Transom material

This has probably been asked hundred times but which type of material should I use on my transom? I'm looking at replacing sometime in the next two months and not sure if I just use a hardwood or if there's a special material.

I used wood on mine and sealed it with 3 coats of Spar Varnish.
BTW welcome to TinBoats.

How thick is the old transom?
Never use pressure treaded wood on an aluminum boat.
Most replacement transoms are made from several layers of exterior grade plywood to match the thickness of the original.
You'll want to use a waterproof glue to glue the layers together. I used Titebond III some used Gorilla glue others use epoxy resin.

So any exterior plywood should be ok?

Any plywood graded exterior is made with waterproof glue. Look for the "X" in the grading ABX, ACX, ADX, BCX, CDX ect ect.

Yep, good advice so far...

......incidentally,, the A in ACX or the B in BCX stands for the smooth (A) finish on the top side...the other side of the board is the C or.... rougher finish.....

The X ,as explained very well above, is the eXterior glue.

I doubt that you need a really smooth A finish for a Transom, but that is up to you.

regards, richg99

Try to use a B grade plywood if possible, it should have no surface voids and if it is BCX then just glue the two C sides together. Most transoms are 1.5” thick so two layers of 0.75” ply work fine. As stated above do not use pressure treated ply. This is probably the cheapest way to go and it will last for years. Also be sure to seal it with several good coats of varnish of epoxy (much more expensive). Any holes you drill should also be sealed with epoxy or varnish too and 4200 caulk.

How do I go about sealing the holes that the ss bolts go thru?

Lots of choices, but 3M5200 is a boater's friend.

richg99 said:

Lots of choices, but 3M5200 is a boater's friend.

Click to expand...

As long as you don't have to ever take those bolts back out. That is some stout stuff. It seals well but it's a little more permanent than I like.

If you are worried about removing 3M5200, just use 3M4200.

https://www.jamestowndistributors.com/userportal/show_product.do?pid=2004

Here's where I'm at with it...

I have this problem now

The thickness of my new board is different

The old wood may have swelled due to not being sealed well.

It's pretty solid and exactly 1" so I think my 3/4 new transom needs to be thicker

Good thing plywood cokes in 1/4 inch size

I agree. It sure looks expanded in the pic compared to the new wood.

richg99 said:

Good thing plywood cokes in 1/4 inch size

Click to expand...

If I get some 1/4 plywood should I bond the 2 together with some type of glue.

I like Titebond III, others like Gorilla glue but any waterproof glue should work.
Does the wood slide in between anything like a knee brace or side supports? Those will tell you what thickness you need.