Collision Avoidance, Cones of Uncertainty, and Appropriate CPA

[ramblinrod]

Originally Posted by Lodesman

Dockhead has explained the 4 stages, and Stu has pointed out to you rule 17 (a) and (b). Do you now acknowledge that your statement (I've bolded) is wrong?

Can you also explain how you think I've changed the Colregs to suit my argument?

Your 3rd request; my second answer - you've violated rule 8 and 17(b); see my explanation in my previous address to you.

Incorrect.

The specific distances posted relating to the four stages are not specified in Colregs rules, and nobody is obliged by Colregs to adhere to them.

Note that per rule 6, everyone is obligated to maintain "safe speed" at alla times. Large ships are obligated to maintain a safe speed allowing ample time to maneuver to avoid collision, especially in proximity of other vessels.

If they wish to maintain high speed and execute course changes quite some distance off (before any real risk of collision exists), that is their business (truly their business decision to get to their destination by fastest possible means). Colregs does not specify any numeric value for distance, nor speed, nor congestion.

RE: Rule 8. The only mention of distance that one must avoid a collision by is a "safe distance".

(d). Action taken to avoid collision with another vessel shall be such as to result in passing at a safe distance. The effectiveness of the action shall be carefully checked until the other vessel is finally past and clear.

What does "past and clear" mean. I believe "past" means "leaving" vs "approaching and "clear" means "missing" vs hitting".

Depending on ones pucker factor, if the collision was avoided by any distance, this could be considered a "safe distance". No where do Colregs require anyone to maintain a CPA of any specific distance.

If you disagree, please quote the specific rule.

RE: Rule 17 a).

(i). Where one of two vessels is to keep out of the way the other shall keep her course and speed.
(ii). The latter vessel may however take action to avoid collision by her manoeuvre alone, as soon as it becomes apparent to her that the vessel required to keep out of the way is not taking appropriate action in compliance with these Rules.

Note part i). This is what I am referring to. The stand on vessel is obliged to stand-on, and unnecessary change in course or speed violates this rule.

For part ii) Note that there is no specific CPA (distance) value. Note that it states "take action to avoid collision" not "take action to avoid an arbitrary CPA value".

RE: Rule 17 b)

(b). When, from any cause, the vessel required to keep her course and speed finds herself so close that collision cannot be avoided by the action of the give-way vessel alone, she shall take such action as will best aid to avoid collision.

This is the only definitive distance in Colregs, it is not a specific value, but if the give way vessel fails to give way (ONLY AT THE POINT WHERE THEY NO LONGER HAVE THE CAPABILITY BY THERE OWN ACTION) the stand-on vessel is obligated only to take sufficient action to avoid collision.

If the vessels clear (by inches), she met her Colregs obligations, if they touch, she didn't.

That simple.

Anything beyond that, is gravy, and the amount of gravy desired by an individual will depend on that individuals pucker factor. For some, under all circumstances it may be 1 nm moinimum, for others under certain circumstances (not necessarily worst case) it may be only 180 ft (or even less).

Whether anyone likes it or not, these are the rules, no more no less. If one claims that Colregs require a specific value of speed or distance, they are wrong. They don't. No where.

[Dockhead]

Originally Posted by ramblinrod

Can you please just answer the question. 3rd request. 1/4 mile away, I determine the give way vessel is not giving way and doesn't have ability to avoid collision on their own. I change course and we miss by 180 ft; what Colregs rule did I break?

The fact that it turns out that you missed -- IF you in fact don't get run down (which would be matter of pure luck) -- would not change the fact that you approached too late on a collision course and failed to take timely action as required by ordinary good seamanship as well as by the Rules. I cited them above.

It's called a "near miss" and there are incident reports and possible legal consequences.

It's the equivalent of reckless driving in a car -- you don't need to actually crash, to be in violation.

If you read the CHIRP site, you will see near miss reports filed even for passes of about a mile, in some cases.

[Dockhead]

Originally Posted by ramblinrod

Incorrect.

