Transom Rot

[Jraysray]

What are the signs of a rotting transom or transom rot?

[Conquistador_del_mar]

What are the signs of a rotting transom or transom rot?

Generally, the only visible signs are going to be cracks showing on the transom around the outdrive assembly or the outboard bracket. Most of the cracks will usually be on the bottom end of the assemblies due to the extreme forces of the drive pressing on the weakened transom. It is the interior wood that rots and creates the weak transom. If you suspect a weak transom, wrap a rag over a hammer head and gently tap the transom over the entire surface area. It should sound very solid. You also need to do the same on the interior bilge side of the transom. If it does not have a solid thud, it is probably bad. The rot can be almost anywhere, but it usually starts at the bilge drain hole or any other place where water has started to leak into the wood. The rot can vary anywhere from very localized soft spots to an entirely rotted transom which can be vacuumed up after cutting away the interior fiberglass from the transom. If you still have any doubts about the transom integrity, almost any good fiberglass repair shop can tell you by checking it for you. I replaced around 50 or so transoms when I used to do repair work. It is not an easy job, and the entire engine/drive packages must be removed first. I hope this helps. Bill

[olredalert]

-------I have also found that older Merc drives with the cork, or composite gasket tend to take on water around the perimeter of the drive housing. In my case at least the DONZI factory seemingly made no attempt to glass over the drive hole in the transom after they cut the hole........Bill S

[MOP]

I did transom and stringers in my 22 three years ago, it had now visual signs. When I pulled the Alpha gimble the wood was very dark and starting to go soft, luckily one of my best friends was the head glass guy for Hustler. He came down and looked things over, first words out of his mouth was why the hull do the run the wood down to the bottom of the transom. He feels and rightly so that almost all transom rot starts from the bottom up, the water slowly weeps in around the drain plug. Anyway he tore int the job, he said like most all manufacturers Donzi also did not isolate the ends of the stringers from the transom wood. By allowing the stringers to be in direct contact with the transom wood the rot had spread into the back ends of the stringers. After he cut out the stringers and transom wood, he laid out the transom he eliminated the lower V section on the transom wood. When he glassed it in he laid glass down in the eliminated V section until in was 3/4" thick more then enough support for a through bolted drain. After the transom was finished then he went on to do the stringer work making absolutely sure there was -0- wood to wood contact. He said do it right not 1/2 azzed, he said 95% are in fact done 1/2 azzed which amazes him as it simpler to cut things square and can't cost more then maybe $50 more to do it right! With the additional bulkheads and stringer knees I have one of the strongest 22's around, it will handle far more ponies then my mouse motor makes and also live a lot longer.
Phil

[Donzigo]

Last July when I installed new engines, I found rot in the back of the Z-33. Here's a few shots of the repair, if it helps. The others have pretty well explained how to find rot and why it occurs.

Richard

[Pismo]

Why does any builder use wood anymore? It's not needed. The most impressive thing Formula did was take all wood out of their hull construction years ago. Time bomb otherwise.

[wannabe]

Do they build cars to last forever ? They don't build boats to last forever either.

[Jraysray]

Why does any builder use wood anymore? It's not needed. The most impressive thing Formula did was take all wood out of their hull construction years ago. Time bomb otherwise.

Well when I tool the 18C into the shop last week I was moaning about the way the previous owner mounted the k-plane pumps and it hit he and I at the same time.

The bilge has always been wet we we get off the water and I have not found the source.

ROTTEN TRANSOM..... CRAP!!!!!!!!!! We will see. re-locating the pumps soon

[Jraysray]

Does anyone have some good pics of the location of their pumps?

[Jraysray]

Tried to upload a couple no luck. Gotta get a new PC.

[Carl C]

Do they build cars to last forever ? They don't build boats to last forever either. Cars can last just about forever if you keep them dry. I agree with the wood thing although there have been issues with some of the composites used to replace the wood. I think Mastercraft was one of the first to remove all wood and offer a lifetime hull warranty.

[MOP]

Curious about when Formula removed the wood, my last one was a 74 it had wood.

Phil

[mjw930]

Curious about when Formula removed the wood, my last one was a 74 it had wood.

Phil

I don't know if they have, entirely. I did some searches and the phrase that keeps coming up is Pressure-treated Perma Panel. I don't know if that's wood or synthetic and they don't elaborate on their site. I know they started removing the wood from the stringers with their FasTec stringer design in the late '90's but it's been my understanding that up until the late '90's or early '00's the technology for synthetic transoms was giving a lot of boat builders grief.

I'm pretty certain that virtually every high performance builder through the '90's was still using wood cored transoms.

[MOP]

The panel you speak of may be the same stuff that Tommy (Rust&Rot) put me onto a few years back, it is guaranteed for life. I used some pretty neat wood in mine when we did it over, 7 ply pressure treated marine plywood. It also is suppose to never rot, I will never find out to old to wait!!!

[olredalert]

-----We have gone completely wood free on the Spitfire. It is now all closed-cell technology with a vacuum bagged transom as well. The work is going forward..........Bill S

[Madcow]

There are some pretty detailed pics of trasom repair and trim pump relocation on this thread.

http://www.donzi.net/forums/showthread.php?t=47197