Thursday 22 January 2009

FARR 40s again?

From the Sailgroove website:

Sailing Videos on Sailgroove


Looks like protests will decide at least a couple of finish places in this race!
Crucial in the hearing: were they outside the zone when the gybing and subsequent luffing first occurred? If yes, the most leeward boat will get DSQd. If they where inside the zone the most windward of the three is in trouble. The middle boat should be exonerated in both cases.

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6 comments:

  1. Jos,

    What am I missing here?

    We're talking about the Grey, White and Black boats coming into frame @28sec. Boats are approaching a the RC boat at the starboard end of a downwind finish line, out towards the Port tack layline?

    @28 Grey is on stbd, White and Black on port, so Grey is right, stbd.

    @31 Grey is boom over centreline, so Grey is port, and becomes right leeward. Grey does not acquire right of way because she was previously right stbd, so rule 15.1 does not apply.

    Is your point that Grey is changing course hard and in rule 16.1 difficulty, so that she needs to be at the zone to get rule 18.5 exoneration?

    As I see it, Grey gets to the finish boat (from which the zone extends) about @55sec, 25 sec after she gybed @30sec. Using my trusty Speed Table Appendix 6 in my Judges Manual, assuming a Farr 40 is doing about 8kts, the gybe was 8 boatlengths from the mark, and the zone would have been reached @45sec.

    Between 31 and 38 there is a good example of problems with video evidence: camera boat is moving opposite direction to the boats, so it appears that Grey is changing course harder towards White than she really is.

    Could you expand on what you think Grey's problem is?

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  2. You are probably right about the distances, I thought it was outside the zone too, although I don't think they are doing 8 knots.
    Grey started on starboard, White I'm not sure but perhaps you are right, on port, but Black is definitely also on starboard.
    So Grey -RoW- gybes in front of White who is until then keeping clear. Grey luffs and White is forced to go up.
    Don't you think that they forced Black -RoW on starboard- to gybe to go up? White had no choice, she was forced by Grey.
    Was Grey in the zone when Black had to gybe?

    You are absolutely right about the video. I'm guessing half the time and could be altogether wrong. According to Chris Love, commenting after me on the SailGroove site, the outside boat (Black) was DSQd. So perhaps they were inside?

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  3. To me it looks like there are two situations here. One outside the Zone and one in the zone. When Flash Gordon Gybes (gray boat) she is well outside the zone she luffs the white boat into the black boat that was on starboard. Black was forced to gybe to avoid contact with white. Flash Gordon should be DSQ for this.

    As the 3 boats enter the zone they have overlap on the boats finishing on Stbd. It looks like Black, who is giving room to Flash Gordon and the white boat is not given mark-room by the stbd finishers, but the video is not conclusive on this.

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  4. Thanks Jos,

    I didn't make out that Black was initially on stbd: I agree she was.

    OK, suppose they are doing 6 kts: then when Grey gybes @30 they are 6BL out, and will hit the zone @42, when Black has just completed her gybe and is rounding up.

    I don't think Grey gybes 'in front of' White. As I see it Grey gybes her main, and while holding downwind to complete the spinnaker gybe, notes that she is about to be able to attack White, and doesn't complete the spinnaker gybe and floats the spinnaker off to leeward out of the way, and then she comes up hard(ish). I don't think Grey begins to come up until about @40.

    I don't think the issue was whether Grey was at the zone when she gybed, but whether she, and White were at the zone (and thus entitled to mark-room) when she started coming up. AS the PC disqualified Black, and not White and Grey, it seems that they were satisfied it was in the zone.

    My comment about the problem with the video wasn't meant to cast doubt on your interpretation. I just thought it was a very good example that would merit being kept and shown in training to illustrate problems with video.

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  5. Agreed. Unless you have a helicopter view videos are notoriously unreliable.

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  6. But some things a video can show very well.

    When the video boat happens to be in the right position as a wing or umpire boat would be, and ability to replay and focus on one boat at a time.

    For example even in this video, by watching carefully and repeatedly, one boat at a time, you can see:

    @27 White's boom out to port, coming across, not yet on centreline so White is on stbd, and gybing

    @28 Grey's boom out to port not yet beginning to move, so she is on stbd, and not yet gybing

    Up to @30, you can't see which side Black's boom is on (although you can make deductions from the curl of her spinnaker), but

    @31 Black's spinnaker lifts and you can see her boom out to port, so she is on stbd

    @31 Grey's boom crosses centreline so Grey has gybed onto port.

    So even this video, which could be quite misleading about turns and rates of turns of boats, can give us some good solid facts found that would probably be very difficult to get at with witness testimony alone.

    ReplyDelete

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