Is Balsa really that bad ??

[rwatson]

Just had a read of the Australian catamaran magazine "Australian Multihull World" may/June 2009

Our mate, Derek Kelsall had an article in there, where he advocates banning balsa as a core material.

He states there are a plethora of articles on the internet on the "wet balsa problem".

I understand most end grain balsa is encapsulated in either Vynelester or Polyester, which is not as waterproof as Epoxy. is that the problem?

Is it really that bad - what have people found ?

[oscarvan]

It's cheap, it's strong, it's easy to work with. If it gets wet, it rots.

[rwatson]

Is it really that cheap ? - my rough calculations make it around $85 per square metre for 1/2 thick. That is more expensive than strip planking in Western red cedar here in Australia.

I suppose you would save on Epoxy V GRP ....

[TeddyDiver]

Polyester is defineatly a problem. Another problem is that balsa cores aren't excactly encapsulated, instead only on the laminate sides, not inside the core itself (compare to striplanking where is a real encapsulating) so a single small hole (besides the sweeping water throw polyester) will destroy the whole boat..

[CDK]

If weight is a major consideration, balsa is frequently used. For all other applications, any other kind of much cheaper plywood -impregnated or not- can be used.
And Glastron nowadays builds all small craft under 27 ft. without any wood because they use polystyrene foam as a core material. Elan, a European builder uses carton in the shape of egg boxes for their cheap fishing boats....

[lymanwhite]

I've had esperience with end grain balsa layed up in a mold with carbon and epoxy, then bagged and heat cured.
There were some 20 - 25 boats pulled with these materials as I recall, about 10 years ago.
There were some decks that experienced areas of de-lamination possibly due to too little epoxy in the layup. These and most problems were due to deck fittings done wrong, allowing the moisture to get to the balsa. This would be a problem with any core. One reason we chose end grain balsa is that it tends to isolate moisture to the area of penetration. Foam can allow moisture to travel via flexing and can create a delam that can be a bigger area by comparison.
Also end grain balsa breaks along the line of the grain, forming a clean edge for repairs. Foam tends to crush by comparison.
Aside from these few isolated problems the balsa, carbon, epoxy schedule is awesome. Very hard, strong, and repairs and deck / hull fittings are straight forward.
I still have one of these boats and would recommend balsa, although most modern layup schedules whether foam or balsa or another core are all pretty close in performance. I find the biggest variable is in the knowledge and skill of the craftsman.
Also Balsa is an old boat building core technology, while foam is much newer.

[Manie B]

My 2 cents

In my travels i have seen some very bad balsa jobs

Either it is too difficult to work with, or poor workmanship, or what ever

The boats that i saw with horrendous balsa delamination were even "repaired"


These boats look great when new, and the first owner may not notice problems. But after 2 maybe 3 years the second owner lands up with a pile of absolute junk.

The combination of balsa and polyester is poor, which is rife around here.
I can well believe that balsa and epoxy could be great BUT you need skilled labour to do these jobs. Unfortunately my country like many others are been used as "cheaper labour" to build boats, i can assure you there is nothing "cheap" about unskilled labour and unscrupilous "boat builders"

I dont like balsa because i have yet seen and old balsa core boat without serious problems, I have been on rust buckets and plywood "wonders" that are absolutely fine and safe.

I cant say that balsa should be banned - Derek Kelsall has got infinitely more knowledge than me - but i believe that there is nobody around here that could do a decent job, either building with balsa or repairing it.

[Stumble]

The problem is not with Balsa but with the lack of enginearing that goes into the design, or with the lack of understanding of how to properly protect it from water damage. The problem is that ANY core material is suceptable to water damage just of different types. Foam can litterly be pulverized when water gets into a core by a process called hydrolic erosion, balsa rotts, not much else is light enough to really be used as a core.

Here are a few articles that do a good job of explaining the issues:

http://www.yachtsurvey.com/core_materials.htm
http://www.yachtsurvey.com/cored_hull_bottoms.htm
http://www.yachtsurvey.com/more_on_cores.htm


Personally I see it as a problem with the process of using a cored design, more than with the core material itself. And Balsa is still one of my favorite core materials, but it does require, like any other highly engineered structure, proper maintenance and care.

[PAR]

There's nothing wrong with the material. In fact, it's quite difficult to find a suitable material that can equal or exceed the performance of end grain balsa in cored construction, all things considered.

Most manufactures have recognized the need to use better resins and engineer tolerant laminate schedules.

In the end, when you look at the millions of balsa cored boats, the vast majority without issue, it's clear the small percentage that have problems are usually owner or damage related, which has nothing to do with material choices made by the designer.

[dougfrolich]

I agree with PAR!
I was just sailing yesterday on a Balsa Cored Santa Cruz 52 Built in 1992 and still as sound as the day she was built ---after over 100,000 miles under her keel. High Quality Materials, High Quality Workmanship, High Quality Product.

[eastcape]

Educating the general public on the correct methods of installing fittings through End Grain Balsa Cores is a difficult task, but would be a very good place to start.

All the failures I have come across in 9 years of using End Grain Balsa panels stems from someone adding a fitting to the vessel and incorrectly sealing the End Grain Balsa Core material or not sealing it at all. There are correct methods for working with this material and in the wrong hands will lead to problems down the road.

End Grain Balsa Core is not for everyone. It should be designed, manufactured, and constructed by experienced personnel. Owners should be educated on how to maintain their vessels and any modifications later should be made by experienced builders.

The ocean is scattered with success stories, but then again you never read about successful projects.

[mark775]

My boat was built in 1979. I replaced the balsa deck to a different design in 1989 and there was no sign of any problem with it.
laminate schedule; 2 x 3208 BTI, 1 x 13oz mat, 1" balsa, 1 x 13oz mat, 1" balsa, 2 x 3208
I have had four wheelers dropped from a crane because of choppy water, 10,000lbs of lumber, skiffs dropped from rail high, and 400lb halibut doing their best to de-construct, all without so much as a groan from the deck. A 11/2" camber helps but the deck is stout and watertight (I cut a hole two years ago and it was dry and still one piece.
When I build my dream boat, it will be full of high tech materials and design... and a hell of a lot of balsa.
32290

[Landlubber]

I think mostly materials are damned by the builders of poor quality constructions. Such as ferro....personally, not for me, but in fact, if done CORRECTLY, it is a century long material to use.

End grain balsa has many advantages, so do most other suitable boat building materials, but the correct usage of these materials is the determining factor in their longevity.

Cost of construction and time of construction are the commercial determinations of the "best" materials for the purposes of boat building, removing the cost and time factors certainly will change the build quality of any boat, and the end grain balsa arguement is affected by these parameters.
Non compliance with known world best standards will render any core material unsuitable.

[mark775]

By the way, as I look at the picture I drew on "paint" ( I don't have a nice rendering program), I thought I'd go off topic a bit about cutting freeing ports at hull/deck joints;
I believe that ports should be cut two inches up the hull side to avoid a delam at the juncture. Also this will prevent stains (fish scales/blood, mineral stains) to the hull sides. Also, this will allow freeing port holes to be aligned for esthetics rather than just follow the deck-line which may be different than the hull lines. Of course this means cutting scuppers in the horizontal, not-cored area - plan for this before deck layup. WHAT? You don't have freeing ports - only a little plastic deck fitting in each corner of the cockpit?

