must have missed it or misplaced it. Ply is also heavy and typically that stuff uses Resourcenol which out gasses formaldehyde and has been known to cause serious respiratory complications.
Ive given serious consideration to increasing the spacing of the framing to a typical 16oc spec just to keep my brain on straight
thats another reason Im after the stats on cold molding
which I guess I got at +25% ( wood for wood ? )
so if I consider same wood and same thickness I could go 25% greater spacing on the frames

poplar is 25% heavier than red ceder and about 30% stronger depends on how you want to measure it with a modulus of elasticity of 1,120 lb/sq (ceder) vs 1,500 (yellow poplar) at 12% moisture content being about 34% stronger and an impact bending limit of 8,600 lb/sq (ceder) vs 13,500 lb/sq (poplar) or 57% stronger at the same 12% moisture content

means poplar would allow me at the same thickness to gain ~30% spacing for a ttl of ~25% + ~30% or ~55% of 9" spacing is ~14" spacing
and then I increased the size of the frames on average from 1 5/8 x 1 5/8 to 1 7/8 x 2 1/2 or ~ nearly 78%
which gives me the 16" spacing for the frames with a significant gain in strength throughout the structure

and I have yet to calculate the weight gain but it only needs to be bellow the typical take up of red ceder and Im good to go

hmmmm
57 x 12 = 684 / 16 = 43 ribs
as apposed to 684 / 9 = 76 ribs
or 77% fewer ribs at 78% greater mass pr rib
well that worked out

but the greater spacing kinda makes me want to thicken the hull from 1 1/4 to maybe 1 3/4 or about 40% using the same four layer system and thus the same amount of epoxy say an inner layer of 1/2 two layers of 3/8 diagonal and one more of 1/2 exactly as Ras suggested
although Im starting to warm up to the idea of a final layer of black locust, at least bellow the line, and since its so much stronger I could go thinner on that last layer, say whatever the weight difference dictates, maybe.

so the sheathing material (poplar) weighs in at 28% heavier pr cubic foot and I added 40% which works out for each square foot of planking to be 2.2 lb/sq ft for ceder at 1 1/4 and 3.9 lb/sq ft for poplar at 1.75 or 77% heavier

the boat is 57' long and an avarage rib length of 22' ( measuring strong just for the sake of argument ) and I get 1,254 sq ft of surface area
cedar would weigh in at 2,758.8 lbs
poplar would weigh in at 4,890.6 lbs

and that's within the 1 1/2 tons I roughly calculated for take up in an old school ceder hull
means the boat floats about were it should and yet is far stronger than it was

I think
if I screwed up anything obvious feel free
otherwise
thanks for the help guys
B

[mark775]

Ferrocement! (Second choice; resin rich chopper gun).









If anything could make us see eye-to-eye, it is the beauty of that vessel. I know you're from Colorado, and all, but the above was a joke.

[PAR]

Why are you bothering with steam bent framing? You have plans for a homogeneous hull shell, why not take this to full advantage. You'll save the trouble and costs of these elements, plus save considerable interior volume as well. Ditto the massive deadwood assembly. With modern engineering techniques, material use, application and build methods, you don't need these huge, ridiculously heavy and costly timbers. Put the savings in fuel and stowage capacity.

[Ilan Voyager]

I would go simpler: strip plank, epoxy and biaxial. Little or no framing, just bulkheads.
Strong as a rock, easy to make, lasts at least 50 years, using a common affordable wood.
I would stop to split my head about calculations and guessings, I would take the Gerr's book "The elements of boat strength" and recalculate the scantlings in less than one day of work. The results are in the strong side. And I'm a naval engineer with more than 30 years of experience and now 161 boats behind me...go simple and Gerr's book is enough good..
With the weight and money savings, I would spend more time and money to nice amenities and good engines. Hull is just a very small part of the job.

[Boston]

Mark
the interior is going to be raised panel cherry and the decks in curly maple ( depends on the availability at the time might just end up being maple )
the framing will have all non bearing surfaces beveled with a saddle left on all bearing points, just like all my other stuff
and a lot of the structural will be exposed
when I start in on the interior design Ill send you some of the drawings if your interested
glad you liked the boat

Par
I have lines for the old elco but no prints
and Im piecing together plans from bits and pieces of info and smatterings of scantlings then modifying them to my own idea of what I want the boat to do. What I come up with is still developing.

I didnt know I was going with steam till someone suggested it
nor did I know I would go with pellets for a fuel source till the steam engine was mentioned
and that came from a consideration of electric
the hole thing is a process that seems to have a life of its own actually
its like following a trail of bread crumbs

where I end up, who knows
but I want to blend function and form wherever I end up and that means its not always going to make sense to the purely linear thinkers. That artistic considerations function must however transcend the purely aesthetic.

make your best case Par, I am listening intently and you may find I am leaning in your direction
I picked the boat and placed the stipulation that it be environmentally friendly using low embodied energy materials and fuels. I also placed the structural consideration out there that it would be transoceanic. beyond that the various alterations must have an intrinsic relationship to the era in which the design comes, if those alterations are going to be visible to the casual observer.

in the begining of this project it was suggested I dont have to use glue at all
but it seems the 21st century is calling and given maintenance considerations it might be wise to answer. also the desire for a transoceanic capable boat seems better met with a cold molded hull.

the take up consideration presented earlier was the final nail in the traditional carvel planking's coffin ( that was almost a pun )

we started talking about glues and I found I was stuck with epoxy
( had to sorry )
even though I swore I would never use the stuff

now its a mater of how much epoxy as its hands down the least environmentally friendly thing in the build

you would suggest I slather the whole thing in epoxy
I would suggest using as little as possible to meet the design criteria that it be as environmentally friendly as possible and yet open water capable

I have 1,254 sq ft of surface area and four layers of sheathing in the hull
thats 3,762 sq ft of glue
I think I came a long way from my no glue days

as for the keel
I was going to begin another thread for that design
but since the answer to the hull planking came so easily I guess I can move on

there are three ways Im thinking of going

A) a simple frame over keel with a keelson and rabbeted gar boards to accept the diagonal planking

B) the Cutts method but with four layers instead of two and with no fabric in between

C) or the standard cold molded, false keel sandwiching the sheathing between itself and a keelson

Im inclined to blend method A with method C
as Ill be laminating the keel anyway and I like the idea of clamping the sheathing and the frames between the keel and keelson

also it eliminates the rabbet line, the garboards and reduces the thickness of the keel moving the main structural member to the inside where its better protected anyway

but
Im not willing to give up the steam bent framing as it adds so much to the look of the interior, Much of which is going to be exposed. Honestly the inside of a cold molded hull just looks ugly. There is little room for the expression of craftsmanship nor the opportunity to have large open spaces as bulk heads are such an integral part of the cold molded method. I suppose if you made the hull thick enough, the stringers huge and used enough glue you could just leave the hole thing open, but that void of barren walls is just not what Im after

best
B

Ian
Ill definitely pick up the book
although figuring things out on my own is half the fun
I will be not only checking my self against the references suggested but I also plan on having the drawings checked by someone who designs for a living before I start the build. I have a friend of mine who does computer modeling it will be interesting to give him the final design and see what it takes to break it.

[Landlubber]

Boston,

Cold moulded or strip planking, to me the ONLY choices today for a wooden boat.

Bugger the "do gooder" bit about using epoxy, if you are going to use all the woods you claim, then do so responsibly, responsibly is to make the best use of the materials and be sure they will have as long a useful life as is possible knowing what we know currently about construction methods.

The interior can be exquisite if you so desire, nice woody surfaces everywhere, that is easily achieved in cold moulded or strip planking, the materials used are assembled into very strong composites either way you choose to fly, both methods produce very pleasing shapes, though the cold moulded would be stronger (i think) weight for weight of materials.

Another very important thing to remember, building a crap design and building a good design cost the same amount of money, resale is another thing that you must consider, why build a crap design when there are so many good designs available for good home builder construction.

I have seen your work posted here previously, you are more than capable at building anything, so think about what you are doing and build your work of art, not just for yourself, but so that when the time comes, it is a valuable asset to be sold. Too many people put hundreds of thousands of dollars into , what they believe to be masterpieces, unfortunately the general public do not feel the same, so their boats become almost worthless when they get sold.

Enjoy the build mate anyhow. I know it is going to be something special.

I do not agree with a lot of what you write, but you certainly are a true master tradesman.

[PAR]

Yachts of that class are given a ceiling, so there aren't any "structures" to really look at, except deck beams, which are also over rated, particularly when you bang your head on them.

Use double planking set in 9 pound shellac. No epoxy and it'll last for generations. Of course you'll be best advised to use Herreshoff scantling rules or slightly heavier to keep the weight down.

I too wouldn't recommend a molded hull for a back yard build, even with your woodworking experience. It's a job best suited for a shop with climate control and vacuum bagging abilities. It's not an easy method and quite labor intensive.

Forget about the Cutts method if you elect to alter the schedule. It only works with the cords in place and of dubious value if you ask me.

Considering your desires, you should read Buehler's book "Back Yard Boatbuilding". It's structure all over the place, very little if any epoxy, big nuts, bolts, timbers and slam bam boat building. His focus is on readily obtainable materials like roofing tar, lagging compound laid fabric decks, etc. Of course it produces a hefty boat as he would but it, stout enough to really bash things if they get in your way. This would require a design with substantial displacement, possibly (quite likely) more then you have available in the design you've selected. Why use drywall when you want a log home . . . which I think is the crux of your issues.

Determine what you want in regards to structure, then select scantlings to fit. Of course they need to suit the boat. That Elco was fairly lightly built for what it is over a moderately stiff framing structure. The scantlings wouldn't be terribly difficult to work out, though I think you currently lack the skills to do so. It's not something you can "take a stab at" in this displacement range. The original plans are still available (at least enough to work from), but you'll have to plop down some cash.

Considering the scope of the project, the amount of man hours necessary, the amount of materials and equipment, having a set of plans worked out for the method of choice seems a reasonably direction to venture into. It insures you get what you want, the hull will float deck side up come launching day and it will not hog the first time you throttle up. Yep, it'll cost thousands of dollars, but this is a small fraction of the total cost of a project like this.

[Boston]

well I got a real bang out of the do gooder comment
bout fell off my chair actually
hardwood is plentiful since folks back east learned to selective cut about a hundred years ago, its not been a problem. Its out west and in the northwest were clear cutting is still allowed that we are running out of old growth, plywood being the main contributor to the forests demise. Another reason I dont much like the stuff.

Im not sure anyone who looks at that old Elco is going to think crap design
but to each his own.

the boat will be as comfortable as I can make it with as few and as large a rooms as I can reasonable accommodate. the cielings are all 7'2', there are two beautiful sets of full stairs with turned railings going one, down from the wheel house to the master cabin and the master bath and the other going forward to the guest berths guest bath and the storage lockers. Im not sure were Im putting the galley yet but its going to be serviceable not extravagant. it seem like a lot but Im going minimalistic with the basic layout and fittings

The master cabin is 18'x10 with two sets of full stairs with turned railings and flared lowers and uppers one going up to the aft deck and the other up to the wheel house. there will be a small wood stove and entertainment area as well as matching built in wardrobes and of course a bar with wall mounted faucet valves and Bates and Bates hand pounded brass sink flush mounted in a black marble counter top over a radius sink base. Ive designed a lot of vacation homes in the mountains around here and I got use of space and interior design down mate, besides Im starting with a classic and just sprucing it up some.

once I get the structural considerations down Ill get serious with the elevations and interiors
but I dont think there is a soul alive who is going to call this thing poorly designed or constructed

besides
Ive got all of you guys to rake me across the coals if I suggest something completely stupid eh

cheers
B
and thanks
confidence appreciated

par Ive heard of people using varnish or shellac like it was glue
I should boil some and see what shakes loose

Im just kinda playing with the scantlings at the moment but I bet Im close in terms of my alterations, however, as previously stated Ill have everything checked by someone professional, but Im definetly going to design my own joinery. The actual prints are going to be interesting to say the least, If you remember the days when a decent set of prints started with an artists rendering of some perspective view and each page went on to have some bit of artistic expression on it thats what Im after. I should scan even just one page off a set of my prints and you would immediately see what Im after in terms not just engineering skills but also style and balance in every aspect of the job.

http://i29.photobucket.com/albums/c262/bostonpyramidbuilder/squrelcrop.jpg

this one was practice for a set of prints on a house up in Estes Park

I've read parts of Buehlers book and thought he was kinda a wood butcher
also has no sense of design whatsoever
and his structural considerations are mainly based on just using bulk crappy wood rather than the correct amount of the correct wood for the job
the man had no sense of joinery whatsoever with everything being butted and bolted or at least most of it

with a 7'2" ceiling I dont think to many people are going to be cracking there heads on the deck beams
Im debating whether to do a tongue and groove on a wish bone layout
its easy and the diagonal layed planks will aid in strength

what I want is an artistically well built and strong boat using the right wood for the job and as little glue as possible
Im a big believer that a joint that is as homogeneous in nature as possible, will outlive joints were some components expand and contract at substantially differing rates than others creating an all to common servumstance were fasteners work and chew there way out of a hole rather than bend and flex with the structure as a whole.
Ive built some serious stuff with all wood joinery and this is no different. Bolts are for those who have never seen a properly turned treenail or have no clue what a foxlock is.

the cuts method didnt impress me that much but I did like the way the planking was continuous under the keel

[erik818]

Boston,
Why do you consider epoxy to be unfriendly to the environment compared to other production methods? I've tried to google the issue without success. I don't know how epoxy is produced and if this causes an environmental problem.

I don't trust that old traditional methods and materials are more environmental friendly than the modern variants. Epoxy/glass makes it possible to build lighter wooden boats than with traditional methods. I think this is a great bonus for the environment, mostly because of reduced fuel consumption. Also wood pellets and wear on steam engines have an environmental footprint.

Erik

[Tad]

There are alternatives to epoxy......

Find Woodenboat Magazine #144 with an article by John Guzzwell on building his cold-molded racer, Endangered Species. John became sensitized to epoxy some time ago, he also happened to be a highly regarded modern wooden boat builder. He coldmolded the hull skin of 5 layers of Sitka Spruce using Borden Wonderbond XB90K5. Then he had his sons sheath the hull in glass using epoxy. For submerged joints he used Cascophen resorcinol glue.

John's book, Modern Wooden Yacht Construction, while long out of print, is the best one on the practical part of actually building the boat. The Gougeon book is good too, just from a different point of view.

Below are some stark interiors in cold-molded boats. The first one is Signe, 100' ketch, 2nd pic is Antonisa 124' Sloop, 3rd is Chanty2 52' Ketch.

