This is because weather is usually worse in winter therefore higher
freeboard required especially winter North Atlantic
wrote in message
oups.com...
Brian Whatcott wrote:
After numerous ship losses, Plimsoll legislated a hull mark
in Parliament, the "Plimsoll Line" which accounts for salt and fresh,
warm n cool water, beyond which a commercial vessel must not be
loaded. Unaccounted ship losses were much reduced thereafter.

The difference between salt and freshwater displacement and waterlines
makes sense to me, since the salt increases the density of the water,
right? But why is there a difference between summer and winter?
Thanks, Brent

That could be a factor but I wonder . . .

It happens that temperature has a greater effect on water
density than salinity.

Dominic wrote:
This is because weather is usually worse in winter therefore higher
freeboard required especially winter North Atlantic

I see you're right. thanks.

http://www.onr.navy.mil/focus/ocean/water/density1.htm