3.3HP on an 11ft SIB?

[SpearRib]

Would the above displace 2 adults against wind and tide (sub 15 knot winds and generic inshore tides)?

[Nos4r2]

Depends what brand the sib is, what your generic inshore tides/currents are like there and the sea state.
I'm not sure I'd want to chance it with less than a 4hp, maybe 5hp.

[Max...]

It doesn't sound good at all, I would not want to go to sea in such a rig unless it was a very sheltered bay.