31638

31639

31640

[Boston]

there are bound to be great alternatives to epoxy

besides the world is swimming in a snowstorm of molecular plastic
plastic outweighs plankton in the ocean 10/1

all you need to do is look at the components in whatever epoxy you are considering and start looking em up. One of the most friendly epoxies is made up of Epichlorohydrin and Bisphenol-A

Epichlorohydrin

I got this from the EPA which is about the most industry friendly report Ive seen on this stuff, other than getting info from the chemical companies themselves


Health Assessment Document for Epichlorohydrin. Final Report

Contact
Technical Information Staff
email at: nceadc.comment@epa.gov

This document summarizes current scientific information regarding the health and environmental effects of epichlorohydrin. Specifically, this document discusses the following topics: physical and chemical properties of epichlorohydrin; environmental occurrence; metabolism and toxicology; and factors most relevant to assessing quantitative health risks, particularly risk of cancer. Epichlorohydrin is moderately toxic by oral, dermal, and inhalation routes of exposure. Long-term animal studies provide evidence that epichlorohydrin is a weak contact carcinogen which appears to produce no metastases. Epichlorohydrin should be considered a potential human carcinogen (IARC category 2B). Epichlorohydrin causes gene and chromosomal mutations in vitro and in vivo, and has been shown to be clastogenic in human lymphocytes. Epichlorohydrin was not teratogenic in mice, rats, or rabbits, but was embryotoxic at doses which were toxic to the pregnant mouse. Transient infertility was observed in male rats exposed to epichlorohydrin. Epichlorohydrin is not expected to persist in air, water, or soil because of hydrolysis. The atmospheric residence time was calculated to be 5.8 days.

Bisphenol-A

I got this from Wikipedia which I typically do not reference but its a ok summery and its reasonably neutral in its presentation

The first evidence of the estrogenicity of bisphenol A came from experiments on rats conducted in the 1930s,[16][17] but it was not until 1997 that adverse effects of low-dose exposure on laboratory animals were first reported.[6] Since then, its endocrine disrupting properties have been extensively investigated, and more than 100 studies have been published "rais[ing] health concerns" about the chemical.[18]
Early development appears to be the period of greatest sensitivity to its effects,[19] and studies have demonstrated developmental toxicity, carcinogenic effects, and possible neurotoxicity at low doses in animal models (see table below).[20][21] Recent studies suggest it may also be linked to obesity[22] by triggering fat-cell activity[23] and have confirmed that bisphenol A exposure during development has carcinogenic effects and produce precursors of breast cancer.[24][25] However, neither the U.S. Environmental Protection Agency[26] nor the International Agency for Research on Cancer[27] have evaluated bisphenol A for possible carcinogenic activity. Most recently, a study by the Yale School of Medicine demonstrated that adverse neurological effects occur in non-human primates regularly exposed to bisphenol A at levels equal to the United States Environmental Protection Agency's (EPA) maximum safe dose of 50 µg/kg/day.[28][29] This research found a connection between BPA and interference with brain cell connections vital to memory, learning and mood.
In 2007, a consensus statement by 38 experts on bisphenol A concluded that average levels in people are above those that cause harm to animals in laboratory experiments,[30] and a panel convened by the U.S. National Institutes of Health determined that there was "some concern" about BPA's effects on fetal and infant brain development and behavior.[5] A 2008 report by the U.S. National Toxicology Program (NTP) agreed with the panel, expressing "some concern for effects on the brain, behavior, and prostate gland in fetuses, infants, and children at current human exposures to bisphenol A," and "minimal concern for effects on the mammary gland and an earlier age for puberty for females in fetuses, infants, and children at current human exposures to bisphenol A." The NTP had "negligible concern that exposure of pregnant women to bisphenol A will result in fetal or neonatal mortality, birth defects, or reduced birth weight and growth in their offspring."[31]
In April 2008, Health Canada released its Draft Screening Assessment for bisphenol A, which concluded that the chemical may pose some risk to infants[32] and proposed classifying the chemical as "'toxic' to human health and the environment."[33] This action follows Canadian regulators selection of bisphenol A in 2006 as one of 200 substances deserving of thorough safety assessments because preliminary studies had found it to be "inherently toxic"; the chemical had not previously been studied by them in depth, having been accepted under grandfather clauses when stricter regulations were passed in the 1980s.[34]
In contrast to the recent actions in North America, earlier assessment by governments in other regions found no cause for concern. In January 2006 the German regulators announced that polycarbonate baby bottles are safe and stated that published research on the health effects of bisphenol A is "difficult to interpret and [is] occasionally contradictory".[35] Also that year the European Union’s Food Safety Authority reached a similar conclusion, expressing "considerable reservations" about the biological significance and robustness of the low-dose exposure studies on rodents.[36] In 2007 Japan also concluded that for individuals in that country, "the current exposure levels of BPA will not pose any unacceptable risk to human health [and] that a ban is not needed."[37]
Some toxicologists and regulatory agencies have criticized low-dose toxicity studies, especially those that involved injecting bisphenol A directly into animals, since human exposures typically involve ingestion and subsequent metabolism in the liver, and the experimental design of a few of these early studies has also been questioned.[38][39] On the other hand, studies have also appeared pointing out flaws in chemical-industry-funded studies that found no evidence of adverse effects from low dose exposure,[40][11] and a study from 2008 concluded that blood levels of bisphenol A in neonatal mice are the same whether it is injected or ingested.[41]


Basically if your building a live aboard and you use these kinds of chemicals you shouldn't be surprised if your grand kids pop out with a few extra appendages or little Jimmy end up shooting blanks.
Then there is the sensitivity issue, why do you suppose so many people develop sensitivities to these chemicals, seems like a reasonable question.
next on the hit parade of questions is if this stuff is so stable why is it that in ( not in an average of human samples taken ) in "every" human sample examined levels of BPA exceeded the allowable safe limits set for human exposure. Turns out the stuff is soluble at room temperature and since its used to line cans manufactured for food contact ( some countries, Canada for instance are discussing banning its use ) its been leaching into our food.

If BPA is soluble in water at room temperature from its polymer position within epoxy then my question is
that has yet to be answered
what is the life span of epoxy if one of its primary components is busy leaching away into its surroundings

Im sure someone will freak out over the question but its valid
what is the life span of epoxy
and why if one of its major components is leaching away should I expect it not have a finite life span

stuff is definitely bad for you and bad for the environment as is Resourcinol
fiberglass is very epoxy intensive

wood is the most environmentally friendly of building materials and wood pellets are carbon neutral
it being one of the least energy intensive fuels to produce and one of the most energy efficient fuels to burn
and
its cheaper per BTU by almost half when measured against diesel at $3 a gallon
and diesel wont be at $3 a gallon for long

also pellets can be made simply by using a machine costing about $2000 producing about 600 lb/hr
a steam engine produces significantly less waist oil and uses significantly less resources to produce than a diesel engine
there are numerous examples of steam engines today that are still in perfectly good working order that have never been overhauled
a simple single expansion single acting steam engine producing 125 hp is about ~27% efficient compared to a diesel at ~35%
in terms of environmental foot print pellet fuels are unbeatable and steam engines are less than half the embodied energy to produce

we can just keep doing what we have always done
course now there's 6.7 billion of us
and go the way of the Dodo
or we reconsider what we do
and possibly survive

its an individual choice

cheers
B

Tad
nice boat that guy built
tons of interior wall treatment
For me at least how things go together is one of the most attractive aspects of any structure. Materials are often wasted on wall treatments designed to hide structural elements that were never expected to meet and aesthetic level of quality sufficient for a finish surface. Why, I have built countless houses were structural elements were manufactured to standards enabling them to constitute finish. Its cheaper, more efficient, uses less materials and more money can go into the actual structure of the build rather than covering up sloppy work.
Mr Guzzwel's boat is beautiful by the way dont get me wrong

that glue suggest is my project for today
Borden Wonderbond XB90K5.
so thanks for the tip

B

I got a file of all the best suggestions
but the one thing Im real curious about is
how close was I on my estimation of the frame size and spacing given my sheathing considerations
someones bound to have that off the top of there head

I found this while looking up the PVA glue mentioned
its an opinion piece but it pretty well makes its point


Older epoxies used solvents to reduce viscosity, and these organic solvents were malevolent compounds. The "100% solids" have no volatile organic solvents (MEK, toluene, xylene, MIBK, etc.) and so are far safer to work with. The epoxy resin is relatively harmless, but the curing agents, particularly the amine-based formulations found in most boatbuilding hardeners, can cause sensitization. Cycloaliphatic amines are nasty too, but you're not likely to run into them building boats. There is a far broader range of during agents and diluents than of epoxy resins. Curing agents come from all sorts of mineral and vegetable sources, and they are not benign. Their specialty is reacting with epoxy, but they're not particular about reacting with whatever else they bump into. If they can cause rash on your tough hide, imagine what they could do to your tender lung tissue. You can't go wrong by wearing a respirator. Make that a real one, with activated charcoal "Organic Vapor" cartridges, the black ones.

This also applies when sanding epoxy, because the stuff frequently takes days for full cure, and a lungful of partially cured epoxy dust is much worse for you than the hardener fumes. Consider this. Asbestosis is a lung disease caused by breathing asbestos-like particles. Microscopically these particles are not much different than epoxy sanding dust. Notice the operative word "asbestoslike particles". It is not just the chemical composition of the particle that is harmful, but its size and shape. OSHA has determined that the TLV for this irritant is 0.00. There is no known safe concentration, infection can be caused randomly by just one discrete particle. There has been a lot of press here recently about Libby, Montana, where 3/4 of the population has some type of lung problem, from an asbestos mine 10 miles out of town that has been shut down for years.

So what is the upside? Temporary comfort and convenience. The downside is nasty lingering death. Tough choice, huh?

[Boston]

Use double planking set in 9 pound shellac. No epoxy and it'll last for generations. Of course you'll be best advised to use Herreshoff scantling rules or slightly heavier to keep the weight down.

Ive got roughly 3,800 sq/ft of surface needing to be glued
both sides
so that ends up being 7,600 sq/ft if I coat both surfaces
at ~150 sq/ft a gallon for epoxy thats about 50 gallons
at about $75 a gallon but I gotta buy 100 gallons to get that price
g-flex type west system

shellac I can get for $10 a pound and the suggestion was made to use a 9 lb mix covers about 215 sq/ft pr gallon at $100 a gallon
so Ild need about 35 gallons

benefit being if it works

shellac is edible and is still used to coat candies
epoxy
not so much

[kerosene]

you should check the shellac article in last years wooden boat. if you already haven't

[peter radclyffe]

I would go simpler: strip plank, epoxy and biaxial. Little or no framing, just bulkheads.
Strong as a rock, easy to make, lasts at least 50 years, using a common affordable wood.
I would stop to split my head about calculations and guessings, I would take the Gerr's book "The elements of boat strength" and recalculate the scantlings in less than one day of work. The results are in the strong side. And I'm a naval engineer with more than 30 years of experience and now 161 boats behind me...go simple and Gerr's book is enough good..
With the weight and money savings, I would spend more time and money to nice amenities and good engines. Hull is just a very small part of the job.
strong as a rock, eh, its not that strong, if a 500 ton rock fell on this boat would it last 50 years or 50 hours

[peter radclyffe]

there are bound to be great alternatives to epoxy

besides the world is swimming in a snowstorm of molecular plastic
plastic outweighs plankton in the ocean 10/1

all you need to do is look at the components in whatever epoxy you are considering and start looking em up. One of the most friendly epoxies is made up of Epichlorohydrin and Bisphenol-A

Epichlorohydrin

I got this from the EPA which is about the most industry friendly report Ive seen on this stuff, other than getting info from the chemical companies themselves



Bisphenol-A

I got this from Wikipedia which I typically do not reference but its a ok summery and its reasonably neutral in its presentation



Basically if your building a live aboard and you use these kinds of chemicals you shouldn't be surprised if your grand kids pop out with a few extra appendages or little Jimmy end up shooting blanks.
Then there is the sensitivity issue, why do you suppose so many people develop sensitivities to these chemicals, seems like a reasonable question.
next on the hit parade of questions is if this stuff is so stable why is it that in ( not in an average of human samples taken ) in "every" human sample examined levels of BPA exceeded the allowable safe limits set for human exposure. Turns out the stuff is soluble at room temperature and since its used to line cans manufactured for food contact ( some countries, Canada for instance are discussing banning its use ) its been leaching into our food.

If BPA is soluble in water at room temperature from its polymer position within epoxy then my question is
that has yet to be answered
what is the life span of epoxy if one of its primary components is busy leaching away into its surroundings

Im sure someone will freak out over the question but its valid
what is the life span of epoxy
and why if one of its major components is leaching away should I expect it not have a finite life span

stuff is definitely bad for you and bad for the environment as is Resourcinol
fiberglass is very epoxy intensive

wood is the most environmentally friendly of building materials and wood pellets are carbon neutral
it being one of the least energy intensive fuels to produce and one of the most energy efficient fuels to burn
and
its cheaper per BTU by almost half when measured against diesel at $3 a gallon
and diesel wont be at $3 a gallon for long

also pellets can be made simply by using a machine costing about $2000 producing about 600 lb/hr
a steam engine produces significantly less waist oil and uses significantly less resources to produce than a diesel engine
there are numerous examples of steam engines today that are still in perfectly good working order that have never been overhauled
a simple single expansion single acting steam engine producing 125 hp is about ~27% efficient compared to a diesel at ~35%
in terms of environmental foot print pellet fuels are unbeatable and steam engines are less than half the embodied energy to produce

we can just keep doing what we have always done
course now there's 6.7 billion of us
and go the way of the Dodo
or we reconsider what we do
and possibly survive

its an individual choice

cheers
B

Tad
nice boat that guy built
tons of interior wall treatment
For me at least how things go together is one of the most attractive aspects of any structure. Materials are often wasted on wall treatments designed to hide structural elements that were never expected to meet and aesthetic level of quality sufficient for a finish surface. Why, I have built countless houses were structural elements were manufactured to standards enabling them to constitute finish. Its cheaper, more efficient, uses less materials and more money can go into the actual structure of the build rather than covering up sloppy work.
Mr Guzzwel's boat is beautiful by the way dont get me wrong

that glue suggest is my project for today
Borden Wonderbond XB90K5.
so thanks for the tip

B

I got a file of all the best suggestions
but the one thing Im real curious about is
how close was I on my estimation of the frame size and spacing given my sheathing considerations
someones bound to have that off the top of there head

I found this while looking up the PVA glue mentioned
its an opinion piece but it pretty well makes its point
well written, oestrogen leeches out of cheese packaging, & feminises fish, what does it do to us, steve mcqeen died of asbestosis,one ,one part glue we used was cascamite made by borden, how comparitively inert is it , there's a tale of an african, breaking silica rocks with his only tool, a 6ft steel bar, 5 years later he's dead from silicosis, when we built 2, 72ft strip planked yachts at Southampton Yacht Services, Silica You See, ran the lads daily joke, you couldn't see one end of the boat from the other, not that the bosses cared, if you died they'd just get another shipwright or joiner,silica filler in epoxy, its lethal, even with a mask, its still all over the yard, in the office, the yard cat, the starlings, bla bla

[peter radclyffe]

you should check the shellac article in last years wooden boat. if you already haven't
shellac & oiled or painted calico work well & are much healthier, on a tangent, if stradivarius had used epoxy instead of a form of shellac on his violins, what would they sound like, & what would they be worth

[peter radclyffe]

Boston,
Why do you consider epoxy to be unfriendly to the environment compared to other production methods? I've tried to google the issue without success. I don't know how epoxy is produced and if this causes an environmental problem.

I don't trust that old traditional methods and materials are more environmental friendly than the modern variants. Epoxy/glass makes it possible to build lighter wooden boats than with traditional methods. I think this is a great bonus for the environment, mostly because of reduced fuel consumption. Also wood pellets and wear on steam engines have an environmental footprint.

