Proper Course when spinnaker collapses

The racing rules allows for fair competition, but it is a challenge to understand every scenario. To help facilitate the process, the Racing Rules of Sailing Forum offers an opportunity for experts to voice opinion. A post by Jim Archer (USA) had a question regarding Rule 17 and Proper Course.

Rule 17 sates that if a boat clear astern becomes overlapped within two of her hull lengths to leeward of a boat on the same tack, she shall not sail above her proper course while they remain on the same tack and overlapped within that distance, unless in doing so she promptly sails astern of the other boat. This rule does not apply if the overlap begins while the windward boat is required by rule 13 to keep clear.

Proper Course is defined as a course a boat would sail to finish as soon as possible in the absence of the other boats referred to in the rule using the term (a boat has no proper course before her starting signal).

Archer asked, “If a leeward boat (subject to proper course limitation) moving downwind with her spinnaker flying has her spinnaker collapsed by a windward boat, is it correct that the leeward boat may not ‘heat up’ because, absent the windward boat, she would not have had her spinnaker collapse and therefore have no reason to heat up? Is there a case on this?”

Here were some of the responses:

Charles Darley (UK); Regional Umpire:
First let’s assume rule 17 applied to the leeward boat. The likely scenario is leeward approached from clear astern, established an overlap and then became blanketed. Leeward would not luff in the absence of windward, therefore leeward would be sailing above her proper course. I see there is a counter argument but it would be tough to persuade a protest committee. Especially since if leeward was not constrained by 17 her move would be to luff the boat trying to pass to windward.

John Christman (USA); Club Race Officer, National Judge, National Umpire:
I would say that the leeward boat is not allowed to sail above her proper course if the reason for the sail collapsing is the presence of the windward boat. If she could then what would be the point of having rule 17 in the book? If leeward can justify luffing a windward boat up simply because her spinnaker collapsed, which is at the point in time when she most wants to luff windward to pass beneath her, it really defeats the purpose of rule 17.

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