planing/porpoising

[thadeusp]

1986 monark f/glas fish/ski w/1996 88 hp evinrude,3 blade s/s prop. gas tank, 3 batteries in rear. have trouble w/porpoising when taking off bow sits high in water, blocks view. have hydofoil. should i move gas tank to bow, change to 4 blade prop, or raise/lower motor w/jackplate?? or any other options....

 

[FlyBoyMark]

Re: planing/porpoising

If ya have trim and tilt start out with the motor fully tucked in and trim out as you acellerate till you get to "edge" of porpoising stability. Try raising motor cavitation plate to 1" above keel. Poor adjustment of trailer rollers and bunks could have "cupped" the botom of the boat and damaged it also creating this situation. The hydro foil should be removed for these adjustments. it too can create this problem if not installed or adjusted properly and ONLY should be installed as a LAST resort. If this does not work, go the otherway and lower the cavitation plate to 1" BELOW the keel. None of this will not reallly help a hull that has taken a set from improper trailer or bunk storage damage. Weight distribution helps some but not entirely.

 

[Down South]

Re: planing/porpoising

Most fiberglass boats do come out of the hole shot with the bow high. Take FlyBoyMarks suggestion by having the motor trimmed in all the way. <br /> Repositioning some of the weight from the rear to the front will help some but like I said most fiberglass boats just come out of the hole with the bow high. <br /> Porpoising is usually caused by being trimmed up to high. If the boat is doing this with the motor trimmed all the way down then there is a trim rod or pin in the bracket of the motor. (I'm not sure if this is the proper name for this pin) Anyway move this pin back a hole closer to the transom of the boat. This will help your hole shot too.<br /><br />Good luck.