Erik
ukanottbsirius, the manufacture of epoxy is lethal

[peter radclyffe]

of all the many types of planking I could go with for my wood build, diagonal seems to be the lightest and strongest of my options. Its glue intensive, which in my book is a strike against it, but, the stiffness it so obviously imparts is a strong consideration in its favor. The main issue I have with it is Ive not any experience in a cold molded technique and so far nothing about this build is outside of my experience in building. Im not adverse to learning something, its just learning it the hard way, I prefer to avoid.

most of you know the boat Im working out the preliminary design for, but since the size and hull configuration is so critical to sheathing considerations Ill picture her again

http://maggiesfarm.anotherdotcom.com/uploads/elco57.jpg

57' of easy radii
no problem to get a bend around with one small area of compound curve
the hardest turn in the hull being about a 5'8" diameter radius at station #7

so far I'm going with a laminated keel out of Black Locust under a white oak skeleton
( turned out to be a pain in the ass to acquire BL in timber sizes )
with a BL keelson and bellow wl stringers the rest being WO

frames are steam bent solid and Im upping the scantlings from 1 5/8 x 1 5/8 each 9" to 1 7/8 x 3 tapering to 1 7/8 x 1 7/8 each 9"
midway through the turn Im about 1 7/8 x 2 3/8 on edge and I think thats about what I can expect to safely bend out of WO without risking eventual damage to the frame over time

Ill make a few and see how they survive
I may have to laminate the frames to get the bend and the size I want
maybe as I think Im in the ball park on that bend limit
this vessel was not originally designed to be a open water voyager so Im thinking it needs some stiffening ( storm shutters and stiffening in the superstructure as well but thats no big deal )

reason I start this thread is that if I went with diagonal planking I might gain sufficient strength to pair down the frames some considering that true cold molded hulls generally dont even have frames in em just bulk heads and stringers.

I want a frame ( for me its half the fun of building ) but the sheathing, laminated keel, and stringers on a diagonal planked hull do most of the work

so
question is
how much strength does a monolithic skin impart to the structure as a whole
for each four layers ( two diagonal two linear ) of what wood do I gain what over the same thickness of the same wood

Im guessing its significant but Im guessing and thats not good enough
someone of you builders have got a chart somewhere
so if you could post it
Ild sure appreciate it

cheers
B
i was in charge of construction of a consolidated commuter 66ft Mohican,1929 in elba ,we restored 50% of her traditionally double planked on white lead /calico , similar to your Elco, mahogany panelled, copper shaft logs for lightness,the right balance maybe between speed, beauty & not screwing the environment

[Boston]

Pete
would you be willing to relay what you can remember of her structural details
Par
you mentioned that prints were available for the elco, Where ? You also mentioned bedding diagonal planking in shellac. After reading all day on that idea I like it, allot, any further insight into that method would be greatly appreciated.
Tad
I checked up on that Borden glue, its in the same family as TB3 and is not intended for below waterline use. what MR Guzzwel did was interesting to say the least. I assume he knows this family of glues is known for failure under high loads and is not the best for structural use, but Im betting he thought that the load of the cold molded hull was spread evenly over the hull meaning that no individual area is subject to inordinate stress that might result in a catastrophic failure. Did you read the book and did he allude to that as his reasoning, or am I barking up the wrong tree. Obviously it worked and its not a bad idea if it does as over in the TB3 testing thread it was mentioned that TB3 survives boiling and prolonged submersion with a significant amount of its strength intact, I better go check that cause I could be remembering it wrong but Im pretty sure that was the conclusion.

[Tad]

While Consolidated or Elco commuter yachts might be fine vessels, there is nothing about their design or construction that makes them a "transoceanic capable" boat. They were flat bottomed, light displacement boats designed for speed over short distances. Tankage was perhaps 500 gallons of fuel and 200 of water, the electrical system weighed almost nothing, there was no capacity for sea stores, etc. The cracker box deckhouse with weak windows, low sides with little reserve stability, and violent motion deriving from this hull form and VCG, make this design a poor choice for ocean work. Of course folks cross oceans in far worse vessels.

Guzzwell published his book in 1979, at that time he used and believed in epoxy, though he also used a lot of resorcinol as well. I believe he discovered the sensitivity to epoxy in the early 1990's. In 1994 he published an article (WoodenBoat #119) on building a boat called Dolly with Wonderbond. He states that he ran some tests and found Wonderbond completely acceptable. "I boiled several samples for an hour in one of my wief's cooking pots and found that the plywood glues failed but the Wonderbond still hung in there. Other tests included glueing fabrics like glass cloth and Dynel to plywood, then observeing the performence over several month's exposure to rain (Seattle) and hot sun. My conclsion was that Wonderbond was a low-cost, easily used, water cleanup adhesive that was eminatly suitable for my project-even though the manufactureers stated that it was not reccomended for "continued submerssion."
I reasoned that if the laminate were kept dry, as it should be, by having the exterior waterproofed with an epoxy fiberglass skin (which my family could apply), the "continued submersion" warning could be disregarded."

I saw Dolly in Port Townsend a couple of years ago, at about 15 years of age, she was perfect.

[Boston]

points well taken
they were lightly built for pleasure cruising in protected waters
but they sure looked good doing it
as for my redesign
the construction is going to be vastly stronger as are the windows
but whats up with the motion you mentioned and how would you fix it
I was thinking of bilge keels
the elco's do not have flat bottoms or at least not the one I have lines for
Im planning on getting an architect eventually although having been a builder for years and always drawn my own I have a natural aversion to there whole species.
sounds like I might concentrate on redesigning the under body some

the 57 is way to pretty of a boat to let slide simply because a problem that was known and could have been corrected, wasn't.

the one you built was a consolidated about 60'
was it anything like the MS Scarlet

http://www.1929gidleyyacht.com/images/gallery/CD_exlaunch.jpg

cause that one definitely had a flat bottom and just looks like it would have a horrible motion in open water and obviously has dangerously to much window area for the open ocean
let me go look up what boat you worked on maybe I can find some pictures and compare them to what Im up to
thanks
B

http://www.classicboat.it/writable/upload/history/immagini/9/26/Mohican.jpg

http://www.classicboat.it/writable/upload/collection/immagini/2/Mohican.jpg

[thudpucker]

I read the account of Gen. Douglas McCarthur's ride to Australia from the Phillipines on a PT Boat.
That should tell you all you need to know about the differences between a boat that can go out on the ocean, and an ocean capeble boat!

[Boston]

the pt boats were elco's first stab at a planing hull with huge engines
this thing is a semi displacement hull with moderate engines
I was kicking around the idea of bilge keels so I could sit flat on a low tide if the occasion or error occurred
seems these would also help in reducing roll
?

[thudpucker]

In AK (and other places) they have large skegs that will support the weight of a boat if you must beach.
I doubt two big skegs will cost you much in energy, and would be a big help in going over obstructions and beaching.

They probably would help in reducing roll. I think that because going diagonally across swells is a problem with those big keels. The boat just dont want to turn quickly. That makes me think the Roll rate would be affected by the resistanc to the roll.

[peter radclyffe]

points well taken
they were lightly built for pleasure cruising in protected waters
but they sure looked good doing it
as for my redesign
the construction is going to be vastly stronger as are the windows
but whats up with the motion you mentioned and how would you fix it
I was thinking of bilge keels
the elco's do not have flat bottoms or at least not the one I have lines for
Im planning on getting an architect eventually although having been a builder for years and always drawn my own I have a natural aversion to there whole species.
sounds like I might concentrate on redesigning the under body some

the 57 is way to pretty of a boat to let slide simply because a problem that was known and could have been corrected, wasn't.

the one you built was a consolidated about 60'
was it anything like the MS Scarlet

http://www.1929gidleyyacht.com/images/gallery/CD_exlaunch.jpg

cause that one definitely had a flat bottom and just looks like it would have a horrible motion in open water and obviously has dangerously to much window area for the open ocean
let me go look up what boat you worked on maybe I can find some pictures and compare them to what Im up to
thanks
B

http://www.classicboat.it/writable/upload/history/immagini/9/26/Mohican.jpg

http://www.classicboat.it/writable/upload/collection/immagini/2/Mohican.jpg
thats it, mohican in the picture, look at classic boats, on the net

[rasorinc]

Bos. why not put a full V hull on it with a large skeg and the driveshaft comes out of the skeg. The side profile would not have to change a bit nor the topsides. I'm sure you can draw that out W/O a problem then somebody here could proof your drawing. I know that it is easy to overbuild, however, someone with an NA after their name could check your numbers and check frame sizing and spans and stringer sizing and number of. Lot easier to look at a drawing that has deminsions on it and it could be single lined. Best, Stan If you are going 16"-24" O.C. framing my guess is (IN NOMINAL DEMINSIONS)
Bottom frames 2 x 8s, Side frames 2 x 6s. keel laminated 4,5" x 6"or 8" with a top layer of 3/4" plywood. Stringers a full 1-1/4"
thickness. I believe in lots of stringers. That way you do not screw the siding into frames. http://www.specialtywoods.net/lumber.html
This boat is a proven ocean crossed. You could use the bottom plan for your boat.http://dieselducks.com/Duck462study1.html

[Boston]

thanks Ras I did find were I had that link noted

I certainly could easily put a full v on her
something I would like to consider first thought is a pair of bilge keels
that would dampen roll well but might actually detract from speed
would be nice to land on a beach ( deliberately or accidentally ) and not damage anything

thing about the v bottom is that it is easy on lumber in that clear shorter pieces are easier to find and in the end cheaper than clear longer pieces so its got a practical appeal to it

not likely to use framing lumber though as I want rot resistance but in order to use materials efficiently a standard lay out of 16" oc seems convenient
also Im concentrating weight into the structural components and reducing the area and mass of the interior wall treatments
also am working on shifting the VCG lower than in the original

[rasorinc]

Here is another hull to look at. Has lots of ocean time read owners blurp. Also has a complete lumber list and study plans for $15.00 https://www.boatdesigns.com/products.asp?dept=400 The lumber list gives you sizes of members and quantities and has been quite accurate. Here are some build pics http://www.glen-l.com/picboards/picboard13/pic675a.html For ocean going I would want a deep bulbous forefoot with reverse curve at the chine.

[thudpucker]

Just looking at a nice boat like that makes me drool. Some time ago, I'd have given a body part to live in that thing and have the money to move it to whereever....
Get it done while you can!

[Landlubber]

"they were lightly built for pleasure cruising in protected waters
but they sure looked good doing it
as for my redesign
the construction is going to be vastly stronger as are the windows
but whats up with the motion you mentioned and how would you fix it
I was thinking of bilge keels
the elco's do not have flat bottoms or at least not the one I have lines for
Im planning on getting an architect eventually although having been a builder for years and always drawn my own I have a natural aversion to there whole species.
sounds like I might concentrate on redesigning the under body some "

here we go again......" I am building this lovely design because I love it",,,,,,,wait, now I might just change this, and that, and alter the keel, and redesign th underbody........

Now Boston, be real mate, you like the basic look of the boat, yep she is pretty....so now lets all change everything.......that is what I mean by building a "good" design in the first place.....build the design that suits your purpose, don't waste time trying to reinvent the wheel.

[Ilan Voyager]

strong as a rock, eh, its not that strong, if a 500 ton rock fell on this boat would it last 50 years or 50 hours
Remarkably intelligent commentary. Very clever, surely the result of years of hard learning.

It would last less than one second, other yachts would last the same. In the same vein of commentaries I add that I do not know yachts that resist to:
- 1/2" machine gun with armored bullets.
- 110 mm anti tank cannon
- 300 pounds mine.

To say something a bit more intelligent; the epoxy/biaxial/strip plank method gives very strong boats, some have more than 30 years now, so it's a proven method.
The main interest of the method that it uses common materials at decent price, not requires high skills, and can be achieved in a reasonable amount of time.
For any educated people about strength of materials, the method appears as very interesting and the refinement of this method invented by Mr Lord gives among the best high speed boats (I'm talking of 60 knots) without going to high cost composites.

[Landlubber]

Thanks Ilan, I was not even going to bother with the comment he made......

[Ilan Voyager]

You're wellcome.

Even if you have an aversion for the N.A. (I understand as so many of so called yacht designers look to me as a monkey with a razor at the hand. ie dangerous animal), some N.A know their job and a good set of plans and well done engineering is a good investment

It's funny that very few people try to design a car (as too complicated) and so many people feel able to design an ocean going boat costing a big bunch of dollars.

[Boston]

here we go again......" I am building this lovely design because I love it",,,,,,,wait, now I might just change this, and that, and alter the keel, and redesign th underbody........

Now Boston, be real mate, you like the basic look of the boat, yep she is pretty....so now lets all change everything.......that is what I mean by building a "good" design in the first place.....build the design that suits your purpose, don't waste time trying to reinvent the wheel.


I thought the name of this page was BOAT DESIGN

nothing wrong with starting with a beautiful old design and bringing it up to speed
you have to admit that old boats got appeal

cant tell you how many times Ive gotten a fistful of pictures from a customer who wanted a house to include all these design elements, well Ild tell them,"as long as one element is conducive to the value of another we can start pasting things together and before you know it", I can give them a traditional design with modern appeal. Ive done it with houses right and left and now Im going to apply the same skill to bringing a really sweet old boat design back to life and at the same time, improve on it.

one reason I gave up on the Sophia Christina was because the design was not tolerant of change, basically the boat was already the perfect answer to bringing an old pilot schooner up to speed, exactly as you suggest but, it was not possible to really make it a nice comfy live aboard so I moved on, using the same logic your suggesting. This design on the other hand does seem to lend itself to change easily in order to bring it up to speed.

Ive looked at modern designed yachts and they look like space ships instead of yachts, some architects attempt to create a name for himself rather than create something that shows a little class.

I want the level of class and craftsmanship so often exhibited in the past combined with the level of knowledge gained and the advantages that knowledge may afford, it takes an open mind, the ability to admit your wrong about something and the ability to move on to whats right with out beating yourself up to much about the change.

the epoxy/biaxial/strip plank method gives very strong boats, some have more than 30 years now, so it's a proven method.
The main interest of the method that it uses common materials at decent price, not requires high skills,

its profits and business catering to a lack of skills that has killed the old craftsmen and replaced them with a bunch of stoned glue sniffers unable to perform at a level necessary for the kind of work I intend to exemplify in this build. each piece of wood will be carefully selected for its intended placement and each joint will be a masterpiece in itself well able to tolerate the scrutiny of any knowledgeable craftsman, you completely misread me if you think Im going to do something because its easy. Ive spent a lifetime working up the skills needed for this build and I intend to use em to my best advantage, asking the design to rise to the occasion rather than reduce the quality to some apprentice level of simplicity is not conducive to the kind of artistic expression Im after and will not be a consideration in my overall plan for what will end up being my home.

that said Id be willing to look at whatever you might suggest
but if its anything thats all that proud of a potential 30 year life span when life spans of several hundred years where common to the old school builders then Ill probably just be looking at the hull form and how I may apply it to the elco rather than be convinced it is capable of being any kind of legacy.

