Re: Ship sinks in calm water as water loses its ability to hold ship up. True?

Archimede's Principle states that an object wholy or partially immersed in a
fluid is buoyed up with
a force equal to the weight of the fluid displaced.  The dissolved methane
could reduce the density
of the water (and hence the weight of the displaced fluid) and therby reduce
the buoyancy of a
heavily loaded ship to cause it to sink.  This is the opposite of the fact 
that
is easier to float
in very salty water than it is to float in fresh water.