NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Compass Checks at Sea
From: George Huxtable
Date: 2008 May 23, 09:57 +0100
From: George Huxtable
Date: 2008 May 23, 09:57 +0100
Jeremy's mailings have provided several interesting surprises, to me. One is the frequency of checks made on the gyrocompass, once per watch. Presumably, there's much cautious overkill in those arrangements. Otherwise, how would ithe navigation cope with a prolonged period of cloudy weather, when no such checks are possible? Does the navigator get uneasy under such conditions, and if so, after how long? Might he then revert to cross-checking against the magnetic compass, with all its known deficiencies? Another surprise, at first sight, was the use of Polaris for checking azimuths. In our waters, we would never even consider that, Polaris being 50 degrees up in the air. But for denizens of the Northern tropics, of course, Polaris is a nice low star for such purposes, always in place. Another surprise, in the first exercise, was his mention of a vessel drifting. To me, merchant vessels are either travelling purposefully, under way on passage from A to B, or they are in harbour, never adrift. That led me to suggest that the exercises might be, to some extent, contrived ones, and it was refreshing to be assured that no, they would be real-life. George. contact George Huxtable at george@huxtable.u-net.com or at +44 1865 820222 (from UK, 01865 820222) or at 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK. --~--~---------~--~----~------------~-------~--~----~ Navigation List archive: www.fer3.com/arc To post, email NavList@fer3.com To , email NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---