Match Race Call D1
Rule 11; On the Same tack
Rule 16.1; Changing Course
Definitions; Keep Clear and Room
Leeward must give windward room to keep clear in a seamanlike fashion, which includes avoiding hitting a mark.
Question 1
Shortly after the start Yellow and Blue are close-hauled on port tack. The boats are overlapped and Yellow is keeping clear to windward. As the boats pass to leeward of mark L, an inflatable buoy that is not a mark on this leg, Blue luffs and Yellow responds. Yellow stops luffing when she hits the mark amidships, which causes Blue to curtail her luff. Both boats display flag Y. What should the call be?

Answer 1
Penalize Blue. When Blue, the right of way boat, changes course she has to give room according to rule 16.1. It is not seamanlike to hit a mark.

Because mark L is not a mark on this leg, rules 18 and 31 do not apply.

Question 2
Would the answer be the same if the boats were passing to leeward of an object that was not big enough to rank as an obstruction, but nevertheless limited her ability to respond and/or could cause damage to the hull or foils?

Answer 2
Yes. Provided Yellow was initially keeping clear, Blue must give her room to respond in a seamanlike way when she changes course.