NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Graham England
Date: 2016 Jul 27, 08:55 -0700
I hope it is OK to ask this type of question on this forum.
Not really a Navigation question but more an experience question.
I had an interesting discussion with some of my weekend sailing friends about setting a course when sailing directly into the wind.
Assume you want to sail 100 miles directly into the wind and your boat points 55 degrees off the wind.
Based on just the math you would sail 55 degrees off the wind for 87.17 miles then do one tack and sail another 87.17 miles also 55 degrees off the wind.
So you would be sailing a total of 174.34 to go 100 miles into the wind.
Some of the guys who race pointed out that racers tend to do many tacks and use the momentum of the boat to gain some distance into the wind on each tack.
Does anyone do this?
The math is (see the image)
b= 100 Miles
A= 55 degs
C= 55 degs
B= 70 degs (180-55-55)
a/sin(A)=b/sin(B)
a/sin(55)=100/sin(70)
a=100*sin(55)/sin(70)
a= 87.17 miles