Sailing vessel and RORO ship on collision courses - what do you think of the outcome?

[HeinSdL]

Dockhead I thought that earlier picture you posted clarified things very well. When still very far apart, at long range referring to your diagram, both vessels are permitted to take action. So at the earliest opportunity, when I see a commercial vessel and the CPA does not look good, I would change course to open up the CPA to 1 mile. Assuming open sea. This is not necessarily a very large change. At this long range it would be weird to start making very large changes in course yet you have all that time to build on the CPA such that a close quarter situation never actually materializes. And yes I would use the AIS to guide me, hand in hand with visual observations.

I think it's OK for a sailing vessel to make a small adjustment at the very earliest opportunity to not have to force the hand of a commercial vessel. Again I stress, open sea. In my case, sailing mainly light handed and hence on the autopilot, a small change of course is easily done with many many miles still to go to see how the CPA stays fixed at 1 mile.

I don't know the exact situation of the PO. Maybe not open sea, whatever, and if you are no longer at long range, yes you do need to make clear what you do. But if the other guy is not moving an inch from his existing course and speed even though he is obliged to do so then I would make sure I would go behind him at a distance satisfactory to me. I might luff up very significantly for a few minutes and then bear away again to give me that space, but really, no need to remind me to feel sorry for that poor guy on the bridge who never had much concern for me in the first place.

Finally, I am still getting used (if I ever will) to communicating on this forum and on this topic there are too many variables to concisely formulate a response so forgive me for perhaps not making a point clearly. But my original remark about this being a storm in a tea cup stands. As I was told many years ago during various RYA courses, if in doubt and the doubt remains re a potential close encounter and you are not being overtaken, turn around and go back whence you came. If I was in a position of the OP I would make sure my boat is very prepared to (even) go about and wait on the other tack while the RORO passes. Though more likely luffing up would suffice. As mentioned too many variables.

[boatman61]

Originally Posted by fxykty

Totally mistaken. You are measuring the track when we were on port gybe, hours prior to meeting the ships, slowly lifting as the breeze went left. The dogleg you you refer to was our gybe to starboard, as the steadily lifting ESE system breeze settled into the NE sea breeze.

The place where we met the RORO in question is marked by the red cross. Well after the gybe.

You say you were doing 9kts and a bit roughly then gybed onto a 6nm max dogleg to take you to your next point where you turned to port to pass down the passage...
Thereby putting you on a course across the ships course around 2.5, 3nm max from the CPA.. to my mind the burden of staying clear falls on you I am afraid.. Just my opinion.
I am sure the Colregs supporters will however disagree..

Quote"
Earlier, two other ships, one a similar RORO and the other a larger container ship, going in the same direction (towards Auckland harbour limits from the north, still 10 miles distant to the harbour limit) had previously altered their respective courses 10-15 degrees to port to go astern of us. Both did so at about 3 and 5 miles distance from us respectively."

Are you saying these two ships were also after this gybe onto your 6nm dogleg.?

[requiem]

Originally Posted by fxykty

The place where we met the RORO in question is marked by the red cross. Well after the gybe.

Understood, so is it safe to assume that your avoidance maneuver doesn't really show on the track then?

Originally Posted by Lodesman

My previous discussion about the futility of a 5 or 10º alteration appears to have fallen on deaf ears. Assuming you wait for him to act, then decide "with a few miles to go" say 3nm distant, you'll be about 2 nm to the intersection point, and 10º will shift that 700yds to the right, still well within a dangerously close proximity.

By my estimate, a 10° alteration towards the other ship is also increasing your closing velocity and decreasing the TCPA. I.e. around the time you reach their course line they will have not yet covered those 700 yards you were hoping to gain, and may instead be right in the new place you were hoping to cross.

[Lodesman]

Originally Posted by HeinSdL

To be honest, if possible I would take action much much earlier when both vessels are still permitted to do as per an earlier post. i.e 5 deg change to starboard.

