Aluminum backer plate to install 115 merc?

[Curtisa1]

I am mounting a 115 merc on a 17 ft fibreglass runabout. Will 1/4 aluminum be a good material too use as a backer plate between the motor and transom? And as a plate for the bolts to go through on the inside of the transom?.

 

[Chinewalker]

Most outboards are mounted straight to the transom, no plate necessary. Large flat washers are usually used on the inside to spread the load a bit.

 

[Curtisa1]

I was under the impression that an extra plate would help spread the load on the transom better and possibly help with vibration.
But it really doesn't make a difference?

 

[Scott Danforth]

Its often used as a band aid on rotten transoms. Not needed on structurally sound boats

 

[JimS123]

If your transom is sound you don't need it.

If your transom is NOT sound, you don't need it - you need a new transom.

If your transom is sound and you put it on anyway, it won't hurt anything. If a plate makes you feel better, go ahead and put it on.

 

[Curtisa1]

Ok thanks jim, it's an old boat and the transom is not rotten but, the boat filled with water this winter and the previous owner did a poor job sealing the drain plug and old bolt holes. As a result my transom is damp. I am well aware that replacing the transom would be ideal, and it is enevidable that it will rot if left wet. Unfortuneately replacing the transom is not an option for me at this time. I plan on useing the boat at least for this summer.

 

[Scott Danforth]

Replace your transom if its damp. It will never dry out

 

[Curtisa1]

I know that's the ideal solution and it's never going to dry out properly. But i have decided too use it for this summer at least.