reelfishin
Captain
- Joined
- Mar 19, 2007
- Messages
- 3,050
I keep reading about all the transom problems everyone has and the many materials that can be used to rebuild them but I have yet to see anyone use or talk about aluminum?
My one boat uses what appears to be stacked, welded aluminum tubing, about 1.5" square, which is glassed in on the outside and partially on the inside. the motor attaches via studs that are attached to an inner 1/2" aluminum plate and there's a smaller spacer plate on the outside to reinforce the transom or to protect the gelcoat from the motor mounts.
That boat is 24 years old and still going strong, I would think that if I had to redo a complete transom, I would most likely copy that set up? I am not sure what the stringers are in that boat, but they are fairly narrow and my best guess says that they are two of the 1.5" tubes stacked and welded to form each stringer.
While aluminum isn't cheap, it's certainly a lot cheaper than some of the alternatives to wood or glass like Coosa board.
Is there some reason why aluminum is not used very often in this way?
While I realize that salt corrosion can and may eventually be a problem, with even minimal care it should outlive me with no problems, it's gone 24 years with no sign of corrosion so far.
I also like the idea of an aluminum plate behind the motor to protect the transom from the motor, while movement there is minimal, it does occur and I've seen numerous boats with an indentation where the motor sits, not that the transom is soft, just that the motor wore away at the gelcoat.
I just pulled the motor off my '73 Starcraft, the 50HP has been on there for about 10 years, and it had an older Chrysler before that. Both were strictly clamp on motors, so the lower part of the transom bracket wore at the hull.
When I replaced the original motor I noticed that the transom had the imprint of the old motor bracket in it so I added an 1/8" stainless steel plate to protect the fiberglass, this helped, but after years of use, even the SS plate has indentations in it. I think some is in part to the marks allowing the plate to flex into the old worn area. I as before, rechecked the transom for any rot, but all looks fine. I can stand my 250 pound self on the lower unit with no flex, and an ice pick test up underneath shows only solid, dry wood.
One thing I do notice is that the wood in the transom is not as thick as the overall transom, in other words, it don't go all the way to the top and the inner side of where the motor clamps is not supported by wood inside, it's only capped with a large aluminum casting. I added an aluminum shim up inside the upper section to prevent the clamps from crushing the top cap or fiberglass. I don't think it's due to age, just a poor design, it appears that the wood in the transom only goes as high on the transom as the lower hull's top edge and doesn't protrude into the deck section which actually is where the motor clamps to. I also considered removing that cast aluminum cap and custom making a piece of wood to fit up inside to fill the upper area of the transom.
What got me thinking was that if I ever had to redo this boat completely, I would most likely make up an aluminum transom and stringer set up, and most likely even the floor supports too, aluminum is light, easy to work with and lasts much better than wood, especially in wet places.
Does anyone see any real drawbacks to such a repair?
My one boat uses what appears to be stacked, welded aluminum tubing, about 1.5" square, which is glassed in on the outside and partially on the inside. the motor attaches via studs that are attached to an inner 1/2" aluminum plate and there's a smaller spacer plate on the outside to reinforce the transom or to protect the gelcoat from the motor mounts.
That boat is 24 years old and still going strong, I would think that if I had to redo a complete transom, I would most likely copy that set up? I am not sure what the stringers are in that boat, but they are fairly narrow and my best guess says that they are two of the 1.5" tubes stacked and welded to form each stringer.
While aluminum isn't cheap, it's certainly a lot cheaper than some of the alternatives to wood or glass like Coosa board.
Is there some reason why aluminum is not used very often in this way?
While I realize that salt corrosion can and may eventually be a problem, with even minimal care it should outlive me with no problems, it's gone 24 years with no sign of corrosion so far.
I also like the idea of an aluminum plate behind the motor to protect the transom from the motor, while movement there is minimal, it does occur and I've seen numerous boats with an indentation where the motor sits, not that the transom is soft, just that the motor wore away at the gelcoat.
I just pulled the motor off my '73 Starcraft, the 50HP has been on there for about 10 years, and it had an older Chrysler before that. Both were strictly clamp on motors, so the lower part of the transom bracket wore at the hull.
When I replaced the original motor I noticed that the transom had the imprint of the old motor bracket in it so I added an 1/8" stainless steel plate to protect the fiberglass, this helped, but after years of use, even the SS plate has indentations in it. I think some is in part to the marks allowing the plate to flex into the old worn area. I as before, rechecked the transom for any rot, but all looks fine. I can stand my 250 pound self on the lower unit with no flex, and an ice pick test up underneath shows only solid, dry wood.
One thing I do notice is that the wood in the transom is not as thick as the overall transom, in other words, it don't go all the way to the top and the inner side of where the motor clamps is not supported by wood inside, it's only capped with a large aluminum casting. I added an aluminum shim up inside the upper section to prevent the clamps from crushing the top cap or fiberglass. I don't think it's due to age, just a poor design, it appears that the wood in the transom only goes as high on the transom as the lower hull's top edge and doesn't protrude into the deck section which actually is where the motor clamps to. I also considered removing that cast aluminum cap and custom making a piece of wood to fit up inside to fill the upper area of the transom.
What got me thinking was that if I ever had to redo this boat completely, I would most likely make up an aluminum transom and stringer set up, and most likely even the floor supports too, aluminum is light, easy to work with and lasts much better than wood, especially in wet places.
Does anyone see any real drawbacks to such a repair?
