Transom Questions

I picked up a 57 Crestliner on craigslist that I'm restoring/converting to a usable fishing boat. The transom was rotten so I'm rebuilding it, but I have a few questions for those more experienced than I:

1. I'm using plywood that I intend to treat with spar urethane. The outside requires a thickness of about 1 inch so I'm gluing together two 1/2 inch boards. Am I supposed to glue them together first and then treat with the spar or the other way around?

2. Am I supposed to put another piece of spar treated wood on the inside of the boat? It seems that this can go either way and I haven't found a definitive answer yet.

Over the course of this project I will have many more questions for this forum, but for now I just want to get the boat solid enough to put on the water. You guys have been a great inspiration so far and I can't wait to share my work with you all!

I'd seal them both on both sides with the spar, then take some 100 grit sand paper and rough up the wood where you're trying to glue to, then glue them togeather with some 3m 5200, then leave it clamped togeather for about 3 or 4 days to fully set the 5200 cause the stuff takes forever to cure.

When i did my floor in my boat i think i might have put too many coats on the plywood because the first two coats of paint would just flake off and the sealer made the wood almost look like it was a polished hard wood floor thats been waxed, and it was way too smooth, so i ended up roughing it up with a wire wheel then reapply the paint, and i'v got about 4 or 5 coats of oil based on it and it's hard as a rock now and sticks like glue.

I'm about positive I did it wrong, but I figured gluing them made them hold together, but what the heck, I was bolting the darn things together as it was! Probably better to, in effect, laminate them together for a good water seal, but I didn't.

Jim seems to have done it appropriately.

On putting another piece on the inside, well, my old alumacraft came with such, infested by carpenter ants. So, I chose to, in no small part because I would be taking the outboard on and off, and wanted the wood to protect the aluminum hull, and perhaps reduce any vibration that the working engine might create.

However, a caveat, I'm just an old guy screwing around with a project. This site is home to some real craftsmen, and experienced water-men. Never rely on what I say without checking with grown-ups.

Have fun.

Couple different ways to do things, including coat first and glue second. I think I'd prefer to glue first, as that's going to give you the most "level" surface for gluing the two boards together. For glue, use a water proof glue such as Gorilla glue or Titebond III. Give plenty of time to dry and outgas for the best bonding per the instructions. Long term, you'll be glad you did.

Using either glue listed, laminate the two sections of plywood together and "dry fit" into the area you wish them to be in. Drill any holes you need to drill through the boards for bolts, etc., making sure to drill slightly over size so you can coat the holes. Once done with the dry fit, then coat the newly made transom with the Spar Urethane, including the holes you've drilled. Make sure you coat the edges of the board real well.

An improved alternative to using the the spar urethane is epoxy resin.

Normally the wood on the inside is the transom and a piece is put on the outside to protect the aluminum when the motor is clamped on. Do you have any pictures of the transom area you can post?

Do not use Gorilla glue, it expands as I learned the hard way on my build. Glued two pieces together and clamped, glue still expanded between the boards to the point where it not only bubbled out but made it so I could not fit the boards in the transom. The recommendation to me was Titebond III, wish I had known that first! :shock: Could also be that I went for the belief that while you only need a little, a lot just has to be better, which was not true with the Gorilla Glue - Good luck on your build!

lckstckn2smknbrls said:

Normally the wood on the inside is the transom and a piece is put on the outside to protect the aluminum when the motor is clamped on. Do you have any pictures of the transom area you can post?

Click to expand...

X2 on this .... would love to see some pics.

I think its a preference thing regarding order of gluing and sealing. Either way should work if you take your time and make sure to get very good penetration with the urethane. I've used it on a transom before and its pretty easy to work with. I did two thin coats and then a really thick one. I don't know if that is correct, but it felt right and worked fine.

One thing to remember, its a good idea to drill any holes BEFORE sealing the wood .... and make sure to work the urethane into the holes.

Good luck!

Thanks for the advice and the replies! I have decided to treat both parts, then glue (with Titebond III), then drill, then mount. Then I fish.

First pic is of the outside of the boat. I'm not done cleaning off the old stuff, but I'm getting there. I made a cardboard cutout of the transom so I could have a stencil for the real one. That made it really easy for me and took a bit of the guess work out of the tricky measurements.



The second pic is the inside of the transom. I think my plan is to only put wood on the top part on the inside and use washers and 5200 to properly seal the bottom parts. Does that sound like a good plan?



Also, there are obviously a lot of holes that have been drilled in the back of this boat over the years. Should I plan on running a bolt through all of them and sealing them with 5200, or can I use the structurally important holes only?

I love this forum so much and I'm sorry I don't have much more to add to it. Hopefully by the time I'm done with this project I'll be able to help other folks out like you are helping me. My wife was really not sure about buying and converting/re-doing a boat until I showed her this forum. She agreed that there is enough of a community to get my sorry butt through this project, and for that I thank you all!

That is a really interesting transom design ... it certainly isn't the most common design, but looks stout that's for sure.

I think you are on the right path with everything you have mentioned.

About the holes .... you definitely want them filled one way or another. Running SS bolts through them with SS washers and 5200 is a very good way to seal them up and tighten up the whole transom. Use bolts that are exactly the same size as the hole. Tighten them up nice and snug, but don't over-tighten as they will sheer off. Lock nuts with the nylon inserts are great.

If you don't want that many bolts, you can patch the holes using one of the many good marine grade epoxies or have them welded.