Do you want to win races?
Use I-Sail! Use I-Sail during races and training.
By comparing your track mainly to that of your competitors, you gain more insight into what should improve your performance.
You can analyse your:
did you have enough room leewards
was your speed ok
what was your position
did you sail the right side of the leg
what was the efficiency of your tacs
what is your competitor's performance
was your tactic that came close to the goal
did you choose the right way leaving the mark
did you have enough free wind
was your down wind speed ok
could the approach to finish be smarter