Question on transom height???

[spdjnky_42]

Bought a flat bottom john with a 22" transom. I recently bought a 89 Johnson with a 20" shaft. I am going to switch it over to a jet drive. Can anyone tell me what height my transom needs to be? Sorry cant measure the motor its too far away at the moment.

 

[ondarvr]

Re: Question on transom height???

You need a 25" transom for a jet pump mounted on a long shaft motor.

 

[spdjnky_42]

Re: Question on transom height???

Thank you very much. Thats what I was afraid of. I have a friend who is one of the best in the world with a tig welder. I also have access to sheet aluminum and am quite crafty with a tape measure. If the transom needs 3" and the center brace is all the way to the top now. Can I just run the angle of the existing transom up 3" with a 3 x 2" piece of sq tube and weld up the ends along with beefing up the corners a little more. then maybe add a brace or two and be good? Boat is rated for 50hp and I will be running a 90hp but 65 hp jet. Local boat shop says the whole back of the boat has to be fitted with mainly a 1 piece aluminum, instead of adding to the existing and they want $600 to do it.

 

[ondarvr]

Re: Question on transom height???

A commom method is to use the 3"x2" tubing and then run a plate down the inside and outside to sandwich the original transom, This can be welded on, or just slide down over the transom and be bolted in place. A couple of extra supports are tyipically added for more strength.

 

[spdjnky_42]

Re: Question on transom height???

so Im guessing if I run the angle up 3 more inches and then run a plate the width of the top of the transom down the front and back it would be good. Will the u shape hanger on the motor bracket fit over the transom after adding two more sheets of aluminum? also Does someone pre fab the brace that runs the height of the transom? <<< If I knew the name of this I would know sorry.

 

[ondarvr]

Re: Question on transom height???

Your motor doesn't rest on the transom, so it doesn't make any difference how thick it is. The supports and braces are fabricated as needed for your application, if your buddy can weld like you said, he won't have any problems making a brace.