Case 8
Rule 42.1, Propulsion: Basic Rule
Rule 42.2(d), Propulsion: Prohibited Actions
Repeated helm movements to position a boat to gain speed on each of a series of waves generated by a passing vessel are not sculling unless they are forceful, and the increase in speed is the result of a permitted use of the water to increase speed.
Facts
Two small dinghies, A and B, were reaching at about hull speed in an 8-knot wind. A large power cruiser passed by rapidly on a parallel course to leeward, creating several large waves. As each wave reached A's quarter, her helmsman moved his tiller without undue force, in a series of course changes rhythmically timed to the passage of the waves under his boat. These actions were repeated for each wave and A gained speed on each occasion. B protested A under rule 42.2(d) for sculling. The protest committee disqualified A and she appealed.

Decision
A's appeal is upheld. She is to be reinstated. The movement of the tiller, while repeated, was not forceful. Any gain in speed did not result directly from the tiller movement, but from positioning the boat to take advantage of wave action, which is consistent with rule 42.1. To do so, a helmsman may move his tiller as he thinks best, provided that his movements do not break rule 42.2(d).