Measuring new transom wood?

I'm ready to put my long shaft outboard on my short shaft transom. I have removed the old wood from the transom and will make the new cuts from exterior grade plywood.
How do i measure the height for the new transom wood? Is there a formula? Thanks! I'd like to stray from using a Jack plate due to a t&t in the future.

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Prowler - Google "anti ventilation plate height" and you will
find dozens of different variations of transom height to match a motor.
Not really a formula per se, just a general rule.
The anti-ventilation plate is somewhere near or a little below
the bottom of the boat when your motor is in the trimmed running position.


my 25hp Johnson was a long shaft on a 15" transom and it rooster tailed
something terrible. I did not know why (I do NOW). Took it to the boat
shop and he installed a splash plate . . . he should have known the motor
was way too low . . . he is gone now, thank goodness.
I am not a fan of jack plates. I would rather see the transom remade
to fit the motor.

Thank you Johnny. I searched and made the cut. Ill see if it works out next weekend. I'll round off the edges in a few.

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This is a mock up with my long shaft 4hp merc that will new used as a trolling motor. The measurement looks to be spot on with the 50hp Johnson and I have room for adjustment up or down if need be.

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yep - just like that





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Awesome![WHITE SMILING FACE]

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