Boat transom Materials

I purchased a Duranautic Offshore 14' Aluminum boat reciently. It had a rotted plywood transom backing inside the al hull.
What are the thoughts of using WHITE High Density Polyethylene Cutting Board Material for a permanent not rot transom fix?
I have a 14? ga sheet of aluminum I plan to use to "sandwich" it to the transom (stern).

I need a 1 1/2 filler, I have thought of 2, 3/4 pt plywood bonded and painted with epoxy resin. This will end up being too thick with that coating.

I need something that willnot wick water and rot. Plastic cutting board material would seem Ideal. H2onxs

Re: Boat transom Materials

I used two sheets of plywood as you mentioned. I treated mine with a mixture of turpentine and linseed oil like is in deck coatings, but just enough turpentine to get the linseed oil into the wood. Didn't use a coating as if it had an opening somewhere it would void the reason for coating.

Mark

Re: Boat transom Materials

While I'm not familiar with your boat, I take it the existing transom wood is exposed and that the max HP rating for your boat is relatively small.

Do you have a plan for fastening the HDPE and aluminum sheet to the hull? If you can get it all sandwiched firmly together with no wiggle or slop it ought to work well. Off the top of my head I'm thinking maybe a bunch of stainless bolts every 4 inches or so sealed with 3M 5200.

EDIT - What thickness HDPE are you talking about? When I said it should work I was assuming we're talking about something substantial, like 1 to 1-1/2 inches thick.

Re: Boat transom Materials

I havwe thought about using cutting boards instead of Starboard for marine applications due to expense. However, I would worry about the cutting boards flexing. I have also seen them fall apart with age, water and sun exposure (bait cutting boards).

I'd go with the plywood. If you have to change it again in 10 years its not like it's a big deal. But for that reason I wouldn't use a permanent seal on the bolts. Also I wouldn't seal the bottom of the board. I would rather have wood able to breath, drain and dry out than think I can do anything that is 100% water tight--no such thing.

These are my thoughts for your basic 14' boat. A transom restoration on a larger boat would go a different route.

Also I have heard here that pressure treated wood should not be used in aluminum boats.

Re: Boat transom Materials

I think it would be way too weak... If it flexed it'll trash ur transom

if the ply is too thick, use a sheet of 7/8 and a sheet of 1/2, epoxy em together and glass em up to your final thickness

Re: Boat transom Materials

Welcome to iBoats!
NOT a good idea. No UV protection, No structural integrity. Arauco Plywood (NOT pressure treated, it will "Eat" your aluminum boat) that is properly prepped and maintained will last for 20+ yrs. I'd stay with it. 3/4 and 5/8 with 7.5oz EGlass and epoxy. Laminated will yield almost exactly 1.5" transom. It will be there for your Grandkids as long as you always predrill any holes and coat them with epoxy.

Re: Boat transom Materials

^^^ X2
Definately stay away from PT. It likes aluminum a little too much and will cause corrosion. 2 layers of 3/4 epoxied together works for most of us.

Re: Boat transom Materials

x3........ Most folks here prefer one of two methods for replacing their floors and transoms. 1.) use non-PT exterior grade plywood and coat with epoxy for strength and water resistance, then paint for UV protection. or 2.) use non-PT exterior grade plywood and coat with polyester resin, then fiberglass (resin alone is insufficient) no need to paint, but most do. I think you'll find that a lot of folks prefer the epoxy method. It's a bit quicker and easier, but does cost a bit more. Be sure you only use Stainless Steel hardware, well coated in 3M 5200, to attach the transom to/through the hull. Check out some of the Starcraft resto threads and you'll see the process.