Tuesday, 17 March 2009

LTW Readers Q&A | 21

Hello Jos,

I have a question for your blog.

I had a discussion with some UMP and JDG about situation under rule 18.3. The rule book says "if rule 18.3 applies .. rule 18.2 doesn't". My question is about rule 18.5.

Q: If a boat is under 18.3 and 18.2 is OFF ..is rule 18.5 still applying?

If one part of rule 18.3 switches off rule 18.2 and the "mark room" right, this means rule 18.5 can not be applied also, because it is written "When a boat is taking mark-room to which she is entitled, she shall be exonerated..."

Seems when rule 18.2 is switched off we have to come back at "normal" rules without the exonerations of 18.5. So the boat inside bearing can infringe rule 16 and have no rights at any exoneration...???

Best Regards,

Luigi Bertini

Well Luigi,

I've had a look at the exact wording in rule 18.3: And you're right that, if all the requirements of rule 18.3 are met ( i.e. boats on opposite tacks approaching a mark and one of them changes tack and is subject to rule 13 in the zone when the other is fetching the mark) , then rule 18.2 is switched off.

That means that the tacking boat can not claim mark-room as inside boat and is subject to all other rules. She either becomes row-boat under 11 with restrictions under 14, 15 and 16, and an additional restriction under 18.3. That is, she may not cause the other boat to sail above close-hauled to avoid her or prevent the other boat from passing the mark on the required side.

In this situation she has no "use" for rule 18.5, she never gains mark-room, therefore cannot be exonerated other then by 64.1(c).

She can also become keep clear boat, if the fetching boat becomes overlapped inside her.

Again in that situation all normal rules apply and she does not gain mark-room, therefore again has no "use"for 18.5. She then must keep clear under rule 11.


If the fetching boat establishes an inside overlap, SHE is the boat who is entitled to mark-room. She then also has the "protection" of rule 18.5!

That rule does not state that only mark-room gained from a rule 18.2 is to be considered. No, if a boat taking mark-room to which she is entitled - however she got it -, she shall be exonerated....|
The inside boat is given mark-room in 18.3(b)....

So, in answer to your question; if rule 18.3 is applicable and rule 18.2 is not, rule 18.5 is still applying for the fetching boat that establishes an inside overlap.

All the best,


  1. all clear.

    but liking to get your opinion about 18.3 a)when it says "to avoid her" (and not "to keep clear")

    W fetchin the mark, starboard tack
    L port tack, tacking inside the zone, 18.3 apply

    L tack is correct, W remains behind, clear astern, no change in her course, parallel to L course, upwind

    On the way to the mark, same course, W obtains an overlap to L from windward

    L became ROW, inside boat, still subject to 18.3

    W is subject to 11, but to keep clear, W have to sail above close hauled

    L keeps going straight, no defense luff

    If W luffs above close hauled to keep clear, is L breaking 18.3 ?

    I am temped to say no, because W luff is "to keep clear" , her obligation under rule 11, a consecuence to his own action of overlapping from windward, and not "to avoid" L because of L tack.

    If L luffs in defense of the overtaking, I belive L breaks 18.3, otherwise she is not.

    Quite stetched interpretation, isn't it ?
    I am not 100% convinced myself...

    Thank you for your kind attention

    Aldo - Italy

  2. Aldo
    Rule 18.3(a)reads "shall not cause the other boat to sail above close-hauled to
    avoid her or prevent the other boat from passing the mark on the required side",
    It does not state any reasons as to why the non tacking boat shall have to avoid. The plain fact that she has to sail above a close hauled course to avoid the boat that tacked is enough for the boat that tacked to break 18.3.

  3. good day Brian

    may i pose a question ?

    boat W and L, both starboard tack, overlapped, approaching a downwind buoy to leave on port (both have to gybe to take the buoy)
    W outside, L inside
    18.4 applies
    17 not appliyng

    a) is L free to luff, inside the zone, before reaching its layline and gybe ?

    b) if not, is L allowed to a atactical approach ?

    c) does it matter wether W and L were overlapped or not entering the zone ?




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