My 208 has bulging around the bang cap. I’ve seen videos of transoms being rebuilt from the inside to preserve the outer fiberglass hull. The process is accomplished by cutting the top deck cap aft of the fuel tank (thereabouts). Is it “better” to rebuild the transom from the inside or from the outside (which seems to be the more classic process)?
Transom rebuild from inside or outside?
- Thread starter Savdriver
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Hookup1
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I'm just finishing up the rebuild of the transom on my 268 Islander. Inside vs outside depends on if the stringers are involved with the transom damage. I suspected string damage but they were "capped" with glass and were fine.
Initially I was going to do the transom myself. Planned on doing it from the inside with all epoxy repair. My Yamaha dealer tells me he finds a lot of bad transoms when he goes to repower. He uses a particular shop to do all his transom work. This shop does transom replacement from the outside with vinyl ester resin in almost all cases. Depends on what they find.
I worked with them to investigate and then went with an outside rebuild with initial Coosa board set with epoxy. The remaining layers of Coosa board, re-skinning the transom, eliminating the bang cap and final finish were vinyl ester and gel coat. Hull is AwlCraft 2000 custom color spray being finished this week. Transom "skin" was re-used but it has to be carefully cleaned up and prepped before finishing. The final repair will be invisible.
After seeing what they uncovered and how they do the repair it was clear that their approach (outside) was the right choice.
Committed this weekend to rebuilding my transom. Been watching it for 10 years. Finally time. Some flex on starboard side. Cracking under rub rail. Swollen transom under bang cap. Cracking around hold down u-bolt.
Both engines electrically/mechanically disconnected from the boat. Four bolts on each engine hold them in. Got steel shipping frames from Robbie at Bluewater to hold the engines while I do the reconstruction work. Replacing plywood with Bluewater Coosa Board. Stringers suspect too.
Both engines electrically/mechanically disconnected from the boat. Four bolts on each engine hold them in. Got steel shipping frames from Robbie at Bluewater to hold the engines while I do the reconstruction work. Replacing plywood with Bluewater Coosa Board. Stringers suspect too.
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SkunkBoat
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So long as your transom is completely flat across, you can do it from outside. It seems all Gradys are flat.
Leaving at least 4 inches all around. Never cut to the corners/bottom or you are screwed.
It is MUCH easier from the outside.
Some boats have angles in the transom. You can't just cut the skin and add flat replacement plywood/coosa.
By doing these from inside, you maintain the original shape of the transom. I did a V20 from inside using pourable Carbon-core.
Here are some videos.
V20 transom part1
V20 transom part2
I suggest you determine how bad the rot is. Since you are willing to cut the transom, you might as well drill a few holes in the transom to see if you hit solid wood, no wood, or mush. (don't drill through the inner skin 
).
A moisture test with the right tool and someone who knows how to use it can tell a lot. Tapping the hull with a soft faced hammer can also tell a lot.
If you are lucky the damage may be limited to a isolated area around the bang cap. In the not so lucky case, there could be lower damage and damage to the transom to stringers. That would be a much larger job if the stringers are rotten. Access to the inner transom skin and stringers is very difficult in that hull
).A moisture test with the right tool and someone who knows how to use it can tell a lot. Tapping the hull with a soft faced hammer can also tell a lot.
If you are lucky the damage may be limited to a isolated area around the bang cap. In the not so lucky case, there could be lower damage and damage to the transom to stringers. That would be a much larger job if the stringers are rotten. Access to the inner transom skin and stringers is very difficult in that hull