The specific distances posted relating to the four stages are not specified in Colregs rules, and nobody is obliged by Colregs to adhere to them.

Have you read them? The four stages specifically come from the Rules.

Originally Posted by ramblinrod

Note that per rule 6, everyone is obligated to maintain "safe speed" at alla times. Large ships are obligated to maintain a safe speed allowing ample time to maneuver to avoid collision, especially in proximity of other vessels.

If they wish to maintain high speed and execute course changes quite some distance off (before any real risk of collision exists), that is their business (truly their business decision to get to their destination by fastest possible means). Colregs does not specify any numeric value for distance, nor speed, nor congestion.

RE: Rule 8. The only mention of distance that one must avoid a collision by is a "safe distance".



What does "past and clear" mean. I believe "past" means "leaving" vs "approaching and "clear" means "missing" vs hitting".

Depending on ones pucker factor, if the collision was avoided by any distance, this could be considered a "safe distance". No where do Colregs require anyone to maintain a CPA of any specific distance.

If you disagree, please quote the specific rule.

RE: Rule 17 a).



Note part i). This is what I am referring to. The stand on vessel is obliged to stand-on, and unnecessary change in course or speed violates this rule.

For part ii) Note that there is no specific CPA (distance) value. Note that it states "take action to avoid collision" not "take action to avoid an arbitrary CPA value".

RE: Rule 17 b)



This is the only definitive distance in Colregs, it is not a specific value, but if the give way vessel fails to give way (ONLY AT THE POINT WHERE THEY NO LONGER HAVE THE CAPABILITY BY THERE OWN ACTION) the stand-on vessel is obligated only to take sufficient action to avoid collision.

If the vessels clear (by inches), she met her Colregs obligations, if they touch, she didn't.

That simple.

Anything beyond that, is gravy, and the amount of gravy desired by an individual will depend on that individuals pucker factor. For some, under all circumstances it may be 1 nm moinimum, for others under certain circumstances (not necessarily worst case) it may be only 180 ft (or even less).

Whether anyone likes it or not, these are the rules, no more no less. If one claims that Colregs require a specific value of speed or distance, they are wrong. They don't. No where.

You're a great electrician Rod, but your legal work is not passing grade.

The fact that a specific speed is not specified in numbers, does not indeed mean that the phrase "safe speed" is whatever you subjectively believe is safe. The judge will not care about your opinion; safe or unsafe speed will be judged according to circumstances and according to common standards of good seamanship. These things are bread and butter of things proved in court.

Same thing with safe distance. 1/4 is too late, and 180 feet is too close, in open sea, with a high speed ship. Period. This will take less than 5 minutes to prove in court. The fact that you have a different opinion is meaningless.

The four stages in Cockcroft are most specifically laid out in the Rules. The last stage (just to name one example), is that period after which Rule 17(b) has kicked in. That happens a lot sooner than 1/4 mile, and you were legally obligated to maneuver when that stage starts.


The fact that you might by sheer luck scrape by at 180 feet (1/3 cable!!), does not mean you have not violated the Rules. It may be true that practically speaking, you are less likely to be actually prosecuted. But you can be.

And one last question I've been meaning to answer -- why the hell would you wait until 1/4 mile, when you are less than a minute from being crushed?

[Lodesman]

Originally Posted by ramblinrod

Incorrect.

You'll have to be more specific. What is incorrect? Did Dockhead not explain the 4 stages? Did Stu not point out the requirements of rules 17 (a)(ii) and (b)?Are you not in agreement that your previous statement that I put in bold, was wrong?

The specific distances posted relating to the four stages are not specified in Colregs rules, and nobody is obliged by Colregs to adhere to them.

Depending on ones pucker factor, if the collision was avoided by any distance, this could be considered a "safe distance". No where do Colregs require anyone to maintain a CPA of any specific distance.

If you disagree, please quote the specific rule.

