CALL UMP 30              

Rule 15 Acquiring Right of Way
Rule 17 On the Same Tack; Proper Course
Rule 18.2 Giving Mark-Room
Definitions Giving Mark-Room

Question 1
Yellow enters the zone clear ahead of Blue. Both boats tack and continue to round the mark. Blue becomes overlapped inside Yellow. Both boats Y-flag, what should the call be?

Answer 1
When Yellow enters the zone, rule 18.2(b) applies until Yellow passes head to wind. When Yellow becomes overlapped to windward and on the inside of Blue in position 3, mark-room includes room for Yellow to tack. After she has been given room to tack, 18.2(b) ceases to apply. From the moment Blue becomes overlapped inside Yellow, rule 18.2(a) applies.
Because this overlap is established from clear astern rule 18.2(e) applies and Yellow is only required to give mark-room provided she has been able to do so from the time the overlap began. Since Yellow is unable to give mark-room, she is not required to give it.
If the overlap was created by Blue bearing away, then rule 15 applies and Blue must initially give Yellow room to keep clear. If Yellow is unable to keep clear, penalize Blue.
If the overlap was created by Yellow bearing away, Blue acquires right of way, at least in part, through Yellow’s actions. Therefore the second part of rule 15 applies, so Blue does not have to give Yellow room to keep clear. Penalize Yellow.
Because the overlap is established from clear astern, rule 17 applies.

Question 2
Yellow and Blue enter the zone overlapped . Both boats tack and continue to round the mark. Blue becomes overlapped inside Yellow. Yellow’s boom touches Blue’s hull. Both boats Y-flag, what should the call be?

Answer 2
See answer 1.