Tuesday, 28 April 2009

Mark-room; For how long? |002

A reply on yesterday's post by Brass:

I think we are not disagreeing about the effect of rule 18, just the use of the words.

Mike B says that when a boat inside overlapped at the zone takes more than the mark-room to which she is entitled 'I believe her entitlement to mark room ceases here and the rules of part 2 apply.'

I think this wrongly describes the way rule 18 works. The boat remains entitled to mark-room, and the rules of part 2 continue to apply (which was a key change in the 2009 rewrite). What the boat loses is her entitlement to rule 18.5 exoneration for breaking a part 2 rule.

A boat's entitlement to exoneration under rule 18.5 may switch off when she is sailing outside her proper course at a mark or her direct course to the mark, but her entitlement to mark-room under rule 18.2(b) does not switch off until she leaves the zone or one boat passes head to wind (even though her need for mark-room may disappear).

Update Tuesday 28/04/09; 23:41 hours; on request of Brass I've changed the diagram to this new picture

Consider three boats, Blue, Yellow and Green on port tack approaching a port leeward mark, all overlapped at the zone as shown in the diagram. Blue, inside and to windward sails wide of her direct course while sailing to the mark, and contacts, without injury or damage, a leeward boat outside her (Yellow). Blue breaks rule 11, Yellow does not fail to give Blue mark-room to sail to the mark, so Yellow breaks no rule, and Blue is not entitled to exoneration under rule 18.5 for breaking rule 11. Following a valid protest, Blue should be penalized.

Blue continues sailing to the mark and reaches the point where she is sailing her proper course at the mark, when Green closes the door, leaving no space between Green and the mark for Blue to fit through, and again there is contact without injury or damage. Blue has never ceased to be entitled to mark-room, and Green has now failed to give Blue mark-room to sail her proper course at the mark. Green breaks rule 18.2(b). Blue breaks rule 11, but because she is now sailing her proper course at the mark, she is taking mark-room to which she is entitled, and is thus exonerated for breaking rule 11, under rule 18.5.

Blue's entitlement to mark-room under rule 18.2(b) never changed from the time it switched on.

Whether Blue was taking mark-room to which she was entitled did switch on and off, and thus:

  • Whether boats close to or in contact with her broke rule 18.2(b) switched on and off and
  • Blue's entitlement to exoneration under rule 18.5 switched on and off.


  1. Having read both Mike B and Brass's points I think both have some merit. Clearly Brass's situation is correct for a multi boat scenario but when there are only two boats, say a clear ahead boat entitled to room, slows down to obstruct a clear astern boat. The clear astern boat hs given more than enough room had the lead boat acted promptly. Why should she get more room?

  2. Geezzz!

    As a result of participating in rules discussions, or just lurking in on the discussions of the rules on this site and over at the BISF site, I think I get it. I think I now understand everything Brass just said.


  3. In the diagram:
    Blue has ROW (RRS 10).
    Yellow has to keep clear.
    Yellow does not keep clear.
    Blue gybe to avoid Yellow.
    Yellow DSQ (10,14). Blue exonerated 14(b).
    Green has to give mark-room.
    Green fails to give mark-room.
    Green DSQ (18.2(b))
    Uli F.

  4. My apologies folks. The diagram does NOT show the situation as I intended. @1 Blue should have been on PORT tack, so all three boats are overlapped, same tack.

  5. I have difficulty accepting the notion that a boat may not sail slowly at the mark When I turn to my dictionary I read: Prompt - "ready in action, acting with alacrity" (defined as brisknes, cheerful readiness), "made/done readily or at once" I can see nothing in this definition that requires a boat to sail fast. A boat entitled to mark room can legitimately sail to the mark and then sail her proper course at the mark in such a way that the boat obliged to give mark rom is also obliged to slow or alter course to avoid her.

    If a boat was not entitled to slow then I suggest it should be a matter of urgency to modify the rules of both appendix C and D, because slowing at the mark is at present considered a legitimate tactic in both team and match racing!


  6. Gordon is right in that the new rule 18 does not really support existing team and match race tactics!
    From reading all these posts it is clear that rule 18 is turning otu to be a bit of a mess.We urgently need a sensible statement as to what 'to' the mark and 'at' the mark mean and some official interpretation as to ewhether Mike or Brass is correct.

  7. @confused, look again. Gordon reconciles 'maneuvering promptly' with the team racing tactics. In its context in the definition of 'room', the word promptly helps describe the path of the boat owed room, not its speed.

    In the old rules 18 switched right-of-way so it was important to know when it turned off.

    I think Brass and Gordon and others say correctly that (some part of) 18.2 is on continually. The requirements 18.2 places on a ROW boat are delimited in terms of space, not time. Thinking this way seems consistent with with Dick Rose's description of 'at/to' the mark, and the answers to Team Call 2009/06 and Case 25, where boats exceed their rights to room.

  8. still a bit confused30 April 2009 at 01:14

    Thanks for the help.
    While Gordon addresses a speed issue he does not address a change of course away from the mark. I am still having a little difficulty with a boat that is clear astern at the zone who becomes overlapped and leeward inside the boat who was clear ahead but luffs away (and slows) from his direct course to the mark. Is the boat that luffed entitled to more room to sail to the mark or does he just have to keep clear?

  9. In the situation just proposed by 'a bit confused',
    certainly windward must keep clear, but I would say that leeward must continue to give windward mark-room, even after the luff.

    Case 63 (from the ISAF casebook at www.sailing.org/9506.php) is not exactly the same, but clearly states a helpful principle:

    "When a boat voluntarily or unintentionally makes room at a mark available to another that has no rights to such room, the other boat may take advantage, at her own risk, of the room. The risk she takes is that the boat entitled to mark-room may be able to close the gap between her and the mark while sailing her proper course."

  10. I cannot see thar "room" and keping clear does not have a speed context.

    If a boat entitled to mark room is ROW then there is no problem it is only when the boat is a keep clear boat entitled to mark room we have the issue.

    In Team racing Call B1 we are told where a boat initially was entitled to room to keep clear that actions it should take may include accelerating.

    Does this mean speed is an issue?

    Mike B

  11. I have to agree that room has a speed context. If one turns too slowly, one uses more room at the mark. The rules say we may rely on the inside boat to 'maneuver promptly' when judging how much room we owe her.

    Keeping clear can also require speed.

    However, suppose the inside give-way boat does keep clear. She can slow to set a mark trap, or sail wider than her mark-room but within the zone. I see no rule saying these behaviors turn off rule 18, nor make her entitlement to room 'expire'.

    (Hmm, if the entitled boat is too slow, her competitor has time to make "the Move" and turn off 18.2b with a tack. So now we know why they put that apparent loophole allowing "the Move" into the rules. :-)


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