All lifeboats shall have inherent buoyancy or shall be fitted
with inherently buoyant material which shall not be adversely affected
by seawater, oil or oil products, sufficient to float the lifeboat
with all its equipment on board when flooded and open to the sea.
Additional inherently buoyant material, equal to 280 N of buoyant
force per person shall be provided for the number of persons the lifeboat
is permitted to accommodate. Buoyant material unless in addition to
that required above, shall not be installed external to the hull of
the lifeboat.