"Roy Smith" wrote in message
...
23.751 Main float buoyancy.

(a) Each main float must have

(1) A buoyancy of 80 percent in excess of the buoyancy required by that
float to support its portion of the maximum weight of the seaplane or
amphibian in fresh water; and

(2) Enough watertight compartments to provide reasonable assurance that
the seaplane or amphibian will stay afloat without capsizing if any two
compartments of any main float are flooded.

(b) Each main float must contain at least four watertight compartments
approximately equal in volume.

I don't see anything in there that would require the supposedly watertight
compartments to still provide floatation in the event of them no longer
being watertight...

On a side note, I've heard that for emergency floats on offshore (oil rig)
helicopters, they often end up with the floats on the surface and the
helicopter suspended underneath it in the water..