COLREGS and DPS

[Dsanduril]

What does COLREGS have to say about vessels using dynamic positioning systems (DPS) to hold station? Especially one not engaged in some other work (most DPS vessels I have encountered are engaged in other work that probably qualifies them as "restricted in ability to maneuver").

This question arises out of sharing an anchorage for the past 24 hours with a 116m superyacht that is not anchored, but rather is holding station in the bay with DPS. The COLREGS definitions (AFAIK) don't include a definition for "at anchor" but do define "underway" as "not at anchor....".

The captain of this particular vessel has determined, since he has no anchor down, that he is underway. His AIS indicates his status as "underway" with a speed of zero. His lights are two masthead lights (one foreward, one aft and higher), sidelights, and a stern light - also indicating that his status is underway (by contrast, his 21m "tender" is anchored nearby and displays an all-around white light, pretty sure the DPS captain is very clear on his decisions). But, he is staying in one place. In a crowded harbor.

As a crossing vessel should I expect him to give way if I am the stand on vessel? Doesn't seem reasonable to me, but how does that flow with the rules? And I'd guess that regardless of COLREGS definitions the give-way vessel at zero speed with only the DPS operational is indeed "restricted". If I'm crossing them at 8 or 10 knots with risk of collision I doubt she is capable of getting out of the way in time to avert the collision. Should the captain instead be showing his status as restricted? Or does he not meet a definition? How do I, as the stand on vessel, recognize DPS (that is holding station)? With AIS I can see the zero speed, but without it it is much harder to confirm zero movement based on bearings (yes, it can be done, but from the deck of a small moving vessel it can take some time).

This is also interesting with regard to anchored boats, the DPS vessel has not moved since we arrived. At all. Every anchored boat here averages a 360 about once an hour (lots of current and wind eddies). So, the DPS vessel actually mucks up the anchorage a bit by not swinging like everyone else. In fact, with the DPS holding position they are closer to "aground" than "anchored." A 45m sailing vessel came in after Mr. DPS and anchored nearby (the only part of the bay deep enough for those vessels). Later they moved as in swinging they were too close to DPS. This would be common etiquette for anchored vessels, the later anchored boat moves if their selection of spot causes a problem. But if the later boat is anchored and the other boat is "underway" does this apply? Or should the "underway" vessel be the one that moves?

Lastly, what about whistle signals? Given that her heading hasn't changed a degree since we came in I'm pretty sure her captain could say he is not altering course to port or starboard. But what about "operating astern propulsion"? I'd guess that there have been numerous times that has happened with the DPS holding position. And just as "underway" doesn't include anything about "making way", "operating astern propulsion" doesn't say anything about going backwards, just that the vessel has engaged astern propulsion. Maybe the vessel is not "maneuvering as authorized or required" by COLREGS and so is not compelled to whistle?

Just curious how the COLREGS scholars interpret the rules with regard to a DPS vessel holding station? Maybe we have to fall back on Rule 2 until DPS is addressed directly?

[sailorboy1]

Originally Posted by Dsanduril

Just curious how the COLREGS scholars interpret the rules with regard to a DPS vessel holding station?

That's funny! Have you never read a rules thread here before

[IslandHopper]

I'll just keep it short....

When a vessel is in DP, and unless the DP vessel is in some way RAM, then she is in nothing more than a vessel underway and all that that implies, the vessel in question is showing the correct lights, there are no special lights for a DP vessel....

As for the Whistle? what you quote is correct "the vessel is not "manoeuvring as authorised or required" by COLREGS and so is not compelled to whistle".....

[billknny]

I am not at all sure what the mystery and why there is any confusion.

He is underway. He can avoid any other vessel as needed, and needs to keep a watch just as if he was moving.

Underway, but not making way.

I am not at all sure why he has to move out of your way, unless you are aimed right at him, in which case you can alter course by a degree and miss him.

Don't overthink it. He can't hit you. If you hit him its your fault. That admiralty court would probably assign a split blame to the collision, if that would make you feel better.

[Dsanduril]

Originally Posted by sailorboy1

That's funny! Have you never read a rules thread here before

I have, and I enjoy them

Originally Posted by IslandHopper

I'll just keep it short....

When a vessel is in DP, and unless the DP vessel is in some way RAM, then she is in nothing more than a vessel underway and all that that implies, the vessel in question is showing the correct lights, there are no special lights for a DP vessel....

That's how I read it too, but that doesn't seem entirely reasonable to me, and as noted, I'm not sure she could 'give way' in a meaningful time frame.

[Dsanduril]

Originally Posted by billknny

...I am not at all sure why he has to move out of your way, unless you are aimed right at him, in which case you can alter course by a degree and miss him...

