Thursday, 12 March 2009

ISAF Q&A 2009-024

This one you'll need to print out and keep under your pillow for a week! I'm still trying to get my head around the scenario's.

Scenario 1:

2009-024 Sc1a

Separated into two positions:

2009-024 Sc1_1POSITION 1
Yellow and Blue are overlapped when Yellow enters the zone. Green is clear astern of both, but moving faster.

2009-024 Sc1_2POSITION 2
When Blue enters the zone Green and Blue are overlapped. Assume there are no constraints on Yellow and she is free to bear away to give as much room as needed.

Question 1: Is Yellow now required to give more room to Blue so that Blue can fulfill her obligation to give mark-room to Green?

Question 2: Is Green an obstruction to Blue? The definition would appear to indicate that this is the case as Blue is required to give mark-room to Green.

Question 3: If Yellow bears away and gives room so both Blue and Green can pass the mark, has Green broken rule 18.2(b) in relation to Yellow?

Scenario 2:

2009-024 Sc2a

And again separated into two positions:

2009-024 Sc2_1

When Green enters the zone, Green and Yellow are overlapped. When Yellow enters the zone, Blue is clear astern of both Green and Yellow.

2009-024 Sc2_2At position 2 Blue becomes overlapped to windward of Yellow.

Question 1: Is Green an obstruction to Blue?

Question 2: If the answer to Question 1 is ‘Yes’, does Yellow now have to give room to Blue under 19.2(b)?

Question 3: If Yellow gives room, would Blue be disqualified under rule 18.2(b) and (c) if Yellow protested?

Question 4: If the answer to Question 2 and 3 is ‘Yes’, then how can you justify disqualifying a boat when, although she has broken a rule, she is only asking another boat to comply with a different rule?


I’ve deliberately separated the scenario’s and questions from the Q&A, so you can try to answer yourselves, before looking at the findings of the panel.

I’ll give you a hint from the text in the Q&A:
No rule states that, when rule 18 applies, rule 19 does not!

After that, you can read the complete ISAF Q&A 2009-024.

I’m off to work for now, but am sure to have a look at them again in my lunch-break, phew!


  1. Scenario 1, yes, yes, no.

    Scenario 2, yes, yes, yes. Its only like rules 11 and 17.


  2. Aaaaaalrighty then, complicated but fun! Excellent example of how the rules 'click together', although I'm not sure I agree with the analogy of rule 17 and 11 with 18 and 19.

    ROW combined with a restriction on the use of the ROW is, in my opinion, something different than two rules canceling out each others room.

  3. Having fired from the hip again, I have just had a look at the ISAQ Q and A page. I see that I am quite wrong regarding scenario 1. I can see why and I see how the definition works with rule 19. However, putting so much significance on the plural instead of the singular is another example of the writes of the rules being too clever.


  4. scenario 2
    1 - No, because a ship which is sailing is not an obstruction
    2 - No at the moment when yellow enters the zone blue is clear astern. That's mean 18.2b yellow isn't allowed to give space to blue.
    3 - Yes because rule 18.2b is broken.
    I think I'm right but if it isn't, would somebody say is to me??
    Greetz Menno

  5. OK here's my thoughts:

    1. No
    No overlap as first boat enters zone

    2. No
    No overlap, no mark room, no obstruction

    3. Yes
    Boat clear ahead entitled to mark room

    1. Yes
    Boat clear ahead, entitled to mark room, obstruction

    2. Yes

    3. Yes

    Yellow allows room for the obstruction to avoid a collision not because she agrees blue entitled mark room.

  6. In scenario 1 I would answer
    1 yes, by rule 19.2. Within the green blue pair, green has overlap before blue enters the zone.
    2 yes
    3 yes, green's behaviour deprived yellow of space to sail to the mark.

    I hope Wag's comment about the plural does not mean the official Q&A interprets the definition of 'obstruction' to be something *both* boats must clear beacuse of the plurals in "to other boats unless they are required to .. give her room".
    1) modern english speakers very often use 'they' an indefinite pronoun, and
    2) in other cases where an obstruction affects only one boat (shallow water) I would want other (shallow draft) boats to give room.

    In scenario 2,
    1 yes
    2 yes
    3 yes
    4 All boats have to comply with all rules. In a starboard-port situation, the port boat is "only" asking the starbord to comply with rule 14, yet must still obey rule 10.

