NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Leg 56 Question # 3
From: Bill Murdoch
Date: 1999 Jul 19, 7:40 PM
From: Bill Murdoch
Date: 1999 Jul 19, 7:40 PM
In a message dated 7/17/99 1:31:35 PM EST, dhhogan@NAV.CNCHOST.COM writes: > So you use only the data you can rely on. Time/speed and distance. Which is why I prefer to DR using a distance log rather than boat speed. I agree and do the same, but then why do the USPS and most texts always multiply time and average speed to get the distance run? I would have thought it to be better to use the logged distance letting the instrument find the intergrated product rather than relying on me to guess the average of the speed readings for an hour. It is also the way I have calibrated my knotmeter. I run a measured distance under power in still water, compare the distance by log to the distance by chart, and figure the error as a percent. Then holding the engine speed constant, I turn the calibration screw to raise or lower the speed by the percent error. It seems simple to me and seems to work. Bill Murdoch
