It's also properly
used for the motion of a ship with a following sea.

Actually, a ship with a following sea pitches up and down, and in the
worst case is pooped.

A ship with a sea off the stern wallows, but is still pitching. It's a
corkscrew motion, say rolling to port while diving down, then rolling
to starboard while climbing up. Very sick-making.

I never though of either motion as a Dutch roll, and it is not really
similar to Dutch roll in an aircraft.

all the best -- Dan Ford
email: (put Cubdriver in subject line)

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