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Transom height and prop conversion

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Transom height and prop conversion

Postby roundtail » Fri Dec 08, 2017 2:46 pm

Hi all,
I have a technical question I was hoping someone here could help out with. I was hoping to swap the jet for a prop on my boat for the occasional lake boating/fishing trip.The boat is a 16" Mod V, transom is 27" (top of transom to top of jet tunnel), I'm running a long-shaft 50. The set up works great with a jet, I and was looking into a long-shaft extension kit to use when I run a prop. This would add 5" to the prop depth, however, according to my calculations this would place the cavitation plate on the lower unit a full 2" above the tunnel. My gut tells me that this setup would likely perform poorly. Has any one dealt with this sort of situation, find any solutions? I thought about using a jack plate mounted 2" low, however, this would likely limit my ability to tilt the outboard. Thanks
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Re: Transom height and prop conversion

Postby Apfeiffer82 » Mon Dec 11, 2017 7:42 pm

A jack plate might be your best option other wise you need to notch your transom at least 1” a 25” prop will run at 26” actually it will run at 27” as well but it will run better at 26” (the racing guys run there motors higher to get more of the lower unit out of the water less resistance) then once notched you will have to unbolt and move your motor every time you swap lower units other people might have other options but that’s what I’ve ran into before! Good luck
2011 20’ Koffler
350/3 stage
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Deck Swab
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Re: Transom height and prop conversion

Postby fishbum » Fri Dec 15, 2017 5:33 am

Vance manufacturing makes a drop down Jack plate
There in Tn. Just have to be sure steering and cables will clear transom
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