Ultimately where the nitty-gritty of the rules are going to be of greatest importance, will be in court, after a collision. This is where the judge(s) will seek the expert opinion of the Elder Brethren, Master Mariners, experts in the field. The Colregs are just the starting point - how they are applied, including the specific distances you seem to crave, will depend entirely on the situation and the characteristics of the vessels involved. So beyond just having the colregs memorized by rote, professional mariners know they must enhance their understanding of the colregs, by reading guidances, interpretations and case studies. They also seek to understand the manoeuvring characteristics and limitations of other vessels - there is a section devoted to this towards the back of Cockcroft (the book, not the man). It would be a good practice for amateur mariners to do the same, and that is what Dockhead, Stu and the others on this forum are trying to do - explain the grey between the lines of the black and white colregs.

There are no specific distances stated in the colregs, but by understanding what Cockcroft and others have explained, you can reasonably estimate what would be considered a "safe passing distance" in any given situation. It doesn't really matter what your "pucker factor" is, if the action you take differs significantly from what the experts would consider to be safe and prudent "ordinary practice of seamen" (Rule 2(a)).

RE: Rule 8. The only mention of distance that one must avoid a collision by is a "safe distance".

Well if nothing else, I am heartened that you appear to be cracking the books - maybe there's hope. Why don't we review rule 8(a):

'Any action to avoid collision' includes action taken in accordance with rule 17 a(ii) or (b) - it tells you specifically that it shall be made in "ample time", not at the last possible moment. It tells you that it is to be made with "due regard to the observance of good seamanship", which I explained above would be based on the opinion of expert mariners, not on the tightness of your sphincter.

What does "past and clear" mean. I believe "past" means "leaving" vs "approaching and "clear" means "missing" vs hitting".

You've got "past" figured out, but "clear" implies that you are no longer in a position to reintroduce a risk of collision with the other vessel; remember this rule covers all the situations and a good example would be of an overtaking situation, where you might be past and opening, but if you were to turn in front of the vessel, you would once again be on a collision course. But once you are far enough ahead of the other vessel, that turning in front of it does not cause you to close on a steady, then you would be "clear". Clear?


RE: Rule 17 a).

Note part i). This is what I am referring to. The stand on vessel is obliged to stand-on, and unnecessary change in course or speed violates this rule.

Good you understand this - this is stage 2.

For part ii) Note that there is no specific CPA (distance) value. Note that it states "take action to avoid collision" not "take action to avoid an arbitrary CPA value".

Good we're getting somewhere - so to make it clear the steering and sailing rules don't actually take effect unless risk of collision exists (I believe Stu explained how risk of collision is determined - it's in rule 7). And from other discussions, you understand that neither vessel is able to maintain an absolutely precise course and speed down a laser-line, so allowances, or safety values have to be made - these are by nature "arbitrary CPA values" and are implied by the rules. Of course, they can't specify a number - what the Brethren would consider a safe passing distance in open ocean, could not be achieved by two vessels passing in the Panama Canal.

RE: Rule 17 b)

This is the only definitive distance in Colregs, it is not a specific value, but if the give way vessel fails to give way (ONLY AT THE POINT WHERE THEY NO LONGER HAVE THE CAPABILITY BY THERE OWN ACTION) the stand-on vessel is obligated only to take sufficient action to avoid collision.

This is the rule that implies you should understand the manoeuvring limitations of the other vessel - you are expected to have a reasonable appreciation of the point at which the other vessel is incapable of avoiding collision. The rule says that "when" that occurs you "shall" take whatever action will best aid the avoidance of a collision. As soon as that condition exists, you shall take action - to do otherwise would be contrary to the requirement of rule 8 to take action in "ample time" and with the observance of good seamanship.

If the vessels clear (by inches), she met her Colregs obligations, if they touch, she didn't.

That simple.

Anything beyond that, is gravy, and the amount of gravy desired by an individual will depend on that individuals pucker factor. For some, under all circumstances it may be 1 nm moinimum, for others under certain circumstances (not necessarily worst case) it may be only 180 ft (or even less).

