SIB Setup

[cyberstoker]

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!

[willk]

I'd try a tiller extension (plastic waste pipe and a jubilee clip) and keep the motor trimmed down.

[Max...]

Ohhh - a four stroke 20?? - that's a heck of a lot of weight on the back of a 3.5m SIB. Sometimes less is more.

[benc]

What sib is it?

Is it an air deck/hull ?

[cyberstoker]

SIB is a Zodiac with inflatable keel and wooden floor.