[rwatson]

The problem is not with Balsa but with the lack of enginearing that goes into the design,
Here are a few articles that do a good job of explaining the issues:

http://www.yachtsurvey.com/core_materials.htm
http://www.yachtsurvey.com/cored_hull_bottoms.htm
http://www.yachtsurvey.com/more_on_cores.htm




Great links Mr S. Thank you very much.

As I am in the process of deciding on materials for my next boat, this has been a great contribution.

All the other points raised are very, very usefull as well -the 'skill of the builder' theme raised in so many of the comments seems to be a huuuuge part of the equation.

[masalai]

I have no issues with balsa cored material in my build - adhere to the designer's instructions and build as the material demands for a lightweight and strong vessel... I was told do not make holes unless they are necessary and that the nothing is allowed to penetrate the balsa... make a hole, refill with resin & cloth then put holes in the "glass/epoxy" part thus eliminating the opportunity for water to get at the balsa and soak/rot it... - That looks like drivel - but you should know what I mean... Do it right and it is worthy and appropriate for the task.... Look up the 'scrumble project', that is a meticulously detailed build project and that boat is balsa cored construction.... link in my link to Bob Oram designs, below...

[lymanwhite]

By the way, as I look at the picture I drew on "paint" ( I don't have a nice rendering program), I thought I'd go off topic a bit about cutting freeing ports at hull/deck joints;
I believe that ports should be cut two inches up the hull side to avoid a delam at the juncture. Also this will prevent stains (fish scales/blood, mineral stains) to the hull sides. Also, this will allow freeing port holes to be aligned for esthetics rather than just follow the deck-line which may be different than the hull lines. Of course this means cutting scuppers in the horizontal, not-cored area - plan for this before deck layup. WHAT? You don't have freeing ports - only a little plastic deck fitting in each corner of the cockpit?

OK Please elaborate.

[masalai]

Balsa cored DuFLEX panels can be an excellent build material ( www.atlcomposites.com & www.duflex.com.au and www.westsystem.com.au ) - High levels of quality control at ATL ensure a consistently superior product... also look at the Scrumble Project which is an excellent documentation of a build project http://scrumbleproject.wordpress.com/table-of-contents/ and follow some links in my post 232 here http://www.boatdesign.net/forums/boat-building/my-little-piece-peace-25962-16.html#post279166 ...

[Jimbo1490]

There's nothing wrong with the material. In fact, it's quite difficult to find a suitable material that can equal or exceed the performance of end grain balsa in cored construction, all things considered.


Some people in aerospace seem to agree with you on this as end grain balsa/Al skinned bonded panels are the most common cargo floor in big commercial jets.

Jimbo

[Landlubber]

Mas.

The trick with composites or balsa cores in fitting deck stuff is to drill the hole to be filled with epoxy, but then get a bent nail, put it into the drill and smash out some of the foam/balsa core between the laminates, then fill with epoxy, it seals the core and allows a great mechanical bond of the plug prior to redrilling for the fittings.

[masalai]

I am sophisticated :D:P - I use hex keys in a power drill - does that part neatly, Sadly the doc reckons I may be reacting to the epoxy (got my pancreas going no good, a while ago).... Bryan has been finalising (doing fit-out) his 44C and I have had ample opportunity to observe from the windward side a master craftsman at work (he was a teacher in the 'manual arts' and is an excellent welder in alloy and stainless, as well as carpentry and grp work).... I am 'just a dumb Johnny come lately' who can appreciate quality workmanship...

[lymanwhite]

I am sophisticated :D:P - I use hex keys in a power drill - does that part neatly, Sadly the doc reckons I may be reacting to the epoxy (got my pancreas going no good, a while ago).... Bryan has been finalising (doing fit-out) his 44C and I have had ample opportunity to observe from the windward side a master craftsman at work (he was a teacher in the 'manual arts' and is an excellent welder in alloy and stainless, as well as carpentry and grp work).... I am 'just a dumb Johnny come lately' who can appreciate quality workmanship...

Keep that shit including fumes, and sanding dust off of you, including thinner.
West has a good basic technical safety read in their literature.
I've seen guys with poisioning so bad that when they come within 10 feet of a epoxy process building, their skin erupts in sores, right before your eyes.
Don't breath it while mixing, keep the skin covered while applying wet, and while sanding dry.
I wish for a prepreg that can be kept refrigerated, has a 2 hour working time, and will set / cure with a heat lamp. I've seen spar makers work w/ prepreg. The shop was so clean, it was amazing, and no fumes, no thinner, beautiful.

[mark775]

Okay, post-by-post. I know Ren Tolman (Tolman skiffs). He's got it bad (epoxy sensitization), now he has cancer. Don't know that the cancer came from epoxy but suffice to say epoxy's bad shit in which to swim. Pre-preg is in my future. See Eric Goetz's work.

[mark775]

When drilling holes, drill only until you get to the bottom laminate, epoxy fill and avoid pissing off the electrician working below...

[mark775]

32325

[lymanwhite]

Same hard spot technique applies to foam or other core materials, as well as balsa, and is even more important.

[Stumble]

OK Please elaborate.

Lyam,

The proper way to bolt something to any coreed material is to:

1) drill a pilot hole from the outside of the boat (or from the side most likely to get wet)

2) from the other side using a Forstener bit ( http://www.mockett.com/furniture-hardware/wire-cable-management/forstner-bits ). Use a bit that is slightly larger than the size of the mounting hardware, I usually go up at least a 1/4 inch, but on a large bolt I may go up to 1/2 inch bigger. Just be careful not to drill through the second layer of fiberglass, it's pretty easy though since wood and glass feel completely different as you drill through them.

3) Tape up the bottom of the hole using clear packing tape, then fill from the top with thickened epoxy. Watch the epoxy fill the void and check for any voids.

4) once the epoxy is cured drill back through the epoxy and bolt the new hardware in place.

What this does is to leave as much of the wet side shell in place to try and minimize water intrusion. Then it seals the core in such a way that there is no path for water to follow into the wood. You also may get some penetration of epoxy into the wood wich will slow down water intrusion into the wood if water does get in.

As for the suggestions to just use an allen wrench or screwdriver to pull out the core... It is better than nothing, but that method has a couple of problems: First you can't control the amount of core taken out, and it is very hard to ensure that there aren't any loose wood fibers left in the hole. Secondly it is harder to make sure the epoxy fills the entire void since you can't watch the epoxy flow into void (I usually use clear packing tape to tape up the bottom of the hole. Third, it takes more time than just drilling a second hole.

[catsketcher]

As to the initial comments by Derek Kelsall, I think they are way over the top. Derek basically says anything that isn't foam is just about to rot. He then goes on to talk about all the great foam boats he has built.

There is a reason why foam went out of favour in multis at least during the seventies and eighties. In fact Derek is involved in more than one. If you get your old multi books out you may find one by Rob James. In it he describes sailing Great Britain IV (I think) Anyway the boat was basically falling apart all the way around Britain. It had a large rig and so beat Phil Weld on Rogue Wave but in the book Rob James talks longingly of a structurally secure boat like Rogue Wave - she was built in wood. After sailing a few Derek boats both he and Chay Blyth use other designers for their next boats - not a show of confidence.

In Australia we had boats like Devils three and Pumpkin Eater that were falling apart after a decade of use. These light foam boats had gone soft and delaminated. Foam certainly was not fool proof. When Ian and Cathy Johnstone built Verbatim it was out of wood too so wood had lots of people who liked its stiffness and toughness when used in a composite situation.

