NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Gyro Error.
From: Geoffrey Kolbe
Date: 2013 May 22, 06:02 +0100
Well, trying to calibrate a compass using a GPS or any other method in 5 foot seas sailing at 8 knots in a small boat would seem to me a triumph of hope over reasonable expectation....
From: Geoffrey Kolbe
Date: 2013 May 22, 06:02 +0100
Bill B wrote: Suppose you are sailing at 8 knots in 5 foot seas, and your GPS is polling every second (likely faster). Suppose you have a GPS antenna on top of the mast. As the boat rolls the GPS is seeing significant lateral motion in relation to the forward motion. I have found this to be true even with handhelds and chart plotters with internal antennas located in the cockpit. Even in swells with the compass steady and a visual object dead ahead, plus/minus 3° is the norm. Trying to calibrate compass deviation with a GPS is truly a fools game. (This fool discovered that experientially ;-)
Well, trying to calibrate a compass using a GPS or any other method in 5 foot seas sailing at 8 knots in a small boat would seem to me a triumph of hope over reasonable expectation....