Rule 18.2 is all about giving mark-room. The rule is in place because traffic around a mark can be hectic. Rule 18.2 gives specific rights and obligations to certain boats so we can round marks in a more orderly and safe manner.
18.2 Giving Mark-Room
(b) If boats are overlapped when the first of them reaches the zone, the outside boat at that moment shall thereafter give the inside boat mark-room. If a boat is clear ahead when she reaches the zone, the boat clear astern at that moment shall thereafter give her mark-room.
(1) she shall continue to do so even if later an overlap is broken or a new overlap begins;
(e) If there is reasonable doubt that a boat obtained or broke an overlap in time, it shall be presumed that she did not.
(f) If a boat obtained an inside overlap from clear astern or by tacking to windward of the other boat and, from the time the overlap began, the outside boat has been unable to give mark-room, she is not required to give it.
Let’s run with example 1 below using Rule 18.2(b) which is by far the most common application of Rule 18. Because yellow and blue are overlapped and on the same tack, the windward boat needs to stay clear of the leeward boat under Rule 11.
So below in example 2, we see yellow trying to take advantage of Rule 18.2(b) by pushing blue to port and away from the mark. Again, it is worth remembering that Rule 18 is merely an overlay and supplement the rules in Part A and Part B including:
- Rule 10 – port and starboard tack
- Rule 11 – windward and leeward
- Rule 12 – clear ahead or clear astern
- Rule 13 – tacking
- Rule 15 – acquiring right of way
- Rule 16 – changing course
- Rule 17 – proper course
All these rules still apply so in example 2 below, yellow is bound by Rule 11 to stay clear of blue because they are on the same tack and yellow is the windward boat. Because yellow is not in her “lane”, she loses her rights under Rule 43 and will not be exonerated for breaking Rule 11.
Let’s look at a small variation. At position 1, blue has reached the zone but is clear ahead of yellow. At position 2, yellow realises that blue is closing the gap for yellow to sail into on her way to round the mark and therefore hails “MARK -ROOM!”. Blue hails back immediately with “NO ROOM!” as she continues to close the gap. When it is clear to yellow that no mark-room is provided she protests and goes into a forced gybe after which she continues to round the mark.
In the below scenario at position 1 there is no overlap when yellow reaches the zone. Then at position 2, red establishes an overlap and promptly hails “OVERLAP – ROOM AT THE MARK!”. When yellow hails back “NO ROOM” at position 3 and gybes to round the mark, red takes action to avoid a collision and protest yellow.
Yellow, blue and green approach a gate mark. Blue has some issues with her sails and gets out of the way tucking in behind green without contact.
The battle is now on between green and yellow. Yellow is hailing for room but green doesn’t reply. At position 4, green touches yellows stern without resulting in damage or injury.
So to sum up Rule 18.2…
- The logical question in determining if we need to give mark-room is this. “Was the leading boat at the moment she entered the zone clear ahead. If so, she doesn’t have to give mark-room.”
- If we determine through Rule 18.1 that Rule 18 applies then it is safe to say that we can get clarification from Rule 18.2(a) OR Rule 18.2(b), the latter being far more common.
- Applies to windward and leeward marks.
- If you allege that there was or was not an overlap you require evidence because if there is any reasonable doubt, your assertion will be denied.
- Rule 18 ends as soon as mark-room was given.