Re: Transom Repair
Roger,<br /> I have just finished my 3rd rotten transom repair (all freebie boats to repair and sell). On the last one the top was pulled off to get to the rotten floor, stringers and bedlog. It was then that I found a completely rotten plywood transom with some good wood left in spots (which made it a little harder to get out). I used a circular saw to score the old transom and slowly chisel it away from the outer skin which was, by the way, only about 3/16" thick. You need those corners. I'll never forget a buddy of mine finding an intact transom with a new Yamaha 90 OB at the bottom of Lake Lanier here in Georgia. I always remember that when I glass a transom. Anyway, I make a paper template of the shape after scraping, sanding and chiseling (wasn't that bad actually) and transfer it to a sheet of 3/4" AC Fir. <br /><br />I double the ply and glue one piece to the other with epoxy mixed with cabosil. Now, please spring for epoxy. Polyester resins barely adhere to themselves and are terrible glues. Good cheap resin for building hulls but will let you down, eventually, when it comes to repairs. Use drywall screws as clamps around the edges of the two pieces and spaced out in the interior. When the piece cures, remove the screws (you'll fill in the holes later).<br /><br />Now mix up a big batch of epoxy glue, cabosil (fumed silica), and, if you have it, milled fibers to form a mayonaise consistancy glue. Spread it generously across the inside transom skin and across the plywood replacement piece. Set it in place and clamp. Clamping may not be so easy. If the boat is to be repainted, no problem. Drywall screws through plywood scraps all over the transom from the outside into the new ply will prove satisfactory. Don't squeeze out too much epoxy. You'll starve the joint (epoxy loves gaps). If you don't plan to repaint then you'll have to improvise as best you can from the inside. Possibly wedging something between the transom and glued in blocks. Those carpet stretchers that run wall to wall always seemed like an intriguing possibility and can be rented.<br /><br />Now you must tie this back to the hull. I use 9oz. biax tape which I lay into a fresh fillet of thickened epoxy around the entire inside joint where ply transom meets hull. Mix a peanut butter consistancy epoxy mixture of resin and silica with possibly some wood flour to make it stiff and load that into a ziplock bag. Cut off one bottom corner and use it like a cake decorator's bag to sqeeze a 1" bead all the way around the inside edge of the transom filling any gaps with the mixture. Using a the back of a plastic spoon, smooth out the bead to form a fillet. Then take some 4" to 6" fiberglass tape and go over the top of the fillet while still wet. The glass will begin to wet out and get translucent. Using an unthickened epoxy mixture fully soak the cloth with a brush. I then will generally add up to 4 more layers for additional strength. With some of the left over "dookie -smutz" (another word for thickened epoxy) fill in the screw holes made from the clamping proceedures.<br /><br />Now structurally it's done, but I like to soak the ply (remember that in marine grade fir the wood is not waterproof only the glue) in epoxy until a nice shiny layer of plastic has formed, especially on the end grain and in any through holes made where the rot generally starts. <br /><br />Good luck and e-mail me with any questions.
