On Mon, 12 Feb 2007 05:38:00 -0600, Geoff Schultz
wrote:

Anything more than 4 hours at night is too long.

I agree. My wife and I usually change watches on a loose schedule
based on when we get tired or when we wake up. This usually works out
to be about 3 hours at night. If we are on a multi day passage I try
to get most of my sleep during day light hours.

One thing I'm meticulous about is leaving my wife with a clear course
line on both the Furuno chart plotter and Maptech OSN on a PC. I also
leave her with an easily read XTE (Cross Track Error) display and
instructions regarding circumstances where she should wake me up.
This would typically be something like a CPA (Closest Point of
Approach) of less than two miles on a radar target, or 1 hour from a
landfall, course change, etc.

I am always on deck for impending landfalls and course changes.

Fortunately my wife does not have sea sickness issues. If she did,
I'm not sure we could do the kind of cruising that we enjoy now.