And if you clear by inches, but get rolled over in the wake and one of your hapless passengers is killed, you'll face manslaughter charges. Let me know how the "tight pucker factor" defence works out.

Whether anyone likes it or not, these are the rules, no more no less. If one claims that Colregs require a specific value of speed or distance, they are wrong. They don't. No where.

It hardly matters that there aren't specific numbers assigned - the colregs do require one to maintain a "safe speed" and pass at a "safe distance", and take action at specified points. Where a specific figure has to be applied, do you think they'll take Rod's pucker factor as the value? - No, they'll get an expert opinion, or fall back on case law. You can wade through old judgments to get an idea of what "specific values" have been applied in the past, or you can go through a guidebook like Cockcroft or Farwell's, where past judgments have been distilled into rough guidelines. And just because you miss by an inch, don't think you'll always get away with it - the OPP can still nail you with careless operation under the Contraventions Act.

[El Pinguino]

Originally Posted by evm1024

Rod,

I don't see where you are adding anything useful to the conversation.

Please help me understand your motivation in your posting to this thread. Why are you posting here?

Regards

Refer back to post #1 where someone( ie the OP ) put the boot into him..... using a post from another thread as a starting point....

Please do try to keep up with the herd, there's a good chap.

[El Pinguino]

Meanwhile.... I recently went for a bit of a looksee - over on Gcaptain - for usage of the term WAFI.... it was an interesting experience.... they even have a poster who calls himself the 'Wafinator'..... golly ... class act. Calling a yachtsman 'Wafi' is all same as calling a person from Africa a Kaffir in my book..... its derogatory.


Anyways this thread may be of interest for many reasons ( and wafi does appear once or twice )

AIS How do you use it? Vs Small vessles - Professional Mariner Forum - gCaptain Forum

[evm1024]

Originally Posted by El Pinguino

Refer back to post #1 where someone( ie the OP ) put the boot into him..... using a post from another thread as a starting point....

Please do try to keep up with the herd, there's a good chap.

Slipped my mind. That was so many posts ago. Long past the time to "clear" ones name.

I think I'll read this after coffee, not before.

[El Pinguino]

Originally Posted by evm1024

Slipped my mind. That was so many posts ago. Long past the time to "clear" ones name.

I think I'll read this after coffee, not before.

Long time past time for the OP to move on as well.....

[Lodesman]

Originally Posted by El Pinguino

Refer back to post #1 where someone( ie the OP ) put the boot into him..... using a post from another thread as a starting point....

Please do try to keep up with the herd, there's a good chap.

That's not entirely accurate - Rod entered into the discussion with Dockhead in the other thread; Dockhead moved that tangential discussion into its own thread here. IMO

[Dockhead]

Originally Posted by El Pinguino

Meanwhile.... I recently went for a bit of a looksee - over on Gcaptain - for usage of the term WAFI.... it was an interesting experience.... they even have a poster who calls himself the 'Wafinator'..... golly ... class act. Calling a yachtsman 'Wafi' is all same as calling a person from Africa a Kaffir in my book..... its derogatory.


Anyways this thread may be of interest for many reasons ( and wafi does appear once or twice )

AIS How do you use it? Vs Small vessles - Professional Mariner Forum - gCaptain Forum

They also call us "Wreckreational Sailors" and "Organ Donors".

It's not nice, but underneath the not niceness is usually a high level of knowledge and professionalism.

[Exile]

Originally Posted by Dockhead

They also call us "Wreckreational Sailors" and "Organ Donors".

It's not nice, but underneath the not niceness is usually a high level of knowledge and professionalism.

Yes. Like with comments from the above link talking about encounters with WAFI's from the 'WAFInator'. Personally, I could care less what they call us since it's not directed at any of us personally but rather as a way of referencing a class of vessels who often don't understand or, for whatever reason, often do not comply with the Rules.

