Replacing a transom on a 1989 Starcraft Islander.

[rolmops]

This thread is sort of a continuation of a coosa discussion.
I will try to make this a log of transom rebuilding
So after deciding not to use coosa, the next logical choice is marine grade plywood. I considered types of pvc and polyethylene but those did not really appeal to me. The decision to use marine plywood is mostly bases on me having build wooden transoms on 4 aluminum boats. A starcraft Holiday, an eighteen foot Sylvan, A 19 foot Starcraft Islander and a 22 foot Islander.
The previous 22 foot Islander transom was build during covid and having to take care full time of my ailing wife. shortcuts were taken and time and material saving measures were also taken. Most of it based on the thought that this rig is a trailered boat and will never be in the water in a slip for the season. I did not even properly seal the wood but put on six layers of deck paint instead and the plywood itself tuned out to be some soft junk.
However, things changed and the boat ended up in a slip for most of the season with me worrying about rot and leaks. Next season she will be back in a slip. It is just so much easier.
I will be replacing that transom with a new one that will be properly built and does not require much maintenance.
Yesterday I went out and bought 2 3/4 inch thick 4 by 8 foot 10 ply dense AA marine plywood. The density is important so there are no imperfections inside the wood and the glue used is impervious to water. The transom will be 1.5 inches thick.
Money wise, compared to coosa board goes like this. A 4 by 8 1.5 inch thick coosa 20 grade board costs $562 before shipping (from FL to NY). coosa 26 grade is more like $680. The marine plywood 2 3/4 inch boards were $426 without shipping cost because I picked them up 5 miles from home.
So far so good.
Next comes the process of gluing the boards together and here comes my first question. How do you good people prepare the wood for gluing and what type of glue do you use. Please let me know so I can use your experience and prevent mistakes.

 

[redneck joe]

You can ask a mod to change title of original thread and continue there or to close it and continue with this new one just to keep everything clean.

For your question im not the correct person to answer however here is what I do when wandering into uncharted territory. Go to Google, type in question followed by the word iboats. It will give you an overview with diff options. Then scroll down a bit and there will be a section with threads from iboats. Run thru those, think about the diff things then come back and formulate your question based on all that. Sometimes you also learn the buzzwords for the project like CSM, PB, etc.

Have fun.

 

[rolmops]

You can ask a mod to change title of original thread and continue there or to close it and continue with this new one just to keep everything clean.

For your question im not the correct person to answer however here is what I do when wandering into uncharted territory. Go to Google, type in question followed by the word iboats. It will give you an overview with diff options. Then scroll down a bit and there will be a section with threads from iboats. Run thru those, think about the diff things then come back and formulate your question based on all that. Sometimes you also learn the buzzwords for the project like CSM, PB, etc.

Have fun.

Thank you very much!
That little google trick you just mentioned took me right to all the correct information.!

 

[redneck joe]

Good deal. You still may have questions like which glue is best for your application, experience level, availability, budget etc but at least you have a starting place.

 

[roscoe]

I used Titebond II waterproof wood glue.
Got it all clamped up.
Then drove 1 1/4” deck screws into it to help hold it tight in the center where my clamp couldn’t reach

 

[Pmt133]

I did the same thing as above, but with titebond III. I removed the screws after and drilled them out larger so the peanut butter would have more bite to adhere to. Not necessary on an aluminum though.

 

[redneck joe]

I used Titebond II waterproof wood glue.
Got it all clamped up.
Then drove 1 1/4” deck screws into it to help hold it tight in the center where my clamp couldn’t reach

rolled on and/or notched trowel?

 

[MikeSchinlaub]

Every transom we do, whether in a glass boat or aluminum, goes like this.

1. Cut and dry fit each piece.

2. On what will be the rear most piece, mark every bilt hole, cut out, and thru hull location with a sharpie.

3. Cut a piece of csm to go between each layer of wood. Remember to account for about an extra 1/8 inch of thickness for each piece.

4. Glass them together, screw them together using drywall screws . Dry fit a couple screws first, or else the top piece will slide all over the place. You will be leaving the screws in, this is why it's important to mark everything.

5. This bit only applies to aluminum boats. Resin the back and sides. Once cured, flip over and resin the front and sides again. The sides will absorb a lot of resin from the first time.

A few extra things.

You might be thinking that you should use stainless to screw the boards together, but it's really a waste of money. If water can get to the screws to make them rust, then it's also getting to the wood and causing rot anyway.

Before glassing, hand sand all of the edges. Those little bits of wood on a rough cut edge turn into a thousand little razor blades once the resin hardens.

With an aluminum boat, you will likely need to grind the top of the transom once it's installed, because it sits at an angle. Just resin the wood again and it's fine. You don't want to try to dry fit the all of the pieces in at the same time, they WILL get stuck, and it sucks to get back out.