Ply wood repairs...but is it worth it

[Paschendale]

hey guys i was just looking at an old trimaran? it looks like there are slots to attack some outrigger pontoons to the side but anyway thats not the reason im here there are some...major holes and i was wondering about tecniques to repair ply wood i searched plywood repairs but i didnt get much back i attacked some pictures i have more if need be

[PAR]

That boat has more then just holes to deal with. If really interested, you should have a boat carpenter look it over or better yet, if a fair amount of cash is require for purchase, have it surveyed.

[Paschendale]

lol i was planning on getting it for afew hundred bucks and spending a summer fixing it if its posible for me to fix...

[rasorinc]

I won't address if the boat is worth it--just how I repair. Also I am assuming no rot. Use epoxy as the adhesive...
cut the hole or tear out from the outside. First draw an outline of where you are going to cut out on the hull. Make sure that the outline is such that you can make a plug the same size and thickness of the hole. On the inside you want to adhesive a patch that gives you a 3" overlay on all sides of the hole.
This can be done with a lesser thickness ply then the hole plug. If the hull ply is 1/2" you can use 3/8 ply or even 1/4" depending on size for the overlay. Adhesive it well and if it is a bottom hole you can use a sandbag for a weight.

then cut out your plug and adhesive it in the hole using a liberal amoumt of epoxy. If you put a fiberglass tape over the repair then it is better than new. sand off any paint both inside and outside to original wood. Holes are easy--rot is not....
fiberglass is not required unless the hull if fiberglassed.

[Steve W]

Looks like a Searunner 31, size? good boats.The nice thing about plywood is it is cheap and easy to repair,rasorinc has pretty much covered it,my guess is the hull skin is only 1/4".Dont buy junk ply locally,you can get decent bs1088 ply quite reasonably from Noahs in Canada.
Is it worth it? probably as long as it was well built in the first place and you do a good job with repairs and cosmetics these things have very good value.
Steve.

[ancient kayaker]

Is it worth it? Ask yourself what kind of ply went into it in the first place, are the scantlings adequate and who built it?

[nobrows1212]

Man, that trimaran could be a wicked fast, fun gal (other than getting her moved, rebuilt, etc.)! I see PAR, whose commentary I am finding most enlightening, is suggesting boat carpenter inspection or survey-- seemingly always good advice, but if you are adventurous, a few hundred bucks as the start of an odyssey may be a great bargain, especially if you aren't looking at it as a "long term yacht". One thing you might consider prior to buying is to get a shard of that plywood and boil test for four to six hours continuous to make sure the beast is marine plywood! That long of a boil should yield no delamination even with attempt to pry layers with a knife. If someone built that out of exterior ply, turn and run-- nothing will make a restoration/rebuild worthwhile. Also beware-- if there are no spars, sails or hardware, this could be a REALLY expensive proposition to get on the water. Good luck if it is soon yours, and post up some photos as you go!