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  1. #121
    Barnac1e's Avatar
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    Quote Originally Posted by aluijten View Post
    Sorry for the small thread drift, but what software are you using in this screen. It looks quite nice.
    I was using http://www.oziexplorer.com/, an excellent navigation program but limited to raster charts. I've since changed to OpenCPN - not such a function-rich application but able to support vector charts.

    I'm following this with interest. The problem is that I'm inclined to agree with all, depending on the view I'm taking.
    Which is why I posted - it's interesting to hear what others would do, despite armchair sailing and desktop decision-making being a world away to the frisson of "seeing 250 meters of heavy steel coming at me".

  2. #122
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    Barnac1e

    How was it illegal? I was crossing a TSS at right angles - more or less.
    Yes, I can see that you were initially crossing the Ro-Ro's track at about 90 degrees, but I got the impression that you then gybed onto a reciprocal (NE'ly) course to the SW bound ships, for some time, while they passed.

    Not so?

  3. #123
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    Quote Originally Posted by Barnac1e View Post
    I would genuinely like to read the panel's opinion of this scenario that occurred during my crossing of the Gulf of Trieste. As can be observed, I had a CPA of 143m and under sail was the stand-on vessel. As it was I slowed right down by roller-furling the genoa to allow the RoRo ferry to pass ahead - at no time had she shown any change of course or speed herself.

    According to most here I should have stood on until a collision was looming then have done something. Instead, because of my action the "professional seamen held me in contempt"
    This is the most common danger situation faced by boats under sail. The assumption by commercial vessels is that, until proved otherwise, they are stand-on vessels against those coming from port.

    Once in sight of the "target", they may or may not decide it is encumbered (under sail, or is fishing, or trawling). In TSS it's common to assume vessels coming from port are un-encumbered, and therefore "give way" vessels, since vessels are not allowed to fish/trawl in these regions, even though they still (all too often) show fish/trawl lights or signals. And there's a not dis-similar assumption about sail boats - that they will be motoring, even if they're not showing cones (again, all too often).

    Of course, if the genoa is rolled, you will be assumed under motor (even with no cones), and therefore the give way vessel.

    I'll say again, the only safe way for a sail boat to remove this uncertainty is, when crossing a traffic lane (not necessarily a TSS) coming from starboard, start the engine, lower/furl the genny, hoist the cone (or turn on the motoring light). Then on-coming traffic will know clearly they remain stand-on vessels. Waltzes, or tangos, should no longer arise.

    As visibility reduces, so this behaviour becomes ever more important.
    Last edited by jimbaerselman; 31-01-12 at 13:20.
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  4. #124
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    Quote Originally Posted by JayBee View Post
    Yes, I can see that you were initially crossing the Ro-Ro's track at about 90 degrees, but I got the impression that you then gybed onto a reciprocal (NE'ly) course to the SW bound ships, for some time, while they passed.
    Not so?
    Yes. You are correct that I perhaps should have joined the column ... but direct to windward? I would have had to have tacked - away from my destination. I could also claim to have been (marginally) in the separation zone between both lanes.
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    Quote Originally Posted by Barnac1e View Post
    I presume you mean the 2nm range ring and the target icon. You must have a much higher resolution monitor than I do. I certainly did not observe any course change within that distance (0.64nm) and I had been monitoring both visually and the screen AIS track for quite some while. If the ship had indeed changed course I think it would have done so by enough to be clearly evident on its AIS data track - no point doing so by some minuscule amount.



    Nothing, it was below in its storage on the bulkhead. I believe the bearing differences we are discussing would have been indistinguishable and lost in the standard errors I get when taking sights on a moving deck.
    Sorry, yes, that is where I meant. I see a kink there even on the screen of my phone. As I said, it may just be a wobble in the AIS data and, like you, would have expected a bigger deviation to be likely if it was a deliberate adjustment, but they may have considered it enough. It only looks like about a 5 degree change on the track line to me.
    Last edited by Simondjuk; 31-01-12 at 13:54.

  6. #126
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    Quote Originally Posted by Simondjuk View Post
    I see a kink there even on the screen of my phone. As I said, it may just be a wobble in the AIS data
    I believe what is being observed is the classic difficulty of representing a straight diagonal line on a X/Y bit-mapped pixel screen. There is a point where the blocked pixel must traverse to the adjacent vector and the transition, depending on the resolution, will appear kinked despite the original data being smooth. This explains your kinked line on a mobile phone screen but straight on my high-resolution monitor.

  7. #127
    john_morris_uk is online now Registered User
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    Quote Originally Posted by Seajet View Post
    For the last time, who said anything about manouvering 'unpredictably' ?!

    I get a feeling I'm talking to accountants who think they should push their and sadly their crews' luck and sod anyone else - to save 5p & 5 minutes or - 'make the other guy give way' - as if they're still in their car -, rather than experienced ( and courteous as well as safety conscious ) seamen.

    I have said ' if in doubt change course EARLY & OBVIOUSLY ! '

    If that is too hard to work out, there's no point continuing this discussion; Good Luck !
    Simondjuk sums it up pretty well in his posts. Try reading them again?

