How To Reinforce A Fiberglass Boat Transom – Easy Steps From Experts

Transoms on boats tend to last for decades. After that, you will have to replace it. In the meantime, though, you might want to reinforce it so that it is strong enough for your applications. Now, this task is easy and should not require a professional.

If you are new to the DIY world and are afraid to navigate on your own, this article is for you. We shall walk you through the entire process with easy to understand steps.

How To Reinforce A Fiberglass Boat Transom – Simple Guide

Reinforcing the transom requires some care because it is slightly messy and can give rise to toxic fumes. So, make sure you wear your safety gear and assemble all the necessary items.

Here’s What You Will Need

  • Acrylic epoxy paint
  • Two-part epoxy 
  • Jigsaw
  • Reciprocating saw
  • Sander
  • Sanding disks
  • Marine plywood
  • Screwdrivers
  • Paint brushes and paint roller
  • Fiberglass cloth
  • Measuring tape
  • Wood chisel and screws
  • Caulking gun
  • Gel coat

The Method

Starting Steps:

  • Check how thick the transom is and use the screwdriver to remove its top rail.
  • You can remove the fiberglass core and wooden parts using the chisel and hammer.
  • Remove the outside of the fiberglass skin using the reinforcement saw. You can put this back later.
  • Measure the void’s dimensions at the stern.

Measuring And Placing The Plywood:

  • With the reciprocating saw, cut the marine plywood according to the measurements.
  • Cut enough number of sheets based on how big the void is. 
  • Pick up the sander and sand the fiberglass inside. Do the same with the first marine plywood sheet.
  • Prepare the two-part epoxy and apply it with the paint roller. You should mix it only when you are ready to use it. Do not mix it beforehand.
  • Make sure you cover every surface.
  • Then, apply the epoxy at the bottom and on the sides of the hull where you want to place the plywood.
  • Place the first sheet in its place. If there’s extra epoxy anywhere, wipe it off.
  • Repeat these steps with all the sheets.

Working With The Fiberglass:

  • Now, go back to the fiberglass skin that you removed earlier and sand the edges.
  • Apply epoxy to the final plywood sheet and put the skin back.
  • Drill holes in the right places and then apply more epoxy to the edges and the screw heads.
  • Take a fiberglass cloth and lay it on the epoxy.
  • You will need to apply 4 layers of fiberglass, each after the previous one is cured.

Final Touches:

  • After complete curing, you can use a #000 sandpaper for the final sanding.
  • Lastly, apply the paint and let it dry.
  • Then, you can apply the gel coating.
  • If you wish to, you can also wax the surface after the gel dries.


We understand that the steps might feel overwhelming in the first go but don’t worry. Read through them 2-3 times and then plan ahead so that you are not caught off-guard during the process. Remember to exercise caution and have a partner to help you. That should make things easier for you. All the best!

Leave a Reply

Your email address will not be published. Required fields are marked *

Back to top button