Raising transom

[spg]

I need to replace my transom. I want to raise it 5-6 inches so that it is level with the top of the stern of the boat. The motor now sits about 5-6 inches lower than the top. The previous owner used solid oak for the transom and it cracked, so he cut it down below the crack. The transom is 60"by 20." The motor is a 15 hp. I'm going to start with 2 sheets of 3/4 ply to get the same thickness as it is now. Should I reinforce both the inside and outside with a alum. plate or just the outside?

 

[architorture]

It's hard to say without seeing a pic of your transom but the strongest option would be to have it welded. I just had mine welded for a long shaft motor and am very happy with the results.

It went from this

To this

 

[mmf]

I need to replace my transom. I want to raise it 5-6 inches so that it is level with the top of the stern of the boat. The motor now sits about 5-6 inches lower than the top. The previous owner used solid oak for the transom and it cracked, so he cut it down below the crack. The transom is 60"by 20." The motor is a 15 hp. I'm going to start with 2 sheets of 3/4 ply to get the same thickness as it is now. Should I reinforce both the inside and outside with a alum. plate or just the outside?

I would use aluminum plate on the inside and the outside of the wood, It really stiffens the transom up! I would make the ouside piece thicker than the inside too.
Good luck with your project!

 

[timebak]

I raised the transom on my SeaArk 1548 DuckHawk from 15" for a short shaft motor to 20" for a long shaft. Basically, we took a piece of 2"x2" square aluminum tubing (or it may have been 1 1/2"x1 1/2") with 1/4" wall thickness and beveled it on either end so it fit the contours of the original transom and welded it in place. Then we took some 1/4" aluminum plate and cut a piece that went from the top edge of the new tube, covered the gap between the tube and old transom, and covered the area where the motor would be bolted. This was for the outside of the transom. Then we cut another piece of plate that covered the inside of the transom where the motor would be bolted, and welded it all together. The outside plate was welded solid around outside perimeter so no leaks. We also had to take out the transom knee brace and reinstall it after welding in the plates. Here are pics:

View from stern, showing outside plate and top of tube.

View from inside, with motor mounted. Everything is painted, but you can see the tube and the inside reinforcing plate we welded in, and also the top of the original transom.

Hope this helps. I can possibly get you better pics if needed.

 

[spg]

Thanks for the info. Now to find someone to do some welding... Called 4 places today and 3 will not touch it. One guy said he could do it but wanted $375. I said no thanks.