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    Re: FW: Avoiding collision.
    From: George Huxtable
    Date: 2003 Oct 9, 17:31 +0100

    As a reminder, Doug Royer said originally-
    
    "a Polish ABS I served with ... won an $1800.00 pool on one
    >transit when his final position was less than 0.2nm from the ships GPS pos.
    >when the evolution was stopped by the master."
    
    to which I replied-
    
    "My, that is encouraging! To think that the art of celestial nav is still
    sufficiently alive-and-well on the brige of American merchant vessels, to
    the extent of that much hard cash riding on the accuracy of observations
    and predictions."
    
    Then, after some stuff about collision avoidance, I commented-
    
    "now Doug's revelation, above, adds something to the picture. Imagine
    the scene on the bridge, when everyone knows that there's $1800 riding on
    exactly where the ship will be, within a small fraction of a mile, at the
    moment the master gives the word. Which one among them is going to be brave
    enough to order a course change to avoid me in my pesky little sailing
    craft, a few miles ahead on the port bow?"
    
    ==========================
    
    More recently, Doug has said-
    
    >George,I
    >wrote about this very same incident in a post shortly after I joined this
    >group.It did not cause you any heart burn then so why or what incident
    >happened to you in the interum to set you off?
    >At the start of the transit the master set the rules for the evolution.It
    >ran from San Fran. with stops in Hawaii and the P.I. to a area east of the
    >Mallucan Str.3 weeks alapsed time.There is not much traffic in this route.
    
    =================
    
    Response from George-
    
    Fair enough, Doug. I remember that earlier posting, and found it very
    uplifting (and rather a surprise) that celestial techniques were still
    being practised on board merchant vessels.
    
    The new information was that there was $1800 of hard cash riding on the
    result. What I deplored was any sort of disincentive to the watch-officer
    altering course to avoid a hazard. Perhaps the modern tendency to
    automatically precompute a track between waypoints is a bigger deterrent to
    the freedom of the watch officer, to use his judgment in overriding it.
    
    But it wasn't meant too seriously. I don't imagine that such competitions
    are a great hazard of the sea, and presumably they wouldn't be indulged in,
    in congested waters. It was, I admit, an attempt (something I find hard to
    resist) to tease and provoke a response: which seems to have worked. For me
    it was a peg on which to hang my argument about collision avoidance and the
    colregs, which I regard a more serious matter. And it's pleasing that Doug
    has responded, giving his own perspective about that. It's good to have a
    picture of the problem from the other fellow's point of view.
    
    ===============
    
    Now to respond to some of the interesting matters that have cropped up.
    
    Doug has said-
    
    >The penalties for a M.M.O. who fails in his duties are much more severe than
    >for someone who isn't lisenced.
    
    Well, in a collision with a merchant vessel, those aboard a small craft
    face a severe risk of the Death Penalty.
    
    >Small boaters(anything 100 GT and under domestic we will consider small)are
    >mostly pleasure boaters and a good majority of them are clueless as to rules
    >and traditions.
    
    That is, unfortunately, all too true, except that in our waters I would
    apply the clueless tag to a minority, not "a good majority". There are
    times when I am ashamed about the activities of a few of my fellow-boaters
    and the problems they create for bigger vessels, especially around harbour
    entrances. It's not a reason for denying them the privileges that the
    colregs provide, however.
    
    >Now George mentioned he sails the English Channel.George,that is likely(I
    >don't know myself)a very congested area.Are there traffic seperation schemes
    >with vessel size restrictions in the schemes presant in the Eng. Chan.?Are
    >most of your problems with merchies coastal or offshore?
    
    My wife and I have made many, many, Channel crossings in our 26-footer,
    though fewer as we get older. Perhaps I can explain what it's like.
    
    It certainly is congested (in places). The English Channel is a couple of
    hundred miles long, plenty wide in the West, where our sailing is mostly
    done, tapering down to a very constricted passage through the Dover Strait.
    There are draught restrictions on deeply laden tankers at the Eastern end,
    going to Europoort (Rotterdam), and many lighten by transshipping
    part-cargo in Lyme Bay.
    