When do you see it as still permissible? At what range from the other vessel do you feel you should be holding your course and speed as the stand on vessel?

The point I was making is that a 10 deg course change is not invisible on AIS.

Let's make this clear. Commercial watchkeepers do not typically use AIS to work out anti-collision. They are not sitting there, making note of minute course changes of every vessel that appears on the display. Anti-collision is done with ARPA, and with switched-on watchkeepers -compass bearings. A 5 or 10º alteration is imperceptible to them.

Then about taking bearings. I stand corrected. I do take bearings perhaps informally lining up eg the steering wheel pedestal and a stanchion with the other vessel, or using my fixed compass but not with a handheld. Just to check if what the AIS is telling me makes sense. But along the same lines, when entering a harbour, I am not likely to plot a triangulation point on a chart using a distant church spire, a lighthouse and some other land mark when my GPS (2 different sources) is doing a perfectly good job.

Yes the GPS does a fine job, at what it's supposed to do. It is an improvement on triangulation on paper charts, as it gives an instantaneous assessment of position, corrected many times per second. AIS is not meant to supplant visual bearings or systematic radar plotting to determine risk of collision. Use the right tool for the job.

[Lodesman]

Originally Posted by Dockhead

H
Wrong on several levels.

1. No one ever has right of way.
2. The obligations do not change when the other vessel is a "big ship" -- extremely harmful nonsense.
3. What is a "restricted" vessel? RAM? And what about NUC, and vessel fishing?

This is truly egregious, one of the worst things on the Rules that I've ever seen in print. And from a lawyer!

He discussed NUC fishing and RAM and quite clearly by "restricted" he is referring to RAM. If you have an issue with "restricted" then you should also have a problem with "RAM" - that's nowhere in the colregs.

I mentioned the issue with No. 2 - that was definitely wrong. And you do have a point with the use of ROW. He was answering a question that used the term, and used it colloquially in his answer. This is sloppy and one would think it's a good opportunity to make the distinction, but given the audience is likely a bunch of punters whose only understanding of the Rools is "sail has right of way over power" then it is generally a helpful article.

[Dockhead]

Originally Posted by HeinSdL

Dockhead I thought that earlier picture you posted clarified things very well. When still very far apart, at long range referring to your diagram, both vessels are permitted to take action. So at the earliest opportunity, when I see a commercial vessel and the CPA does not look good, I would change course to open up the CPA to 1 mile. Assuming open sea. This is not necessarily a very large change. At this long range it would be weird to start making very large changes in course yet you have all that time to build on the CPA such that a close quarter situation never actually materializes. And yes I would use the AIS to guide me, hand in hand with visual observations.

I think it's OK for a sailing vessel to make a small adjustment at the very earliest opportunity to not have to force the hand of a commercial vessel. Again I stress, open sea. In my case, sailing mainly light handed and hence on the autopilot, a small change of course is easily done with many many miles still to go to see how the CPA stays fixed at 1 mile.. .

I agree with this. If you are dealing with one isolated ship in open sea and you have AIS then collision avoidance becomes fairly trivial. I think it's absolutely the right thing to do, to adjust the course at >10 miles. And then just keep a sharp watch. Job done.

That is not the typical collision avoidance task where I sail, however. The Baltic is not as bad as the English Channel or German Bight, but we have pretty heavy shipping traffic mostly concentrated into fairly narrow shipping channels, so when we are in traffic, we are normally dealing with multiple ships at once. Here there is no way to just prevent a risk of collision situation from ever arising -- you have to thread your way through a bunch of ships, and you will have risk of collision simultaneously with 2, 3, 4 or even more ships. This is a vastly more complex job. It's sometimes not even possible to maintain 1 mile CPA; sometimes your gap might be only 2 miles or even less, in which case you aim to pass close behind someone to stay as far ahead as possible of the one you are passing ahead of. Sometimes it is very burdensome indeed being required to stand on with regard to one vessel when you need to steer clear of a different one, and such cases can be hairy and can necessitate explanatory calls.

