Posted 1 Year ago Sailor Senior Boarder Posts: 48   ive got a 98 model gp800, does anyone else have the problem of it porpoising badly when building up speed? even with the trim adjusted with the bow down it still does it. The administrator has disabled public write access. Posted 1 Year ago saj Senior Boarder Posts: 52   All 97-99 Gp's have this problem. Best solution add Tau Ceti hull extenders (trim tabs). 80% of your porpoising will be gone. Add a shredmaster ride plate or a RIVA closed course ride plate and 95% of your porpoising will be The administrator has disabled public write access. Posted 1 Year ago dah6098 Senior Boarder Posts: 55   How about SPEED lose?? The administrator has disabled public write access. Posted 1 Year ago Sharath Senior Boarder Posts: 44   in 98 yamaha came w 2 diferet hulls in the midle of the year they changed to the new model and they cut the ride plate The administrator has disabled public write access. Posted 1 Year ago ugadasalli Senior Boarder Posts: 48   Considering the amount of porpoising going on without this stuff, you probably lose 1-2 mph in flat water and gain 1-2 in choppy water The administrator has disabled public write access. Posted 1 Year ago calladus Senior Boarder Posts: 54   Have you ever thought about the trim pushing the nose down is causing the porposing? Think about it. When you push something down against something it doesn't want to be pushed against, doesn't it bounce??? Perry Wright The administrator has disabled public write access.