NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Silicon Sea: Leg 85
From: Dan Hogan
Date: 2002 Nov 14, 06:10 -0800
From: Dan Hogan
Date: 2002 Nov 14, 06:10 -0800
On 12 Nov 2002, at 14:30, Paul Hirose wrote: > 1. Total distance from Hanalei Bay to L.A. Light = 3990 miles Too high. waht method are you using for calculations? Try using Mid-Latitude leg-by-leg. > 2. Based on a Speed of 10 Kts it will take 16.6 days to L.A. Light. See Q1. > 3. At 7.5 gallon/day total water consumption, total to the L.A. light > will be 125 gallons. The vessel has a 220 gallon capacity, so there > appears to be enough. OK > 4. TC from Hanalei Bay to MOP1 is 013. OK > 5. Departure was at local apparent noon. Right > 6. TC to MOP1 = 014. OK > 7. Steer 1 degree left for current and subtract 11.5 deg compass > error. Compass course = 002 to MOP1. OK > > Mostly I used plotting sheets and did the computations graphically. > For the current correction I'd normally use an E-6B slide rule, but > this time I drew a current triangle on the plotting sheet for the > sake of variety. If you like plotting sheets and non-calculator try Mid-Latitude for the leg calculations. > Looking at the answers, my distance was about 25% off. Even on > plotting sheets I think I should have done better. May have made a > mistake. At least I got the initial course right within a couple > degrees. As an instructor told my class many years ago, the most > important output from any nav system is "which way do we go". Saiboat compasses are divided into 5 degree increments, sailing closer than 2.5d to that is guess work. Dan Hogan WA6PBY C27 "Gacha" dhhogan1@earthlink.net Nav-L Page: http://www.wa6pby.com
