NavList:

My own 2 cents worth are as follows. Checked my wrist against NIST time a minute or so ago, it was dead on, so far as could be seen. The watch in question is a Casio G Shock that I've had for several years, which is used for "celestial navigation", position finding/verification when we get down to the beach in North Carolina. Most times, my calculated position is within a couple of miles of GPS coordinates. Don't have a boat, and tend toward sea sickness in sail boats anyhow.