At the same time there were good foam boats being built- Top gun and D Flawless - well she did break up actually! but there was certainly no monopoly by foam or wood on the best boats around.

Derek is trying to sell plans and ideas. He knows an awful lot but if he is not going to be generous enough to acknowledge the good things other cores have done his ideas must be treated with a fair bit of skepticism.

[eastcape]

For those of us who don't read SAILING multihull magazines...hehehe :P

Would someone be so gracious as to PDF the article here, or a link by chance?

[mark775]

32330 Master Captain, Admiral G. Rubin Esq.lll, Phd. PCP, STP, Any Tonneage, Any Ocean, Any Thing That Floats... Speaks; "Harumpf (Cough up phlegm), I say, and my title doth precede me, that the PROPER way to go about resolving the aforementioned conumdrum is to enlist the services of a borrowed Forstner bit. Because the things come so dear and smoke as to be rendered useless for the woodworking for which some misguided souls believe they shall be reserved, one is always a leg up by using one's mate's and reserving one's own for "later". Also, take precautions to ensure that the Forstner diameter is larger than the object to be attached by said twice-augered hole to demonstrate to the untrusting eye that, indeed, the core was replaced by a suitably aquaphobic resin.

[Stumble]

LOL and drink more rum.

[masalai]

Harumpf, and another serve of scrambled eggs for the captain, as he seems to have coughed at the wrong time and coloured the forpeak of his cap and the shoulders.... Harumpf Harumpf Kkkkoooiiiiptong-tong ahhhhgh that be better - Two bells is it? - - Aye, another tot O that liker squire....Aye...

[mark775]

Good Sport, G'nite.

[Boston]

after a long good read including all the links
Im cured
and mine will undoubtedly be
a traditional build in wood
no plastics no sandwiches no minimum wage help involved
wow
and I thought I knew why I didnt like plastic boats
yikes
what a nightmare

wood wood wood
and to top it all off
it floats

[mark775]

Boston, I've a plastic boat since '84. A boat with a soul that has soon raised three wives and four kids, carried 30,000 passenger bent on cutting cheese on every surface, vomiting in every corner, dragging 74qt. coolers of beer and ice over every piece of teak trim, and with nay a whimper.
But I, too, long for the warmth and character of a wood boat I experienced in my youth. One day...

[Manie B]

My 2 cents

epoxy and glass over marineply is most certainly within the reach of the average amateur boatbuilder

its a little bit like me

he he

strong - stiff - and "rigid"











the part about epoxy over marineply is true :D

[Boston]

that was really well said Mark
I guess my prejudices were pretty well rooted and then I read those three articles
it just kinda lit a fire
I new they were having troubles with the stuff but had no clue how severe they really were

Im ordering a few thousand feet of black walnut for a custom porch, entry foyer, door and staircase with turned railings
so I guess I've the privilege of working with wood all the time, maybe sometimes I forget what a privilege it is
I really didn't mean any disrespect towards those who do own well built cored boats

raises three wives ? my god man what were you thinkin :D
Im betting you started with just one and simply forgot the rules
keep them out of the light
do not feed them after dark
and never
ever
give them any water

[P Stuart]

Guys, I agree with Dereck only only on spec and all of you seem to have the same opinion and so does he really - just a different way of saying it. Build it right and use the correct techniques.
In my opinion all wood laminates should be totally encapsulated in epoxy as its not porus - that is the problem with polyester, gelcoats and unsealed primer coat paints.
Also if you are going to use wood laminates extreme care should be taken to design the structure in the corect load sense. Plus it requires protection from damage either mechanical or structural.
Vacuum bagging is an extremely eficient way to encapsulate the Balsa in epoxy resin.
I will qualify the argument by telling you of the build of my yacht an its problems with Balsa Core over the years. First off the yacht has had a hard race life being an Admirals Cup One Tonner of 40ft and being completely vacuum bagged and built from Balsa Core, Kevlar, Foam and Epoxy Resin in 1984, and to date no structural failures or even any cracks, one suspect crease, which turned out to be a paint line from a piece previously fitted.
The decks are a laminate of Balsa, Kevlar, Glass and Epoxy resin. The yacht in question is almost 25 years old and the only repair we have needed to make (so far) is a core replacement under a deck block, where the core failure was caused by mechanical damaged to the deck block from an item hitting the block and breaking the decks through deck seal allowing water into the core.
The time period to when we found the problem is unknown but I suspect at least 5 years. the core structure was reduced to what I describe to people as wasps wings (anyone who has seen it will know what I mean).
The block was removed the damaged areas deck was cut and lifted (an area of 15 by 8 inches approx), core replaced and epoxied down and vacuumed. all took about 4 hours - not including curing and refinishing etc.
Carrying out the repaires looks just as brutal as duing a strip plank repair, but I think with the right equipment and techniques and not being afraid to tackle such problems that its quite quick and relatively simple to repair.

[masalai]

Boston,
Have I seen that advice in a movie featuring cute little animals with big loveable eyes? :D:D:D:D who turn vicious when the rules are broken? - - I do not think those rules apply to those who become wives.... although their demands seem similar to that required by boats:D:D:D

[Boston]

well ya
I think it was called "the dating game"

Ive seen the bewildered and shell shocked look some of my buddies get shortly after they get married and start
feeding there wives

an old Chinese man once told me the rules
and mind you Im not superstitious
the Magui is a gift
a great responsibility

and then he mentioned that little set of rules I noted

so far it works for me
trick is do not overfeed em

[barks]

Balsa has all the best properties for boat building except 1. If you can overcome this then it is fine. Unfortunately it acts like a sponge in contact with water and will need digging out and replacing it if after contact with H2O. You will enjoy its higher performance characteristics while it is dry and all who praise balsa have been successful in doing this.

[Boston]

anyone tried encapsulating it in shellac and seeing how it behaves as a primary building material

I guess what Im driving at is
could it or maybe some of the other lightweight materials typically used in say aeronautics be applied ot yacht construction in a way similar to a traditional wood build but
if engineered up to standard also serve in a duel role of both structural components and flotation
one thing balsa wood does really well is float
its also reasonably strong for its weight
as is spruce
soooooo
if various members of a traditional wood hull were sized accordingly and properly encapsulated would something like balsa or spruce which both have at least some rot resistance
be used as the major components in a yacht build
minus the plastic
with the planking in say a double diagonal configuration rather than some kind of fiberglass, core or not
just a thought
but wood that breaths tends not to rot
would that is buried in a plastic bag and subjected to water
rots

ps
if this is to far off subject please pm me your response so we can keep this one on track
I learned a lot from this thread
would be a shame to see it twist away from its original topic

[PAR]

Balsa's sole role in these types of laminate is to offer it's very high compression strength to weight ratio, within the sandwich laminate.

Boston, these engineered laminates (sandwich construction with a balsa core) are very different then the structures you are accustomed. They bear little resemblance to things you've seen or understand. This isn't a dig, it's just that most people have a hard time understanding these types of material combinations.

[BeauVrolyk]

I own a balsa cored boat that was built in 1980. It's called a Moore-24. There were a little over 150 of these boats built between 1976 and 1984 or so. Almost all of them are still sailed and raced extensively. For example, we regularly get over 40 boats in a race. This construction technology was also used by a number of other boat builders in Santa Cruz with very good results long term.

