Tuesday, 29 September 2009

LTW Readers Q&A | 029 Overlap?

Last Monday I received the following questions from a LTW-reader. Since there is still the possibility this might go to an appeal, I'll restrict my answers to his questions.


RE: Overlap, Luffing Rights, necessary contact, etc.

Situation:  two boats at the start 15-10 seconds before the start on the verge of being overlapped.  Leeward Boat (L) has ~ 45º rake in bow. Windward Boat (W) has a  45º reverse transom and wide flat step in transom.

L has more speed than W.

L claims "overlap," W responds with "no-overlap."

L luffs and makes contact near center of transom causing damage to W.

L protests under Rule 11 - believing that they were clearly overlapped at the time. Claimed contact was necessary to prove overlap.

W protests under Rule 12 and 14 - believing that the instance the point of contact occurred L was clear astern and made no attempt to avoid contact.

Q1: is there an imaginary vertical plane that two boats cannot intersect?  I.e. if the bow swings over a transom, but does not touch is that considered contact? A spinnaker pole or boom over another boats side with out physical contact, etc.

Q2:  Since this incident occurred by two boats approaching the starting line from a point to leeward of the lay-line of the starboard or committee boat end of the line, is there any way this can be construed as "Barging."


In answer to your first question I've looked at CALL UMP 7:


That vertical plane does exist to determine the overlap, but even when there is an overlap, like in the call above and one of the boats changes course to pass behind the other, the keep clear boat is keeping clear.

The test if a boat is keeping clear is always done according to the definition:

  • Can the row boat sail her course with no need to take avoiding action?
  • And if on the same tack & overlapped: Can the leeward boat change course in both directions without immediately making contact with the windward boat.

Both test-questions are answered positive, even when the bow (or bowsprit) swings over the transom.


I'm not an expert in language but in my understanding "barging" is something only a windward boat can do. That boat is sailing lower then a leeward boat and does not want to luff in fear of crossing the line too early or not being able to pass the mark on the correct side. By barging he forces the leeward boat to bear away, in compliance with rule 14 - to avoid contact. A barging boat ALWAYS breaks rule 11 and possibly rule 2.

In the situation you describe the leeward boat luffs. I would not consider this barging by the windward boat. Not on the lay-line to the starboard-end of the start-line and not if it happened leeward of that lay-line.



  1. I would think this is a Rule 12 and/or Rule 15 situation. If they were overlapped, it's Rule 15 as the "trailing" boat just acquired ROW.

  2. Q1: There can't be an imaginary plane, after all boats heel and a windward boat must keep her rig clear of a leeward boat. Similarly, a piece of rigging may pass over the stern of a boat without making contact, thus the boat astern is "keeping clear". There is no provision for, or definition of any "plane", thus we need to avoid inventing one.

    Q2: This could be a case of "barging", but it doesn't sound likely from the description. Rather, this is most probably a case of windward/leeward and the key question is: Was there an overlap.

    Regarding the question of the existence of the "overlap". I think this is the KEY POINT of this encounter. It seem difficult to imagine a situation in which a boat from clear astern could possibly strike the MIDDLE of the transom of a boat that it claimed to be overlapped with. This is made even less plausible by the statement that the boat ahead was moving more slowly than the one astern. To strike the MIDDLE of the transom (as described) the leeward boat would have had to establish and overlap, by going faster, then turn to windward and break that overlap to allow them to strike the middle of the stern. While it is possible that the leeward overtaking boat might have had an overlap prior to coming up towards the windward boat ahead, it is clear that they broke their overlap by turning (the only possible way they could have struck the middle of the windward boat) and they were then clear astern just prior to the moment of impact. If there had been an overlap at the time of impact, then the point of impact would have to have been on the side or quarter of the boat ahead, not the middle of the transom.

    As a result of this last point, I believe that the boat astern should be penalized under rule 12.


  3. I agree entirely.
    Overlap is one thing keeping clear is another.
    To touch to prove an overlap must be wrong and looks like RRS 15.
    To alter to touch is 16.
    Alternatively you are clear astern.

    We do not now about damage but probably no 14.
    The leeward boat buys it all ways!

  4. You must sail in very flat seas.


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