NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: How Many Chronometers?
From: Lu Abel
Date: 2009 Sep 22, 12:46 -0700
From: Lu Abel
Date: 2009 Sep 22, 12:46 -0700
NavList@fer3.com wrote: > Hello from a frequent reader, but not a member of the list. > > ... As an experiment on one of the ships, we rated our two dozen watches instead of resetting to NAVSAT time. The purpose was to compare watch brands and purchase price. We found the mid-priced watches of two particular brands did as good as the expensive watches and all were much more consistent than the ship's chronometers as long as we wore the watch. I had a friend who bought a Rolex. Turned out it was a terrible time-keeper. She brought it back to the dealer who said "sorry, it meets specs." Rolex heavily advertises that its watches are "chronometers." Turns out that their spec (see http://en.wikipedia.org/wiki/COSC ) allows for a daily rate of -4/+6 seconds/day -- that's as much as 2-1/2 minutes per month!! (Wasn't the Longitude Board's spec 1 minute per month?) Worse, a rate change of -6/+8 seconds is allowed between horizontal and vertical positions of the watch! How many of us would keep our hands in a constant position to avoid this allowed rate variation? In 1970 I bought a Seiko watch (obviously mechanical, given the date of purchase) for under $50. It was an incredible timekeeper, rate was under 5 seconds per month. So, yeah, high price seems to buy advertising, not accuracy... --~--~---------~--~----~------------~-------~--~----~ NavList message boards: www.fer3.com/arc Or post by email to: NavList@fer3.com To , email NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---