    There are short traffic schemes at each end of the Channel, and another,
    off the Casquets, about halfway through. Most of the area is a free zone,
    however. Because the through traffic has been shepherded into lanes in
    those traffic schemes, it tends to keep to its separate queues, in each
    direction, in between. This results in the traffic densities elsewhere,
    though high, being nothing like as great as it is in those queues. Crossing
    those queues is more-or-less the same whether it's within a traffic scheme
    or not, though the rules are a bit different.
    
    Approaching a line of vessels going at 15 to 20 knots (sometimes more) in
    your 4-knot craft needs a lot of care, combined with a bit of boldness. I
    liken it to a hedgehog crossing a motorway. Sometimes there are bunches in
    the traffic, which implies there are also gaps, and if you can spot such a
    gap and time things to get there at the right moment, the rest is easy.
    Often, though, the vessels are in a steady stream, in line, with perhaps
    only a mile or so of gap between them. At 20 knots, that's only a
    three-minute interval, in which my boat will travel only a fifth of a mile.
    
    Approaching that line-ahead, which in clear weather you can see stretching
    from over the horizon, you make as good a guess as you can of where you
    will get across. Not across the nearest ship perhaps, or the next behind
    it, or even the next, but maybe between the third and fourth is the gap to
    try for. Then you have to get close to the quarter of vessel 3 so that as
    soon as she's passed, you can head close across her stern (wake from
    merchant ships is seldom a serious problem), lighting up the engine to gain
    another knot or so, hoping to make it across the bow of vessel 4. Sometimes
    that will fail, if you have wrongly estimated the speed or the track of
    vessel 4, and then you have to quickly backtrack, or heave-to, or turn to
    starboard until vessel 4 has passed. And try the next one.
    
    No doubt officers of the next-following vessels, observing this on radar,
    wonder what on earth is going on, and blame it on incompetence; except for
    those few who have themselves been to sea in a small craft, and know the
    problems involved.
    
    As for those in the small boat, once across, they can breathe again for the
    next hour or so, until they have to tackle the next lane, going the
    opposite way.
    
    You will note that in all this, there's no element of cooperation expected
    from those ships, to assist the crossing vessel. There will be none. If
    that ever does happen, it's something to write home about.
    
    That's what crossing the lanes is like, in a craft which (outside the
    traffic separation schemes) is in theory entitled by the colregs to
    priority over the others! I have assumed daylight and clear weather. When
    it's rough, or night, or poor visibility, the problems multiply.
    
    What I complained about in my first posting was that even elsewhere, in
    less-frequented parts of the English Channel, with no other ship in sight
    over the horizon, a merchant ship won't deviate from her course at all for
    a small boat in her path. I exaggerate slightly; perhaps one in ten may do
    so. Doesn't seem to matter which flag or line: they are all the same.
    
    Dan and Doug have raised the question of stopping distance of a large
    merchantman, but I suggest that's beside the point. Nobody requires, or
    expects, such a vessel to take her way off to avoid a small craft. Much
    more effective is a small, but timely, twitch of the rudder, to make a
    small adjustment in course. Just a matter of pushing a button or two on the
    bridge. In some circumstances, such vessels are more manoevrable, not less,
    than is a crossing vessel under sail, if she is trying to make ground to
    windward or trying to avoid a gybe or needing to dowse a spinnaker.
    
    Doug is a valued member of our list and a representative of the seagoing
    professionals, and I would expect him to defend them, but I hope he doesn't
    take my criticisms of that community as any sort of attack on him. For all
    I know, he may be the most courteous ship's officer on the high seas,
    ceding passage to smaller vessels whenever he gets the chance. Indeed, I
    hope he is.
    
    Yours, George.
    
    ================================================================
    contact George Huxtable by email at george@huxtable.u-net.com, by phone at
    01865 820222 (from outside UK, +44 1865 820222), or by mail at 1 Sandy
    Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK.
    ================================================================
    
    
    

       
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