Cost Of Traditional Wood Build Vs Various Modern Techniques

A vessel's "cost" has a great deal to do with volume and weight. You pay for a boat like steak, by the pound. This is true for initial cost in materials and time to build it, the equipment to run it, and the haulout and yearly painting costs. If you pick a simple workboat design, no outside ballast, iron fastenings, domestic woods, the per-pound cost is low. If the word "yacht" creeps in, the cost quickly goes through the roof. BERTIE was designed and built to traditional workboat specs and the cost was, and remains, low for the displacement.

 

why does that look like one of Buellers Duck designs

 

OK so here is an interesting question

I hate reusing fasteners
basically I never bother
so if I spend a fortune on these silly bronze screws and they last basically forever whats the point
I need to go in and replace the planking from time to time anyway so why not also just plan on replacing the fasteners as well

nothing worse than struggling to drive some old worn screw and constantly slipping off leaving a gouge in the wood

might as well just replace a cheaper fastening every say twenty years or so than pay for one that will outlive my kids when the planking itself is basically disposable

what say you merry men
is there any sound logic to be had in that last or am I destined to attach $2 of wood with $200 in screws

 

"destined to attach $2 of wood with $200 in screws"

....yep

"I need to go in and replace the planking from time to time anyway"....nice to be able to sinply unscrew the fastener after all those years, knowing they have held her together for you....or do you prefer to be at sea in a gale wondering WTF did I save on those bloody screws....hope they are OK......

 

Well it depends on the maintenance schedule doesn't it. I mean if I know I'm going to be reapplying bottom and checking for water infiltration every few years as well as replacing any questionable planking then would it not stand to reason that the fastener if embedded in epoxy anyway is not generally subjected to sea water.
I realize how difficult it is to actually inspect the planking screws but still its pretty obvious how they are holding up even just replacing one row ( ok plank but we always called it a row )

Im just throwing out an idea on maintenance schedule
the live forever screws are limited by how many times I can reuse them
which in my ex is about once effectively
after that its a pain in the ***

something else I been meaning to bring up is these plastic fasteners used in cold molding
if I'm planking thick as in double diagonal and using epoxy between am I not basically cold molding thick planks and if so then whats the level of fasteners needed from the outside layer. The epoxy holds stronger than the wood so if I attach say the inner two or three layers and only use the plastic fastener on the outer layer which should hold long enough for the Epoxy to dry them whats the point of using the million dollar fastener when its burred an inch deep in epoxy impregnated material anyway

Im just throwing around some ideas for the moment
what I do in the end will likely be completely different from what I am suggesting

B

 

Exactly! If a traditional wooden boat gets somewhat reasonable maintenance, meaning new coat of paint or lacquer and impregs in every 3 to 5 yrs, the hull is gonna last >50 easily. In this case no meaning to use 10yrs cycle fasteners..

 

Boston,

so you have decided to build double diagonal , why not cold moulded instead, it will be stronger (a good thing in a boat), easier to build (more pliable strips) and can use less framing inside (more room).....what advantages do you see in glued double diagonal instead of cold moulding mate?

 

thickness
its a simple mater of knowing Im going to hit a rock eventually. Having grown up on the cape and watched every parent of every kid out there slam a rock at some point or another I am just accepting the inevitable.

My thinking is when I hit that first rock I want to have a reasonable chance of survival and that will be with the thickest hull I could float.

my two cents but Im feeling pretty good about that logic

the boat calls for 1 1/4 planking in yellow cedar and I've added volume by going 10% larger
that extra buoyancy I want to spend in thickness and probably a different planking material

not sure if its doable but I'd love to have 2" of planking on the bottom with the outer and inner of white oak all soaked in epoxy and screwed to the gills all in

 

.....soooooo......cold moulded is not just one or two layers, it is as many as the design calls for, certainly as thick as you desire in two double planks if so desired.

As you well know, plywood is far stronger than planks of wood, multiple layers of veneers are certainly stronger than any wood plank thickness of the same moulding.

 

The particular design and the actual location along a hull dictates the number of layers not withstanding any uniform thicknesses in almost all cases. There are numerous designs that you can bulk up your hull thicknesses in some layers and finish off with thinner more finner woods too that also stabilizes the complete stucture.

 

You're intent on hitting rocks so you go cheap on the fasteners and buy 316 or 18-8 ss screws? But you are careful and don't hit any rocks.....and in twenty years you need to refasten the boat.....instead of never....

It's a trade-off...but is probably your kids or grand-kids problem......

 

I think that statement is a mistake.....plywood is made of wood...how could it be "stronger" than a plank of wood? (round here we call it "tree wood" )

The 0-90 alternating grain structure of plywood lends dimensional stability and puncture resistance, but in tension and compression (say parallel to the face grain) plywood will be considerably weaker than a plank of equal thickness. Because half the grain (half the thickness) is going in the wrong direction, across the load......

The same or better puncture resistance can be achieved with a layer or two of uni-directional or biax fiberglass inside or outside planking.

A cold-molded skin with few (or no) frames will not be stronger (puncture resistant) than 1.25" fir planking on 1.75" by 2.5" bent oak frames spaced 10", with a 1" yellow cedar ceiling inside, and triple 1.625" by 3" fir bilge stringers with lots of 3/8" galvanized bolts holding it all together. The traditional structure can take groundings as everything moves and bends a bit, they were designed to do this. When the point load is removed the structure goes back to it's original shape. Once you bond it all with epoxy nothing will move and the wood will shatter rather than a joint giving.

The cold-molded skin will be stiffer (the hull will bend less), will never rot or grow fungus (done properly), done properly it will remain tight for a long time, it will remain lighter forever, it will be much more expensive in time and materials (eventually killing the builder) and be more valuable in the market place. Every method and material has it's place.....

 

As Tad, said..

I am surprised you made this statement...

 

well that was kinda frightening

ok so my idea to double diagonal and use epoxy as a glue between thus creating basically a thick cold molded type section is actually not more resistive to accidental strikes
if I understand you correctly
thats torture
ok so what do I do to get the best of both worlds
double diagonal not glued ?

I understand the need for "give" in the system, but I thought the epoxy was pretty darn flexible
granted not as flexible as no glue at all but still among glues its about the most flexible

oh well I guess it is I who must remain flexible in the end

I need to pick a fastener as well and this silly bronze seems a "tad" expensive
question is
isnt it overkill to use a fastener that will last a 100 years on a board that will only last 30
B

 

I'd try to avoid mixing methods and stay away of your present problems. Either traditional planking with screws and no glue or modern cold molded/strip planking epoxy biax no screws..
Boards can last easily 100yrs with good care in a well designed boat.