Raising transom to accomadate 25hp long-shaft motor using plywood

[Dmessmer]

What do you guys think about using plywood (no metal reinforcement) to raise my transom ~3.5 in.? I am thinking about replacing the plywood backing on each side of the transom with 1/2" plywood and having it extend 3.5" above the current transom then sandwiching more sheets of plywood in between and bolting everything down good.

Does anyone see a problem with this, remember its only a 25 and more than half of the plywood will be below the top of the inside of the transom and a lot more on the outside

 

[tmcalavy]

Re: Raising transom to accomadate 25hp long-shaft motor using plywood

How much does your 25 hp weigh. A regular on this board, tashasdaddy, has posted pix in the past of his home-built jack plate...might try a search on that. It used wood and L-angle metal brackets/supports.

 

[Chris1956]

Re: Raising transom to accomadate 25hp long-shaft motor using plywood

How about using "biscuit" joints to join the original to the extension, and then using aluminum angle iron bolted thru the transom to reinforce the extension? This will not increase the thickness of the transom, which might be necessary to accomodate the transom clamp of the OB.

Plywood on both sides of the transom is a good idea, if the transom bracket can accomodate it. If not, the metal is the only option.

You should use solid lumber if you use the biscuits

 

[tashasdaddy]

Re: Raising transom to accomadate 25hp long-shaft motor using plywood

i would not use the method you suggest, it is not the weight of the motor. it is other forces. what if you hit a log, stump etc at wide open. you could loose it all.

these are my jack plate:

this is my transom elevator:

 

[redneck27]

Re: Raising transom to accomadate 25hp long-shaft motor using plywood

i got a 1990 20ft pontoon boat with a johnson 70 on it. the motor is bolte to a peice of plywood and it broke on me in the water and almost lost the motoer what do i need to gt to replace it?