Have borrowed a friends 3.5m SIB with 20HP fourstroke for a couple of weeks, but don't seem able to use all the power. Gets up to about 15 knots, but then more throttle seems to make the prop lose grip so 3/4 throttle is max usable.
As others seem to get 15-20Knots with 10 or 15HP and similar boat I was hoping to go a bit faster.
I've tried moving more weight to the bow, which helps a bit, I've also tried all the trim settings, but if I move the trim out it porpoises significantly.
Any thoughts on this situation welcome!