Re: 3/4" plywood for buil

Posted by Bob Santore on Jan 2, 2007

Yeah, I agree with Ron. Plywood might not be at all suitable in this case. You didn't mention what wood and what dimensions are specified in the plans, and that is a critical piece of info. Solid wood frames are often designed to be a reasonable width based on material availablilty (and still strong enough when solid hardwood is used), but plywood could be very weak when ripped into pieces with similar dimensions. This is especially true for the typical 3 or 5 ply building-supply 3/4" plywood you might find at a lumber yard.

I would not be comfortable substituting fir for oak either.

Then again, are these frames a temporary mold that you bend planks around (but will not ultimately be part of the finished boat)? In that case, plywood might be just fine (if this is the case, I would guess these would have to be some old plans, but I have seen cases where solid frames were specified for a station mold).

I suspect he is also right that you might be able to find the type of wood the plans call for locally if you get out of big-box stores. I know that is true around here - I can get almost anything I want from small mills/lumberyards but can only find softwoods, popular, oak, and cedar in the bigger yards.

I would also add that the real person you should be asking about a major structural substitution is the boat designer, if that's at all possible.

What design are you considering (and why?).

The forum for WoodenBoat magazine might be another good place to ask these questions, and you might even be able to find people there that have built the design you are considering.

- Bob

In Response to: 3/4" plywood for building by Ron on Jan 2, 2007


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