    In response to your post quoted above: what do you mean when you say you change course 'early and obviously?' How have you assessed that a change of course might be necessary? If you are using a handbearing compass, then you might not know if the bearing is changing until the ship is a couple of miles away. By this time, the ship will have been watching your course and worked out the CPA and decided what to do. The reality of collision avoidance from a ship's point of view in your world is that the ship almost certainly will have been tracking you for some time, and then they see you make some illogical course alteration and they wonder what you are going to do next.

    No-one is suggesting that you stand on blindly into danger, but the impression that you give is that you alter early for everything. What does 'early' actually mean? As has been said by myself and others, this is the sort of behaviour that leads to much cursing on the bridge of large ships. In their mind, you have already made one illogical course alteration, and they spend the next few minutes trying to see if you really know what you are doing, or are going to make another equally illogical alteration and put yourself in their path. You know what you are doing in your own mind - and it might make perfect sense to you - but try to see it from the position of the bridge watchkeeper. He really doesn't want to guess what you are doing next. Nice steady courses with alterations as appropriate according to the IRPCS makes him/her a much happier person and keeps you JUST AS SAFE. Stand on until its obvious what is happening - and then you can use your ability to change course quickly to keep out of the way if necessary. You will be pleasantly surprised by how infrequently you have to do anything at all.
    Last edited by john_morris_uk; 31-01-12 at 16:49.
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  8. #128
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    Quote Originally Posted by Seajet View Post
    ...Read the ColRegs again, ' No craft under 20 metres LOA will impede a merchant vessel '....
    I've read them .. many times, and I've never found that bit.
    Maybe you could refer us to the Rule number?

    It's quite easy to do. If, for instance, I want to refer you to the bit that says "Where one of two vessels is to keep out of the way, the other shall keep her course and speed", I simply need to say "Rule17 (a) (i)".

    Talking of Rule17(a)(i): can you tell us where it says that doesn't apply to yachts? (Just quoting the rule number will do).

  9. #129
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    This debate is primarily between those of the "might is right" persuasion and those who prefer their interpretation of the IRPCS.

    The name of the thread is "Crossing Separation Zones in a Small Yacht" but it has widened out into a more general discussion of ship/yacht collision avoidance. This post is about collision avoidance in a TSS.

    I believe that there is some confusion surrounding the use of the word "impede" in a TSS.

    Rule 10j states that: "A vessel of less than 20 metres in length or a sailing vessel shall not impede the safe passage of a power-driven vessel following a traffic lane." A common interpretation of this is that by NOT keeping her course and speed (as the stand on vessel, (Rule 17 (a) (i)) these vessels are in contravention of Rule 10j by introducing confusion into the situation.

    However this is contradicted in a commentary in "Farwell's Rules of the Nautical Road":

    "If the small craft or sailing vessel follows a course that requires another vessel following the lane to alter course or speed, the small craft or sailing vessel is guilty of impeding the safe navigation of the other vessel. Once again, however, if the situation develops so as to involve risk of collision, the applicable steering and sailing rules apply to the vessel following the TSS; however, Rule 8(f)(ii) makes it clear that the encroaching vessel is not in any way relieved of her obligation not to impede the other, and therefore she can not seek shelter as a potential priviledged vessel under the steering and sailing rules. If collision results, the vessel’s breach of her duty not to impede will be a basis for allocating fault for the collision."

    FWIW, I think the question turns on the point when "encroaching" begins and this is unfortunately a bit subjective. It is not helped by wildly inaccurate perceptions, by some yachtspersons, of the manoeuvring capabilities of large ships and of their standards of watchkeeping.
    Last edited by JayBee; 01-02-12 at 12:59. Reason: sp

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    Quote Originally Posted by JayBee View Post

    Rule 10j states that: "A vessel of less than 20 metres in length or a sailing vessel shall not impede the safe passage of a power-driven vessel following a traffic lane." A common interpretation of this is that by NOT keeping her course and speed (as the stand on vessel, (Rule 17 (a) (i)) these vessels are in contravention of Rule 10j by introducing confusion into the situation.

    However this is contradicted in a commentary in "Farwell's Rules of the Nautical Road":

    ..... however, Rule 8(f)(ii) makes it clear that the encroaching vessel is not in any way relieved of her obligation not to impede the other, and therefore she can not seek shelter as a potential priviledged vessel under the steering and sailing rules. If collision results, the vesselís breach of her duty not to impede will be a basis for allocating fault for the collision."
    It may well be that Farwell is confusing the IRPCS with the US inland regs because Cockroft and Lameijer (who are the usual reference in Admiralty Courts) say very clearly that :

    " a sailing vessel..... should... wait for a suitable oportunity to cross a traffic lane but a power-driven vessel following a lane is not relieved of her obligation to keep out of the way if there is a risk of collision with a sailing vessel. "

    also :

    " ...sailing vessels are not required to avoid impeding the safe passage of power-driven vessels crossing a lane ...."

    I would ignore Farwell's comments.

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