Sunday, 25 January 2009

Tactical Rounding with Mark-Room? | 2

Since we are having a discussion about Mark-room in this post: Tactical Rounding with Mark-Room?, I thought it prudent to give you the exact text the working party - the ones who wrote the new rules 18,19 & 20 - said about this issue:

Mark-Room – A comparison of the old and new rules with respect to what ‘room’ a boat is obligated to give while sailing to or at a mark:

The old rules required boats to give ‘room’. The meaning of ‘room’ for the purposes of old rule 18 was stated in two sentences located in two widely separated places in the rulebook – in the Definitions section in the definition Room and in the preamble to rule 18.
New rule 18 requires that a boat obligated to give room give ‘mark-room’, a new defined term.
The amount of space that constitutes ‘mark-room’ depends on where the boat entitled to receive mark-room is located. Before a boat entitled to mark-room is ‘at’ the mark she is entitled to ‘room to sail to [it]’. While she is ‘at’ the mark, she is entitled to ‘room to sail her proper course’. (The use of ‘to’ and ‘at’ in the definition Mark-Room is discussed in more detail below.)

The old definition of room at a mark was incomplete; the new definition Mark-Room is not. The old definition lacked two important features, both of which are covered by the new definition.
  1. The old definition only granted room for an inside boat ‘to round or pass between an outside boat and [the] mark’, and it was silent on what room, if any, was granted between the time one of the boats entered the zone and the time the inside boat needed space between the outside boat and the mark. The new definition covers both those time intervals.
  2. The old definition stated that it covered room ‘in rule 18.’ Old rule 18 imposed requirements to give room on ‘outside’ boats and also, in old rule 18.2(b), on boats clear ahead or clear astern. However, the old definition only specified room that an outside boat was required to give an inside boat. Thus, it was not at all clear what the obligation to give room meant for a boat clear ahead or a boat clear astern that was required by rule 18.2(b) to give room.

The new term ‘mark-room’ only applies to the space that must be given under new rule 18, and that new rule applies only at marks (including marks that are also obstructions). However, if a mark is a continuing obstruction, then new rule 19 applies and new rule 18 does not. At obstructions that are not marks and at all continuing obstructions (including those that are marks), new rule 19 applies, and it only requires an outside overlapped boat to give ‘room’ and not ‘mark-room’.

The new definition Mark-Room answers a question that competitors have been asking for many years. It makes it clear at what time an outside leeward boat with luffing rights may no longer luff an inside windward boat towards the ‘wrong’ side of a mark. Consider two overlapped boats running on port tack to a leeward mark to be left to port. After one of the two boats is in the zone, the leeward boat is obligated by new rule 18.2(b) to give the windward boat ‘room … to sail to the
mark’ (see the first part of the definition Mark-Room). Inside the zone, if the outside boat were to luff the windward boat to a course taking her to the wrong side of the mark, the outside boat would not be giving the windward boat space to sail to the mark. Therefore, that luff would break new rule 18.2, even if the outside boat later bears off and lets the inside boat sail to the mark. If such an outside boat luffs the inside boat towards the wrong side of the mark before either of them is in the zone, then, provided she complies with rule 16.1 (and, if it applies, rule 17), the outside leeward boat breaks no rule. Under the old rules, there was no clearly defined moment at which such a leeward boat could no longer luff the windward boat towards the wrong side.

The use of ‘to’ and ‘at’ in the definition Mark-Room:

Several experienced sailors, upon reading the new definition Mark-Room, have asked what ‘to’ and ‘at’ mean in that definition. In the Terminology section of the Introduction, readers are told that words such as ‘to’ and ‘at’ that do not appear in italics are ‘used in the sense ordinarily understood in nautical or general use.’