While some of these boats have had water get into the core, it has always (to the best of my knowledge) been caused by the owner/crew drilling a hole to mount a fitting and not properly sealing the hole. It's easy to fix with a drill, heat gun and penetrating epoxy, much easier than wood.

I also own a plank on frame wood IOD from 1946, all wood all the time. Having maintained both boats for a while, I have to say that the Moore is a MUCH better boat with regards to durability, strength, weight, and endurance. As much as I love my old IOD, there is simply no comparison. I have re-planked, re-bedded, re-everything on the IOD and as much as I love the wonderful smell of the wood, the great feeling of working with wood, and the look of it, it is simply not anywhere near as good a material as a glass/balsa boat. Not as strong, much higher maintenance costs, much more fragile; while the problems are a little different on the wood boat, they're much more numerous and severe.

Finally, there are poorly built boats of all types and one shouldn't judge the characteristics of a construction material and technology on the basis of examples of badly built or mistreated boats. It is trivial to find bad examples of wood, glass, steel, alloy, you name it. If one compares well built polyester/balsa boats with well built boats of other technologies, one will find that typically there is much lower maintenance cost and much higher performance from the poly/balsa boat - it's the reason there are so many of them. My boat, at 29 years old is a pretty good example - not one soft spot anywhere. One does have to know how to treat the material, just as one needs to know the same thing about wood. No material can withstand an ill-informed or careless owner.

Beau

[Boston]

no Im ok with that
Ive never really worked with the stuff (fiberglass is a complete alien to me )
so all I know is what I read and see when I occasionally make it back to the water ( about once a year if Im lucky )
what Im reading and hearing is that if your dam careful as an owner and were lucky enough to land a good builder you could end up with a good boat
baring any materials defects like some of the ones discussed in the articles presented
which are apparently more common than the industry lets on
thats a lot of maybe's which leaves me inclined to lighten up a wood structure rather than go with composites

things like those articles kinda sound spooky from the perspective of a life long woodsman
sounds like more of a crap shoot than an informed decision
wood I can feel it
check its grain pattern
sound it or smell it and tell you if its good to go
and the best part
it floats

reason I ask is that a laminate is a laminate
layers of stuff
Im about to laminate a front door together out of white oak and black walnut (raised panel front door for that black lacquer job I may have mentioned )
course thats got nothing to do with fiberglass but still
the strength and consistency imparted by the layering process I got down
its the particular material being laminated that Ive no experience with
fiberglass or composites cored or not

so you hit the nail on the head

that said
has anyone successfully built a yacht predominantly from laminates of strictly the lighter wood materials ( no fiberglass )
like say Sitka Spruce ( one of my faves )
that stuff is seriously strong and lite
relative to its density
or balsa maybe a third the weight and Ild have to look up how it stacks up in terms of strength
seems like it would make a strong light structure
obviously with segments laminated to impart the strength needed for certain components or certain areas
or even just a complete cold mold

[Jimbo1490]

Boston,

I know you must have some understanding of 'I' beams. Engineered wood 'I' beams have become common construction site fare as they can be made any length, have much higher stiffness to weight ratio (makes for a nice solid 2nd floor!) and save a lot of wood compared to regular lumber beams.

Think of composite sandwich structure (like balsa core with glass skins) as a sort of 'planar I beam'. The skins serve the same function as the top and bottom cap of the 'I' beam while the core material (be it balsa, foam, plywood honey comb, etc.) serves the same function as the web of the 'I' beam.

Study up on how loads pass through 'I' beams; where in the beam there is compression, tension and shear and then apply that to sandwich composite structure. Then you can understand why this or that thing is important or not important.

Jimbo

[Boston]

nah
I recommend TJI's regularly, micro lambs, glue lambs and parallel strand beams
basic engineered lumber
Im down with that although I am firstly inclined to go with a solid beam if practical ( if its going to be exposed and I want it to look like anything )
but this biz of fiberglass mat or rove in epoxy with some unknown bond between core and substrate is just a little to much
oh
Im guilty of having little experience with it
but at the same time
I just get story after story about how it fails ( pretty dam disconcerting actually )
and every time I hit the coast I see fiberglass with rot and more rot
whereas with the engineered lumber I deal with (glue and wood no fiberglass or submerged applications )
it seems to hold up just fine
the TJI's use hot pressed glue
and the glue lambs use resourcenol
microlambs
Im not sure what they use
but Ive worked with all of em numerous times and I know what the failure rate is
and I know they are not recommended for outdoor use
houses I built back in the 70's are still standing ( better be )
not sure about you guys but I guess my whole ego revolves around the stuff I build
my whole heart and soul goes into making shit what ever it is
to last
what houses Ive built
every last one of em is still standing
no fires
foundations sound
no structural defects
no rot or bentonite damage
still standing no cracks

when I build my boat
I want at least the idea of it lasting generations
but epoxy is seriously in question
and its the main ingredient in all these composites
first question and not the last is
what's it's life span
perfectly reasonable question if you ask me
and why wont the industry divulge that answer
how long will epoxy last
simple question
should be a simple answer

silence

why is the industry silent on that one
it does beg the question
is there something they know, that they dont want us to know?

whats the deal
how long does epoxy last as a bonding agent
simple question
should be a simple answer
so

whats the answer
why the silence

why wont the industry divulge what it knows concerning the lifespan of epoxy

specially in the light of all these failures in the fiberglass industry
which is also by and large dependent on the vagaries of epoxy

not trying to be difficult but if Im going to spend half a mill on a yacht
I want some real answers as to the glue holding it together
seems fare to me
some biz wants my money ok
how long will the product last
silence

that seem odd to anyone else
cause frankly it makes me a little uncomfortable

in the light of silence I can only decide to go with what is known
wood lasts for x amount of time and then you need to replace it
at least then I know what Im getting into
with epoxy
only folks who know
aren't telling
anyone else wonder why
cause I sure do

[Jimbo1490]

Most 'failures' as you refer to in the boat business are from core rot, apropos this thread, which is about that most 'rottable' of cores, balsa. If you want a boat that lasts forever, build it entirely from synthetic materials. Use good quality PVC foam and glass it over with the resin of your choice. With a synthetic material, it's not as critical to use epoxy, since the core won't rot anyway, even if a little water ingression happens at a damage point. DIAB's 'official' glue for their core foams is polyester resin based, not epoxy. Epoxy allows us to use the much cheaper natural cores (wood) that do not hold up nearly as well when assembled with poly resin. The resin will outlast the wood, if protected from UV. This does not mean a given boat will last that long, but epoxy resin failure will not likely be the reason for its obsolescence.

Jimbo

[mark775]

If using foam cores, in my experience, one ought core areas rather than the whole part (hull). I don't agree that foam is all that cool - I've done some backyard destructive testing of a manufacturer/repair facility's scraps. Whatever one attaches to foam "unzips" with alarming ease. This doesn't happen with balsa. I like how a couple of guys trying to destroy a piece of balsa cored poly seriously have their work cut out for them. Also, an impact damages more area with foam that I know. Also, you may not call it "rot" but "turn to mush" it does. I have some interior decks made of some stiff, red foam on my boat, tho. They are dry, obviously light, strong enough, and completely stable.
Tangent: I hung a typical Boston Whaler on the shop wall for more than a year and water was still draining out of the foam from the two 2" holes I cut. I don't know which of the little problem areas the water got in at but, to me, this is unacceptable.

