Grind the gellcoat back a few inches all the way around . Bevel the glass a bit and install a few layers of glass .. You could do it after you put the new transom in if you want ..
There are two popular opinions in iBoats on how to fix a transom cut like this one
First one is basically do nothing. The wood of the transom when glued to the skin will take care of "healing" the cut and restore the structural integrity/strength of the outer skin. Cosmetic repair from the outside is all you need.
The second one, is to fix the glass properly. Grind around the cut at least 3-4 inches from each side as well as top and bottom and dish the area. In other words, bevel it so its at deepest in the middle and higher toward the edges. Clean with Acetone.
apply multi layers of 1708 each one is progressively bigger than the previous one until you reach the final layer.
I personally prefer and follow the second approach. I don't like to take any chances. If this is not the transom and the fiber glass will be standing alone, for example a cut in the hull in a place that is not backed by wood, I would repeat the same exact steps from the outside as well.
Thanks guys! I'll go with approach #2.... Just so I understand... From the inside, apply the new transom wood and ignore the damage. From the outside, grind away some gelcoat, apply multiple layers of 1708 (small, med, then larger).
Yep , as DB said if it was a cut that was not backed up by wood you would most definitely want to patch from both sides . You can patch from the inside at the transom also if you want but it,s not really necessary ...
When you install the transom, you'll be using Thickened Resin, what we call Peanut Butter (PB) to glue the wood core to the outer skin. All you need to do is tape over the cut on the outside and when you clamp the transom in the PB will Goosh (is that a word) out into the crack and fill it. You can then do the grind, bevel and layers of glass repair on the outside. She'll be good as new. You can learn a lot from this members transom install...http://forums.iboats.com/forum/boat...irius-total-gut-and-rebuild/page9#post8512409