Look in The shorter Oxford English Dictionary and you will find many thousands of words in fine print devoted to ‘to’ and ‘at’. We must ask what those words mean in the context of the definition Mark-Room for a boat that is sailing a course in compliance with rule 28. We picked the words ‘to’ and ‘at’ instead of several alternative words because anyone at all fluent in English has learned to use those two two-letter words accurately in a variety of contexts.
An easy to visualize, land-based analogy may be helpful. Suppose that you are driving your car north towards and then into a traffic circle or roundabout. Cars in the circle are required to drive counterclockwise around a paved ‘island’ in the middle of the circle. You plan to drive around the island until you can exit headed west. First, you drive to a point where the northbound road intersects the traffic circle’s circular road – i.e., to a point at which you can begin to round the paved island. You leave the traffic circle using the exit that takes you to the road headed west. The island is analogous to a rounding mark for a racing sailboat, and your car’s track into the circle, around the island and out of the circle is analogous to that of a boat sailing to and around that rounding mark leaving it to port.

To drive the ‘course’ described above, you will first need to drive ‘to’ the circle – that is, to a point from which you can enter the flow of traffic around the island. Once you reach that point, you are ‘at’ the circle. From there you enter the circular road and drive on it until you reach the point at which you leave the circle on the westbound road. Carrying this analogy out onto the water, a boat is sailing ‘to’ a mark until she is in a position close to the mark from which she begins the maneuver of rounding or passing it on the required side. From that time, until she
leaves the mark, she is ‘at’ it.

A boat entitled to ‘room to sail to the mark’ is entitled to the space she needs in the existing conditions to sail promptly in a seamanlike way until she is in a position close to the mark from which to begin the maneuver of rounding or passing the mark on the required side. If a third boat is inside her and she is obligated to give a third boat mark-room, then she must be given space to comply with that obligation. If the mark is moving in large waves, then she must be given space to sail to it without risk of it touching her. While sailing ‘to the mark’ if the boat entitled to mark-room is required to keep clear of the boat giving her markroom, then she is not entitled to the space needed to sail her proper course to the mark – i.e., the course she would sail to the mark in order to finish as soon as possible in the absence of the boat obligated to give her mark-room. However, from the position where she can begin to maneuver to round or pass the mark until she leaves the mark, she is entitled to space to sail her proper course.

You can read the whole paper from the working party (Dick Rose, Ben Altman, Chris Atkins, Rob Overton and Richard Thompson) here: Comparison of Old and New Section C Rules (2).pdf.



  1. I am still not altogether clear. Sailing to the mark, is it acceptable if the outside ROW boat is on a course to the left of the mark until one of the boats reaches the zone, at which moment he bears away? Alternatively, does the ROW boat have to manoeuvre so that, once one of the boats reaches the zone, no bearing away is required.

    I think the analogy of a roundabout is poor. You approach a roundabout close to a radius and have to steer first one way, then the other. You approach a mark outside a tangent so that you only need to steer in one direction. Arguably, you only begin to steer round a mark when it is abeam amidships if the approach has been 'seamanlike'. To me, you would be at the mark when it was beside the front part of your boat.


  2. Perhaps I look for certainty where there is none. A key question is when does 'Mark Room' allow you to change from seamanlike to tactical. Every time that seems to have been pinned down, a fresh uncertainty arises. The attachment to which you have a link contains the following:-

    However,from the position where she can begin to maneuver to round or pass the mark until she leaves the mark, she is entitled to space to sail her proper course.

    Well I can begin to manoeuvre to round or pass the mark very early by swinging out so as to come in wide and leave it close. The roundabout analogy appears to support that. I cannot believe that is intended.

    Is the only effect of 'proper course at the mark' to allow you to avoid making a handbrake turn?


  3. Dear Jos & Al Schonborn ;
    Quotation from Understanding the Racing Rules of Sailing, DAVE PERRY.

    When the outside boat has the right-of-way, she only needs to give the inside boat mark-room; and no more space than that. Note that rule 18.2(a) and 18.2(b) do not shift the right-of-way from the outside/right-of-way boat to the inside boat. If a keep-clear boat sails farther than from the mark than allowed under mark-room, the rules of Section C no longer apply to her and she is subject to the rules of Section A and B.

