extending the transom

Hello all, I have an older model Fisher marine 16' jon boat. I want to extend the transome rearward 18'' using 2 pontoons to convert the hull to a tunnel, i will use a 40 hp evinrude with a jetfoot for power. i will have to build the pontoons out of plywood and stitch and glue every thing together. my question is will the added weight (3/4'' plywood) make the boat to stern heavy? and will it steer "funny"? thanks for any help i can get before i waste any more time and money! ....Charles

[yipster]

here some thoughts:

why do you want to extend the transom? if there is no good reason i think its only taking risks with time and money. dont know the Fisher marine 16' jon boat but when its a monohull doing the rebuild wont make it a tunnel boat, if i understand rite you'll leave the transom and OB adding pontoons backwards?

the pontoons will chance the centre of buoyancy of the boat. a litre volume equals about a kilogram upward trust. in time i'll like to do a similar build as illustarted in the thread sterndrive tunnels in buoyant swimplatform steering i dont know but it seems to make sense in my case, the boat hangs back a bit. i'm thinking about the stepped hull, it can even improve perfomance. not free of risk however.

yipster

thanks for the reply Yipster what i had in mind was extendin the motor back 18" to allow me to raise the intake of the jet foot even with the bottom of the hull. i fish some very shallow waters around Cedar Key FL. and need to run in 6" if i can....charlie

[SailDesign]

Guest,
Why not just raise the motor without the 18" setback? Surely you can add height to the transom.....

the intake of the jet extends about 6" forward and a hull traveling flattens the wake right behind the boat, it needs a tunnel to be really effective

[yipster]

yip, now i'm getting the picture, got a photo of the jetfoot?

[SailDesign]

Quote: the intake of the jet extends about 6" forward and a hull traveling flattens the wake right behind the boat, it needs a tunnel to be really effective

As the Yipster says - now I'm getting the picture. And it wasn't that hard to drag the information out of you either ;-P
Lemme think for a minute while yipster comes up with the answer....

[yipster]

3 people thinking now, who else joins us?

only some more thoughts here...
that wake stays down a long way at speed. others must have looked for solutions... a jet drive is the only good solution i can think of.
sawing the whole boat up you may think of cutting a triangular flat bottom or tunnel at the end of the centerline.
its an interesting question and the first idea with pontoons comes down to the same idea. but will it work well or is that why people buy dept sounders?

ha! i decided this ol boat is gonna catch hell on oyster bars and rocks and sandbars anyway and i will probably replace it in ayear or 2 so what the heck i will just run it the way it is! lets fish!

[SailDesign]

Guest says:
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ha! i decided this ol boat is gonna catch hell on oyster bars and rocks and sandbars anyway and i will probably replace it in ayear or 2 so what the heck i will just run it the way it is! lets fish!
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Now you're talkin'. ;-)