Crowding the stern
The situation
Same tack upwind, Ada is just clear ahead of a faster boat coming up from astern. The astern boat noses right up close behind and starts to slide alongside to leeward.
The question
When does the boat astern actually get rights — and what must she do until then?
The ruling
Until an overlap truly exists, the boat clear astern keeps clear of the boat clear ahead (rule 12). Getting close gives her nothing; she must steer around. The instant she establishes a leeward overlap, right of way switches under rule 11 — but rule 15 then makes her give Ada room to keep clear, and if the overlap came from clear astern within two hull lengths, rule 17 caps her at proper course. Crowding the stern hoping an overlap 'just happens' is exactly how fouls happen.
Clear astern keeps clear until a real overlap forms — sailing up close earns you no rights (rule 12).
Opens the situation on the boat-length grid — scrub it and see exactly how the boats meet. Free, no account needed.
Rules cited
- Rule 12 — On the Same Tack, Not Overlapped
- Rule 11 — On the Same Tack, Overlapped
- Rule 15 — Acquiring Right of Way
See the underlying rule: Rule 12 — On the Same Tack, Not Overlapped.