[Boston]

Most 'failures' as you refer to in the boat business are from core rot, apropos this thread, which is about that most 'rottable' of cores, balsa. If you want a boat that lasts forever, build it entirely from synthetic materials. Use good quality PVC foam and glass it over with the resin of your choice. With a synthetic material, it's not as critical to use epoxy, since the core won't rot anyway, even if a little water ingression happens at a damage point. DIAB's 'official' glue for their core foams is polyester resin based, not epoxy. Epoxy allows us to use the much cheaper natural cores (wood) that do not hold up nearly as well when assembled with poly resin. The resin will outlast the wood, if protected from UV. This does not mean a given boat will last that long, but epoxy resin failure will not likely be the reason for its obsolescence.

Jimbo

hey Jim did you get a chance to read the articles presented back in the thread a ways
testing seems to show that those synthetics are just as likely if not more to fail as the balsa
something that surprised me as well
Ive always preferred natural materials and been gun shy of plastics
being mostly concerned about there toxic nature
but I to was under the impression they were at least impervious to the elements
apparently not

I mention the epoxy cause it seems like there is something someone is not telling us
deliberately
it just seemed like the most obvious one to mention

thing is with wood at least you know what your getting into
these plastics, epoxy or not, seem to come with a grab bag of serious boat killing issues

B

[Boston]

a few more articles I found
http://www.google.com/url?sa=t&source=web&ct=res&cd=3&url=http%3A%2F%2Fwww.yachtsurvey.com%2Fsearay_balsa_core_bottoms.htm&ei=j9k0StuNKobwsQOdpr3DDg&usg=AFQjCNFMXjralAzVq9tfdbo7UVHeKO-pIw&sig2=ezSZRbSinrkYjcnUDwr3cQ

actually there is a whole pile of articles located here

http://www.google.com/url?sa=t&source=web&ct=res&cd=1&url=http%3A%2F%2Fwww.yachtsurvey.com%2Fstructuralissues.htm&ei=U9w0SumCC4e6swOx5e3YDg&usg=AFQjCNETM6lTXl_zyvEGGAOQoyNeVIcnwg&sig2=c-K6Az9DHze0WkygvQGxRA

[lymanwhite]

'Whatever one attaches to foam "unzips" with alarming ease.'
Plus when you 'thunk' balsa is sounds really good!

[Stumble]

Boston,

I am a big fan of David Pascoe as well, most of his articles are well thought out and informative.

The article you linked had to do with the rott of balsa in a cored hull, which for quality builders is a big no-no, and has been for many years. The reason is that any surface below the waterline will absorb water over time (except metal hulls). It is a property of both fiberglass and wood, of course this water migrates to the core where it works its destructive magic. This is why any boat that uses a core below the waterline is questionable in my eyes, no matter what the core material is. Proper building techniques only start to core the hull a few inches above the waterline, meaning that the osmotic intrusion of water stays away from the core.

This thread started about wether balsa was a bad material for cores, and in that regard I would say that it isn't. But both foam and balsa are subject to damage from water intrusion when used as a core material. balsa from rot, foam from hydrolic erosion.

Parallel to this conversation is if a core is a sensable design for marine construction, and this seems to be what you are raising. I think like any other construction method there are trade offs that have to be made. A core makes the boat lighter, stronger, faster to build, and cheaper. However it must also be protected against water intrusion and could require significant repairs if it is damaged.

Compared to solid wood construction however the proper use of cored construction still leaves a much easier and cheaper boat to maintain. Just think about it like this... A core MAY need to be maintained over the years as water intrudes and degrages it's structual integrity. A wood hull WILL need to be maintained yearly as one board then the next rotts away.

If you feel comfortable already working in wood then it may be nice to think that it would be easier to detect problems with a wooden hull, but a few days spent banging on fiberglass will teach you the sound of a rotten core and delamination. Then it is just a process of regular inspections

[Jimbo1490]

If using foam cores, in my experience, one ought core areas rather than the whole part (hull). I don't agree that foam is all that cool - I've done some backyard destructive testing of a manufacturer/repair facility's scraps. Whatever one attaches to foam "unzips" with alarming ease. This doesn't happen with balsa. I like how a couple of guys trying to destroy a piece of balsa cored poly seriously have their work cut out for them. Also, an impact damages more area with foam that I know. Also, you may not call it "rot" but "turn to mush" it does. I have some interior decks made of some stiff, red foam on my boat, tho. They are dry, obviously light, strong enough, and completely stable.
Tangent: I hung a typical Boston Whaler on the shop wall for more than a year and water was still draining out of the foam from the two 2" holes I cut. I don't know which of the little problem areas the water got in at but, to me, this is unacceptable.

I think it's important to remember that the 'foam-in-place' foam constriction method pioneered by Boston Whaler uses a grade of foam that nobody would even consider in a one-off build; it's strictly a production OEM deal. The poorest grade of PVC foam you could buy from a composite materials supplier will be superior to the foam BW uses. You'll not find a book on marine construction that recommends using expanding foams as structural cores either. They are recommended strictly for insulation and flotation.

Jimbo

[Jimbo1490]

. This is why any boat that uses a core below the waterline is questionable in my eyes, no matter what the core material is. Proper building techniques only start to core the hull a few inches above the waterline, meaning that the osmotic intrusion of water stays away from the core.

Remember that there is no such thing as osmotic intrusion into epoxy resin; this is a fault strictly of polyester resin.

Jimbo

[Boston]

interesting twist
we might want to all agree on what osmosis is before we can effectively discuss it

http://captkonz.tripod.com/marineprofessional/id19.html

describes the process as it effects epoxies reasonable well

oh
some woods are extremely rot resistant
one of the best in this regards Ive been looking into a lot recently is black locust
fence posts of old growth BL have survived 100 years buried in the wet soils of the southern us

use of black locust wood has been for fence posts which, due to flavonoids in the heartwood, can endure for over 100 years in the soil.
http://www.hort.purdue.edu/newcrop/proceedings1990/V1-278.html
White Oak is none to shabby at resisting decay either

biggest draw back is that both are heavy
cedar is light but takes up only slightly slower than your prom date at the punch bowl

[BeauVrolyk]

interesting twist
we might want to all agree on what osmosis is before we can effectively discuss it

http://captkonz.tripod.com/marineprofessional/id19.html

describes the process as it effects epoxies reasonable well

oh
some woods are extremely rot resistant
one of the best in this regards Ive been looking into a lot recently is black locust
fence posts of old growth BL have survived 100 years buried in the wet soils of the southern us


http://www.hort.purdue.edu/newcrop/proceedings1990/V1-278.html
White Oak is none to shabby at resisting decay either

biggest draw back is that both are heavy
cedar is light but takes up only slightly slower than your prom date at the punch bowl

Boston,

Thank you for attempting to get folks to use the terms correctly. However, this article as a number of terrible errors in it. Osmosis is a technical term with a very specific meaning, which is misused terribly by the marine industry, including this guy. For a good definition that most folks can understand see:

http://en.wikipedia.org/wiki/Osmosis

Also, the article claims that a boat ends up being "70% resin and 30% glass". This is certainly NOT the case of any high quality boat building I am aware of. Perhaps some chopper guy beater boats are this bad, but I would have been fired if I'd ever had the glass fall to less than 60% of the panel weight when I was building boats.