[HeinSdL]

Originally Posted by Lodesman

Yes the GPS does a fine job, at what it's supposed to do. It is an improvement on triangulation on paper charts, as it gives an instantaneous assessment of position, corrected many times per second. AIS is not meant to supplant visual bearings or systematic radar plotting to determine risk of collision. Use the right tool for the job.

Alright, food for thought. Here to learn, never too late. Won't discuss much further but will bear this discussion in mind next time when these situations present themselves. It's part of my reason for being on CF.

[jmh2002]

Originally Posted by Lodesman

...Let's make this clear. Commercial watchkeepers do not typically use AIS to work out anti-collision. They are not sitting there, making note of minute course changes of every vessel that appears on the display. Anti-collision is done with ARPA, and with switched-on watchkeepers -compass bearings. A 5 or 10º alteration is imperceptible to them.

...Yes the GPS does a fine job, at what it's supposed to do. It is an improvement on triangulation on paper charts, as it gives an instantaneous assessment of position, corrected many times per second. AIS is not meant to supplant visual bearings or systematic radar plotting to determine risk of collision. Use the right tool for the job.

Originally Posted by HeinSdL

Alright, food for thought. Here to learn, never too late. Won't discuss much further but will bear this discussion in mind next time when these situations present themselves. It's part of my reason for being on CF.

Yes, something to bear in mind for the smaller cruising boats that don't have or use radar on regular basis.

Radar and Arpa is used extensivley on large vessels (and it's a large part of bridge officer training too).

As Lodesman said, most anti-collision is done with ARPA, and a switched-on watchkeeper hopefully takes compass bearings too. The AIS is being used for identification, not really for tracking / collision avoidance.

Although something I like about modern integrated bridge systems (you can have this on smaller boat radar too) is that the AIS data can be overlayed onto the Radar plot. This gives you an extra level of information as you can perhaps more clearly differentiate one target from the next, ie: the AIS says this target is a cruise ship and it's name, and visually you can confirm that via binoculars and take your bearing. Useful too if you want to communicate with that vessel via VHF.

As a side note, on commercial radar there is even a tool available called "Trial Maneuver" whereby the watchkeeper can enter a proposed change of course and the radar display will change based on that, and therefore all of the relative positions, CPAs, etc of other traffic will be recalculated too.

There are some videos on YouTube if you would like to see this in action.

[Group9]

I know of too many instances of unmanned bridges (or poorly manned bridges) to every play chicken with a large commercial vessel just because I was sure I had the right of way.

[jmh2002]

Originally Posted by Group9

I know of too many instances of unmanned bridges (or poorly manned bridges) to every play chicken with a large commercial vessel just because I was sure I had the right of way.

Nobody in any of these threads or posts has suggested 'playing chicken'.

That seems to be mostly something raised by those who have posted that they don't know or use the COLREGS.

[Shrew]

Originally Posted by jmh2002

Nobody in any of these threads or posts has suggested 'playing chicken'.

Just some basic math.

1 nautical Mile = 6076.12 feet

Both vessels were travelling at 9kts (54,685.08 fph)

54,685.08 / 60 = 911.418 fpm

At 0.5 nautical miles the sailing vessel made contact with the commercial vessel. 6076.12 / 2 = 3038.06 feet

3038.06 / 911.418 = 3.33 minutes to collision.

So, the sailing vessel noticed the commercial vessel appeared to be on an intersecting course at around 5+ miles out, however both parties took not action until the sailing vessel was within 3 minutes and 20 seconds from collision. Then starting hailing.

Calling it chicken or not seems like a game of semantics at this point.

[jmh2002]

Thanks for the maths lesson, although as you may note in the other thread I am more than used to doing the calculations.

I agree that action could / should have been taken earlier but I think that the OP's original plan was always just to head up if and when necessary - if the ship didn't alter it's course to pass astern.

