Need some Help Please

[booger man]

Ok Here is the problem : I have a old Lonestar 14.5ft aluminum riveted semi v fishing rig with a short transom and a 9.9 short shaft for hp limited lakes...I picked up a 25hp merc long shaft for a great price so i can get out of the way of the ski boats at the large lakes....So i could run both the long and short shaft outboards I made a jack plate from 2 1/2 x2 1/2 inch x 3/8 aluminum angle.This set-up works great with the long shaft 25hp(she will fly!!!} but it also caused me to raise the short shaft 2.5 inches higher so it will mount to the jackplate thus causing the anti-ventilation plate to be 1.5 inches above the semi v keel ...I'm right at the verge of ventilating at wot and she porpoises a little with just me in the boat,and ventilation is bad with sharp turns .....Will a doel fin help with the cavitation if not what will ....I do not want to take the bracket off every time i want to switch motors {right now i just remove a few bolts ,switch sides with the removeble bracket pcs and bolt them back to the angle pcs that are mounted to the transom} the Tru-transom holes are sealed{when the two angle pcs are boltled together they look like a c looking down at the transom with a 2 3/4 inch setback......also the clamp on the short shaft doesn't have a wide enough bite to mount on the transom and the bracket also{tried that already.I thought the setback would compensate for the higher ventilation plate.....Any ideas would be greatly appreciated......... I'm getting just over 20mph per a gps with the 9.9 johnson {10 pitch less than a year old}and just over 30 with the 25hp merc and old worn out prop 13pitch {still playing with the motor angle}befor the jack plate i was lucky to get 18mph with the 9.9 and 19mph with the 25 with just me and fishing gear....also the boat has some weight to her {full floor ,carpet,seats,2 batteries toward the bow,live well,fuel, etc} Give Me Some Advice Please...

 

[CalicoKid]

Re: Need some Help Please

If your jackplate is a two piece design, how about making copies of the rear pieces (that the motors clamp to), drill the new set to extend the motor farther down for the 9.9 and leave these pieces mounted to your outboards. This way you can swap motors by seperating the jackplate halves and reassembling without unclamping the outboard from the angle stock, and each plate will be setup specifically for its own motor. You could, as long as you're at it, build in a little more setback. From what I understand, the farther back a motor is the higher you can run it and still avoid ventilation. I doubt if a hydrofoil of any kind will prevent or reduce ventilation.

 

[mellowyellow]

Re: Need some Help Please

find a short shaft for the 25hp. should be able<br />to get enough money for reg. shaft to make it a<br />wash....