Fiberglass Boat Transom Repair and Replacement

The crew is hard at work removing the old rotten fiberglass boat transom on this 33′ Formula.

Sometimes this goes well and sometimes not so well. The Captain estimated eight to twelve man hours to remove the old transom and it took 12 man hours to get it done. The factory boat transom was two 3/4 marine plywood laminated together. The owner’s choice of new coring was our Michigan Composites 3/4″ density 24# are Fiberglass Materials Catalog #TS48750-24 known as Tuff-Stuff. Michigan Composites Tuff-Stuff Marine Board is made of rigid, structural polyurethane and is available in selected densities to replace wood in boats. Tuff-Stuff Marine Board possesses qualities superior to many competitive products available to the boat building industry to day. But it comes with a price tag of $231 for a 4’x8′ sheet x 2 =$462.The owner on a tight budget said build the new transom of marine plywood. Labor runs close on either material so marine plywood it is!

Jerry, our grinder, is cleaning up the inner side of the outer fiberglass boat transom skin removing the old plywood transom completely. This is a very important part of the boat transom repair job! As it ensures a good bond for ARJAY CORE BOND 4001 Fiberglass Materials Catalog #ARJ-CB and the new boat transom board to the fiberglass boat hull.

The fiberglass boat hull transom surface is then ready for the Arjay Core Bond 4001 putty to be applied. ARJAY formulates its Core Bonding Compound with premium polyester resins resulting in high tensile and flexural strength. Its high bonding strength provides an excellent bond between the core and laminate. It is suitable for all coring applications and is compatible with all popular core materials including balsa and PVC foam. This material provides a high strength bond between the boat transom board and the boat transom hull and will make a sound fiberglass boat transom repair.

The Captain then applies Arjay Core Bond 4001 putty. The Captain uses red tinted MEK to catalyze the ARJAY 4001 to ensure good mixing of the MEK hardener.  Next is resin treating the new boat transom board with General Purpose Polyester Resin while cutting fiberglass Fabric to laminate the new boat transom board. Two boat transom boards are sandwiched together with a 1 1/2 ounce fiberglass mat between the boards. 3/4″ drywall steel fasteners are run in to marry the two boat transom boards together before the polyester resin kicks. After the polyester resin cures the fasteners are removed and the fastener holes filled with polyester resin. This will create a true liquid screw. The boat transom is now fabricated ready to be installed.