So although it all sounds very exciting and dangerous, in reality it wasn't really so.

A quick head up, and a quick bear off on a high performance cruising multihull with a very experienced skipper who knows his boat.

Meh... not really quite as death defying as some are imagining

To me "playing chicken" would mean trying to get across the ships bow
Nobody in their right mind should do that in this situation

[rslifkin]

Originally Posted by jmh2002

Thanks for the maths lesson, although as you may note in the other thread I am more than used to doing the calculations.

I agree that action could / should have been taken earlier but I think that the OP's orginal plan was always just to head up if and when necessary - if the ship didn't alter it's course.

So although it all sounds very exciting and dangerous, in reality it wasn't really so.

A quick head up, and a quick bear off on a high performance cruising multihull with a very experienced skipper who knows his boat.

Meh... not really quite as death defying as some are imagining

Agreed. He waited longer than may would have, but as long as you take action while you still have enough room to definitely resolve the situation on your own, then it wasn't too late.

[fxykty]

Originally Posted by boatman61

You say you were doing 9kts and a bit roughly then gybed onto a 6nm max dogleg to take you to your next point where you turned to port to pass down the passage...
Thereby putting you on a course across the ships course around 2.5, 3nm max from the CPA.. to my mind the burden of staying clear falls on you I am afraid.. Just my opinion.
I am sure the Colregs supporters will however disagree..

Quote"
Earlier, two other ships, one a similar RORO and the other a larger container ship, going in the same direction (towards Auckland harbour limits from the north, still 10 miles distant to the harbour limit) had previously altered their respective courses 10-15 degrees to port to go astern of us. Both did so at about 3 and 5 miles distance from us respectively."

Are you saying these two ships were also after this gybe onto your 6nm dogleg.?

Yes, that’s correct

[Uricanejack]

Originally Posted by Dockhead

This should be printed out and kept on board.

Small alterations when there is a risk of collision should be avoided at all costs. They are forbidden by the Rules, which say:

"Any alteration of course and/or speed to avoid collision shall, if the circumstances of the case admit, be large enough to be readily apparent to another vessel observing visually or by radar; a succession of small alterations of course and/or speed should be avoided." Rule 8(b)

Which actually applies even when there is no risk of collision yet. It should not be done for two reasons: (a) It is really important that when you change course it is really glaringly obvious and not just in AIS, so that he doesn't assume you're holding course and speed. The consequences of that can be tragic. (b) Remember you can't predict exactly where either his or your vessel will be at CPA -- every vessel has variations in course and speed, especially one under sail.

This last thing informs several aspects of collision avoidance. You're not trying to avoid the actual ship, because you can't know exactly where he will be. THere is a cone of uncertainty as to his position. What you are trying to avoid is where he COULD BE. That's why your CPA needs to be more than 10 feet and why in most cases it needs to be a mile, at least in open water. By the time you meet, he could be anywhere within the cone of uncertainty built up out of variations in speed and course, including possible CHANGES of course, which could happen for different reasons, even by accident. So the CPA has to cover this. A safe distance to pass a ship is a lot greater distance than many yachters realize, especially where there is a big difference in speed (not the OP's case).

Nice,
I was going to post something about this silly concept but don't need to.

If you are altering for collision avoidance make it obvious.

When the OOW adjust the auto pilot a few deg just to open the CPA a bit.
He deserves a boot 6 lace holes deep.
For the reasons Posted by DH.

When I alter. I like to show the other vessel my other side light.

What's a bold or a substantial alteration, according to the usual experts.
60 degrees.

I don't suggest you should always do 60 deg unless its rule 19 which we are no talking about.
But show the other side.

5 10 even 15 is not readily apparent, Particularly if you are sailing its just within the normal range of bobbing about.

When I am looking at another vessel to see if it acting, I am looking for the other light.

Ok before some one say so, In day light you cant see lights replace light with side.