Absolutely I can alter course to miss him. And I would (and I did).

But, in doing that I am treating him as an anchored vessel. If I treat him as a vessel underway then I am obligated under the rules to stand on until such time as I believe action on his part alone will not prevent a collision. And since he didn't take action to prevent a collision should I be reporting him to his licensing authority?

[deblen]

Originally Posted by Dsanduril

Absolutely I can alter course to miss him. And I would (and I did).

But, in doing that I am treating him as an anchored vessel. If I treat him as a vessel underway then I am obligated under the rules to stand on until such time as I believe action on his part alone will not prevent a collision. And since he didn't take action to prevent a collision should I be reporting him to his licensing authority?

1. If you have determined that he is not moving,regardless of lights that he is displaying,how can you still be the stand on vessel?


And:


2. Rule 2 pgh b special circumstances & limitations of......




Suggest you signal & alter course 20+ deg ,to avoid this "fixed hazard", & continue on.



Len

[Adelie]

Originally Posted by deblen

1. If you have determined that he is not moving,regardless of lights that he is displaying,how can you still be the stand on vessel?

And:

2. Rule 2 pgh b special circumstances & limitations of......

Suggest you signal & alter course 20+ deg ,to avoid this "fixed hazard", & continue on.

Len

If the DPS vessel is not anchored to the seabed and not NUC then they are underway per the letter of the COLREGS whether they are making way or at a standstill. As such they would be required to GiveWay under certain circumstances. That means moving out of the way of the StandOn Vessel.

If I were the CO of the DPS vessel I would consider tossing out a token anchor on a very long rode and switching to anchored status.

Alternatively they might try to claim RAM status which would alter things but legally that would be fuzzy.

[Adelie]

Originally Posted by Dsanduril

What does COLREGS have to say about vessels using dynamic positioning systems (DPS) to hold station? Especially one not engaged in some other work (most DPS vessels I have encountered are engaged in other work that probably qualifies them as "restricted in ability to maneuver"). . . .

COLREGS say nothing about this circumstance. Technology is too new and not that widespread. Although they did put in a rule about WIG craft which are not that widespread but that's been percolating since at least the 1970s.

Give it time and they may add a rule but I wouldn't think so. As equipment is being actively used to "propel" the boat if only to stay in one location then I'm pretty sure most IMO reps are going to ask why should this vessel be granted special privileges?

[Shrew]

Originally Posted by Dsanduril

As a crossing vessel should I expect him to give way if I am the stand on vessel?

Stand-On does not mean "everyone get out of my way". The concept is two vessels making way on an intersecting course. What you're describing is navigating toward a stationary vessel and making them move.

[Adelie]

Originally Posted by Shrew

Stand-On does not mean "everyone get out of my way". The concept is two vessels making way on an intersecting course. What you're describing is navigating toward a stationary vessel and making them move.

He gets that as evidenced by post #6. And as indicated there, he could have reported the vessel to authorities for not GivingWay as required by the COLREGS.

[belizesailor]

I agree that "underway, but not making way" is the most likely interpretation.

Given the lights displayed the captain likely agrees...and I suspect there is a watch posted 24x7...one tap of the joy stick and hes out of the way...I suggest you test that theory late one night...just to liven up the night watch! [emoji6]

Also, owners and their insurance arent likely to entrust a megayacht to just any bonehead, I suspect this aint his/her first rodeo and that their interpretation is correct...maybe confirmed by the on call admiralty law attorney.

[Tillsbury]

Get the sailing dinghy out and sail straight at her, see what happens...

[markpierce]

If the ship is showing running lights, one should presume the boat is underway and will behave accordingly. If such a boat does not maneuver when required, one is still obligated to avoid collision.

In "my world," the subject boat acts like it is anchored. It should show lights and day shapes indicating that.

[Dsanduril]

Originally Posted by markpierce

If the ship is showing running lights, one should presume the boat is underway and will behave accordingly. If such a boat does not maneuver when required, one is still obligated to avoid collision.

In "my world," the subject boat acts like it is anchored. It should show lights and day shapes indicating that.

This.

Personally, I employed Rule 2. Using the "ordinary practice of seamen" I evaluated the "special circumstances" and decided to treat Mr. DPS as an anchored vessel, the same as the other 20 or so vessels anchored in the bay. Easy-peasy, no dramas, all is well.

That seemed reasonable to me, but also in conflict with the rules. Everything in approaching the situation indicated to me that he was "anchored". Except for the signals required by the rules. There was no black ball, all his indicators showed "underway", and the rules seem to require that interpretation.

Seems that the easiest thing would be to include a definition of "at anchor" in the rules. Then the rule makers can debate whether or not to include DPS and similar technologies when they are used for station keeping.