SailNet Community - View Single Post - Course to steer at a given speed.
 View Single Post
Old 12-06-2012
nolatom
Senior Member

Join Date: Jun 2005
Location: New Orleans
Posts: 2,171
Thanks: 10
Thanked 49 Times in 46 Posts
Rep Power: 13

Re: Course to steer at a given speed.

I'd do what my old man taught me..

"Put some 'money in the bank', head up higher than you think, it's easier go spend the money than it is to get more later on".

And I'd watch the shore once I could see it... is my bow "giving up land"? then head up. "eating land"? bear off. Steady bearing? then keep on. And it won't be my headstay that's heading toward port, it'd be some point on my stbd bow that's heading towards our course-made-good. So if the heading is 253 to make good 270, then the seabuoy will come up 17 degrees on the starboard bow.

That would get me there without a lot of course change. And I could do the hypotenuse calcs roughly in my head. And by pocket GPS would give me the speed made good, so I could figure out how many minutes to get there. But I couldn't necessarily make it come out 60 minutes, if we weren't making the speed. Speed along that hypotenuse is much trickier under sail than power. We sheet 'em in, and that's our speed. So we take what we can get, we don't control speed, and luffing for 10 miles (or more, once you know what 'C-squared' is) to slow down is hard on the sails.

So precise trackline-following for sailboats, and precise predicted-log speed, is more seat-of-the-pants than it is math for most of us (meaning me), this is especially true on a beat. So we'll reach port when we get there.

Also sailboats sideslip more than powerboats, it's our nature. So you have to allow for a crosswind even in still current.

Last edited by nolatom; 12-06-2012 at 12:32 PM.
nolatom is online now