These errors make me question the entire article, even though I can't check on all of it.

B

[Jimbo1490]

Boston,

Water does not attack epoxy resin, no matter how long the exposure. Polyester is highly water resistant, but it is not 'waterproof'. Eventually with very long exposure time, water does indeed attack and break down cured polyester resin to some degree. Epoxy resin is waterproof. The type of blistering described on the page you referenced does not happen to cured epoxy resin.

Jimbo

[Boston]

I think you are right about that water does not "attack" epoxy in the sense that it degrades it
thats what UV is for
but neither is epoxy perfectly water proof
or I should say vapor proof
Im looking for a few articles that I read a while back concerning water vapor and various materials
I think epoxy was on top with 95% impervious
and shellac a close second with something like 90%
but dont quote me on that cuase I need to find the articles before Ild stand by those figures

gortex is a good example of how a material can be water proof but not vapor proof
the epoxy may be fine in contact with liquid water although if it breaths BP-A a relatively large molecule
it is likely to be able to breath water vapor
a relatively small molecule

Beau
feel free to critique that article
Ild be real interested to hear what your assessment would be

only experience I have with fiberglass is fixing dings and dents
( which as it turns out I am particularly good at )
one of the industry reps of extruded fiberglass told me the mix is 60/40 glass to resin
and those guys were diffidently going for an optimal mix for the lightest construction

[BeauVrolyk]

I think you are right about that water does not "attack" epoxy in the sense that it degrades it
thats what UV is for
but neither is epoxy perfectly water proof
or I should say vapor proof ...snip...

Beau
feel free to critique that article
Ild be real interested to hear what your assessment would be


Boston,

I don't believe, from looking at the West web site, that Epoxy lets vapor or liquid water through. Indeed, West Epoxy is used to make GRE (Glass Reinforced Epoxy) tanks for all sorts of terrible chemicals in addition to water and water vapor, so I really can't see how it could allow vapor though.

Regarding the article and glass to resin ratio's, here's a manual from the West web site:

http://www.westsystem.com/ss/assets/HowTo-Publications/Vacuum-Bagging-Techniques.pdf

Go have a look at section 4.2.2 where it describes the ratios of 65% glass and 35% resin. Also, these are resin's applied to "dry" glass. Now that we buy PrePreg (which is glass which has the resin already applied) it is possible to get much higher glass to resin rations. PrePreg is glass that typically has a resin that is hardened with either UV exposure or heat in an oven, not a separate chemical hardener. It comes already soaked in resin and all you do it put it where you want it and heat it up.

It's a lack of knowledge of these sorts of things that makes me doubt the article. Sure, back in the '60s and '70s we used to build boats from buckets of resin mixed with hardners that were then squished into the glass with a putty knife or brush, but that was decades ago. Boat builders don't do it that way, even if home repair folks do. There have been massive advances in construction technologies and folks who are writing papers they think are authoritative need to keep up with the times.

Beau

[Jimbo1490]

Boston

It has to be even more waterproof more than that. All the epoxy resin spec sheets I've looked at (and I looked at a LOT back in the day :D) showed less than .1% weight gain (water intrusion) after a one week boil. I never saw a specification with a more precise number than the "less than .1%" figure, which may mean that the actual precise number is even lower than that, but the standard test method does not make it practical to quantify amounts smaller than .1% . It is basically zero for all practical purposes.

UV is not an issue; we can deal with UV by covering or using a UV stable formulation. Yes they make those; what do you think they use to attach Chattahoochee stone? It's clear epoxy designed to hold up outdoors. They use this same family of epoxy resins to make tile grout and stone facia adhesive, all for outdoor 'engineering grade' use in constant sun. The Epon 8000 series was advertised for this.


Jimbo

[Boston]

well as I said
dont quote me on that
still
it seems the logical thing to do if your after an heirloom piece to use materials that are seriously rot resistant and sacrifice some of the initial ease of maintenance or construction

Balsa apparently has some good qualities and some bad in this regard

something Ild be curious about is if the varying thermal expansion qualities of different materials found in the laminate are not a primary cause of delamination rather than impact or overloading the surfaces
those hot and cold cycles have a real habit of tearing stuff apart over time
and most of the time boats are just sitting in the sun

[BeauVrolyk]

well as I said
dont quote me on that
still
it seems the logical thing to do if your after an heirloom piece to use materials that are seriously rot resistant and sacrifice some of the initial ease of maintenance or construction

Balsa apparently has some good qualities and some bad in this regard

something Ild be curious about is if the varying thermal expansion qualities of different materials found in the laminate are not a primary cause of delamination rather than impact or overloading the surfaces
those hot and cold cycles have a real habit of tearing stuff apart over time
and most of the time boats are just sitting in the sun

Boston,

Here in San Francisco there is a very small change in temperature. No more than 10 or 15 degrees. Our balsa boats do just fine. You may be on to something.

Beau

[Jimbo1490]

Balsa as discussed in this thread means end-grain balsa core. Because of the architecture of the construction, thermal expansion is not going to be much of an issue, even with very divergent Cte between core and skin. The Gil flooring used in many commercial aircraft uses balsa core with aluminum skins. That has to be a pretty divergent Cte, yet those panels are known for their durability and damage tolerance. One very good thing about balsa coring is that it maintains very good compressive strength even after a crush failure. This is not at all true of honeycomb, and less true for the rigid foams.

Jimbo

[Stumble]

Boston,

Wood expansion and contraction may have something to do with delamination, but the amount of expansion is pretty minimal. The linear coefficient of thermal expansion properties of eng grain balsa is in/in/degree F - Longitudinal 10.5X10^-6 compared to 20X10-6 for a difference of 9.5X10-6 in/in/Degree F. Written out this is .000,009,5 inches difference per degree F. If we assume that the materials were originally layed at 70 degrees that gives a normal service range of maybe 70 degrees up or down. So the lagest material thermal expansion from 0 to 140 would be .0000665 inches. While measurable this is such a small difference I can't see it causing delamination on its own.

[mark775]

I felt guilty as I was writing the Whaler thing, Jimbo. That's why I wrote it as a "tangent", because I didn't think of it as a core but wanted to point out the example somewhere. You caught me. I would have thought it was a "non-expanding" type pour-foam though.
In the land of freeze/thaw cycles here, I have seen these dang things weigh...I don't know, as much as one can imagine a high dollar boat full of wet mush weighing. Still "UNSINKABLE" - Yay!!! Cored construction, in general, is given the supreme test here.
Boston, that time of year here. Four black cod longliners showed in Homer this week, gettin' ready to go out west, I 'spose. The average age was a spry EIGHTY!
32468
From the Time of Czars
and still making a living

I'll try to get a pic tomorrow of all four - Not all as pretty as the Polaris, not all schooners, but on one of these guys, you are sung a song to sleep and sleep well in anything I have seen Mother Nature dish out. Steel is the only thing that can compare, IMO, and IT doesn't talk you down from your fears and it sweats on you.

[tauruck]

Too many people working with materials that have very little or no experience. You do a lousy job so you blame the material. Nothing wrong with Balsa.

