At what distance...

[jimi]

Not TSS

Actually I had not intended to refer to TSS with their own nuances! The tricky thing is assuming they have'nt seen you but act in a predictable enough manner just in case they have. I too prefer seeing the light at night as it is then a lot easier to see the aspect changing.

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[david_e]

Re: Shipping lane

What's a shipping lane?

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[dralex]

I really would hope that I'd noticed the one passing astern!!! If you were that close to a ship passing astern, then you really have planned it wrongly! I personally spend time on deck looking for ships as well as using the radar /forums/images/icons/wink.gif

<hr width=100% size=1>Life's too short- do it now./forums/images/icons/wink.gif<P ID="edit"><FONT SIZE=-1>Edited by dralex on 10/08/2004 08:41 (server time).</FONT></P>

 

[Oldhand]

The MAIB report on the infamous Moody/contianer ship collision last year (can't remeber their names now) stated that not only should a radar be used if fitted but a plot of potential collision targets should be kept. I have been trying to implement this recommendation on Channel passages and acquired a re-usable radar plotting board for this purpose.

I realised it could be a very time consuming operation and on my last crossing I was totally overwhelmed with potential collision targets by the time I was entering the northern shipping lane. As a result I had to resort to previuosly used shortcuts of using the 2 EBL's and cursor on the 3 most dangerous looking targets and just keeping an "eye" on the rest. However, this did not prevent me missing a large tanker crossing the north lane at 45 degrees heading SE, lurking amongst SW bound traffic which had already crossed my bow and thus not getting much attention. Fortunately it was seen visually in time to avoid. This ship was trying to avoid confusing everyone by calling potential collision vessels on VHF, presumably using AIS to identify them. Of course without AIS we didn't get such a warning.

However, one radar plot I did carry out soon after leaving Cherbourg was very educational and I was very glad I kept a plot going on this particular target. Initially the target looked like a large vessel breaking away from the Casquets TSS to head inshore to Le Havre. However, the plot initially showed him slowing down off Cherbourg, then speeding up again and turning onto a NE course with a closest approach of 1/4 mile, which is exactly what occurred. It was the confidence obtained by the radar plot which made this close passing acceptable. I later concluded that he had picked up a deep sea pilot from the "deep sea pilot" pick up station marked on the chart, which I had never seen happen before. Anyway, I was very glad I had kept a lengthy radar plot rather than assuming he would pass well astern heading for Le Havre, a 1/4 mile distance is too close for a surprise!

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[Oldhand]

In less than good visibility using radar on at least 12 miles range gives you much more time to work out where problems lie than waitng for the ships to come into view. Yes, if there is some visibility, it is a great help to stick one's head up and confirm, or otherwise, the picture you have built up from the radar. Radar plotting at 6 minute intervals should leave plenty of time for looking around too, unitl one gets overwhelmed with radar targets. Then its up to the individual how best to allocate time with the circumstances prevailing, i.e visibility and location of targets relative to one's heading and any lanes etc. The alternative is to have an ARPA radar with high speed heading input, know how to use it and use it but that can still be time consuming.

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[Guest]

Sorry ....

seeing both side lights is no guarantee of anything - nor seeing only one side-light.
In both situations you can still have a collision - depends on relative course and speed ............

think about a boat crossing - you only have to set speeds accordingly and you can have a nice 90 degree cruncher !!


<hr width=100% size=1>Nigel ... and of course Yahoo groups :
http://groups.yahoo.com/group/gps-navigator/

 

[Guest]

Radar ...

a) Col Regs actually state that a vessel navigating with aid of radar may consider a speed lower in restricted viz than a vessel without .... sounds stupid - but is true, why ? Because he sees more potential hazards
b) very unofficial rule !! When screen has too many targets to plot and starts to get confusing - go down a range and treat targets as they come.
c) many a time see the radar screen covered with confetti .... so shut-up, stand-up and look out window and act as each one comes visually ..... makes for a easier heart and reduces possible attacks !!

OK - so many will argue with above .... but its true for many a 'old-hand' ships watch.........

If you have ever tried to con a way through a Chinese fishing fleet etc. - then you will understand the truth in above ....


<hr width=100% size=1>Nigel ... and of course Yahoo groups :
http://groups.yahoo.com/group/gps-navigator/

 

[dralex]

i agree with having the radar on longer range- it does allow you to build a far more accurate overall view of the shipping situation. My latest TSS crossing was in unforecast fog- scary, but the radar made things a lot more comfortable. The turning 180 degrees is a last minute get out of trouble move- hopefully it would never come to this.

<hr width=100% size=1>Life's too short- do it now./forums/images/icons/wink.gif

 

[Guest]

Bedouin - splitting hairs ?

Constrained by draft has always been considered as a party to restrict ability to manouevre.

Having been officer on some pretty big tankers and bulkers .... my last vessel at sea was 440,000 tons deadweight ...... I can honestly say that the english channel and particularly dover str. are deeper because of such ships having knocked the pinnacles of banks / ridges etc. underwater IN THE lanes ..... Don't believe me ? I wish I had photos of the water behind some of the ships after passage through ...... the sand and silt stirred up.

Stand on vessels are all fine - but to stand on to a 1/4 million tion tanker / bulker steaming down the channel is a bit foolhardy and I for one would up and steer away boldly to ensure he knows what you are doing ..... and REMEMBER he wont see you most likely ..... as when you are out of the shadow of his bow, you are too far away for him to see ....... the distance of that he should be able to see you - you are most likely hidden by deck / bow flare etc.

