Coaster Verity and Bulker Polesie Collide Off Helgoland

Seen some good videos there but that’s not one of them. The movements of the two vessels are attributed solely to collision avoidance maneuvers but most are the two vessels following the traffic lanes.

here is a nice video with distances btw both ships
(177) Verity collision with Polesie - YouTube

Latest update from Dr.Sal -WHAT THE SHIP shows all: trafic , charts and all movements.

Can not find info abt conditions of visibility prior and during accident to establish “if” and “when” both ships were in sight of each other.

There is another thing that worries me , meaning , that the currents there are strong at times and in such conditions the CPA , TCPA offered by ARPA ( with speed through the water input) can be markedly different from CPA, TCPA generated by AIS.

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I get that the vectors would be different, but the end results of the calculations (TCPA, CPA) should be the same. Otherwise you’d have the ship being in two places at once.

Must observe that REQUIEM is a very fitting alias . Trust You know what it means.

So if it really means , what it means , then my recommendation and advise is , that You head straight to some well recognised and USCG approved training facility for re-education purposes because being a clear and present danger to navigation you may threathen other peoples lives . Or in line with your alias take a rest from navigation of ships and do some other less threathening chores.

However if You are still on a ship having the con in the area of strong currents - say near Miami or else , where Gulf Stream is very strong, do try to learn by the way of experimentation , checking/comparing ARPA CPA, TCPA with AIS relevant data.

The link below shall serve You as clear evidence that our further conversation on this topic is simply pointless. Have a wonderful rest of your day.

And if I am wrong in Your assessment , then feel free together with other honorable members of this forum to call me an asshole.

https://www.preventionatsea.com/assets/public/files/DCP-Circular%2008-2021%20OFFLINE.pdf

You’re conflating stabilization modes with AIS vs ARPA. Both are separate discussions.

Taking AIS out of it for a minute, radar stabilization mode does not affect an ARPA’s CPA and TCPA calculation since those are based on relative motion (ie, the relative vector). What will differ is the computed speeds and courses of the targets (assuming there’s a significant set/drift).

As pointed out in that Prevention At Sea bulletin, deriving CPA/TCPA from just AIS information can be a bit of a roll of the dice, as you’re relying on the target’s AIS putting out accurate information. But stabilization mode doesn’t protect you against that at all. Furuno’s Target Fusion mode offers a clutter free way to cross check AIS target info with that calculated by the ARPA and allows varying tolerances between the targets that will “break” them, if exceeded.

I don’t have any experience in the waters where this collision took place, but looking at the chart of it, I’d want my radar to be ground stabilized as it gives a much better representation of my own set/drift and when other vessels may be making course changes or coming up on a buoy, etc.

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I’m happy to be corrected on this, but potential issues with AIS aside (e.g. data delayed or incorrect) the end results of the calculations should still align. Where you’d get into trouble is if you mix the data and don’t compare like-for-like.

E.g. I’m heading due north at 5 knots STW, with another vessel oncoming (both sidelights in view 10 miles distant, also 5 knots STW). Add a 3 knot current pushing us both eastwards, such that my COG is 031T instead of 000T, their COG is 149T, and out SOG is almost 6 knots.

Suppose I’m using a very old radar: I plot the other vessel’s position thrice and scribe a line through the points: I can then determine CPA (0, since it passes through me) and TCPA (based on the distance between the plotted points and the time taken, in proportion to the distance from the last plotted point to me). STW, SOG? Not used; that blip is coming straight down the screen at a pace to reach center in 60 minutes.

So, AIS: if I draw the ground-referenced vectors I get two eastward-angled courses, also converging, showing the nearer 6 knot speeds. But here again collision time is in… one hour, CPA 0.

Where things would go wrong is if I tried to compare their ground-referenced motion against my water-referenced motion. E.g. when that blip’s coming down the screen, seeing that COG line pointed off to the side doesn’t mean the target will end up passing clear.

Looks like two above ,very professional replies about colating, stabilizations ( what i have never mentioned or even suggested) are a good reason to succumb to I expect overwhelming pressure of forum spectators and convert my nickname from spowiednick to an asshole with, of course, moderators kind permission.

But I have rather encouraging news for myself , knowing I will have a good crowd to keep me company as per below pdf. Have never used Furuno with it’s fusion technology and algorythms , however vaguely remember from logic that conjunction “and” produces the following outcome : TRUE and FALSE = FALSE. irrespective of sofistication of algorythms.

Therefore I will stick to my asshole old fashioned ways immune to disruptive technologies keeping in mind that" "when technology/machine is your master, you reach disaster faster. Cheers. .

The Navigator All about Ais.pdf (3.0 MB)

6686-stoploss-74-v4-english.pdf (1.1 MB)

stand on vessel going to port is never going to end well

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What’s going on with shipping has an updated video.

Verity made a slight change to stbd. Perhaps enough to clear astern but not sufficient to be “readily apparent to the other vessel”. Better to show the stand-on vessel the red side light.

Polesie made a turn to port maybe also enough to clear if Verity maintains course and speed but contrary to the rules. Also not readily apparent.

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From this video: (177) Verity collision with Polesie - YouTube

Polesie made an 8 degreeturn to port with Verity broad on the port bow at 1.1 mile.

image

Verity started a turn to stbd with Polesie at 0.5 miles on the stbd bow. At the same time Polesie again began turning to port.

image

Polesie’s first turn of 8 degrees may have been just to align with the traffic lanes. After that Polesie made a series of small course adjustments. Started at 273 degrees and here she’s steering 238 degrees.

In extremis, both vessels turn to stbd.

image

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Yes, I see it this way, too.
Then, they had seen Verity continuing her way without any reaction and they continued the port turn to pass behind Verity.
Verity probably had not seen these course changes and was surprised by the new picture… and made an unfounded emergency turn to starboard.

Without the VDR recordings this stays indeed a speculation…

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Yes, speculation, but that’d also be my guess. Starboard turn might have been better at that point to lessen the angle of impact.

How awful for the Verity to be hit at that speed.

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