Sunday, October 21, 2012

Rules 17 & 11 - when you can luff up

During the week, I received useful feedback from Michal, Rob and Luca about what I had written on Rules 11 and 17 - these two rules govern when you are allowed to luff up, particularly important in the pre-start and downwind legs of Match Racing. So some clarification/correction needed.

Rule 17: I said that the opposing boat did not luff us up because we had pointed out to them (loudly) that they had approached from astern for the overlap. Michal K commented that RRS 17 says that the boat which establishes overlap from clear astern cannot luff above its proper course - however, there is no proper course before the starting signal - so they could have luffed us up all the way to head to wind.

If that is the case, the starboard reach along the line before the start of a reach is a weak strategy as you can be luffed head to wind (and lose control of the start).

Rule 11: I had described how we luffed up the opposing boat on a downwind leg and gained a big advantage. Rob V sent me a clarification by email. 

Figure: Overlap established more than 2 boat lengths distance so A is allowed to luff up

“Beware in situation 4: the way you've drawn it, overlap was probably established from clear astern within 2 boat lengths lateral distance. In that case, red (Alex's boat) would be subject to RRS 17 and would not be allowed to sail above its proper course.” 

“In the actual situation, you weren't overlapped just after the mark. The boats diverged and an overlap was established at a distance that I judged to be larger than 2 boat lengths… Hence, you were not subject to RRS 17 and were allowed to luff. You did so and forced the other boat to follow your luff (RRS 11). At every change of your course, you had to be careful to give the other boat room to keep clear (RRS 16.1). This you did… The other boat should of course have gybed or taken its spinnaker down much earlier because it was fairly obvious you would luff.”

Links I Like:

Handy intro to the physics of sailing explained by a NASA engineer 

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