How To Repair Transom Fiberglass

Fiberglass Transom Repair

Step 1: Before beginning removal:

Have measurements of all the parts around the transom; fiberglass thickness of exterior peel, plywood thickness, inside transom pare thickness, stringer location, stringer thickness, etc... You will want these measurements as a reference afterwards.
Before removing anything structural yous must have the hull properly supported. Removing stringers and/or a transom with out properly supporting the hull tin can consequence in a deformed or "oil canned" hull. The best back up is a bunk trailer with additional blocks under the keel and transom.

Step 2: Proceeds access to transom skin and core:

The next step is to gain access to the transom so yous can remove the rot. Each boat volition be a little different, sometimes you will have to cutting the deck, the top cap, side walls or all the higher up, removal of cap is sometimes necessary in society to achieve the entire inside of the transom.
The next step in the removal of the one-time plywood core and inside fiberglass transom pare. Yous volition demand access to the entire transom plus at least 12" up the side and lesser of the boat. If you postal service pictures at our forum we can advise you on the all-time places to make these cuts to avoid time consuming fairing work (hiding seams).

Transom before wood removal

Transom after grinding sides

Y'all must completely remove the old plywood core. A reciprocating saw, grinder, hammer and chisel, flat prybar are good to accept. If you accept an air compressor, a minor air hammer with a wide apartment blade is a good investment. Be careful to not inflict damage to the exterior fiberglass skin.

Transom before wood removal

Once the old plywood and putty are removed, make a template of the transom using cardboard, doorskin or inexpensive plywood. You lot will use this template to cut your transom cadre and also to draw/cutting the wide fiberglass pieces that will go between the new plywood and outer skin.

Installing the new core:

your new plywood core should exist the same total thickness every bit the original plywood. If y'all are changing anything about the blueprint of the transom (college engine mounts, enclosed transom, bracket, etc...) you may need to make adjustments to the thickness of the core.
Mail service details on the forum and we can help with this. Most powerboat transoms are made by laminating multiple layers of i/ii", 5/eight" or three/iv" plywood.
The new core tin be either made in ane piece, then bonded into the hull, or you may laminate ane layer at a time into the hull. It is generally easier to laminate the core outside the boat and bail it into the hull one time, simply on very large transoms this may not be possible due to weight and difficultly in handling.
To laminate 2 pieces of plywood, first coat the faces of the plywood that volition be glued together with united nations-thickened epoxy resin. This is a thin coat of epoxy, just plenty to let the confront of the forest soak up a niggling epoxy. While this epoxy is however tacky, mix a batch of epoxy glue. Using a notched spreader, apply even amounts of epoxy glue to each plywood face.
Now clamp the 2 layers together using weights, clamps, or dry wall screws (temporary, removed after glue cures). Do not apply too much pressure! Epoxy is gap filling and extremely strong, y'all want the epoxy to remain between the plywood layers. Once the epoxy begins to clasp out the sides evenly it is time to stop the clamping pressure and wipe off backlog epoxy glue that squeezed out. Fasco Epoxy Gum

Before final glassing of cadre:

The gaps between your new core and the sides/bottom of the hull will need to be filled with putty. Afterwards filling the gap, using the same putty, you volition make a fillet all around the joint between the core and the hull. A fillet is a radius of putty that allows fiberglass to brand a plow effectually an bending. Fiberglass and ninety degrees exercise not fare well together. All inside corners of transom should take a round fillet.

Tabbing unto the hull bottom and sides:

The adjacent step is the tabbing of the transom core to the sides and lesser of the hull. For tabbing, use 1708 Biaxial fiberglass tape. This tape is stronger than traditional woven tape due in part to its cobweb orientation (45/45 degrees). It is also very easy to work with, wets out hands, and is epoxy compatible.
Use multiple layers of the 17 oz Biaxal tape, the amount will depend on the particular boat. Nosotros highly recommend doing the fillet and glass tabbing all in ane piece of work session, this is called working "wet on wet" and results in a much better lamination quality with less clean up and no grinding/sanding between layers! Just be carefull of heat build upwards if your putty is thick in some places. Biaxal Tape

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