42 PROPULSION

42.1 Basic Rule
Except when permitted in rule 42.3 or 45, a boat shall compete by
using only the wind and water to increase, maintain or decrease her
speed. Her crew may adjust the trim of sails and hull, and perform
other acts of seamanship, but shall not otherwise move their bodies to
propel the boat.


42.2


42.2 Prohibited Actions
Without limiting the application of rule 42.1, these actions are
prohibited:

(a) pumping: repeated fanning of any sail either by pulling in and
releasing the sail or by vertical or athwartships body movement;
(b) rocking: repeated rolling of the boat, induced by
(1) body movement,
(2) repeated adjustment of the sails or centreboard, or
(3) steering;
(c) ooching: sudden forward body movement, stopped abruptly;
(d) sculling: repeated movement of the helm that is either forceful
or that propels the boat forward or prevents her from moving
astern;
(e) repeated tacks or gybes unrelated to changes in the wind or to
tactical considerations.

42.3 Exceptions
(a) A boat may be rolled to facilitate steering.
(b) A boat’s crew may move their bodies to exaggerate the rolling
that facilitates steering the boat through a tack or a gybe, provided that, just after the tack or gybe is completed, the boat’s
speed is not greater than it would have been in the absence of
the tack or gybe.
(c) Except on a beat to windward, when surfing (rapidly accelerating down the leeward side of a wave) or planing is possible, the
boat’s crew may pull the sheet and the guy controlling any sail
in order to initiate surfing or planing, but only once for each
wave or gust of wind.
(d) When a boat is above a close-hauled course and either
stationary or moving slowly, she may scull to turn to a close-
hauled course.
(e) A boat may reduce speed by repeatedly moving her helm.
(f) Any means of propulsion may be used to help a person or
another vessel in danger.
(g) To get clear after grounding or colliding with another boat or
object, a boat may use force applied by the crew of either boat
and any equipment other than a propulsion engine.
Note: Interpretations of rule 42 are available at the ISAF website (www.
sailing.org) or by mail upon request.