'With small targets, I tend to wait until we are closer. I've found that small vessels might not appreciate a course change so early, and their perception of danger or a collision situation doesn't occur until closer ranges. At 10nm, they might not even be aware that there is a situation developing with this shadow they may or may not see near the horizon.'

10nm is oft-repeated by other commercial mariners on the thread. Additional confirmation that they have already maneuvered long before we may recognize any sort of issue. And as far as the WAFI terminology goes, even the Wafinator is more forgiving than his handle suggests:

'I for one, follow the navigation rules. There may be some here that play by tonnage, but that is far from an acceptable excuse if something were to happen. But the Rules are mutual, and the commercial sailors on here have all had close calls that muddy our perspective, shoot, even my username is remnant of that!! But I've learned that not every sailboat is a W.A.F.I.; that is reserved for a special breed, and over time the ratio of good to bad that I've encountered has improved.'

And maybe particularly poignant to recent discussions:

'Now, if you are sailing erratically and you are the stand on, I expect you to stand-on. The rules make no allowances for a vessels that feel free to do whatever they want; everyone has responsibilities. Part of my job as a watch officer is to monitor your actions as well to make sure you are doing what we discussed and what you are required to do within the Rules.'

Not all of these guys are so articulate or forgiving, but an interesting thread from their perspective for a change.

[El Pinguino]

A little bit more from some big boat drivers...

'JemplayerTop ContributerJun '13
How about this, get out of the way regardless of what the rules say.

In the end only this rule should apply. He who has the most tonnage make the rules.

Most of us are oil filed guys in the GOM, so for us we set up on a course that will let us cut through the most fields with as few course changes as possible. Nothing pisses me off more then somebody who is piddling about makes me change course and now I have to figure out a whole new route because even a 5 degree course change causes everything I had planned to fall apart. I'm sure ships working around the Islands have the same considerations due to their draft and feel the same way.'

and...

'skycowboyTop ContributerJun '13 mtskier
Remember, when hailing a foreign ship you have to allow for the time of the initial call until the time they can go find the guy that speaks English.' ... he would be speaking about ships manned by 'filipino monkeys'....

[TJ D]

Originally Posted by El Pinguino

A little bit more from some big boat drivers...

'JemplayerTop ContributerJun '13
How about this, get out of the way regardless of what the rules say.

In the end only this rule should apply. He who has the most tonnage make the rules.

Most of us are oil filed guys in the GOM, so for us we set up on a course that will let us cut through the most fields with as few course changes as possible. Nothing pisses me off more then somebody who is piddling about makes me change course and now I have to figure out a whole new route because even a 5 degree course change causes everything I had planned to fall apart. I'm sure ships working around the Islands have the same considerations due to their draft and feel the same way.'

and...

'skycowboyTop ContributerJun '13 mtskier
Remember, when hailing a foreign ship you have to allow for the time of the initial call until the time they can go find the guy that speaks English.' ... he would be speaking about ships manned by 'filipino monkeys'....

It looks like the WA's don't have the corner on the market on being FI's. There are some serious boneheads on that thread.

[markpierce]

Originally Posted by StuM

Only when required by Rule 34 (a):

When vessels are in sight of one another, a power-driven vessel underway, when manoeuvring as authorized or required by these Rules, shall indicate that manoeuvre by the following signals on her whistle:

Which is rarely the case when leaving a berth. If a risk of collision exists, I don't leave the berth until the fairway is clear so no signal is required.

When I'm on commercial, sea-going ships, I pay attention to their horn signals and hoisted flags. On my own boat, I attempt to imitate. I've failed in not having a "fueling" flag, however.

[Exile]

Originally Posted by TJ D

It looks like the WA's don't have the corner on the market on being FI's. There are some serious boneheads on that thread.

No question about that, and a bit startling to think some of those guys may be the ones on the bridge in an encounter. But also found it ironic that the 'Wafinator' was the most sensible and had the kindest words for our ilk.

Couldn't help womdering if OP 'MarkJ' was the same of local CF fame.