NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Wind & Current Navigation
From: Rodney Myrvaagnes
Date: 2003 Apr 22, 23:44 -0500
From: Rodney Myrvaagnes
Date: 2003 Apr 22, 23:44 -0500
I don't think theory, except at the crudest level, will help practice in this case. Your boat has a certain exposure to current, which may or may not be the same at the surface as at the bottom of your keel. It also has a windage exposure. The wind makes no difference in a calm, but if it gusts hard enough it can become comparable to the current for a moment. So, current (if any) always matters, wind sometimes matters, and how much depends on the boat. The current can be predicted from tide tables after you have been there through a couple of cycles. On Tue, 22 Apr 2003 08:56:00 -0700, Dan Allen wrote: >On Monday, April 21, 2003, at 02:36 PM, Charles Tait wrote: > >> I severely doubt that any equation will fix this better than judgement. > >I know that the equations that govern marina navigation are very >complex with currents and winds added, and that there may be no current >good real-time calculation mechanism to make use of them. > >But I am looking for us to develop a more rigorous theory of what is >happening so that we can learn from it and make some progress on >understanding the physics of winds and currents so we can have some >first principles to work from while at the helm. I am therefore >looking for the theory that will help practice. > >Dan Rodney Myrvaagnes J36 Gjo/a "That idiot Leibniz, who wants to teach me about the infinitesimally small! Has he therefore forgotten that I am the wife of Frederick I? How can he imagine that I am unacquainted with my own husband?"