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A well-functioning transom ensures that fiberglass boats, especially outboards, can support the weight of the motor and other equipment. Boats with wet transoms encourage wood rot, which further affects the performance of the boat. A wet transom loses the ability to support mounted engines and will permit water to seep into the interior levels of the boat. To fix this problem, discover how to reinforce a fiberglass boat transom with the step-to-step guide featured below.
Step by step guide on how to reinforce a transom
Items you will need
- ½-inch marine plywood
- Jigsaw
- Sanding machine and sanding discs(#000)
- Circular saw
- Epoxy(two parts)
- A drill and corresponding bits
- Epoxy paint(acrylic)
- Paint brushes
- Gel coat
- A roller
- Fiberglass material
- Hammer
- ¾-inch Chisel
- Caulking gun
- Measuring tape
- Screws and screwdriver
How to rebuild a transom on a fiberglass boat: Estimated time to complete the task
Replacing or repairing a boat transom is no easy feat as it is a labor-intensive process. Many boat owners would avoid repairing the transom if it didn’t affect the boat’s performance. Reinforcing or repairing a boat’s transom can take anywhere from a couple of days to a couple of months depending on the size of the boat.
Things to do before removing the transom
If it’s your first time learning how to repair boat transoms, it is important to be organized to avoid missing a step. First things first, ensure the boat is hoisted on a secure platform such as a trailer. Working on a stable platform ensures your safety, and avoids issues such as an ‘ oil canned hull.
If you have an outboard motor, you’ll need to remove all the equipment attached to the transom to give easy access to the inner core.
Having gathered the things you need for reinforcements, it is vital to take some measurements. Taking measurements ensures any replaced parts fit perfectly and you do not cut through unwanted sections. The measurements you require include the plywood’s thickness, the thickness of the fiberglass skin, and the location of the stringer.
You might also want to place a plastic cover on the floor to make cleaning up afterward easier.
Cleaning the surface
Boats have different designs, thus you may need a cutting tool to slice through the external fiberglass skin. Using a circular saw is an easy way to do this, but be sure to adjust the height of the blade because you don’t want to slice through the internal fiberglass wall. A hammer and chisel will assist in prying off the fiberglass skin without incurring too much damage.
Once you expose the core, it is time to remove the plywood. Again, the hammer and the chisel come to the rescue because typically the plywood is stuck to the surface. You need some muscle to carry out this work, especially if your boat is large.
If the softcore is in fairly good condition, it might be hard to pry the plywood off using a hammer and chisel. Using solvents such as acetone will soak inside the plywood and loosen the epoxy to make removal of the softcore easier.
If the core is not fully rotted, products such as the TotalBoat Clear Epoxy Wood Sealer can be of use. Such epoxy products seep into the dried wood and prevent further damage/rot to the wood.
Use the Transom as your template
Now that the plywood softcore is successfully removed, it’s possible to use the transom as a template to measure new pieces of plywood. Using the transom as a template allows for accurate measurements to fit the design of the boat in case there are any curves.
To do this, you need a glue gun and door skin plywood that is easily accessible at the hardware store. Take the door skin and cut it according to the length of the section you are working on, making sure to connect each piece with some hot glue. The idea is to create a makeshift frame/outline that you can remove and use to cut the plywood to fit the exact size of the transom.
This is especially useful when the top and the bottom of the transom are uneven. You can make these frames for the top and bottom sections of the transom to ensure both areas receive even coverage.
New Core Installation
You must cut enough plywood to fit the transom snugly before mixing a durable epoxy like The Epoxy Store Clear Resin. Some prefer to cut the plywood and stick them together creating one structure, and others find it better to stick one plywood to the transom at a time.
If you choose to stick one piece of plywood at a time, you need a sander. The sander is vital in roughening the texture of the transom surface to create an even surface and allow the epoxy to adhere well. You might also want to sand the surface of the plywood to prepare for the epoxy application and remove sharp edges for a better fit.
Mix the unthickened epoxy, apply it to the interior transom surface, and add the first sheet of plywood. Let the epoxy cure before gluing on another layer of plywood. You can use clamps to ensure the plywood is firmly secured to the transom surface and each other.
Apply the epoxy and give it finishing touches
After the epoxy cures, you can remove the clamps and fill any gaps with more epoxy to create a tight seal.
It is essential to sand off any leftover epoxy from the edges that might prevent the securing back of the fiberglass skin. None of the plywood should be sticking off the edge of the transom’s edge.
Make sure that by this time, you have the holes where screws need to go in marked and drilled before securing the fiberglass skin. When this is done, apply epoxy to the plywood, and use a roller to flatten the fiberglass material over the surface. Keep applying epoxy between each layer of fiberglass and use a small thin roller to remove any air bubbles before the resin completely dries.
Cut off any excess fiberglass material and sand any uneven edges. Remember to seal the top of the plywood with epoxy, let it cure and sand it down to create an even surface. Cover the top with epoxy and secure several pieces of fiberglass material including the sides of the transom to tie everything up.
After the fiberglass layers are cured, fill any gaps with marine putty, sand the surface down, and prepare for the gel coat. Cover the transom with a few layers of acrylic paint and you are done.
Warnings
In this process, you will come into contact with chemicals and dust, you don’t want to expose your respiratory tract to dangerous particles and fumes. Wear a mask to avoid inhaling the dust or any toxic fumes. You can also wear protective eyewear to prevent dust particles from entering the eyes while sanding.
Tips on how to replace a transom on a boat
Now that you have most of the information on how to fix a transom on a fiberglass boat, here are a few more helpful tips
- Use waterproof marine-grade putty such as the TotalBoat Fixwood | Marine Grade Epoxy Putty to fill any gaps and sand it down, ensuring the surface is even.
- Epoxy tends to dry fast; therefore, do not mix it until you need it. By this time the plywood sections should be ready for attachment.
- A caulking gun is convenient for filling voids, and it is easily accessihttps://geni.us/RELKnLlble in paint stores.
- Always cut the fiberglass material oversize to give room for error. You don’t want to cut an exact piece and have it shrink once the epoxy dries.
- Using a small thin roller in between applications of fiberglass to remove any bubbles that may weaken the structure over time.
- Ensure to sand the surfaces even to avoid an uneven-looking transom.
FAQs
How do you measure a boat transom?
For this, you need a measuring tape, a grease pencil, and someone to help you. With a friend holding one end of the tape measure, pull it across the width to measure the taffrail’s length. This is basically the width of the boat across the stern.
Then measure from the center of the taffrail down to the bottom of the transom where it joins the boat. This measurement is crucial for determining the length of the shaft, especially on an outboard boat.
Also, set the edge of the tape from the taffrail’s outer edge inwards to the inside edge. This measurement is crucial in choosing the appropriate width of the outboard motor.
How thick should a boat transom be?
Typically, on an outboard boat the thickness is 1.5″, but some boats could go up to 2″. You can always take these measurements before you clean out the softcore to avoid any apparent flaws.
Final Thoughts
Boat transom reinforcement is not something you can skip if you want your boat to support the weight of the engine. Considering that it is a detailed process, you must take your time to do it well or risk spending more money on future repairs, which will be expensive. The good thing about such boat repairs is that they don’t occur often, once it’s done, you can enjoy using the boat for a long while.
