Why should I work on my head if I want to go faster?

In your class everyone sails the same boat. Above a certain level everyone sails at the same speed, and then the head decides. The head is the last boat you can still make faster.

There is more to it: you train once a week, when parents, weather and water all cooperate. Mental training you can do on any other day. That doubles or triples your training time, with nobody having to drive you to the lake.