World Sailing Official Case Book
Case 89
Except on a windsurfer or a kiteboard, a competitor may not wear or otherwise attach to his person a drinking container.
Question
Does rule 50.1(a) permit a competitor to wear or otherwise attach to his person a drinking container while racing?
Answer
No. Except on a windsurfer or a kiteboard, there is no necessity for such a practice, and therefore its primary purpose must be considered to be to increase the competitor’s weight. (Note that rules B4 and F4 modify rule 50.1(a) for windsurfing competition and kiteboard racing.)