A friend on mine just bought a used Stratos 20' bass boat with a 250
Yamaha Vmax. He called this afternoon and asked me to take a ride
with him because he couldn't get his boat to plane right.

We met up at Webster Lake and took it for a ride after checking
everything over - everything seemed to be working, nothing out of
sorts with the hull.

Got on the water and it's the oddest thing - no matter what trim
position, the boat would porpise (pitch) at speed. Vary the speed and
you'd get a yawing action - trim made no difference. No roll to speak
of.

All the bolts are tight, properly torgued, the prop is symmetrical,
the skeg on the outboard is straight, keel is straight - no obvious
repairs.

Any ideas? I'll admit it - I'm stumped.