Tobin Sports inflatable

[SteveBoyle]

Hi, my tobin sports inflatable seems to porpoise quite alot when opening up the throttle. Got a 9.9 on the back (rated to 15hp), and inflated to manufacturers recommendations.
Manufacturer recommended 3.5psi for tubes and keel, 5psi for air deck. Anyone have this issue? Any ideas?

[Steve509926]

I would suspect that even though it is rated at 15hp it is probably overpowered.
5psi for the deck and 3.5psi for the keel is very low when compared to other airdeck/sausage keel sibs. An Excel SD330 for example is 10psi for the deck and 6.5psi for the keel, it is also rated at 15hp.

[Fenlander]

>>seems to porpoise quite alot when opening up the throttle

Just refine this comment as to what you actually experience... nose up just in transition or once on the plane at speed a constant up and down??

[Peter_C]

Have you tried changing the manual trim? What about moving weight forward?