A while back there was a thread about compasses, whenever I hitch up the SR I seem to automatically put on my Casio ProTrek.
It's the most solid dependable watch I've had.
The boat needs a compass but a back-up is always cool. And the Casio is actually very accurate.
Solar powered with compass, tide display, sea level, barometer history over 24 hrs, obviously watertight, not too precious, properly lit display with alarms and properly visible display.
Seriously tough metal strap too.........only trouble is that the strap doesn't expand over drysuit/wetsuit.
SUUNTO do a few models but seem a bit too good for smashing about under water, in sand and trying to cut ropes off props.