Forum: The Racing Rules of Sailing

Propulsion - 42.1 Basic Rule and 42.3(a) Exception

Jerry Thompson
Nationality: United States
  • National Judge
  • Umpire In Training
  • Regional Race Officer
Sailors of the ILCA, 420, and Opti classes sometimes use a technique at the start which includes: 

1. Steering down below close-hauled.
2. Rolling the boat to leeward with their bodies to facilitate heading back up to a close-hauled course without using the rudder (brake).
3. Flattening the hull to the water often accompanied by 1 body pump.

Many coaches I have spoken to believe that this maneuver does not break Rule 42 if the boat clearly propels out of the maneuver so long as a roll and turn were part of the maneuver citing the exception 42.3(a) A boat may be rolled to facilitate steering.

One roll and one body pump do not break a rule. However, I believe that if the boat clearly propels out of this maneuver which is possible in light air, she breaks the Basic Rule, Interpretation Basic 4. 

What is the exception, 42.3(a) for?

 I believe that a roll used to facilitate steering does not count towards Rocking, Interpretation Rock 7, which is repeated rolling. For example, downwind when S turning before waves, rolls to steer do not count towards Rocking. Otherwise a boat rolling repeatedly to turn before the waves would break 42.2(b).

I welcome your opinions.
Created: 24-Feb-13 18:06


Rob Overton
Nationality: United States
  • National Judge
  • International Umpire
Jerry, I think you're right, technically. The 2021 INTERPRETATIONS OF RULE 42, PROPULSION (available from the World's Sailing website) says "ROCK 2  One roll that does not clearly propel the boat is permitted".  The "does not clearly propel the boat" implies that if the single rock does propel the boat it is illegal.  There's some controversy over whether the flattening aids steering (it stops the turn) and/or whether the flattening motion trims the hull and so is permitted in the basic rule. But the ROCK 2 interpretation is pretty clear.

Having said that, I note that it is virtually impossible to determine conclusively on a starting line that a boat has accelerated by flattening. (I think you have to believe that the flatten accelerated the boat to a speed higher than if she had been sailing close hauled the whole time, not just that she went from STOP to GO.) Cues we use on the open course, such as bow wave, are not commonly visible from behind the boats starting, which is where we commonly position ourselves. As a result, umpires and on-the-water judges  look for the turn while heeled, and if they see that turn they don't penalize the boat for flattening hard.  
Created: 24-Feb-14 18:30
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