Rules are fine and a lot like to quote them .... but practical is practical and cannot always follow the letter exactly.

Oh and another thing for those others about FOC .... Bahamas flag is administered from London and based on the old British MN regs.


<hr width=100% size=1>Nigel ... and of course Yahoo groups :
http://groups.yahoo.com/group/gps-navigator/

 

[ParaHandy]

<<(MAIB) stated that ............ a (manual) plot of potential collision targets should be kept>> no such statement was made by the MAIB as a recomendation in the conclusions. The MAIB did state in their Analysis that 'both masters actions were based on scanty radar information (by, inter alia, not undertaking a manual plot), which contravened Rule 7(c) of the Collision Regulations'

this (the lack of a recomendation to use a manual plot) puzzled me .... perhaps it recognises that most yachts have the display in front of the helm where such activity might be impractical

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[AndrewB]

No, not necessarily.

In the Dover TSS any tanker constrained by its draft is required to inform the CG. This information is transmitted on the routine information VHF broadcasts. I listen to these broadcasts when crossing the TSS in my yacht and certainly pay attention if there is mention of one that might affect me. Otherwise I expect ships to respect their normal IRPCS responsibilities, including giving way to me where they have space to do so, and behave accordingly.

The skipper of ANY ship that "won't see you most likely" on a clear day in the Dover Straight, deserves disqualification in my opinion. A bit like saying the average lorry driver can't be expected to notice a cyclist on the A2.

 

[Gunfleet]

Dear Capt Nitpick

Well of course relative course and speed are an issue but all other things being equal the situation I described is true. What's more however you argue it . seeing both lights means the blinking thing is aimed at you and requires your attention.
Yours
Another Nitpicker ;-)

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[bedouin]

Re: Bedouin - splitting hairs ?

I think that the "do not impede" rules is one of the worst in Colregs (and let's face it - there are plenty to choose from).

From the deck of a small boat I find it very difficult to estimate whether I'll pass a mile ahead or a mile behind a big ship. In practice my actions are independent of whether I am stand on or give way - by the time I have to consider taking avoiding action it is far to late for the ship to do anything

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[dralex]

Re: No, not necessarily.

I still feel that playing stand on games is a bit like playing Russian Roulette. I think the best way is to maintain a rock steady speed and hope you're visible on their radar. This enables you to be a predictable target. Given the choice of turning or standing on, I'd rather not take the risk. The speed differential puts yachts at a severe disadvantage and I'd rather assume that the action I'd taken would definately avoid conflict, rather than hope a 500000ton monster would alter course to avoid me. There's a difference between taking rules by the letter, and using some common sense.

<hr width=100% size=1>Life's too short- do it now./forums/images/icons/wink.gif

 

[AndrewB]

Re: No, not necessarily.

Obviously its crucial not to persist in your course if the give-way vessel doesn't give way. In any case the COLREGS require this (rule 17aii), so its not simply a matter of common sense versus the rules. Any decision to stand-on must have a plan B for this contingency: mine is to abort if the give-way ship shows no sign of doing so within about a mile of me.

But giving way when you are not supposed or expected to can also cause problems, and worst of all is dithering. It would be so much easier if yachts crossing a TSS were always understood to be the give-way vessel!

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[duncan]

Good question Jimi, and some interesting points get raised. However, back to the basic question and, if you assume that you are crossing at 90 degrees, are making 5 knots, and the ship is doing 25knots up the chanel, then my arithmatic says that to keep 0.5miles between you and the ship at all times you need to be within 0.5 miles of his track when he is still 5 miles down it, that way you will be 0.5miles clear as he crosses your track.
Is this realistic or is the panel happy with less / wan't more clearance?

<hr width=100% size=1>madesco madidum ..../forums/images/icons/smile.gif

 

[bedouin]

Re: No, not necessarily.

But to be honest the same issues apply whether or not it is a TSS. Those of us based in the Solent rarely have to deal with TSS but do have a number of "shipping lanes" to cross on our way to (e.g.) Cherbourg.

A side issue is which way to turn. If you are give way vessel then you should turn to pass astern of the stand on vessel. If you are stand on vessel and altering course because the give way vessel has not given way, then any action you take is likely to make collision more likely, should the give way vessel give way at the last moment. Under such circumstances I prefer the option of turning onto the same heading as the Give way vessel. Doing a 180 is also valid, but I would suggest that an alteration to pass astern would be a dangerous option.

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[Oldhand]

The Wahkuna/P&O Nedlloyd Vespucci report states in paragraph 2.5.2 (2. Wahkuna)) "a manual plot was not undertaken" and in Annex 4 quotes COLREGS 7(b) "Proper use shall be made of radar equipment if fitted..... and radar plotting or equivalent systematic observation of detected objects.

I appologise, I think it was the RYA that stitched these together to advise you must use radar if you have it and targets should be plotted. However, whether one has read the appropriate input or not, COLREGS 7(b) is quite clear on the matter.

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[Oldhand]

Re: Dear Capt Nitpick

This only applies to the very limited case of a head on convergence. In any other situation you shouldn't see both lights together unless you have decided to cross ahead and he should have had your attention long before you could see both lights.

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[dralex]

Re: No, not necessarily.

I agree with your second paragraph- there's room for lots of confusion if people give way when not needed. As I said before, I think the crucial thing is to maintain steady course and speed and be a predictable target, but have a no fail get out clause.

Regards

Alex



<hr width=100% size=1>Life's too short- do it now./forums/images/icons/wink.gif