[Boston]

Tauruck
Im inclined to agree

sorry just in from the club so not in the best of condition to elaborate
but ya
craftsmanship is key

cheers
B

[AndrewK]

I was under the impression that no resin is 100% water proof including epoxy which is approx 98%. After reading the discussion here I decided to check the data sheets that I have.
SP Ampreg 22; hardener depended range is 1.4 - 2.3% water absorption for ambient cure. This reduces to 0.6 - 1.9% if post cured 16hrs at 50'C. No test methods stated.
Hexion RIM 235; at 23'C for 24hrs 0.1 - 0.5% & 7 days 0.2- 0.8%.

Also another article I read quoted 35% loss in inter lamina shear strength for a polyester thin laminate after 12 month water immersion, 10% loss for epoxy laminate.
And we are discussing thin laminates used in cored construction.

Regarding laminate resin : glass ratios, dont confuse weight and volume fractions.
There are plenty of cored boats built by hand lay-up with stitched fabrics at 50:50wt resin:glass ratio, this is only 31% vol glass and 69% vol resin.
Even a very good infused laminate at 70%wt glass 30%wt resin is 50:50 by volume.
Also there are many production boats with solid laminates incorporating CSM and woven roving these will only have 20 - 25% vol glass the rest is resin.

Andrew

[Boston]

mark
would love to see some picts

[tunnels]

Just had a read of the Australian catamaran magazine "Australian Multihull World" may/June 2009

Our mate, Derek Kelsall had an article in there, where he advocates banning balsa as a core material.

He states there are a plethora of articles on the internet on the "wet balsa problem".

I understand most end grain balsa is encapsulated in either Vynelester or Polyester, which is not as waterproof as Epoxy. is that the problem?

Is it really that bad - what have people found ?

What a load of rubbish . All and any problems will be from Bad workmanship not the fault of the balsa to get water in a core the glass has to have porous patchs and that means not enough resin and air bubbles etc in the glass , Is that good or what !
Just remember 90 percent of glass problems are caused by Bad workmanship and 10 percent is from bad choice of materials and how they are used !!:P :P

[BeauVrolyk]

Originally Posted by rwatson
Just had a read of the Australian catamaran magazine "Australian Multihull World" may/June 2009

Our mate, Derek Kelsall had an article in there, where he advocates banning balsa as a core material.

He states there are a plethora of articles on the internet on the "wet balsa problem".

I understand most end grain balsa is encapsulated in either Vynelester or Polyester, which is not as waterproof as Epoxy. is that the problem?

Is it really that bad - what have people found ?

Three comments on Mr. Kelsall's reported article:

1) There are a "plethora of articles on the internet" claiming aliens have landed on Earth, Kennedy was shot by the CIA, whatever you like. This is NOT a credible argument for anything. I am stunned that any journalist, other than a FOX news reporter, would use the "Internet" as a source for anything. In the article, has Mr. Kelsall done his own research rather than writing an article about what a bunch of keyboard pounders are saying on the Internet?

2) While there are certainly problems with Balsa core boats, it is a tiny fraction of all the boats built utilizing this technology. Do people consider banning houses built of brick because a similar percentage have failures, no they write regulations that specify the way in which brick houses are to be built. Kelsall's logic is again flawed in the extreme.

It is trivial to build a balsa cored boat that will last for decades. There are literally thousands of them floating around all over the world, did Mr. Kelsall cite any percentages of boats with this problem, do a survey, provide any real data?

3) Do you REALLY want the government to decide what materials are to be used in boat building? Good God man, they'll decide everything should be built in double bottomed steel or something similar because it's safest. One should be REALLY careful about asking any government to regulate the design of anything.

Perhaps you could post the article or send a link to it so we could examine Mr. Kelsall's logic directly.

BV

[rwatson]

Perhaps you could post the article or send a link to it so we could examine Mr. Kelsall's logic directly.

I tried finding a copy on line, but with no luck. I dont feel like typing in the whole transcript, but the same sentiments can be found on his website

http://www.kelsall.com/images/articles/thecoreofthesandwich.pdf

"Get rid of the Balsa TimeBomb"

and the rest.

Re letting the government dictate boat building material - I know I wouldnt leave it to boatbuilders alone. Its not like they are paragons of quality.

[mark775]

"I know I wouldnt leave it to boatbuilders alone." Okay, Mr. "Unsafe at Any Speed", We could open a can of worms here!

[rwatson]

"I know I wouldnt leave it to boatbuilders alone." Okay, Mr. "Unsafe at Any Speed", We could open a can of worms here!

I dont know why ?. Just a quick check of a large percentage of boat problems discussed in these forums, from rotting plywood to bad welds in steel, to engine problems .... goes on and on, making fascinating reading.

Try it - you'll love it!

[apex1]

"I know I wouldnt leave it to boatbuilders alone." Okay, Mr. "Unsafe at Any Speed", We could open a can of worms here!

Please do´nt ! We already have much more than enough idiotic overregulations in the market.

Regards
Richard

[rwatson]

Please do´nt ! We already have much more than enough idiotic overregulations in the market.

Regards
Richard

Yeah - professional boatbuilders and designers will aways provide a reliable, solid product free of defects

http://www.beneteau235.com/f235_rudder.htm

[apex1]

Surely not. What a statement. But new regulations, rules and penalties have proven to fail either. But thats on tax payers expense, so the wealthy do´nt mind!
Regards
Rcihard

[rwatson]

Please do´nt ! We already have much more than enough idiotic overregulations in the market.


Name your two most onerous (relating to boats)

[tunnels]

When i started in the glassing industry in 1972 we used Balsa all the time and never ever had a problem . Working in a Boat building company making one complete boat a week and laying lots of balsa throughout the boat . We never had wet balsa prblems ever , we never got osmosis, we never had the things that are associated with bad workmanship . Faded gel coat was never and issue gel coats were always brushed as no one knew anything about spraying or pressure pots . It seems as we have aged ,the NEW materials have changed and the workmanship and workers have never learned as time has gone by .
I have just in the past month returned from Korea and the company was having every problem in the book with a new Gelcoat they had desided to start using on a new boat . Pointing the finger at the product , the poor rep was saying no it a users fault . I totally agreeded with him and asked him to go that i would sort the probems . Every item that had beem made was take out of the moulds and everything bare to start again . After one day and a wet film thickness gauge they leaned how to spray to the recomended minimum thickness and when the items were finished NO PROBLEMS !! Also to mix gel with the resin on small hatchs and the like to give it colour and not having to paint the insdie as it was already white all the way through to the gel coat surface .
Balsa is the same, people trying to take short cuts and use materials that are not recomended . Sticking balsa down in wet glass is ok but has to be done properly and there are trick associated that no one has taken any notice to learn !!.
Me, i always use a slurry mix formulated over a period of time by the guys i worked with ,We never have loose blocks , we never have air pockets , we never have to fill any where ,we have never had any probelms at all!!!! Articals in book are usually written by people that have never come from the factory floor and spent hours and hours working in a glass shop , they will have learned every bad method there is and never thought and learned from theres or others mistakes .
For the past 10 years i have spent my life travelling to differant countries to simply show people how to change there new ways and get back to basics and THINK about what they are doing . The problems never change and are the same where ever i have gone . :P :rolleyes:

[mark775]

CFR. ABS. If you deal with these or other certifying agencies, you will quickly weary of being told what to do by someone who doesn't know as much about it as you do. Just having to know how to look up the applicable reg and bear in mind that these regs are superceded by equivalencies, or "intent" at the certifying inspector's discretion is onerous. Actually applying regulations by the book when some of these are out-of-date, mal-appropriate, or just plain dumb is an exercise in frustration.
Just two? How about two thousand? How about demonstrating two instances where a government took over something and it got better... Amtrak? Postal Service? Housing? Banking? Medicine?
32748
"I'm here to help"

[apex1]

Name your two most onerous (relating to boats)

Well, the banning of all our old, reliable, fat displacement engines due to "environmental" hazards! The Industry as the merchant shipping companies do´nt have to worry for the next decade, but tha tax payer has to. I am sure that all boats in Europe do not pollute as much as ONE of the VLCC does, per annum.
Today we have to play with the Nintendo generation of Diesels, which may be sufficient for the average boater, but not for a true passagemaking vessel.

