Builders' Forum Archives
Re: Luan is underated
Posted by Laszlo on Oct 19, 2004
Lee's point is a good one, though I interpret it as an argument for glassing both sides of the hull, rather than as a testament for luan.
I really like the CLC Chesapeake series to the point where I showed the most sincere possible appreciation - I bought a kit. That said, the design is somewhat of a transitional hybrid. It appears to have started out life as a glass reinforced thin plywood hull and has been slowly becoming a wood/glass composite hull ever since.
In the first type of boat, the wood carries virtually the entire structural load and must be of high quality. Doorskins will definitely be inferior in this application.
In the second type of boat, the wood is a core for the composite structure. All the strength is in the outer layers. The core simply separates the outer layers to provide stiffness. In this case, the wood quality can be relaxed. It still needs to have good center plies with no voids to to resist compressive loads and to avoid forming local stress concentrators. It also still needs to have sufficient glue strength to resist the shear forces that will try to break the outer layers of the wood from the inner ones. For these reasons I would feel comfortable going from BS1088 okoume to BS6566 meranti or even selected exterior meranti on a small, low bending radius composite boat, but I wouldn't use doorskins, at least not the ones I've seen at the local hardware stores.
If you use the boat lightly, or are willing to do regular maintenance, the glass reinforced plywood style will work fine. The boat will be light, but you should plan on using the more expensive wood.
The wood/glass composite style is best for people who give the boat rough use and/or want to reduce maintenance. In this case, you may be able to use a less expensive wood, but the money you save will go right back into epoxy and glass. The extra glass will make the boat a bit heavier, but it will be much stronger. BTW, for max strength, use biaxial (not woven) glass.
There is no one right answer, which is why wood selection always turns into a religious discussion. It's all a matter of trade-offs and it's up to each builder to pick whichever makes most sense. Just be sure to be aware of the true costs and benefits, and if you've built a cheap 1 season disposable for use on a mill pond, don't take it into the Greenland surf.
In Response to: Re: Luan is underated by LeeG on Oct 19, 2004
- Re: Luan is underated by LeeG on Oct 19, 2004