NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Dr
From: Dan Hogan
Date: 1999 Feb 22, 18:24 EST
From: Dan Hogan
Date: 1999 Feb 22, 18:24 EST
Millard: > Silicon Sea, [Snip problem stuff Q2] > I must admit that these problem have been a great learning experience > for me. If one uses the current to get the DR is it really DR or estimate > position (EP). Bowditch - Dead reckoning (DR) determines position by > advancing a known position for courses and distances. A position so > determined is called a dead reckoning (DR) position. It is generally > accepted that only course and speed determine the DR position. Correcting > DR position for Leeway, current effects and steering error results in an > estimated position (EP) My fault. We agreed during the legs from Maldives to Sydney to call DR= no current and EP=current. Will change my terminology. I'm having a hard time with this since in all my sailing all I used the term DR for everything. [Snip] > To get DR on the Celesticomp V it asks for Departure Lat & Lon, Steered, > Speed, Var&Dev and Turn Point time. I guess the "Steered" always did > drive me little crazy in the DR program because there is a program that is > called STEER/CUR which give one the Course to Steer if one has Desired > Course (TC) Var&Dev, Log Speed, Current Dir, and Current Velocity. So if > I use the "Steered" Compass course from the STEER/CUR in my DR program I > actually get EP not DR. The problem is that Bowditch has been made "politically correct", a lot of earlier navigation books, texts, and methods use the earlier definitions, I.e. Course-to-steer, Course Made Good.etc. In my hard drive double crash of '98 I lost most of my tips and hint for Silicon Sea. If anyone has the definitions list please post it. Any how from now on: DR = position based on distance = time x speed EP = DR plus the correction for current. Dan Hogan WA6PBY dhhogan@XXX.XXX Catalina 27 "GACHA" =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=--=-= =-= TO UNSUBSCRIBE, send this message to majordomo@XXX.XXX: =-= =-= navigation =-= =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=--=-=