    And also there is an attached diagram (at a situation of rounding leeward mark);
    - WI is the windward/inside boat. Because she does not have right-of-way over LO, she is entitled only to enough space to sail to the mark in a seamanlike way, as opposed to the space she might like to take in order to make a tactical “swing wide-cut close” type of rounding. WI is taking too much room while sailing to the mark, and by hitting the leeward boat she breaks rules 11 and 14.

    sen yamaoka

  4. I have just returned from the RYA annual conference. I asked when you become at the mark.

    There was some reluctance to answer. A man who was on the committee which wrote the rule said that the key moment was when the front of your boat was next to the mark. A sort of overlap working back from the front.

    Another question was about mark traps in team racing. Room is room to sail promptly. Do you risk a right to mark room by slowing?

    The call book has many cases where a boat slows but the answer always depends on her course, not whether or not she slowed.


  5. Wag,

    Interesting point about a boat sailing slow.

    The promptly/sailing slow consideration would only apply when the boat was at the mark and proper course was a consideration. While sailing to the mark, a boat has no proper course limitation: she is just limited to her right of way entitlement or an entitlement to sail the direct course.

    Boats may sometimes sail slow to establish a particular rules entitlement (for example, under the old rules, to reach the zone overlapped, instead of clear ahead and avoid the head to wind switch off that applied in old rule 18.2(c), but not (b)). The need to do this has diminished with the new rules, and in any case would, as far as I can see, be over and done before the boat became at the mark.

    Where a boat's proper course at the mark was to sail slower than she was able, for example to deal tactically (sail above or whatever) with a boat other than the boat owing her mark-room, then this sailing slow would not offend the 'promptly' requirement of the room definition. The entitled boat must be given the space she needs to manoeuvre onto her proper course promptly, but this does not mean that she must change course more quickly than is favourable to her, or that, once there, she must sail her proper course any more quickly than is required to finish as soon as possible, taking into account boats other than those to which the rule applies.

    Does this help?

  6. Thank you for your reply Brass. I am still unsure. Sailing slowly to get the other boat overlapped outside is still relevant. 'Mark room does not include room to tack unless....'

    In team racing, if you are a give way boat entitled to mark room, you might want to sail slowly to the mark once rule 18 is switched on to allow a team mate to catch up without an opponent getting past. You are not entitled to sail a proper course here. You are only entitled to the space you need whilst manoeuvring promptly.

    At the mark, when you are entitled to sail a proper course, you might swing out a long way to let your team mate in. Is that a proper course?


  7. Wag,

    Ok, got your point about room to tack, but it seems a bit hypothetical to me. The only practical scenario I can imagine is a boat clear ahead while sailing to the mark, then stalling to get inside the boat behind so as to gain an entitlement to room to tack, but if she was clear ahead and not outside, then she would have room to tack, without needing a rule 18 entitlement. And all this has to happen while the boat is at the mark, because the promptly consideration in proper course only applies at the mark, not while sailing to the mark or before reaching the zone.

    In your team racing example you say 'You are not entitled to sail a proper course here. You are only entitled to the space you need whilst manoeuvring promptly.' I think you have this wrong. While sailing to the mark you are not entitled to sail your proper course, only your direct course, but you are not limited to sailing your proper course. Proper course does not apply at all while sailing to the mark. Proper course only applies in any way once you are at the mark. While sailing your direct course to the mark, as long as you hold the direct course, you can sail as slow or as fast as you choose.

    Last team racing issue: if letting your team mate through means you sail other than so as to reach the finish as soon as possible you are not sailing your proper course.

  8. I think thre is a problem with terminology. If you are in the zone, you are not necessarily at the mark.

    You are right about proper course. I did not have in my mind the part about 'as soon as possible'. I was thinking too much about 'in the absence of the other boats referred to in the rule using the term'.



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