Transom Replacement

I have an Old Town square back canoe and the transom has rotted. Marine grade plywood is difficult to find in this area, and I only need two 18"x12"x5/8" pieces.

I’ve looked into using regular plywood and sealing it with a marine epoxy. The smallest resin/hardener size available would cover 10x what I need and cost ~$75. Seems like a lot of waste.

Does anyone have any suggestions for transom material, or replacement in general.


A friend repairs boats for a living and
transoms are the most common repair. He uses exterior plywood and seals it with polyester resin.

One Question
You say you need two 18x12 pieces of plywood. That makes me envision that the two pieces bolt to the hull, with one piece on the outside and the other on the inside. If that’s the case, I see no reason to spend much on materials when it’s only a 10-minute job to replace the wood in the first place. If you really want to seal the wood, just use wood primer and exterior paint, which you can buy in such small cans that there would be very little waste (for what it’s worth, porch enamel is very durable).

I replaced the wooden backing plate of the transom of an aluminum Jon boat about 20 years ago. I “needed” one-inch-thick plywood for the job, but I was in a rush so I used what I had on hand, and made the backing plate from two layers of 3/8th-inch plywood instead. No paint, no sealer, nothing. It’s still in good shape, and if it ever rots out again I’ll take that opportunity to get the thickness right and use two layers of half-inch plywood.

Thanks for the responses. Yes, it’s a quick fix with one piece inside and the other on the outside. I have Kilz primer and porch enamel. I’m going to go that route and see how long it lasts. If I happen to come across a more durable material in the meantime I’ll make a more durable set for next year.

Thanks again.