Transom plate options- which one

[Antoine]

I took my engine off the transom and the piece of plywood that was under the motor mount. As suspected, I had some corrosion going on. One member said I had some electrolysis going on from the salt water and suggested that I replace my engine anode. I ordered an anode for the engine. I took a 4inch grinder with a sanding disk and took down the pitting.
I wanted some suggestions on replacing the mount. I did not want to use plywood as the previous owner did. I thought about using a marine polymer but do not know much about it. Below is the link.
https://www.overtons.com/modperl/product/details.cgi?pdesc=King-Plastic-Starboard-Marine-Lumber-24-x-54-x-1/4-White&i=742829&r=view&aID=601L13&utm_medium=cpc&utm_source=googlebase&s_kwcid=googlepla&cvsfa=2587&cvsfe=2&cvsfhu=373432383239&cID=SHOPPING_742829

My other option is a piece of a aluminum I purchased at the scrapyard. I could use the old plywood as a template and cut it maybe with a sawsaw. I am trying to prevent the electrolysis pitting.

 

[Charger25]

I've got the same deal. Not sure to use plywood as the PO did or go with a aluminum plate. What I would like to do though is make it larger and go the full height of the transom .

 

[Antoine]

The marine polymer is bad idea. It expands and contracts with temperature. I am going to try to cut the aluminum plate and use it.

 

[panFried]

Funny, I just put one on my boat this weekend. I bought a 3/8" thick cutting board from Wally World and cut out a plate. Took the idea from Gillhunters transducer mount. It won't deteriorate and it's BPA free. Click my project in the sig for pics.

 

[Charger25]

The marine polymer is bad idea. It expands and contracts with temperature. I am going to try to cut the aluminum plate and use it.

Just curious as to how you're going to attach it. On my old one, the plywood is bolted at the top with silicone adhesive gluing the bottom below the water line.
I was thinking about doing the aluminum the same way. :-k