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More specificly, has anyone ever tested point fracture strength on same panel thickness materials?
Example: +-45 deg. 3/8 mahogany (total to 3/4), cold molded,resin'd sealed.
VS.
Standard layup with 1/2 or 3/4 balsa core
I know the latter would be lighter,more expensive and not technically qualify as a wood boat. I'm really curious about penetration strength, say small log or debri at speed as well as general dynamic forces at speed.

You may find this a little hard to believe but wood is actually lighter. This is a fact that the fiberglass boating industry has spent a lot of time misdirecting the buying public in an effort to present their plastic products in the best light. But one only needs to look at the racing industry to see the difference. Virtually all the formula 1 & 2 boats are made of wood as are the unlimited hydros.

Also, here's some food for thought. Let's suppose that you have a piece of fiberglass of a given size and a piece of wood EXACTLY the same dimensions. Throw them both in the water and see which one floats and which one heads for the bottom.

A number of years ago, Bryant boats in Knoxville started touting the fact that their boats were 100% wood free. The seat bottoms and cushion backs, everything in the boat was made of fiberglass or some other kind of plastic. Of course, they could say that, with no wood in the boat, there would be no rot. Personally, I really like their boats and for the consumer that simply refuses to take care of a boat, and there are a LOT of those people out there, this type of boat would probably be the best buy. But I got to noticing that the size of the stringers was absolutely MASSIVE on these boats. This was because they HAD to be in order to compensate for the loss of strength once the wood was taken out of the equation.

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Isn't it amazing!! The person that never has the fortitude to pursue his own dreams, will be the first to try and discourage you from pursuing yours.

The real important part of composite construction is the density of the inner core and the glass used. While the inner core of form creates a hull shape, the cores are only as good as the skin which incorporates the two components to create a sea worthy hull. Most all cored hulls also depend on interior structures which must be engineered to achieve strength but not to create unnecessary additional weights, which wipes out the reason for building the hull using such materials as the Balsa cores. While numerous race boats have used balsa and like products, they also use Kevlar on the surface to eliminate the needs for heavy glass work to make up for the loss of rigidity for impacts too.


Added expense is also incured and additional time in the initial setup is generated too. In many of these discussions some folks seem to also have a phobia about wood these days which sometimes stems from some past experiences or from their neighbors also whispering in their ears their own notions and experiences of a hull that experienced neglect causing some of the issues of rot.

Pound for pound in the boats that the homebuilder builds here, plywood still creates the best of all worlds long term too in the area of repairing punctures and dings. Patching is a breeze and hiding an area thats been repaired is even easier.

Here here! Mike is absolutely correct! One of the biggest problems is that many so called fiberglass boat building manufacturers use wood in their designs under the glass. But the real prob is that they do their layups with polyester instead of epoxy. Polyester and wood don't really get along all that well but it's certainly cheaper than epoxy especially when mass producing the boats. But a few years down the road, the wood and polyester start seperating, the wood gets wet and the rot begins. .....and they BLAME it all on the wood and NOT the choice of inferior materials.

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Isn't it amazing!! The person that never has the fortitude to pursue his own dreams, will be the first to try and discourage you from pursuing yours.

Polyester resins in their post cure stage unlike the epoxies creates a brittle surface under repeated use which also allows dampness to enter making the boat heavier and the neglect from the silly notion that a fiberglass hull is forever and needs not to be maintained even on their gelcoat finishes and is the best all the way around. There are many production boats that have gone all composite cores but costs jump way up. A 16 foot liteweight flats skiff cost about 40 grand for a completed boat built with super modern materials.

These guys did some pretty sophisticated strength tests on fiberglass covered plywood panels.

http://www.thag-o-mizer.net/index.html

David Gerr 'The Nature Of Boats' has two chapters on the strengths of different materials. Very good reading .Wood is probably the best building material when the strength to weight ratio is taken into consideration.

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I also have Gerr's books. Yes, he has done research on the subject.
I can attest that my 25' plywood boat with engine is lighter than the 19' fiberglass hull that my motor came out of. I know because I weighed them both.

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Thanks fellas, wow. Great response's from all. I intend to build nearly entirely from cedar, western red to be more precise. Topped off with a veneer of mahogany, in strip plank form. Bottoms will be painted of coarse. Any paticular part of the forum to post a build thread? I'll be beginning in Jan .

Having a forum dedicated to builds only has been disscussed in the past, in the mod only forum, but as of yet there is no specific spot to do this. I guess just find one of the forums that is closest to what your doing and post it there.

try whichever category applies under the design heading

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Boat building can best be defined as an endless series of
tragedies obscured by the occasional miracle, followed by a good bottle of beer.

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