Do´nt get me wrong I am one of the first to sign environmental friendly contracts, but the main polluter first, then the poor rest.

The new MCA related standards of crew accommodation, the sheer nonsense.
Again, do´nt get me wrong, but a 7m² single cabin as a minimum accomm. regardless of the size of yacht is a bit far away from being sensible.

Just two, you asked for that.

Regards
Richard

[masalai]

Caveat emptor, and pay attention when building by doing your own supervision. Do not ever trust the salesman - even when you are holding the gun and squeezing his testicles...

rwatson, on toilet treatment & pumpout but no places to pump out http://www.thecoastalpassage.com/outhouse.html ... Registration of boats Federally (Australian registration) and State registration with NT free, and Qld a right pain in the hip pocket.... Insurance compliance in Queensland and our loveable customs/quarantine/immigration http://www.thecoastalpassage.com/gov-shame.html http://www.thecoastalpassage.com/lifeandpolitics.html all good reads though:D:D:D

[BeauVrolyk]

I tried finding a copy on line, but with no luck. I dont feel like typing in the whole transcript, but the same sentiments can be found on his website

http://www.kelsall.com/images/articles/thecoreofthesandwich.pdf

"Get rid of the Balsa TimeBomb"

and the rest.

Re letting the government dictate boat building material - I know I wouldnt leave it to boatbuilders alone. Its not like they are paragons of quality.

Thanks for the URL, I read the article. He is certainly proud of his boats, and I must admit to be more than a little amazed that he actually claimed to have practically invented building PVC cored boats. But, the arrogance aside, he is making a large number of claims utterly unsupported by anything other than his own opinion and a few stories.

No experimental data was provided, other than a reference to his "personal" test of sloshing bare foam or balsa or whatever around in water. This is something that has very little to do with the environment in which the core will be used. The "testing" of cell structures was without controls, without any descriptions of the parameters, without comparisons to controls.

I am someone who deals with scientific testing of materials all the time. Unfortunately, that's not what we have here. I'm afraid that this document shows nothing but opinions. Granted, these are the opinions of an experienced person; unfortunately, there are equally experienced people on the other side of this argument.

[rwatson]

When i started in the glassing industry in 1972 we used Balsa all the time and never ever had a problem . ...
Balsa is the same, people trying to take short cuts and use materials that are not recomended . Sticking balsa down in wet glass is ok but has to be done properly and there are trick associated that no one has taken any notice to learn !!.
Me, i always use a slurry mix formulated over a period of time by the guys i worked with ...
For the past 10 years i have spent my life travelling to differant countries to simply show people how to change there new ways

So basically, unless they have spent 10 years in the industry, no-one should be using balsa because it requires so much "trickiness" to make it work ?

[rwatson]

without controls, without any descriptions of the parameters, without comparisons to controls.

I am someone who deals with scientific testing of materials all the time. Unfortunately, that's not what we have here. .... there are equally experienced people on the other side of this argument.

yes, I think you have it nicely 'encapsulated' there (old Balsa Pun).

Like Tunnels, dont trust anyone's opinion until you have tried and tested it personally.

It always seemed stange to me that "the whole boatbuilding industry is useing it" but "it should be banned". Seemed that there might be a bit of middle ground there somewhere.

[Boston]

I may not know Jack about fiberglass construction methods
but I do know all about woodwork
you cannot legislate quality
Ive seen guys sporting all the tools, eons of experience and certainly look the part who I wouldnt trust to build an outhouse
on the flip side Ive seen guys who looked like they just got out of the penitentiary who were some of the best carps I ever worked with
hell you should see the hillbilly's I guy my raw lumber from
your not going to influence either type much with a few new rules

I definitely follow code, however, consider it a minimum standard and not always exactly the bulls eye, Its often advantageous to exceed code and I make it a point to do so regularly

the threads an interesting read though

in a nut shell
any further regulation isnt of much use if the regulations there already are can hardly be met by the butchers most builders are anyway
whats needed is craftsmanship
although there did seem to be some excellent arguments to be had concerning materials failures
so will be reading along
best
B

[dougfrolich]

This is getting re-DICK-u-lous.
I think we should ban stupidity,-- immediately--because IT is dangerous.

[Alan M.]

Just had a read of the Australian catamaran magazine "Australian Multihull World" may/June 2009

Our mate, Derek Kelsall had an article in there, where he advocates banning balsa as a core material.

He states there are a plethora of articles on the internet on the "wet balsa problem".

I understand most end grain balsa is encapsulated in either Vynelester or Polyester, which is not as waterproof as Epoxy. is that the problem?

Is it really that bad - what have people found ?

I read this article too.

I was very unimpressed by Derek Kelsall's contribution.

All the other kit boat designers were simply stating the positives of their build method, whereas Kelsall spent the majority of his time criticizing other designs, criticising anyone using different materials from him (including epoxy), and casting doubts over claimed build times from other designers.

The rest of his time was spent claiming credit for virtually every advance in boatbuilding that has ever occurred.

Frankly, I doubt the claims HE makes for build times. All you hear about are his workshops - where there might be a dozen people working, and the huge job of building a perfectly flat and airtight table which is longer than the boat is never mentioned.

[rwatson]

Frankly, I doubt the claims HE makes for build times. All you hear about are his workshops - where there might be a dozen people working, and the huge job of building a perfectly flat and airtight table which is longer than the boat is never mentioned.

This boatbuilding time thing is an interesting issue. Derek quotes about 4 hours work per square metre for strip planking, which from my experience is about right.

I dont think that building a long flat table from say, melamime covered mdf is a big chore. I hope not, because that is what I will have to do on my next boat. The 'infused' setup scares the heck out of me though

Farrier uses foam in 'baskets' and claims good time results, but sanding and finishing two sides of a foam core doesnt sound really fun.

I am getting the impression that hand laying over balsa is fraught with problems based on responses to this article.

I wonder if there has actually been any 'scientific' studies of boatbuilding methods and the times involved. I have read a lot of 'I think that...', but has anyone ever kept logs, and detailed records??

[masalai]

Just look at the number of well built balsa cored boats that are still around - If the advantages and disadvantages are acknowledged and a boat built, in the understanding of the measures and techniques that must be used to build a durable boat then no problems - Look at that thread "...do a lap" http://www.boatdesign.net/forum/showthread.php?t=21058 and http://www.woodenboat.com/forum/showthread.php?t=73818 as well as http://www.flickr.com/photos/mmm_beer/tags/tincan/ in a home made alloy cat, have a laugh then critique "all alloy builds on that example" as only another fool would... The essence is to know your material and work appropriately....