No luffing room from clear astern
The situation
On a reaching leg, Blue comes up from clear astern and establishes a leeward overlap on Green, less than two hull lengths away.
The question
Can Blue, now the leeward boat, luff Green up?
The ruling
No. Under rule 17, because Blue got the overlap from clear astern within two hull lengths to leeward, she may not sail above her proper course while the overlap continues within that range. She does have right of way as the leeward boat (rule 11) and Green must keep clear — but Blue can't use that to drive Green above her proper course.
A leeward overlap gained from clear astern within two lengths can't be used to luff above proper course (rule 17).
Opens the situation on the boat-length grid — scrub it and see exactly how the boats meet. Free, no account needed.
Rules cited
See the underlying rule: Rule 17 — On the Same Tack; Proper Course.
Related cases
- Overtaking to windward · Reaching
On a reach, Blue catches Green from clear astern and goes to pass to windward, establishing a windward overlap.
- The leeward boat luffs · Upwind / Beating
Two boats sail close-hauled side by side on the same tack, overlapped. Green is to leeward, Blue close alongside to windward. Green begins to luff, heading up toward the wind.
- Defending your lane · Upwind / Beating
A boat is creeping up to windward, trying to roll over Priya. Priya, the leeward boat, luffs gently to slow the windward boat and protect her wind.
- Rolling through to leeward · Running / Downwind
On the run, Mia catches the boat ahead and slides up to leeward of her, establishing an overlap from clear astern less than two boat-lengths away.