I hear what your saying
but show me a boat designed to modern standards that matches in style and grace what those old commuters and Chesapeake Bay boats did
then you will have all my attention
Ive looked and been sorely disappointed at the lack of taste exhibited in modern motor yacht design

[Landlubber]

Boston, Thanks for you reply, and I understand your plight, it is not meant to be personally critical of you, but more of a generalisation of design and builders.

No point me posting 1001 different designs for you mate, I do not know what is in the melon for whatyou want to see.

Point is, now you can grasp why we have able Boat Designers (NA), they can note down your requirements, and crate what you want...just don't alter what they do, or you loose the plot....much like what is happening now.

Sorry if i do not write what i think very well, I am not a writer, just a dumb boatbuilder.

All the best in whatever you do anyhow, I really mean that, I am sure it will be a great creation, as you are prepared to see others ideas and think about it.

[kerosene]

I think the point is not so much the fact that old designs wouldn't work or be nice/pleasant/awesome/whatever.

The way I understood the criticism is that you are trying to take a boat designed (well designed) for purpose A and then change everything to get a boat designed for purpose B. It is a little like squeezing a square through a round hole.

The core beauty of the commuter (or any boat) comes largely from the fact that its is built around its function in an efficient way. Once you try to keep the looks but make it another boat something goes missing and the core sensibility of the boat is disturbed. Thus - would make more sense to design the ocean vessel from ground up (yes you can keep aesthetic cues from the boats you love) or start from a design that is much closer to its intended use.

Above is mixture of my opinions and my interpretation of what was said earlier.

And about strip planking - I think it is unfair to label strip planked builders as glue sniffers. For a short series boats it is a terrific way - cold molding is probably better but gets far more complicated and expensive. If you prefer bronze screws on oak frames and caulking etc. That's fine too but it is unjustified and unfair to label craftsmen who use more modern methods as fools.

All the best.

[Boston]

I get a little harsh sometimes on the modern methods as I see them as by and large a response to two things, a way around failures of our educational system to produce the craftsman necessary to continue in the traditions of the past and also an effort to maximize profits by minimizing skills
mas production techniques favor lower skills and cheaper labor rather than exemplify craftsmanship and its associated artistry

Im not against strip planking or the ashcroft method or diagonal for that mater, as I fully intend to apply methods offering various improvements into what is decidedly an ancient and inefficient design. The point was made that the take up in that old ceder hull is substantial that fact offer's some possibilities in itself and so I moved on to a more modern sheathing and have pretty much decided on double diagonal sandwiched between for and aft bedded in shellac ( still working on that part ) and the outer layer sealed with epoxy and copper bottom

I have found it more and more difficult to continue being competitive in my chosen field given the availability of cheep foreign labor and the expectation of lower standards of quality. Its frustrating to have a bunch of pencil pushers and bean counters force me out of business as Ive had no major builds in the last few years and might have to move back to the mountains in order to secure any work at all. The folks in Aspen and Vail are always looking for capable craftsman who can do the kind of work that is expected in the higher end homes.

the economic circumstances have served me well in that it gave me time to learn how to day trade and thus afford my retirement. Now I can finally use all my skills without compromise and build for myself instead of someone else. Although I need more money before I begin.

when the folks moved to Colorado I had intended to maintain my shipwright skills with a job in some small inland marina repairing small vessels for the locals. I was horrified to find only fiberglass hulls and stoners working in poorly ventilated shops that contained no tools. I dejectedly turned to framing houses to work my way through school.

I was so used to working with two grumpy old men with an intransigent sense of craftsmanship that I couldn't even remotely substitute what amounts to auto body repair for fine woodworking. I guess the disappointment shows sometimes.

I owe you an apology for the insinuation although I was not speaking of strip planking specifically
you guys are being dam helpful and it is appreciated

seems though that there must be a simple way to preserve the look of that old elco and still meet the more stringent requirements of open ocean cruising

its a simple mater of hull form bellow the water line and maintaining the rest above
while redistributing the mass to be lower and strengthening certain critical elements

a chine hidden bellow the water line is certainly a consideration as are a few other possible solutions

I kinda am partial to the twin bilge keels as it affords me that accidental grounding without to much damage ( depends on what I accidentally ground on )

although after looking at the suggested designs from a few posts ago I find that a top speed of 12 knots is not much better than 10 and that ten with significantly less engine

Ill keep looking and Ill sertainly continue considering all possibilities but the modern designs are not even remotely what Im after in terms of style there ability to exemplify craftsmanship or environmental considerations

I after a wooden 60' ish open water cruiser with that old time style of Widgen and the 57 flat top

turns out diagonal planking is the way to go

[peter radclyffe]

Remarkably intelligent commentary. Very clever, surely the result of years of hard learning.

It would last less than one second, other yachts would last the same. In the same vein of commentaries I add that I do not know yachts that resist to:
- 1/2" machine gun with armored bullets.
- 110 mm anti tank cannon
- 300 pounds mine.

To say something a bit more intelligent; the epoxy/biaxial/strip plank method gives very strong boats, some have more than 30 years now, so it's a proven method.
The main interest of the method that it uses common materials at decent price, not requires high skills, and can be achieved in a reasonable amount of time.
For any educated people about strength of materials, the method appears as very interesting and the refinement of this method invented by Mr Lord gives among the best high speed boats (I'm talking of 60 knots) without going to high cost composites.
i am well aware of the strength of epoxy strip plank having built 2, 72ft charter yachts, by bill dixon & tony castro at sys, but i prefer facts not wild claims,

[Landlubber]

Boston,

The unfortunate thing about modern designs, (and why we do not like them), is because they are customer driven (often salesmen), more so than the older designs that were designer driven.

Only a few years back, designers would make a design, people would fall in love with it and ask for it to be built (by craftsmen).

Today's market has been driven by people, asking if they can have all the crap of the house transferred into the boat, keep it level, no rocking about, no maintenance, have three "bedrooms", go flat out so that they can use their limited "boating" time to get them as far as possible and back again for dinner.

Remember when we went out in the boat for the day as kids, she woul "pop-pop" all day, run on the smell of an oily rag, and bring you home safely, having been no where in particular, just "out on the boat".

So many "semi displacement" boats of today are pushed way past their displacement speed, have way too much hp to enable this to be done, dig enormous holes in the water and create wakes big enough to surf behind (and destroy the river banks), yet people still buy the crap.

I guess the good thing about the current financial situation world wide is that not so many of these messes will be made in future, and hopefully people will come back to earth a bit and realise that the old designs (like you have there were very practical boats for the purpose they were designed for.)

I expect to see many more displacement boats built in the future, as costs of fuel and associated times changes the buying power of the boatinmg public.

How many of us oldies have gone from the dinghy to the power skiff, to the "big boat" and now are back to small, comfortable sensible displacemant vessels that are affordable to use, do not take up half of the marina, and are actually great fun boats again.

such is life.......

[peter radclyffe]

i am well aware of the strength of epoxy strip plank having built 2, 72ft charter yachts, by bill dixon & tony castro at sys, but i prefer facts not wild claims,
the result of 35 years wooden boatbuilding , being in charge of 100 people, for 4 years on the construction of lulworth & www.patience.it , a week before the launch i was fired, uninvited to the launch,by the violent jealous junkie project manager, 3 weeks later i had a heart attack , so dont give me any crap about hard learning

[Ilan Voyager]

Oh la la Boston...my first profession from 69 to 75 was naval carpenter ( but I was mainly a loftman), and I was able to build a classic boat, with the S shaped planks, tightly fitted , delicately shaped rabbet and tutti quanti.
But you know what? I'm happy like Droopy and I prefer the most efficient method.

It's the Occam's razor; faced to a problem I'll take the simplest solution.

In the old days, the complicated and skillful method was required because there was no other possibility (diagonal planking was considered by the traditionalists as degenerate method, used by unskilled people unable to get a fit joint in planking, read the english yachting mags of the 1900's)

Nowadays we have better alternatives and as generally I work for a client I'll take the best and cheaper method.

For making a hull, I'm sorry to say that a strip plank hull is stronger and cheaper than a diagonal plank. And for an amateur, as it requires less skill its a foolproof method. You can't ask to an amateur other than basic skills.

A part 2 or 3 aficionados, nobody will appreciate the craftsmanship of a classic naval carpenter. Specially after the caulking and painting. Just good for an article in Wooden Boat. Even worst; nobody gives a s...

I like virtuosity and craftsmanship where it's needed and appreciated like the interior joinery, but not in a hull where is a waste of time and money.

The hull is the support, not the finality of a boat.

[Boston]

point well taken
but how does a strip planked hull end up stronger
everything Im learning says the diagonal planked cold molded hulls are the strongest

http://www.brayyachtdesign.bc.ca/25.jpg

those twin keels I keep thinking of adding


The main advantages are as follows:

Bray Yacht Design and Research Ltd.


1. Higher sailing speeds than an ordinary cruising yacht of similar dimensions. Surprisingly, part of the reason for this is the relatively small wetted surface, which yields improved light air performance. Modern twin keels are of high aspect ratio and present less wetted area then a full keel or long fin keel while retaining the steady helm associated with full keels.

2. The twin keels become more effective with increased angle of heel, while a single keel becomes less effective. Because twin keels cant outward at the tip, the leeward keel becomes more vertical and deeper in the water as the boat heels. The windward keel is working more horizontally creating downward lift that increases righting moment giving more power to carry sail. Also with this cant outward from the vertical, leeway forces water up to the root of the fin as opposed to spilling over the tip in a single keel. Hydrodynamic tests have shown that decreasing end tip loss can double the effectiveness of a fin (the sole purpose of keel winglets).

3. The wave pattern reshapes to reduce the fore and aft crests. At hull speed a hollow forms amidship, but the bilge keels cause a wave to form in this hollow, canceling out the stern wave and giving a flatter wake. This increases the maximum speed of the hull, as much as 15 - 20%, in the same way that a bulbous bow or stern bustle works; by reducing wave making resistance at hull speed where it constitutes 85 - 90% of total resistance. To ensure the desired effect is at cruising speed the correct fore and aft placement of the keels and proper proportions must be checked by model testing. This placement is critical, as the model data shows. Too far forward or too far aft and the resistance will dramatically increase.

4. The deep plunging of an ordinary hull is avoided by the stabilizing action of the fins which are also very effective in dampening out rolling motions. The fins also provide a certain amount of lift to the stern at speed when the hull is upright. The effect of this lift is to flatten the trim angle, i.e. reducing squatting, which flattens out the wake and lowers the resistance.

5. Directional stability is markedly enhanced by the fins. This is demonstrated both by tank tests and full size yacht performance.

6. Speed and fuel consumption under power are better then usual. The prop can work in clear water without being shrouded by the keel and rudder. In the case of the motorsailer we were testing, 85 h.p. would produce 14 knots. Also the yacht can be controlled in reverse, which is seldom true of single keel yachts.

7. The rudder areas are smaller for the same reason as the keels. Each rudder is more effective as it works upright, deep in the water.

8. Both keels and rudders can be asymmetrical (more curve on one side than the other) like a wing, and tailored to work on their one specific tack. This again makes them more efficient allowing smaller appendages. Generally it is felt that both the rudders and keels can be made 25-30% smaller because of the greater efficiency.

9. Windward ability equal to that of an ordinary yacht is achieved on a fixed draft approximately comparable to that of a centerboarder without the problems associated with lifting foils. Windward performance in rough water is superior because of the roll and pitch dampening abilities of the keels.

10. Stability is equal to that of an ordinary yacht without recourse to extreme beam. Righting moment and range of stability are at least equal to those of a well designed centerboard yacht of relatively deep fixed draft, because ballast can be placed in each fin the ballast is as low as any keel-centerboarder.

11. The general advantages of twin keels include the ability to take groundings in a level position. This allows the bottom to be cleaned and painted (although the shorter and shorter keels are making this more precarious), without the cost and nuisance of a haul out, as well as being easily shipped without a cradle. When sailing in shallow water, if one should touch bottom, the boat rights and clears itself. This is possible because twin keels draw more water when heeled than upright, unlike single keel boats which when righted dig themselves in deeper.

there is a thread on this in here somewhere and those would not be to hard to add to the hull design of the old elco

http://upload.wikimedia.org/wikipedia/en/thumb/c/c4/Bilge_keeled_Konsort.JPG/800px-Bilge_keeled_Konsort.JPG

[peter radclyffe]

Pete
would you be willing to relay what you can remember of her structural details
Par
you mentioned that prints were available for the elco, Where ? You also mentioned bedding diagonal planking in shellac. After reading all day on that idea I like it, allot, any further insight into that method would be greatly appreciated.
Tad
I checked up on that Borden glue, its in the same family as TB3 and is not intended for below waterline use. what MR Guzzwel did was interesting to say the least. I assume he knows this family of glues is known for failure under high loads and is not the best for structural use, but Im betting he thought that the load of the cold molded hull was spread evenly over the hull meaning that no individual area is subject to inordinate stress that might result in a catastrophic failure. Did you read the book and did he allude to that as his reasoning, or am I barking up the wrong tree. Obviously it worked and its not a bad idea if it does as over in the TB3 testing thread it was mentioned that TB3 survives boiling and prolonged submersion with a significant amount of its strength intact, I better go check that cause I could be remembering it wrong but Im pretty sure that was the conclusion.
hello boston, im looking for the details of mohican

[Ilan Voyager]

"point well taken
but how does a strip planked hull end up stronger
everything Im learning says the diagonal planked cold molded hulls are the strongest"

Boston, I'll have later the pleasure to expose my statement, but now Duty is calling me...Interesting the twin keeler...

[Tad]

By flat bottomed I mean that these old commuters have a deadrise angle at the transom of approximately 5 degrees and midships deadrise of about 10 degrees. That's fairly flat an infers a hull form floating on top of the water. This shape runs out of reserve stability quickly and has a quick motion. A deeper form will roll more slowly and CB shift is more gradual, giving a more comfortable motion and better reserve stability.

These are similar era examples of boats intended for seagoing use...

31686

31687

31688

31689

[Tad]

Re the list of advantages claimed by one marketer of twin keels.......

This list pertains to sailing vessels....has this Consolidated Commuter now morphed back into a sailing vessel?

There are ways to achieve a far more comfortable ride with far less drag. Towing Paravanes is the answer, small drag when in use, zero drag when not in use, second only (somewhat controversial) to active fins in roll attenuation. No computers or hydraulics involved. A Flume tank may be next in the order of simplicity and effectiveness.

[kerosene]

Tad - the last boat (tacoma?) is very handsome. The livelier sea too helps in selling the boat I guess.

[apex1]

"point well taken
but how does a strip planked hull end up stronger
everything Im learning says the diagonal planked cold molded hulls are the strongest"
.

You are dead right Ilan! NOTHING in the wooden yachtworld is as strong as a multiple diagonal, EP prepped, cold moulded hull..............
One could make (and I have done) a wooden sandwich composite, using inner diagonal hardwood veneers, a longitudinal strip of softwood, and outer layers of diagonal planked hardwood again. That is the very strongest possible structure you can achieve with wood / EP. But that is not what we call "strip planked" in terms of everyday boatbuilding methods and it is twice the effort for a few percent gain. (over plain cold moulded)
First shows 5 layers, same material, same properties, 45°, -45° alternating.
Second picture shows two layers diag. one long, two layers diag.
Questions?

