Tacking for speed
The situation
In steady wind and flat water, a coach notices a sailor tacking and gybing again and again, seeming to squirt the boat forward each time with the turn.
The question
Is there a limit on how often you can tack or gybe?
The ruling
Yes. Tacks or gybes that aren't justified by wind shifts or tactics are prohibited propulsion under rule 42.2(e) — you can't spin your way upwind. Tacking on a shift, to cover a rival, or for a clear tactical reason is completely fine; turning the boat purely to gain speed through the water is not. In steady wind and flat water, rapid-fire tacking with no tactical purpose breaks rule 42.
Tack and gybe as tactics demand — but spinning repeatedly just to gain speed breaks rule 42.2(e).
Opens the situation on the boat-length grid — scrub it and see exactly how the boats meet. Free, no account needed.