Friday, March 4, 2011

Velocity Made Good Calculation


Velocity made good (Vmg) from wikipedia is the velocity toward a mark. To compute Vmg the following quantities must be know:
  • Yacht speed -- Vs
  • Apparent wind direction -- (B - lambda)
  • Apparent wind speed -- Va
  • Leeway Angle -- lambda
"The solution of this equation electrically would require equipment both too costly and bulky forgeneral use. The further complication of correcting the measured values of Va and (B - lambda) to allowfor the errors introduced by the heeling of the yacht make an exact-solution computer impracticable." from R. N. B. Gatehouse

"Vmg is given by Vs cos gamma. The angle between the yacht's track and her fore-and-aft axis is the leeway angle lambda"


I think that the tiny 1/2 looking like sym

bol exponent position under the devision sign is 1/lambda.

By trig we have:





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