Transom Replacement - Small Fiberglass Boat (Gheenoe)
Written by Travis Fickett, 2026-09-22
Introduction
Rebuilding the transom on a small boat is a pretty common request so as an example we're going to talk about my Gheenoe I recently replaced the rotten wood transom on. On smaller boats like the Gheenoe often the transom is made of a couple of laminated pieces of plywood. You have a couple of options for replacing it, generally we prefer using Coosa board because I never want to replace these again once done. Plywood would certainly be cheaper but it is difficult to keep sealed and not rotten for the next 30 years.
On my boat I opted to replace the stair step plywood with one piece of Coosa over the entire back inseated of recreating the plywood as it was.
You'll need a few tools to accomplish this project, I used an oscillating multi tool, grinder and jig saw to cut the transom board.
Procedure:
- Remove old wood transom, and grind off old fiberglass and gelcoat.
- Template Coosa board and cut to shape
- Install new transom board into putty or mat with clamps.
- Laminate over new transom board onto hull sides.
- Finish as desired.
Details:
Transom Drain
I installed a new brass tube into the coosa transom and sealed it with Bostik 920 type Urethane adheasive.
Here you can see the transom with the old wood core removed.
Making a template out of paper for the Coosa board.
Cutting the Coosa board out from a sheet with the template, we used a jig saw.
The Coosa board has been installed into two layers of wet mat and putty has been filled in around the edges to make them flat.
Installing the final structural layers of fiberglass to bond the top of the Coosa.