  7. According to the answers in most comments, I see that I am not the only one who answered differently then the panel. After reading their replies I understand why. But it shows that I need to change my "mindset".....

  8. Frankly the rule writers screwed up. 19 should not apply at marks period.

  9. Another question arises from Scenario 2 Answer 3.
    If Yellow fails to give room to Blue and Blue luffs to keep clear would Yellow be disqualified for breaking rule 19.2. The answer, following the logic that both rules apply equally, would appear to be Yes. Yellow cannot be exonerated under 64.1(c) as she would not have been compelled to break the rule. Sounds a bit silly to me as Yellow would be subject to protest from boats trying to barge in and would in many case be in an indefensible position!

  10. In answer to OHara, the ISAF Q and A does interpret a boat racing as an obstruction only if both (other) boats must keep clear. The shallow water he speaks of can be an obstruction to only one boat.


  11. Hello,
    as a sailor just trying to learn the Rules, may I present my considerations about Situation 1.

    1. Yes
    I assume that 'manoeuvring in a seemanlike way' includes the opportunity for a boat to manoeuvre in such a way that she complies with the Rules. Knowing that 'mark-room' (per def) includes 'room' which includes 'seamanlike way' (per def), we can conclude that if a boat is entitled to mark-room she is entitled to manoeuvre in a way which enables her to comply with the Rules as well. These Rules (in our case 18.2(b)) require Blue to give mark-room to Green. Therefore the mark-room to be given to Blue by Yellow includes the space Blue needs while she gives mark-room to Green.

    If I try to apply the term 'obstruction' in two-boats situations when boat X is the obstruction while boat Y is the keep-clear (or give-room etc) boat, rules 18 and 19 does not seem to me applicable because only one boat is present (Y) while X serves as an obstruction only.
    So I would not ask 'is G an obstruction to B?'. I would ask rather 'is G an obstruction to B and Y?' My answer is No, because Y is not required to keep clear or give room or mark-room to G.

    But Y is an obstruction to B and G (rule 11 and 12) and rule 19 requires G to give room to B. At the same time rule 18.2(b) requires B to give mark-room to G. They give room to each other. I don't see any conflict here.

    3. No
    G interacts primarily with B not Y. In the absence of B, if Y voluntarily gives space that G could use, G does not break rule 18.2. If G compel Y to bear away to avoid collision with G, then G would have broken rule 18.2(b).

    Sorry being too long presenting the thoughts of a layman.
    Many thanks for Jos mantaining this beautiful page and for all of you who contribute to it.


  12. Whilst it would be nice to agree with Anonymous that rule 19 should not apply at marks, this would be OK except that rule 19 does not only apply to boats that are racing. Also what about a boat that maybe capsized in the zone?

  13. Jos, do you already know what the right thing is and what not about the scenario's? When I read the comments, I saw that everybody has his own interpretation. So I don't know what now the right thing is.


  14. You can read the official answers of the Q&A panel when you open the actual Q&A. The link is at the end of the post.
    And her again:
    the complete ISAF Q&A 2009-024.

  15. In reply to an anonymous Anonymous:
    Yellow would indeed be subject to protest from a boat barging in without an overlap at the zone, if she doesn't allow room to avoid the obstruction - in this case a boat entitled to mark room.

    The answer is to give room for the obstruction and protest. Then it is the barging boat that is in the indefensible position.

    Note that 19.2 does say of the yellow boat:
    ... unless she has been unable to do so from the time the overlap began.


  16. Thanks Andrew,
    I can see a scenario where Yellow would suddenly get a yell of 'protest' from behind when she was unawre of Blue's approach, and it is too late for her to give room and therefore, by complying with her rights under 18 she is now defenceless of a protest under 19. I do not think this is particularly fair - but then I suppose fairness doesn't always come into things!

  17. Somewhat late, I notice that Rapid Response Team Racing Call 2009/001 addresses the same situation, with a different answer:
    Q. Yellow, Blue and Green are approaching a mark overlapped, with Yellow required to give markroom to Blue, and Blue required to give mark-room to Green. Does rule 18.2 require Yellow to give enough room to Blue to enable her to give mark-room to Green before Green is at the mark?

    A. Yes. ... Room to sail to a mark includes room to give room to, or keep clear of, other boats if required by the rules to do so.
    This logic is very similar to what Agnes used above. I hope this way of thinking eventually prevails.

    (Sorry for the duplicate post, Jos. I mistakenly posted this to the LTW Q24 thread.)


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