Author Topic: long shaft or X-tra long for Widebody???  (Read 4893 times)

Offline gakonasteff

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long shaft or X-tra long for Widebody???
« on: June 16, 2008, 10:43:40 AM »
  I am getting ready to purchase  a F90 Yamaha and need to know for sure if I need the long (20") or x-tra long(25")shaft for my widebody...I am planning to move the engine off-center 10" according to Renn's instructions and the transom height is 20"...any one care to set me straight before i plop down $8 grand???
Steffan
Gakona,Alaska

Offline AlasKen

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Re: long shaft or X-tra long for Widebody???
« Reply #1 on: June 16, 2008, 10:50:45 AM »
My understanding is you would need a long shaft (20") on a widebody.  The jumbo takes a xlong (25') shaft.  The transom height on a jumbo is 25" so I think it stands to reason that if your widebody is a 20" transom you would need a 20" shaft motor.  Since you are offsetting 10" you will have the motor raised some as well.  When on plane and your motor trimmed down slightly from prop cavitation, your cavitation plate should be at water height.
That is the way it was explained to me.
Kenneth Dodson
Crystal Dawn
24' Jumbo

Offline tolman_paul

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Re: long shaft or X-tra long for Widebody???
« Reply #2 on: June 16, 2008, 11:22:15 AM »
The stock design for the widebody is a long 20" shaft.  You can modify the transom to take a 25" xtra long shaft. 

Offline gakonasteff

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Re: long shaft or X-tra long for Widebody???
« Reply #3 on: June 16, 2008, 12:56:09 PM »
thanks for the quick reply, i will be picking up the 90, a kickerand a new trailer soon, any comments on the hi thrust vs regular? i know the 8 and the 9.9 are about the same on weight so what gives?
Steffan
Gakona,Alaska

Offline jim shula

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Re: long shaft or X-tra long for Widebody???
« Reply #4 on: June 16, 2008, 01:43:18 PM »
If you're offsetting 10", you may want to build the transom up another inch or two and stay with a 20" shaft.  Think about it.  The transom cutout and waterline are parallel, but with the deadrise of the bottom, the further out you go, the less the distance between the bottom of the boat and the top of the transom cutout. 

Offline kchace

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Re: long shaft or X-tra long for Widebody???
« Reply #5 on: June 17, 2008, 05:35:51 AM »
thanks for the quick reply, i will be picking up the 90, a kickerand a new trailer soon, any comments on the hi thrust vs regular? i know the 8 and the 9.9 are about the same on weight so what gives?

  The high thrust model has a lower gear ratio for turning a bigger prop. The best prop to get for kicker use is one of the 4 blade 'elephant ear' props. They won't push your boat any faster, but make a big difference in wind or waves.  Solas makes them.

http://www.cabelas.com/spodw-1/0031313.shtml

Ken
Ken Chace
The Lucky C
25' Jumbo