Regards
Richard

[Boston]

seems like we have reached a conclusion then
double diagonal cold molded

the other issues are superfluous to the topic
thanks guys
B

although Peter I would love to see whatever details you may have on Mohican

Par you mentioned plans being available on the elco's
you have all of my attention mate

Tad
points well taken again
it is possible to fiddle with the lines of the old Elco and make the alterations you suggested earlier
I could easily deepen the hull aft and by adding anti roll devices or bilge keels ( propably the later ) I can further enhance her sea kindliness without loosing the look Im after. Any major alteration I undertake will need to be confirmed by at least one NA in an overall review of all the proposed alterations.

[apex1]

seems like we have reached a conclusion then
double diagonal cold molded

the other issues are superfluous to the topic
thanks guys


Excuse that I do´nt agree (as usual), there are by far toooooooo many alterations you made (at least in your homemade theory) to some proven designs, that a "pro" could assume it may fit a seagoing vessel after all.
If we are talking a building method only, there is no choice for a "wood" man. WOOD EPOXY. Metal is a different and valid choice though.
But stating that almost everything is said, sorry mate, that is a bit broad.
I love your emphasis for the old fashioned craftsmanship (and you remember I showed you the most outstanding examples of boatbuilding art), but you must cool down a bit and allow, that boatbuilding is one of the most painful sorts of unsatisfying compromises one can think of.
I am a bit in doubt if you are really out to sea, or out to build!?
And I understand your passion for steamers, lobsterboats, classic shooners, commuters and the like, (all of them I´ve sailed, many of them I´ve built), but you are not focussed on a BOAT or a style of boat, you are focussed on building something precious that is able to go to sea!
Find your niche first, lets talk technique then, please!
I hope you do´nt misunderstand that as a offense.

Regards
Richard

[rasorinc]

Just a nice boat picture for Boston. http://www.boatdesign.net/gallery/showphoto.php/photo/5587

[Ilan Voyager]

I'm a very lazy man so I go always to the simplest:

There has been some confusion of vocabulairy:

Diagonal planking, almost classical: mecanically fastened, or riveted, or nailed. That was primitively a double planking, the two layers are separated by a compound. A lot of things have been tried; white lead, oiled calicot, tar, and at last glue. The planking is done over a classical structure: wood, or steel or aluminium (German S boats).
Some boats have a V bottom double planked, chine, and classical top sides.
An old method. But very useful for example in Third world countries for fishing boats because it can use simple materials and galvanized nails.

Strip plank: there are a lot of variants:
-One of italian origin, used on fast boats with slim strips all glued and nailed over a classic structure.
-One of North American origin, used on fishing boats entirely nailed with a compound between each plank. The purpose to use very smal planks which swell very little.
These methods are obsolete now.

-One appeared in the fifties I think (at least one french shipyard was using it around 1960) using resorcinol or similar glues. Finishing with nylon cloth (Cascover for example) glued with resorcinol. I know several english examples.
A light classic structure remains. its the beginning of the strip plank we know.

- First variant: Cold molded wood is very time consuming, a lot of pieces of wood to adjust, spill, glue and a lot of grapes or nails to put and take off after, plus a sanding at each layer.
So why not to replace the central plies (3 for example) by strips of same thickness of the replaced plies. A lot of job is saved. At least 2 outer and inner plies at 45 degrees are required.
Very strong. A light wood can be used as strip, the requirement of quality is lower so cheaper wood can be used. A lot of big yachts have been done by this method. An fast calculation shows if the skin is thick enough a lot of internal structure can be saved.
Little problem: not for yachts under about 50 feet. It would be too heavy on a 35 feet for example.
If I understand well it is about this method you're talking about. In epox class finishing with 6 or 10 oz glass cloth, many times clear and varnished.

- Second variant is going further to composites and to replace the outer plies by glass, kevlar or carbon cloth (kayaks) or UD, or biaxial on bigger boats. It's a sandwich where the core is active and gives the longitudinal rigidity, the fibers at 45 degrees give the torsional strength. The structure is totally suppressed, only remain a few bulkheads. I won't describe all the possibilities of playing with the densities and thickness of the woods used as core (you have also the Duracore strips) and the fiber reinforcements.
It's my preferred method.
First you can make virtually any shape without using a costly mold. For a one off boat it's a big saving.
Second it's reasonably fast and rather foolproof. Difficult to make a total mess. I have seen once the infusion of a sandwich boat going wrong; expensive accident.
Third the outer and inner fiber/epoxy skins are rather thick (ok not for varnished boat...) so the resistance to impact is pretty good and the waterproofing excellent. Very little probability that water will find its way into the wood. Generally these boats are totally impervious to rot.

The first boat I saw using this method was in 1976, and last time I saw it 30 years late it was like new. The method asks a good epoxy resin with 5 % elongation and rather fluid (about 1000 centipoises), a resin too rigid will give trouble.

There a lot of small tricks speeding and easing the construction of a strip plank composite boat. You can attain ratios of rigidity/strength/weight very good, juste under sandwich and exotic fibers. But if you add a fourth factor: cost, that becomes very hard to beat.

The nicety of the method is a relatively low tech method so it can be done by a good amateur or a small shipyard without a costly tooling and installation.

I have used it on several fishing boats (alone or combined with plywood) and on a Formula 40 race catamaran in 1989 (just at the moment when the french federation killed the formula...) and I think that 1900 kg complete, ready to sail is a very good weight for a boat made in a barn.

The formula 40 trimaran Adrenalin by the Gougeon bros used the same method.
Ilan Voyager, the motor trimaran designed by Nigel Irens, built in strip plank/fiberglass in 1989, goes well and strong 20 years later, used as ferry in Cabo Verde Islands (hard seas in this place), and makes the journey from Africa to England directly...nice for a 5 metric tons (dixit Nigel) boat for 21 meters long. Ultralight doesn't mean delicate.
This boat reaches 28 knots with a single 250 HP Yanmar 4 cylinders and made the trip around Great Brittany (2200 nautical miles) at 21 knots of mean speed...Never had a structural problem. That's proof, not unverifiable claims.

[apex1]

Very strong. A light wood can be used as strip, the requirement of quality is lower so cheaper wood can be used. A lot of big yachts have been done by this method. An fast calculation shows if the skin is thick enough a lot of internal structure can be saved.

Completely d accord, and as mentioned above "wooden sandwich".
But the "strip planking" methods promoted and widely spread for amateur buildings have NO inner layer of hardwood or glass usually. So the whole junk is weaker than a multiple diag ply of cold moulded (a irritating term, the usual high tech layup is tempered to degrees that would ignite some bare wood) veneers.

the "unverifiable claims" were addressed to?

Regards
Richard

[kerosene]

Just a nice boat picture for Boston. http://www.boatdesign.net/gallery/showphoto.php/photo/5587

more - really nice boat indeed
http://www.cannellclassicboats.com/cbb_acadia.html

[Boston]

no worries Richard
and you got me
Im all about building it
the living in it part is just gravy
Im about done contracting and as soon as I get my stock trading account up to limit then Ill probably never work again
at least not as a contractor
ill play the rest of my days building boats and occasionally sailing off into the blue

those old commuters suet my tastes just perfectly and I think I can make a few minor alterations to the hull form that will seriously improve on there seaways

Im also guilty of knowing all about one thing
old school building, caravel or clinker planking, pine tar and whiting
copper bottom paint

I got joinery down and I remember a few things about basic seamanship
but thats about it
I know what woods I want where
although Ras clued me in to Black Locust and I am better off for it
cant believe Id never used it for anything before

I want to build and be left alone basically
Ive learned to hate my customers and love my job
building
Ill be building till the day I drop

its the design elements that I need work on
each carefully ties into another to make a whole
one piece out of place and youve made a useless hole in the water as old Roby used to say

nice picture Ras
your killing me

APex

If I understand well it is about this method you're talking about. In epox class finishing with 6 or 10 oz glass cloth, many times clear and varnished.

close
but no glass or epoxy glue
Im going to go with the diagonal planking between two longitudinal layers all wood and bedded in 9 lb shellac with tree nails turned out of black locust
Im still up in the air on what glue I might go with but sample shellac is on the way and once I boil some up Ill know a lot more
I am preferring shellac because its permeable to vapor and not liquid which will allow the wood to breath, its completely safe ( you can eat the stuff ) and it used to be used as a bedding and as glue, so might as well test it and see what I see

the exterior of the hull will be painted in epoxy paint and copper bottom
over shellac
with everything else lathered in shellac over light stain
depends on what and where

best B

[Ilan Voyager]

I agree with you Apex: a sandwich must have 2 skins to be effective...I know the reasoning behind no plies inside so you put a little varnish and go on, if the strip is thick enough. But I do not feel that safe in a high stress event. Light woods are not strong in shear.
If the guys ( NA) could show me a good pack of data, trials, destructive experiments etc I'll admit. But without that all the experience ask for 2 skins.

Boston you'll build your boat as you want. You're a free man. But unhappy are you for hating your customers (said with Yoda's voice...)

[Landlubber]

Boston,

Shellac originally is the excretions from the Lac beetle, it was mixed with metho to form what we call shellac. There are modern versions of this that are in fact plastics, so be very careful what you are using if you expect to retain the qualities of the old shellac.

[apex1]

I agree with you: a sandwich must have 2 skins to be effective...I know the reasoning behind that; no plies inside so you put a little varnish and go on, if the strip is thick enough. But I do not feel that safe in a high stress event.
If the guys ( NA) can show me a good pack of data, trials, destructive experiments etc I'll admit. But without that all the expenrience ask for 2 skins.

Sorry Ilan,

a little varnish?

who promoted that? Or was that not addressed to me?

[Boston]

more - really nice boat indeed
http://www.cannellclassicboats.com/cbb_acadia.html

I knew one of you home slices would come up with something
those guys didnt modernize much but they sure got the look I was after
my bet is they are the ones to check modifications on my Elco plans

maybe not, I dislike the ribs to keel assembly technique and would have liked to see her being built the easy way,
upside down. The teak cockpit was well done and the raised panel was well done but the companion way steps edge treatment was not a large enough piece and looked unsupported by the stringers or the risers. There steam bending technique would have sent old Roby into fits and the lack of horizontal supports from beam to beam almost guarantees an uneven top side. Im probably being to critical of there style but we had a set manor of building back in the old shop and any deviation from it was always more trouble than it was worth.

[apex1]

Boston
the black locust is a very nice wood
and a very difficult to machine one as well!! It has his valuable properties though. And I would like to talk my clients into it for a substitution of Teak decking, but boaters are thumb, blind, greedy and scrooge if it comes to a sort of skimp on their dreams.
And the boat you would love most if it was the shape and nothing else is:

This???

[Boston]

Boston,

Shellac originally is the excretions from the Lac beetle, it was mixed with metho to form what we call shellac. There are modern versions of this that are in fact plastics, so be very careful what you are using if you expect to retain the qualities of the old shellac.

ya I found a suplier of old school shellac buttons
they offer bulk discounts for boat building and are dying to have me use there product
Ill send random samples to a chemist friend at the university to have it checked for authenticity as I hear the fake plastic stuff is indistinguishable from the real stuff

[Boston]

This???

that would be spounce
french schooner
I looked into it long ago
the guys prints are extraordinary with every screw and its placement noted
a work of art he should be dam proud of
I dont really have enough good things to say about that boat but its got the same issues as the Sophia Christina in that although it is flawless for its intended use it is less conducive to live aboard use than one of the old commuters

Ill give the locust a turn on the lathe and see how it does
it can be a little rough and still work as a nail its just I insist on the old tapered real tree nails instead of just a dowel on planking
as I kid I turned thousands of them
boring but if you want it to hold with or without glue
Ive also whittled barn spikes
tells you how old school the folks were eh
B

[Boston]

for those of you who know were I sorta work
I got offered a grant today to cover all my expenses
one step closer to having a real job
( fingers crossed )

and was asked to do the training for the volunteers
which surprised me since Ive only been there for a few months

[peter radclyffe]

for those of you who know were I sorta work
I got offered a grant today to cover all my expenses
one step closer to having a real job
( fingers crossed )

and was asked to do the training for the volunteers
which surprised me since Ive only been there for a few months
thats great news

[apex1]

that would be spounce
french schooner
I looked into it long ago
the guys prints are extraordinary with every screw and its placement noted
a work of art he should be dam proud of
I dont really have enough good things to say about that boat but its got the same issues as the Sophia Christina in that although it is flawless for its intended use it is less conducive to live aboard use than one of the old commuters
B

Yes, it is "Shpountz" and it is In My Humble Opinion the furthermost designed and engineered boat ever. (In terms of ability and beauty for a pleasure craft)
And the most beautiful watercraft I have ever seen!
The prints are unbelievable exact and as you mentioned every single bolt and screw is shown in the drawings!! I have never seen any NA doing such effort, even at three times the fees.
Regards
Richard

[Boston]

and thats exactly what Im talking about
Spounce has set the bar and I say every set of drawings should look exactly like it
I was privileged to get a peak at the prints once and they are a work of art in themselves

I have every intention of doing my best and if by some chance I can aspire to an equal achievement then I would call the job well done
that is why I want to do my own prints
the artistry I can handle
its the engineering I am not familiar with
at least not naval engineering



thing came out three times the size I drew it

another practice run for a set of prints
rear elevation deck area
needed some wild life in it

[apex1]

and thats exactly what Im talking about
Spounce has set the bar and I say every set of drawings should look exactly like it
I was privileged to get a peak at the prints once and they are a work of art in themselves


Yahh, you´re right mate, and all of our grandfathers did have this knowledge!
Building a seagoing vessel is first related to the "ART" of making a ship. Experience and knowledge has to follow then. Profit was not part of the design table.

Bombigher was one of the last, I think, who did just what he felt to be good, and calculated later if it was to the rules. Today the first question to be answered is the "shareholder value" then it might be of some interest if the sampan is able to float right side up. If a design can provide a feasible turnover, it might provide a feasible turn over as well, who cares. And the risk of being catched is a low one, 95% of the boats are not more than floating allotment garden homes. And another 4% hardly see any sea condition through their whole life. So, what is it worth to design, build and handcraft a piece of art, if the average ***** is using it as a barbeque platform?
R
R

[Ilan Voyager]

Apex be not paranoiac, keep your head cool, I wasn't talking about any one in particular and surely not of you as I do not know you or even what you design if you design.

It was a very general statement as I had in mind some internet sites that leave me open mouth. As good christian I won't give names.
After being naval carpenter, loftman, navy officer and naval engineer I have now a small idea about boats, maybe I'm beginning to understand what's a boat. I even hope to have a zen illumination to grab the concept of boat in its totality and I meditate very hard on that two hours a day. So I got enough education to have cartesian opinions.

I'm not yacht designer, I have no plans to sell, not customers to find or convince, so I feel free to say what I think, and to share my small knowledge.

As my own customers are totally out of the field of this forum and are personal acquaintances, there is not competition.

PS I dislike the Bombigher's pastiches of schooners...I have his book (in French) about the Schpountz published by Loisirs Nautiques. A sure fact:his boats are horribly expensive to build.

