NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
When to turn?
From: Anders Reed Mohn
Date: 2002 Mar 19, 18:25 +0100
From: Anders Reed Mohn
Date: 2002 Mar 19, 18:25 +0100
Greetings, navigators. I stumbled across this list, searching the net for an answer to a question. I'm totally stumped here, so I hope maybe someone can explain it a bit to me. Yesterday, I was shown the formulas for calculating GC-routes/initial course, vertex latitude etc.. So far, so good. But then, my teacher came up with a formula for calculating _when_ to turn one degree towards your destination, while sailing that route. I.e. in an example he gave, the initial course was about 62 degrees, total distance would be som 3700 Nm, and he showed that at every 115 Nm, we would have to turn one degree towards our target. Now, I fell off the train of thought here, so I never got around to writing down the exact formula, and I haven't been able to find it on the net. My big problem here is that the formula contained speed as a factor. The sample above was calculated for 5 knots speed. I don't see how speed fits into any of this... Does this sound familiar to anyone? The formula was something like 60/(x*V*x) where x and Y are trigonometric expressions (sines and cosines), and V was boat speed. Anyone?? Cheers, Anders RM :)