Hi Guys, How much effect does air temperature have on the boat performance? I find warm wind is less powerful for a given wind speed but I wonder how much of that is because I am warmer and in a better or more positive state of mind. Thanks Timb
Colder air is denser and has more force, so it's not all in your head. This time of the year in Ohio, even if you can barely see the wind on the water, you can still count on surprisingly good sailing.
I Can see the air temp argument and wonder if anyone has any thoughts on how big the differance is like would 15 knots in cold air equal 20 knots in warm air.
Where does the water temp come into it?
Assuming constant conditions (barometric pressure, relative humidity, turbulence, wind speed), and just varying air temperature the effect should follow the ideal gas law. This states that the number of air molecules hitting the sail per time varies as Temp2/Temp1, where Temp[1,2] are in degrees Kelvin. For example, if Temp1 = 20 degrees F = 273+ (20-32)*5/9 = 266.3 degrees K, and Temp2 = 80 degrees F = 273+ (80-32)*5/9 = 299.7 degrees K, then Temp2/Temp1 = 1.125. So, a 15 Kt breeze at 20 degrees F feels like a 16.9 Kt at 80 degrees F.
Of course, from personal experience, sailing in 20F isn't anything at all like sailing in 80F.