[Tad]

Daniel Bombigher was a fine artist, but his drawings, paintings, and books, should just stay art to be appreciated for what they are. His boats are filled with questionable structural details and very outdated ideas on hydrodynamics. For instance almost all his external long keels are flat sided (poor hydrodynamic shape) and too thin to be good structure when the boat goes ashore (twisting loads).

I understand that, working alone, he spent years on a single design. That's great, it's nice not to have to make a living. He also did not concern himself with making the boats straightforward to build or accommodating of their owner's needs. But it takes all kinds....boat design is a diverse field, that's what keeps it interesting.

[apex1]

Ilan I am cool. Where did I harm you?

[Ilan Voyager]

Apex, nothing just teasing, but your questionning messages were a bit dry (example "Or was that not addressed to me?"). I like the martini dry, very dry with a good spanish olive but I prefer the messages a bit more "rhetorical".

Tad, I'm very glad to hear from you. Yes Mr Bombigher was an artist, not my kind, but with some artistic sense. I have made short trips on a Schpountz 40 and a bigger one about 60 feet (Sitting Bull? I do not remember) and I've been very far from impressed.

Not specially comfortable (if a boat has to be heavy and slow, at least it must be very comfortable), and had nothing remarkable.
I agree totally with you about hydrodynamics and engineering flaws added to an indecent cost of building (and pretty high NA fees, for those who dislike to pay fees to a NA). When working at the Arsenal de Cherbourg, I saw the kits of the Schpountz 40 nicely made by the CNM (a contractor for the French Navy) but I scratched my head in front of such complexity and quantity of materials for a 40 feet sail boat.

The boats looked as pastiches, like a WV Beetle disguised in 1930 roadster by the magics of a polyester kit.

Do not believe I despise classic boats. Some were horrors like the RORC boats, some are very pleasant and well mannered as the boats designed by late Francois Sergent, a gentleman and very able man. Great specialist of cold molded wood with a solid background of engineering.

So his boats had the best of two worlds; nice construction very well engineered, beautifully done plans with a nice design without "tape a l'oeil" (big mouth, flashy) but a true equilibrium of the lines. At sailing his boats are rational, comfortable, and pretty fast. Very easy to handle, good everywhere.

So I have the greatest respect for NA like Sergent, Amiel, Herbulot, Mauric, Van de Stadt, Newick, and many other. They share all a solid technical background (for example Mauric was a mathematician able to explain the tensors theory of Levi-Civita and their application in the General Relativity...every one who has sailed on the 1978 Kriter V stayed open mouth on the performances and ocean going capabilities of this boat...it was "the" step for the nowadays 60 feet, but the multihulls proved they were faster) at least as self educated engineer (I respect highly the self educated, they worked twice harder), with the artistic spark that transforms a boxy thing to a beautiful object.

Nigel Irens is also included in the group of NA I admire. Very versatile, and beautiful and very efficient designs.

We are in 2009, I'm not a nostalgic, nor a dreamer of a golden era (golden only for a few riches), so let's go for nice boats of our time without the horrors of the design dictated by "Fashion Design" (you know the melted wax designs with useless narrow black triangular windows, and so overlong bows that they look just copied from a Tex Avery Cartoon).

I'm very inferred in the concept that the function creates the shape; all the beauty of a Sukhoy 27 comes from lines born from aerodynamic and construction contingencies, nothing is due to any fashion design.

[Boston]

ya but the prints look dam good

LOL

I never sailed it just a peak at the prints and last time I even was near the ocean I got slapped by a sneaker wave while standing in a tide pool
Oregon coast
dam cold water
I went from standing in ankle deep to being up to my chin before I could even think of rock hopping back to dryness
girl laughed her ass off at me


your mention of design vs construction is exactly what I lack in
I can build anything but know little about naval engineering
thing is Ive seen what most architects are like to work with and it's one part of my job I wont miss. so if naval architects are anything similar
I just assume hang out here in my spare time and learn how to just do it myself then have someone check it once the basic design elements are established

best
B

[Landlubber]

Boston, is the chipmonk gathering fuel for your boat?

[Boston]

nah I just erased him
I get tired of looking at my own artwork and take stuff down and put stuff up almost every day
got a room full of pencil sketch's and frames
but hey
if they can train dolphins to go get stuff for a treat
maybe I can train a few squirrels

actually my cousin owns a tree trimming service and he's got more wood chips than he will ever know what to do with
uses em for mulch and has about a hundred tons of the stuff at the moment

http://i29.photobucket.com/albums/c262/bostonpyramidbuilder/lilium.jpg

[Landlubber]

Well there is the perfect oportunity for you do do some landscaping for the wealty mate, go for it!

[Ilan Voyager]

Boston,

If you want to learn more on the technical side of Naval Architecture of small boats:
You have a lot of books, a lot very old and obsolete. But with a limited budget I'll go to three books:

1/ Pierre Gutelle The design of sailing yachts. Gives an excellent panorama, good theory part and a lot of practical calculations for sail boats old and modern.
After that you'll look to some plans with another eye (a very critical one...)
Just secondary school maths level needed.

2/ David Gerr The nature of boats. A big bunch of info, gives also a good basis to judge plans.

3/ David Gerr Boat strenght. Very useful. You won't become a structural engineer with this book, but you'll be able to do good work and to judge some scatlings with a fresh eye.

For those interested by motor boats; an excellent and didactic article by Tad : http://www.tadroberts.ca/about/pdf/power-boat-design-form-and-function.pdf.

[Boston]

there was one suggested earlier called "elements of yacht design" that sounded great
and there have been a few others
Ive got several victorian porches lined up and am looking at another tomorrow what is up with that
last year I had two spiral stair cases in a row and then another at the end of the season
am I the porch man this year or what
anyway
thanks for the tips
Ill definitely look for them

next thread I may start might be a discussion about propeller tunnels in hulls and if they add so much surface area to offset the gains in draft and shroud effects on the prop
Ive seen several and it looks like a lot of wetted surface area

[peter radclyffe]

of all the many types of planking I could go with for my wood build, diagonal seems to be the lightest and strongest of my options. Its glue intensive, which in my book is a strike against it, but, the stiffness it so obviously imparts is a strong consideration in its favor. The main issue I have with it is Ive not any experience in a cold molded technique and so far nothing about this build is outside of my experience in building. Im not adverse to learning something, its just learning it the hard way, I prefer to avoid.

most of you know the boat Im working out the preliminary design for, but since the size and hull configuration is so critical to sheathing considerations Ill picture her again

http://maggiesfarm.anotherdotcom.com/uploads/elco57.jpg

57' of easy radii
no problem to get a bend around with one small area of compound curve
the hardest turn in the hull being about a 5'8" diameter radius at station #7

so far I'm going with a laminated keel out of Black Locust under a white oak skeleton
( turned out to be a pain in the ass to acquire BL in timber sizes )
with a BL keelson and bellow wl stringers the rest being WO

frames are steam bent solid and Im upping the scantlings from 1 5/8 x 1 5/8 each 9" to 1 7/8 x 3 tapering to 1 7/8 x 1 7/8 each 9"
midway through the turn Im about 1 7/8 x 2 3/8 on edge and I think thats about what I can expect to safely bend out of WO without risking eventual damage to the frame over time

Ill make a few and see how they survive
I may have to laminate the frames to get the bend and the size I want
maybe as I think Im in the ball park on that bend limit
this vessel was not originally designed to be a open water voyager so Im thinking it needs some stiffening ( storm shutters and stiffening in the superstructure as well but thats no big deal )

reason I start this thread is that if I went with diagonal planking I might gain sufficient strength to pair down the frames some considering that true cold molded hulls generally dont even have frames in em just bulk heads and stringers.

I want a frame ( for me its half the fun of building ) but the sheathing, laminated keel, and stringers on a diagonal planked hull do most of the work

so
question is
how much strength does a monolithic skin impart to the structure as a whole
for each four layers ( two diagonal two linear ) of what wood do I gain what over the same thickness of the same wood

Im guessing its significant but Im guessing and thats not good enough
someone of you builders have got a chart somewhere
so if you could post it
Ild sure appreciate it

cheers
B
SOME PHOTOS

[Boston]

Why are you bothering with steam bent framing? You have plans for a homogeneous hull shell, why not take this to full advantage. You'll save the trouble and costs of these elements, plus save considerable interior volume as well. Ditto the massive deadwood assembly. With modern engineering techniques, material use, application and build methods, you don't need these huge, ridiculously heavy and costly timbers. Put the savings in fuel and stowage capacity.

as I go through the process of considering various building techniques I am gradually coming to the conclusion that your suggestion is the most practical approach
thing is I want at least some of the charm of an internal frame
and am struggling to find the right balance of old school building techniques and new school performance

I suppose the question is
how few bulk heads can a 60 wooden build have
60' 13' beam ~4' draft aprox 20 ton displacement
I suppose it would be partly dependent on the stringer dimensions or vice verse but whats the requirements on bulkheads for a vessel of this size

[thudpucker]

I lived in Denver in 65 n 66. Great place too.
As I read your post on the 60' boat, I am wondering where you gonna put it in the water?
The south Platte is only a few inches deep and hardly any of it is straight for 60' or so.

[Boston]

LMAO
no Im not going to build it here
thought had crossed my mind but the idea kept going fortunately
although I did start overbuying on wood for the various summer projects
turns out this new mill is pretty generous with the quantities and now I have way more than I ever needed
they loaded up about half again what I ordered no charge
and I over ordered to begin with
now to see how the stuff surfaces out
I start planing it off tomorrow
for as much as I hate surfacing wood I hate how badly a job the mills tend to do so I just broke down and got a Jointer

no worries
Im not building in Colorado
that was a very fleeting thought
cheers
B

oh
and I might have given up on the transoceanic requirement
at this point Im thinkin serious coaster but no real open ocean work
inside passage and northwest west coast Alaska to Portland and the Columbia river area
if I had to pick a nice spot along the coast were the fishing is still good and the land unspoiled
that would be it
it does have some serious waves though
besides there is a nice inlet I can anchor in somewhere up there with my name on it
that and a bar stool in some local pub not to far away

[STLNOBLE]

? on the cutts what size cable do you use?

thanks patrick

[Easy Rider]

I'd like to double plank with the seams staggered and the planks parallel to one another. A bit like making batten seams with the battens as large as the planks. Dolphinite or sim would seem reasonable between the planks. With planks on top of one another how should the 1st screws be located so as to not interfere with the screws of the 2nd planks. On any double plank would wood preservative or anti-fouling paint be worth the trouble?

Easy Rider

[Boston]

anti-fouling is always worth the trouble. On the screws its been a long time and someone with more experience than I should chime in but I seem to remember both staggering the screw pattern and also sometimes removing the ones that were going to be in the way. Depends of the situation.

best of luck
B

[PAR]

STLNOBLE, the Cutts method is a proprietary building technique and you'll need to contact the "old man" in Maryland.

Easy Rider, you describing a known method often called Ashcroft planking. It's one of my favorites to work with, because it's the quickest way to mold a hull. Typically, you mark the second layer for first layer fasteners, as you lay the planks. Dolfinte or other sealant between the layers would require the fasteners to bear all the loading, which takes the planking out of the loop to a large degree.

The ideal method is not to seal the two layers, but bond them tightly, so they act more like plywood. This way the planking skin becomes a monocoque shell, not a lightly assembled bunch of planks, riding on frames. If you glue them, you don't need frames, but if you just use sealant, you do need frames, lots of them.

Most round bilge build methods can be converted to Ashcroft, but it does require an experienced designer or NA to perform the conversion. I make conversions like this a few times a year, it's a fairly common request.

If it's a boat that will spend it's life on a trailer, then you don't need anti fouling paint. In fact, I have an Ashcroft built runabout I built over 20 years ago. It's never had a drop of paint of any kind, anywhere on the boat and though it will get a varnish job this winter, it's no worse for wear. It's a trailer boat and lives indoors when not in use.

[thudpucker]

EasyRider your idea brings back memories of my Dad's observations. I had an old Cedar boat which I loved. I had the same I dea you mention. I'll just put another layer of boards over the seams of my big 22' Cedar Skiff.

Dad said: "That's Hill billy Siding!" what we'd call board and batton of it were vertical on your house down in Southern MO. But it works very well in houses.

On my Cedar boat, I had 3/4" Cedar boards about 6" wide.
Cotton/Oakum and caulk in between each.
That was one meeezzerrrrrbulll job! I did both sides, the full lenght of that boat by myself.
I had a mallet and three ripping tools, four Packing tools and the energy of youth.

Up in Thorne Bay you should be able to come up with enough Torrredos to eat a Cedar boat in a years time.
What kind of wood would you use? If you used Yellow Cedar, how would you keep the Torredos out?

[PAR]

An Ashcroft build doesn't need caulked seams, just good contact between the inner and outer layers.

[STLNOBLE]

thanks PAR

Some one told me the the cutts Patent time ran out so it was legal to use it

patrick

[FAST FRED]

resorcinol glue. ,, and good quality ply (Thames ply) with Monel staples (dont have to be pulled) does a fine job for a really lightweight stiff hull.

Interior bulkheads and simple stringers define the hull , little waste , little weight.

Very low labor skills required to diagonally ply , a 6x30 table sander to take care of edge fitting is about it , roofers hammer stapler is enough to set the staples , no worries about oil contamination from an air tool.

FF

[PAR]

STLNOBLE, I've seen the Cutts method up close and I see absolutely no advantage to this system at all. I know the patent was coming up, but I'm not sure if it's finally spent. If you want to pull the patent and find out, that's great, but frankly, I don't see the need. It's a difficult, costly technique and you can have hulls just as strong without all the rabbets and high tech cordage.

[Easy Rider]

Hey Thud,
Whats zis about Torredos? I've heard of them but not up here. We have both yellow and red cedar and several mills to cut to whatever.
Easy Rider

[Easy Rider]

Yes I can relate to the high strength achieved by fastening or gluing all the planks together but how on earth would one repair the latter. One of the remaining virtues of building a wood boat is that you can take it apart. If one used glue, and the glue held I would think the planks would break apart with expansion and contraction. Staying together with 6" wide planks? .. hard to belive.
I was thinking in terms of a modified flat bottomed Atkin cruiser rendered as an open skiff and cross planked on the bottom. Absolutely everything in Yellow Cedar except the outer topside planks in Red Cedar (just because it's so beautiful varnished). I hope the Yellow Cedar would have the fastener holding power for frames ect. The boat would be on a trailer and I meant for the anti-fouling paint to go between the planks. The Bay here is about 6 miles long and 1/2 to 3/4 mi wide. It's alive in the summer with aluminum skiffs, 25' aluminum boats and a few aluminum barge like catamarans. Ugly boats all and I even have a skiff. Thanks PAR,Boston and FF for your input.

Easy Rider

[apex1]

Teredo navalis
is a clam, known as "ship worm" it eats a wooden boat for breakfast when there are enough of them around.

A epoxy coated and properly painted hull is safe. (they do´nt know there is wood under the plastic crap)

Regards
Richard

[PAR]

If you build using traditional methods (plank over frames) then you are working an assembly of pieces, which usually requires little glue and lots of caulk. If you use modern methods, you're building a monocoque structure, with lots of glue and probably no caulk. There is a huge engineering difference between the two and as a rule, they can't be intermixed successfully (at least it's very difficult).

