Y and B are overlapped, sailing parallel courses, with about ½ boat’s width between them. Y has no proper course restriction. Just before position 3 Y luffs slowly and B promptly responds. Y continues to luff and there is no longer any means of B avoiding Y. B tries to keep clear by luffing and there is contact. Y protests. What should the call be?
Positions 1 and 2:
B is keeping clear because she is sufficiently far from Y that Y is able to change course in both directions without immediately making contact.
After Y’s first change of course, B still has room to keep clear. B must, promptly and in a seamanlike way, do whatever she can to establish sufficient distance between her and Y so that she is keeping clear. If B does this she is protected by rule 16.1
Between 3 and 4:
Y continues to change course, and B is no longer able to keep clear. Y breaks rule 16.1
. Penalize Y.
If Y continues to luff and B continues to respond promptly and in a seamanlike way to each luff, Y will ultimately have to stop luffing when the boats are so close that any further luff from Y will result in B being unable to keep clear. If Y does stop luffing at such a time, and B continues to respond to keep clear, neither boat breaks a rule.
A boat that is required to keep clear must promptly take any opportunity to keep clear when a right-of-way boat changes course, but does not normally have to anticipate any change of course by a right-of-way boat.