Double planking can be done both ways. If a traditional method, the planks are narrow and sometimes caulked on the outer layer. This limits movement (big pieces have big movements with moisture gain) so it doesn't rip itself apart.

If it's a modern build you can use huge planks, like full sheets of plywood. This is because the planking is stabilized and not going to move, the moisture content remains constant.

Ashcroft method (which is veneer molding, not double planking) if traditional uses 7 - 9 pound shellac between the layers which is a very effective glue. Modern methods use regular adhesives.

A neat trick old timers use to defeat the Teredo and other water born beasties, is to simply nail a nice fresh hunk of balsa at the LWL, so it's well exposed. No paint, nothing to interfere with their dinner. They'll eat it first before chowing down on your bottom planks. When it gets about half eaten, replace it with a new "entree" and they'll leave you boat alone. A 12" 4x4 hunk is common, nailed to the transom at the LWL.

[Landlubber]

....PAR...sacrificialy docking plank is what we use here in Australia, does exactly the same thing and serves both purposes.

[thudpucker]

An Ashcroft build doesn't need caulked seams, just good contact between the inner and outer layers.

that's the way my 14' Cedar skiff was.:) It was good till I left it for bigger and better boats.

[apex1]

Did´nt know the Balsa trick! Thanks Paul!


one gets older than a housepig and amateurs are telling one how the water freezes.........sometimes life is nasty.


At least for a unstable personality..........

[dskira]

An Ashcroft build doesn't need caulked seams, just good contact between the inner and outer layers.

I built only one boat with Aschroft system, a 40' motor fisching boat.
I used a lot of longitudinals frames, widely spaced sawn frames, and I find the system allowing a strong hull. I designed the hull in prevision of the Aschrof system. It has limitation, the hull has to be smooth without to much hard bilge, and no return at the garboard (Built down).
The construction was fast. But I will not recommend it.
The boat was intended to be neglected and it took well the beating and lake of care.
But I prefer double longitudinal planking. I don't like longitudinals frames they keep pocket of water, and promote root and decay.
By the way who want to bother with the Cutts system. It is a pain in the neck for nothing, but a lot of work. This is realy trying to complicate a construction, for the sake of complication. I don't get it. Must be masochist the guy who invented that :p Or didn't want to go home, and find an excuse to stay working at his shop.
Cheers
Daniel

[bertho]

i'm agree with Ilan , do it simple !! hull is only 20/25% of the completed boat !!! don't forget it :) , look on my blog , easy, quick to built, and very strong ! any shape !
www.fusionschooner.blogspot.com
nice project you have...
all the best ! :)
bertho

[Ilan Voyager]

i'm agree with Ilan , do it simple !! hull is only 20/25% of the completed boat !!! don't forget it :) , look on my blog , easy, quick to built, and very strong ! any shape !
www.fusionschooner.blogspot.com
nice project you have...
all the best ! :)
bertho

Salut, un Francais parle a un francais...

Very nice page on the 50 schooner. We see "la patte" of Nigel with the smooth lines...and the simplicity of the main concept. 40 mm thick is more than strong, it will stand up any abuse. The shipyard is beautiful and the quality of the work seems on the pics outstanding, you are lucky to have all these good carpenters...how many workers? That went fast!
I have to make a jump in the Philippines to see all that, here unhappily it's the naval no mans land.
I have also admired the straight and simple way of making the mold. Who made the bronze castings? Impatient to see the pics of the building of the masts.
YES strip planking is one of the simplest method to have a good, strong hull and your pics are the best illustration.

[Boston]

nice boat Bertho
I particularly liked the photo documentary of the build process

hope all is well
B

[bertho]

hi ! Ilan, and all !
small correction link with this original post... the workers here have never built a boat before !!! that the secret and rule to work here and with strip/cold molding wood .! you have to be there EVERY day ! teach them, there are willing to learn ! that the nice point ! bring the proper wood/resin/tools and soo , and you get a good result ! that the cold molding and strip planking interest... long and repetitive, but no need the skill requered as for classic planking for example , just need to have some very precises procedures and implement them... under your own control !.
i decide to not use vacuum for the cold molding for this reason, do it simple, even if it's take time, you need to adapt your work process in exotic country!
(but for the masts..no ways..all under vacuum of course..)
kenavo !
all the best !
bertho

[Boston]

so what did you do just staple the living crap out of the veneers

[FAST FRED]

"so what did you do just staple the living crap out of the veneers"

A tight joint is the requirement for resorsinol glue , lots of staples is fine , if there monel and don't have to be removed.

Of course if labor is cheap enough , removal of std staples would cost less than monel.

If the labor is not capable of really good tight fits , epoxy is required.

FF

[apex1]

Use plastic staples and save labour. Even when labour is cheap, saving time makes always sense.

Regards
Richard

[rasorinc]

here iS some info on the plastic staples and nails. They won't go in a pure, dry piece of HARDWOOD. That's my experience.
http://www.toolbase.org/ToolbaseResources/level4FAQ.aspx?ContentDetailID=1481&BucketID=1&CategoryID=35
HERE IS THE SUPPLIER IN THE US http://www.raptornails.com/english/firstframe.html
Requires an air gun not an electric driver

[Landlubber]

When using staples, you shoot them over that plastic parcel wrap stuff, it is about 1/2 inch wide and very thin, the stuff kids use to bust into cars.
That way when you want the staples out you just rip up the plastic strip and the staples come out all at once (except the few that always muck up the theory).

[apex1]

When using staples, you shoot them over that plastic parcel wrap stuff, it is about 1/2 inch wide and very thin, the stuff kids use to bust into cars.
That way when you want the staples out you just rip up the plastic strip and the staples come out all at once (except the few that always muck up the theory).

Well proven method and already used by Gougeon brothers in the 70ies, but still time consuming.

The raptor staples mentioned by rasorinc do a better job and penetrate 3mm of Mahogany without trouble.

Regards
Richard

[Landlubber]

Yes, mahogany, no problem, but we do a lot of planking in plywood, and the staples are great for that.

[Boston]

ok so cold molded hull chine form bulk heads and stringers. you guys convinced me so. thickness and width of planking depends on the species of wood. I like the idea of BLack Locust as its pretty much rot impervious. its a hard wood with the following charictoristics and Im thinking of planking the entire hull below the line with this stuff. only trouble is its heavy. White Oak would be lighter but this stuff has the highest resistance to rot of any of the north american hardwoods

the real question is depending on its stability how wide to cut the planks for the molding process. Yes it depends how sharp the bends are but most of this hull has no reverse curves or any hard curves for that mater.
I was thinking 3" x 3/4 epoxy bonded edge to edge and layer to layer

Black Locust Amount of Figure
Intermediate

Black Locust Amount of Natural Luster
Medium

Black Locust Availability of Wood
Plentiful

Black Locust Available As Lumber
Yes

Black Locust Available as Veneer
Yes

Black Locust Available only in small sizes
No

Black Locust Bending Strength
High

Black Locust Blunting of Tool Blades
Moderate

Black Locust Botanical Name
Robinia pseudoacacia

Black Locust Carving
Difficult to carve

Black Locust Clear Finish or Varnish
Insufficient Data Available

Black Locust Color of Wood
Yellow or Golden Brown

Black Locust Contrast between growth rings
Ring Porous

Black Locust Crushing Strength
High

Black Locust Decorative Figure
No

Black Locust Density
Very high

Black Locust Drilling
Insufficient Data Available

Black Locust Fill before Finishing
May require a filler depending on the intended result

Black Locust Gluing
Average - Requires control

Black Locust Grain
Straight

Black Locust Growth Ring Pattern Plainsawn
Well-defined or Conspicuous growth ring

Black Locust Growth Ring Pattern Quartersawn
Noticeable or distinct growth ring stripe, ribbon or flake pattern

Black Locust Hand Tooling
Somewhat difficult

Black Locust Hardness
Hard, difficult to dent

Black Locust Hardwood or Softwood
Hardwood

Black Locust Harmful Properties
Non Toxic

Black Locust Interlocked Grain
No

Black Locust Kiln-dried Shrinkage
Moderate

Black Locust Machine Tools
Average

Black Locust Mortising
Insufficient Data Available

Black Locust Movement after drying
Moderate

Black Locust Nail Holding
Very good - Nails are very difficult to pull out

Black Locust Nailing
Tends to split wood - Requires pre-drilled pilot hole

Black Locust Natural Durability
Moderately durable

Black Locust Number of Knots
Intermediate

Black Locust Painting
Fair

Black Locust Planing
Average

Black Locust Polishing
Fair

Black Locust Pounds per cubic foot maximum
48

Black Locust Pounds per cubic foot minimum
48

Black Locust Reacts with Iron Fasteners or Hardware
No

Black Locust Sanding
Insufficient Data Available

Black Locust Sawing
Moderate cutting resistance

Black Locust Screw Holding
Very Good - Difficult to remove screws

Black Locust Screwing
Tends to split wood - Requires pre-drilled pilot holes

Black Locust Shaping
Insufficient Data Available

Black Locust Size of Knots
Intermediate

Black Locust Size of Pores
Large Pores - Open grain

Black Locust Specific Gravity
Very high

Black Locust Specific Gravity maximum
.69

Black Locust Specific Gravity minimum
.69

Black Locust Staining
Fair - May stain unevenly or change colors

Black Locust Steam Bending
Very Good

Black Locust Stiffness
High

Black Locust Surface Preparation for Finishing
No

Black Locust Texture of the Wood
Coarse

Black Locust Toughness
Moderate

Black Locust Turning
Good

Black Locust Weight
Heavy

Black Locust Wood Defects
Check (or split,) warp

Black Locust Work Notes
Requires sharp tools

apparently its a pain in the ass to work with because its so heavy and hard but I think I can handle it

[Tad]

Black Locust......Why?

There is no precedent.....I know of no cold-molded boats planked with Black Locust...why would you re-invent the wheel. Because it's rot resistant? Where is the epidemic of rotting bottoms in cold-molded boats? It's hard, heavy, difficult to work, and long term bonding with epoxy is questionable.

If you are building a cold-molded hull, by definition each piece of that hull is entirely coated (all surfaces) with epoxy. This coating limits moisture entering or leaving the wood to a tiny amount. Thus it remains roughly at the moisture level you started with......forever.....as far as we know. This means properly built cold-molded hulls will not rot. Only when the epoxy barrier is broken will deterioration start.

Douglas Fir is strong, easy to obtain, light (weight is only useful in steam rollers), easy to work with, and bonds with epoxy beautifully. Why use anything else? Don't say, "because it's free". That's not a sufficient reason.....you'll be investing thousands of hours in building this boat...to use questionable materials makes no sense...then the whole endeavor becomes worthless.

The only experience I have with Black Locust in boatbuilding is the laminated ring frames and backbone in the 90' cold-molded WhiteFin, built in Rockland Maine in 1983. The guys building her hated it and seriously questioned the bonding (West epoxy). Her hull skin is 2.25" thick, in six layers, four diagonal and two fore and aft. Her deck is 1.625" thick in four layers. After 10 years it was found that her Black Locust ring frames were tearing the structure apart, I guess with the tiny movement associated with wetting and drying of the various woods. The Black Locust is so strong it was ripping up the softwoods bonded to it. There was also some delamination of the ring frames. Her first 10 years were not the best as far as maintenance goes, it's been better since. That was found 15 years ago and further rebuilding has been done since. See WoodenBoat #57 for more info.

Buy the Gougeon Brothers book on boatbuilding and follow it...it works.

[Boston]

hmmmm
well one thing I can say is you folks sure are tops when it comes to saving people from themselves
Is epoxy impregnation really all that good that wood species is almost irrelevant. Thats wild, I never would have imagined it.

I was just doing a weight budget for planking stringers and bulk heads in black locust and you are right on about that weight adding up
stuff is dam heavy at 48lb/cu/ft

poplar is only 28 and cherry 36 and white oak is 42. I keep getting blasted every time I mention poplar because of its poor rot resistance. If Im cold molding whats the difference, so I went with a highly rot resistive wood. I can beat any wood into submission so how difficult it is to work with is irrelevant but weight is a concern. Also you mentioned that this wood has proven itself unstable or prone to motion. Yikes. Ill definitely go read that article.
Thanks again Tad you are most helpful
B

ps
just looked up that book
good call
Ill have to give it a try

[oldsailor7]

I have read this whole thread through with great interest---when I should have been doing more constructive work. :o
BOSTON (Who has my greatest admiration I should add) Said:-
"hmmmm. Is epoxy impregnation really all that good that wood species is almost irrelevant."
The answer is a vehement YES.
I have built sailed and sold twenty nine boats in my time. nine of those were foam/fibreglass hulls. The rest were wood. Only one of those was a 38' double diagonal plywood construction. I hated it. So messy and time consuming, not to mention expensive.
The biggest sheet ply boat was a 51 ft Catamaran of simple sheet plywood on integral frames mounted on a strongback. It was made of douglas fir plywood which is not the best for rot prevention. It was built using epoxy glue. All the parts of the boat were saturated with a thin, penetrating epoxy. The hulls and decks were coated with two coats of epoxy on the inside and three coats on the outside. All exterior joints were sealed with fibreglas tape set in epoxy. Two coats of polyurethane marine paint finished the job. That boat was built 37 yrs ago and is still sailing today.
We also built several other boats --mono and multi , in 1/4" marine ply, non of which were covered externally in glasscloth, only glass tape on the seams and epoxy/ polyurethane coated. Multi-chined bottoms are easy to build and approximate the ideal round bottom section for minimum wetted surface and good performance.
The method is simple and could be easily understood by non skilled workers, who produced light, strong, and durable boat hulls.
Worked for me.
Paddy :D

[apex1]

I have read this whole thread through with great interest---when I should have been doing more constructive work. :o
BOSTON (Who has my greatest admiration I should add) Said:-
"hmmmm. Is epoxy impregnation really all that good that wood species is almost irrelevant."
The answer is a vehement YES. But that´s wrong, no matter the vehemence.
I have built sailed and sold twenty nine boats in my time. nine of those were foam/fibreglass hulls. The rest were wood. Only one of those was a 38' double diagonal plywood construction. I hated it. So messy and time consuming, not to mention expensive.
The biggest sheet ply boat was a 51 ft Catamaran of simple sheet plywood on integral frames mounted on a strongback. It was made of douglas fir plywood which is not the best for rot prevention. It was built using epoxy glue. All the parts of the boat were saturated with a thin, penetrating epoxy. The hulls and decks were coated with two coats of epoxy on the inside and three coats on the outside. All exterior joints were sealed with fibreglas tape set in epoxy. Two coats of polyurethane marine paint finished the job. That boat was built 37 yrs ago and is still sailing today.
We also built several other boats --mono and multi , in 1/4" marine ply, non of which were covered externally in glasscloth, only glass tape on the seams and epoxy/ polyurethane coated. Multi-chined bottoms are easy to build and approximate the ideal round bottom section for minimum wetted surface and good performance.
The method is simple and could be easily understood by non skilled workers, who produced light, strong, and durable boat hulls.
Worked for me.
Paddy :D

You might have misunderstood the question.

The encapsulation in epoxy makes no difference if applied on a weak timber, say birch, or on a stronger as mahogany. It just makes it "waterproof" and glues it together.
But the strength of the bare timber is of course still the main provider of the structural strength of the boat! Therefore it makes a immense difference, which timber one uses.

Regards
Richard

[Boston]

thanks Paddy
I was thinking that the epoxy negates the issue of the differences in rot characteristics in various woods so that say Poplar could be used in hull construction, regardless of its inferior durability ( it does have tremendous bending strength ) . The structural considerations would still apply as Richard is suggesting

my two cents

cheers
B

[oldsailor7]

[Quote] But the strength of the bare timber is of course still the main provider of the structural strength of the boat! Therefore it makes a immense difference, which timber one uses. [Quote]

OF COURSE. That is taken as a "Given". I said "Species of timber".
I didn't say any old weak species of timber. And I dont consider "Birch" to be a weak species. I wouldn't condone a boat built with Balsa wood for instance.

I would expect any responsible builder to do his homework and choose a suitable wood for his boat.

[Boston]

exactly so consider this

a lot of wood species have been passed by because of there poor rot resistance yet have in some cases at least excellent strength characteristics, so what if you impregnated them with that light thin penetrating epoxy you mentioned, seems like now you have a perfectly viable wood for marine construction, readily available and dirt cheap.

B

[ancient kayaker]

I'm not really a denier of the value of epoxy coating, although I think that - having gone to the trouble and expense of epoxy - one might just as well toss in glass for the durability and, in the case of fir, the prevention of checking. I read elsewhere of the impossibility of truly sealing wood with epoxy and these sources note that, once in the wood, the moisture cannot easily get out again. So the seal has to be perfect and I am sceptical of perfection, shall we say.

I question the extra cost of the epoxy when it is used to justify the use of a cheap wood, if inferior. I think that it might be a good idea if it allows the use of a wood like poplar, which has good characteristics other than lack of rot resistance, and is also available in wide planks unlike many other formerly boat-useful woods.

[Boston]

well there is a lot of precedence for the use of poplar in the past, there is a neolithic site just discovered with a 6500 year old poplar door perfectly preserved so ya, old growth heart wood poplar does seem to have some sticking power. Thing is that if the impregnation is not complete then yes infiltration does seem like it would be an issue although, thin enough veneers will ensure complete penetration of the epoxy which ensures resistance to decay.

Perfection is not necessary but care and consideration in construction methodology definitely is

a little thought and some careful planing might just go a long way in building a modern yacht and taking advantage of modern materials

[PAR]

Yellow Poplar, if you can find good old growth or old second growth it's a great material, but not a common item any more, unless you pull it off a 50 year old mid western barn, which I've done.

The thing I think Terry and Dan are missing is that epoxy can afford modern building techniques, which will dramatically reduce building costs with savings in materials and labor cutting and assembling them. Yes, you run the risk of trapping moisture under a plastic coating, but the alternative is to not use epoxy as a coating and now you're back into massive deadwood assemblies, frames, floors, stringers and other assorted pieces that simply aren't necessary with modern building techniques. Yea, some of us like to look at 2" thick planking with 6" deep sawn frames and 1" thick ceilings nailed over them, but hell man that's a lot of wood to hang.

How substantial a difference between an old style build and a new, encapsulated build? I'm currently working up scantlings on a friendship sloop, built in Lord's method strip plank, which is the lightest of all, without getting into fancy cores. It's very similar in every regard to the Morse built boats at the turn of the 19th to 20th century. At 28' on deck, she's bigger then Dictator, though she looks a lot like her, except I've got a more stylized bow rake in it. 7 to 8 tons would be reasonable for for a traditionally built craft of this scale, I'll likely see this one built with 4 full up and carrying a healthy ballast ratio too.

What does this mean? Money, you get to keep more of it, because you don't have to buy it, labor over it's shaping or install it. This has been the motivating force behind most building trends in recent centuries.

On small craft you have choices and often they don't cost enough to force your hand, but on larger projects, traditional is nice, but you're paying for the look and massiveness of these structures. Dan, as you know a timber frame building is fun to build, but can't compare to platform framing in cost, which is the ultimate bottom line for most signing the check. Hell they'll install some foam beams and paint them brown, who'd know the difference, right.

[Boston]

ever have one of those aha moments, well reading that was kinda one of mine. I've been looking at a 32" friendship sloop and thinking of how I would rebuild her ( see OK I dont own it ) my thinking is I would use the old hull as a mold and cold mold over it then loose the ole hull and place the two halves over a few stringers and a false keel. Ends up lighter, stronger, cheaper, better all around. Bolt on the lead and finish to suet.

completely not suitable for the inside passage though but hey
a guy can dream eh

anyway I have been looking into cost comparisons for a while now and I can only concur. Cold molded over stringers is the way to go as far as I can see for not only ease and cost but also for creating the driest hull possible.

chears
B

[oldsailor7]

When we were building lightweight boats, we would lay up all the wood we were going to use on scrap wood distance pieces and cover them with polythene plastic sheets. We put a small hot air electric heater at one end with an outlet at the other, and left it running for seversl days. after the first few hours water was literally running out from under the covers. We aimed to lower the water content of the wood to about 12% from the common amount of 24%. This not only made the wood lighter and stronger--but it enabled the Epoxy soak coat to really bite into the surface of the wood. This prevented the wood absorbing water vapor again . Don't let anybody tell you that a proper 100% solids epoxy can't keep out water. It can keep out water vapor which is a much more insidious thing. We used to convince unbelievers by showing them a piece of wood which had been coated with two coats of epoxy, weighed, then left in a capped jar of water permanently. When the jar was opened the epoxy coated wood weighed the same as before it was immersed. :cool:

[fg1inc]

G'Morning Boston,
As Tad mentioned, the Gougeon Bros. book is very good and fairly thorough. But you might be surprised at how helpful and genuinely interested all the guys at their tech line are. Give 'em a call, you'll get a lot of information and probably enjoy it too - (866) 937-8797
And thanks for these threads! Very interesting and entertaining.

[Boston]

Morning to you as well
Ya I think I might have that book around here somewhere. At present I'm reading "The Sail-makers Apprentice". Really interesting read, covers a lot more than just sailmaking.

[ancient kayaker]

Yellow Poplar, if you can find good old growth or old second growth it's a great material, but not a common item any more, unless you pull it off a 50 year old mid western barn, which I've done ...

Poplar posts have, I am told, been pulled out of 100+ year old houses after demolition and were in near-perfect condition. It’s the young stuff that’s not durable.

... The thing I think Terry and Dan are missing is that epoxy can afford modern building techniques, which will dramatically reduce building costs with savings in materials and labor cutting and assembling them ...

Huh? I love epoxy; as an adhesive. Because of it I can build lightweight boats - I have never built a boat I couldn’t pick up and carry. Epoxy is the best thing since sliced bread - way better actually as I prefer to bake my own, but I digress. I cannot bring myself to use it as paint though.

Par: the friendship sloop sounds great.

[PAR]

Her's what it's shaped like Terry.

[ancient kayaker]

Thanks Paul. The stem is neat and the rake of the mast seems to complement it nicely.

[oldsailor7]

I love epoxy; as an adhesive. ---but I cannot bring myself to use it as paint though.

Epoxy should never be used as "Paint", because it deteriorates quickly with exposure to the ultra violet in sunlight.
I prefer to refer to it as a protective coating. Good quality marine polyurethane paints bond exceptionally well to an epoxy surface without an underlying primer and since they usually contain an anti UV element they also protect the underlying epoxy coating.
I have a little book on boatbuilding with a particular brand of epoxy, which shows a picture of a boats transom saying "Magnificent Mahogany Grain Finishes which will stand up to sea and sun are possible using ----epoxy plus a clear polyurethane with UV filter. This 28' boats transom is an example".

[Landlubber]

Epoxy should never be used as "Paint",

...very true, NEVER can it be used as paint, but I think that expression was more as a description of layering more so than actually painting, but you are very right, it must be always covered.

[wardd]

here's something you could build

[dskira]

here's something you could build

Send me some money and I built one, a Ferris hull like this one of wood ordered by the Emergency Fleet Corporation in the 1917. I have the set of plan. Look at the construction of the stern planking, quite nice.
I have to order a million board feet of fir, so don't waste to much time to send the check, the mill is waiting ;)

http://www.boatdesign.net/forums/attachments/boat-design/49265d1288741778-diagonal-planking-ferris_d1-1-.jpg

[wardd]

Send me some money and I built one, a Ferris hull like this one but of wood like the Emergency Fleet Corporation did in the 1917 with the Ferris design.
I have the set of plan.
I have to order a million board feet of fir, so don't waste to much time to send the check, the mill is waiting ;)

http://www.boatdesign.net/forums/attachments/boat-design/49265d1288741778-diagonal-planking-ferris_d1-1-.jpg

this is a ferris wooden ship

want the link for the book about then?

[wardd]

http://ia311221.us.archive.org/3/items/buildingawooden00sectgoog/buildingawooden00sectgoog.pdf

http://www.cocatrez.net/Water/FerrisShips/FerrisShips.html

[dskira]

I have several book about this period of shipbuilding, mostly the Ferris design. But I will be interrested to know the one you have, please send a link.

[wardd]

see post above

[dskira]

Thank you for the link.
I have the first one, and printed the second one also.

Boston I apologise, I am hitchhiking your thread, I will get out now.

I love so much these wooden ship that I can control myself when i see a picture like this Ferris.

But I should know better.

Daniel

[Boston]

eh dont worry about it

welcome to the pile

B

[Boston]

nice hull shape Par

http://www.boatdesign.net/forums/attachments/boat-design/49262d1288731996-diagonal-planking-byyb-137.jpg

looks like it would be a lot faster than the typical friendship sloop
if I remember you mentioned 28' which on a friendship would mean a beam of about 9'4"
whats your draft and led# if I might ask
I'd guess the draft at a bit under 40" and the led at about 4.5 tons, the mast would be about 31' off the deck and likely out of carbon cause at that shallow a draft and reduced displacement you would need to have a similar reduction in weight aloft in order to maintain the traditional rig. My guess is that thing would blow the doors off the completion at the friendship sloop races even if it did slip a bit more going upwind.

[apex1]

How substantial a difference between an old style build and a new, encapsulated build? I'm currently working up scantlings on a friendship sloop, built in Lord's method strip plank, which is the lightest of all, without getting into fancy cores. It's very similar in every regard to the Morse built boats at the turn of the 19th to 20th century. right.

Now that we have heard about this method so often, I would like to know more Paul.
What exactly is Lords method?

Regards
Richard

[rwatson]

That would be Lindsay Lord, mentioned in a Dave Geer book

http://books.google.com.au/books?id=y2GT5JyVrzAC&pg=PA162&lpg=PA162&dq=lindsay+lord+boatbuilding&source=bl&ots=wvPRNXt8hz&sig=GMUfV7aU9G5ggiVIxNsQvXhndo0&hl=en&ei=SSLRTN2AJZTSuwPCuMC3DA&sa=X&oi=book_result&ct=result&resnum=7&ved=0CDAQ6AEwBg#v=onepage&q=lindsay%20lord%20boatbuilding&f=false

[PAR]

Dan the boat is on the narrow side for a Morse style Friendship and has a much shallower hull, which is understandable considering her displacement. This draws out the WL's a bit for an easier entry and run, though she shouldn't be confused with a boat that can run much above her LWL imposed speed limitations. Draft is quite shallow at 32" with the board up, considerable with it down. Yes, it's ballasted. In fact all of her 1.3 tons of ballast is external except for about 400 pounds.

The mast is birdsmouth and will weight about 62 pounds for it's 29' length, which is only 27' off the LWL. The gaff is 31' off the LWL and the topsail yard, if used would be about 36' off the LWL.

As far as beating other Friendships, she'd do about as well in a straight line as any other, but she'll be much crisper in maneuvers, possibly a bit closer winded for better shaped appendages and less wetted area, so if it was close racing, then she'd win for handiness.

Richard, the Lord method, which I've modernized and updated a bit, is fairly clever considering when it was derived. "Naval Architecture of Planing Hulls" in 1963 by Lindsay Lord and the process was tested fairly well with everything from high speed 80' patrol craft to little 20' pleasure runabouts. In a nut shell it's a cored composite hull using a softwood strip core that's epoxied together, then covered in fabric like Vectra, Xynole, Dynel, etc. Now, I know what you're thinking and I thought it too a number of years ago, those fabrics have pretty high elongation properties and you're right, but this is the point. Lord discovered that when done over a light structure, an area can deflect and absorb loads, then return to it's original position relatively unharmed. Because of the high cyclic capacity of the softwood core and the fabric/resin matrix, you can build a lighter structure that can absorb as much energy as a heftier, but stiffer one. In fact, he was big on minimum internal framing structure, typically using furniture and bulkheads to bear loads. This is common place today, but not in the 40's and 50's when he was working on it. He used a lot of plywood in his builds and very little real carpentry, such as rolling bevels in rabbits, etc., just butter it up with thickened goo and slapped the next piece down. So, on this hull above, the scantlings seem ridiculously light, but they're not. The hull core is 7/16" with 3 external plies of Xynole and two internal plies of Xynole. The is a keel of plywood sided 1.5", there are two longitudinal frames the width of the cockpit foot well and cabin sole of 3/8" plywood and some athwart plywood forms of mostly 1/4", but not much else as far as structure except for seat and berth tops, cabinets and soles. Naturally, this is a laminate schedule best suited for bagging as the fabrics float and the last thing you want is a lot of resin.
http://ecx.images-amazon.com/images/I/41YsUqDitoL._SL500_AA300_.jpg
This is long out of print and has always been a bitch to find. I found one on Amazon for $200, which is twice what I payed years ago.

[Boston]

you sure you didn't mean 42" draft, cause if you scale the 36" station grid its looking like about 40". Oh well no big deal it looks like a nice modern take on the design while maintaining the traditional appearance above which is exactly the kind a thing I think needs to happen more often than less. The traditional designs just have an appeal that cant be ignored and bringing some of em up to speed through improvements in hull shape and construction techniques is bound to be a hit with the "I'd like to build a boat" crowd. Hows the cabin head room ?

OK so I been looking around here for that cold molding book you guys recommended so long ago and dam if I just cant find it. Driving me nuts, I'm starting to wonder if I ever ordered it.

cheers
B

hmmmmm
old Daves book should be here in a few days
course with my luck by then I will find the one I thought I had floating around here somewhere.

[apex1]

I know which Author was meant watson.

Now I would like to know the method, not that Gerr mentioned it too (which was not new either)

PAR

thank you Paul, all clear now.

Regards
Richard

[PAR]

No it's 32", so maybe your screen has a mis-calibration, which is often the case. Using a drawing program, draw a square and zoom in so it fills the screen, then measure it. If it's not the same in both dimensions, you need to alter your screens aspect ratio, which are usually little buttons on the front or side of the monitor. It's one of the first things I do when I get a new monitor. There are also intentional non-reconcilable "errors" in the drawing, the shapes are accurate, but the drawing, if lofted would quickly cause a lot of head scratching. The draft is proportionate in profile and section.

Yes, Gerr mentions this method and has some rules covering it Richard, though his rules are a tad heavy (typically with his scantling system), especially for this system, which must be light to be worth the effort.