First, as I said, the 3 miles range was taken as a hypothetical range at which I may well have concluded my preliminary collision risk assessment. It was not intended to be precise. The actual range could be 4 miles or 2 miles. Indeed, I may not know with any substantial accuracy what the distance is. Why should I need to? It's like the braking/stopping distances in the highway code. They have absolutely no practical relevance or application in everyday driving.
Second, my hypothetical illustration is that it appears that I will pass ahead. But am I sure? Snowleopard's analysis indicates that the actual change in bearing for a CPA of 400m between 4 miles and 2 miles separation is only ~3°. And even if I am sure, does the CPA (which I cannot measure accurately anyway) provide a safety margin that I am willing to accept? I know I said I could manoeuvre out of the way in nearly all cicumstances, but the risk of engine failure or hitting something in the water at the critical moment, even if remote, does exist, so I do not discount it entirely. So my real choice (it seems to me) is to eliminate the possible conflict with certainty (the sooner the better), even if that means [bending the rules a bit] [perhaps "a flexible interpretation" is better], or to wait until the range has reduced to ~1 mile, at which point the avoiding action, if needed, will have to be more substantial.
Third, why is 2 miles the range which I should set as my rule 17(a)(ii) decision point. Why not 2.5 or 1.5? You said (I think) that ship's OOW will usually have commenced avoiding action at ~2 miles, but should I rely on that?
Agreed. But we can debate the interpretation of Colregs. We can debate the scope of meaning of "appreciable" in 7(d)(i) and the intent of "if the circumstances of the case admit" in 17(c). I think you felt it otiose to debate the scope of meaning of "apparent" in 17(a)(ii), but what about "appropriate" in the same rule. We can debate the point at which a CPA crosses the line between "no risk of collision" and "risk of collision"; and whether that distance may or may not vary depending on one's perspective (small vessel or otherwise), appetite for risk or simple subjective judgement. We can also debate whether and how CPA can be reliably measured (by a small vessel or otherwise), and how that influences the interpretation of rule 17 and the previous judgements.I thought that, too. But whilst we can discuss opinions, there is nothing to be gained by discussing facts: it just becomes boring. And the fundamental fact is the text of Rule 17. We can't change that.
You may be persuaded by my arguments and acknowledge that early avoidance, albeit not in accordance with the narrow interpretation, could, in some cases, actually be 'a good thing', or just an acceptable, practical measure (I'm not holding my breath) :-). We could debate which of the available alternative avoidance measures is more or less appropriate. I suggested a 10° turn to port, which geometrically would work (comfortably I think) if made at ~3 miles range. However, I can see the argument for a more decisive turn (showing the other bow), hold for a while, then equal and opposite turn back on to original heading. Or something else (I don't like 360° turn for several reasons but it could be discussed). And would that 'appropriate action' be different if the small vessel is a yacht at 5kts rather than a power vessel at substantially greater speed?
Plenty to talk about. I respect your experience and expertise and I am genuinely interested to hear your opinions, but I will keep challenging you to justify them if I see any weaknesses or gaps. That's just the way I am.
View Poll Results: Which Colregs should small craft skippers be encouraged to ignore?
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Rule2: the ordinary practice of seamen
Rule 5: Lookout
Rule 6: Safe speed
Rule 8: Action to avoid collision
Rules 9 and 10: Narrow channels and separation schemes
Rules 12-16: the everyday steering and sailing rules
Rule 17: Action by stand-on vessel
Rule 18: the pecking order
Part C -- lights and shapes
None of the above: We should obey all of them
Thread: Which colregs should we ignore?
15-10-09, 13:39 #71
Last edited by Observer; 15-10-09 at 13:54.
15-10-09, 13:48 #72I don't agree that "apparent" is capable of objective interpretation ahead of analysis of the facts and circumstances of a specific case. In law, it surely falls to be decided by a court on those established facts, in the same way as (for example) "careless driving" is assessed by the court by reference to the established facts against the standard expected of a "careful and competent driver". It doesn't have an objective meaning outside a courtroom - and even then not until the tribunal of fact has so decided.
15-10-09, 15:08 #73timbartlett Guest
Sorry, gentlemen, but I can't cope with all the nested quotes. This post is too long even without them, I have three dogs demanding a walk, and I really do have to do some constructive, money-earning work! So please pick what you can out of this:-
At very long ranges (let's say over 6 miles, partly so that other understand what kind of distance I have in mind, and partly because that's the only figure that is specifically referenced in law), I suggest that both vessels are free to manoeuvre.
At that stage, the small craft probably cannot be certain whether a steady bearing situation exists or does not. But Rule 7di says that we have to deem a risk to exist unless the compass bearing is changing. Fortunately, the MCA's proposed "Long Range Rule" was rejected by IMO, so the precedent is the Banshee case that says you can't collide with a ship that's six miles away. Even without Banshee, if you think you can avoid a collision by allowing your vessel to yaw a few degrees to port, while you are still at 6miles +, who's going to know, and who's going to complain?
Once the range is <6M, there is no ambiguity. Rule 7di says that we have to assume there's a risk of collision unless we know there isn't. And Rule 17a1 says the stand-on vessel has to stand on if there's a risk of collision.
From the ship's point of view, Rule 8 requires that an alteration of course has to be large enough to be readily apparent to another vessel observing visually or by radar. So if it is not "readily apparent"to the watchkeeper on the stand-on vessel(using an ordinary dictionary interpretation of "apparent")then he isn't obeying the rules.
(It would be up to a court to decide whether 10 degrees was plenty or whether 20 degrees was not enough in any particular situation)
But just because he hasn't apparently altered course when the range is five miles, or four miles, there is no reason to believe that he isn't going to. So Rule 17 a i applies.
By the time the range has closed to three miles, some of us might have just noticed him, some of us might be wondering whether his bearing is changing, and some of us might be wondering why he hasn't altered course yet...but none of us have any reason to believe that he isn't going to. So the obligation imposed by Rule 17 a i still applies.
We are not allowed to alter course until it has become apparent that the stand on vessel is not taking action in accordance with the rules. And we cannot argue that he is not acting in accordance with the rules until the range has closed to such an extent that any normal watchkeeper on a similar ship would have altered course if he was going to. Until that moment, he could be taking bearings, checking with the radar, consulting with the captain, asking the engineroom if it's OK to change engine revs yet, disengaging the autopilot, etc.etc.
The precise moment at which it becomes "too late" depends on the handling charatcteristics of the ship, which we don't know. Normal practice puts it at about two miles in open water. But why argue about precisely where, in this grey area, we cross the dividing line at which 17aii begins to apply?
It's a fairly narrow grey area, and in a small and manoeuvrable craft, there is very little -- if anything -- to be gained by altering course at the earliest possible moment that we are allowed to do so. Why not carry on until there is no doubt? By the time the range has closed to (say) one mile, the watchkeeper on a big, unmanoeuvrable vessel has clearly left it too late, but we still have plenty of time and sea-room available.
My concernsI'm relieved that this discussion has got back to a sensible argument about the issues, rather than personal insults, but I'm afraid I still feel distinctly uneasy about any argument that advocates altering course towards the give-way vessel, at exactly the sort of range at which it is most likely to be altering course itself, and at a stage at which Rule 17 is quite unambiguous.
And whilst it doesn't relate to this particular rule, I can't help thinking of the Wahkuna incident. It's one of very few actual collisions between ships and yachts -- and it would never have happenned if Wahkuna hadn't stopped to give way to an approaching ship.
15-10-09, 16:08 #74Registered User
- Join Date
- May 2001
I am not happy with your view that risk of collision has to be deemed to exist in your "medium range" cases as I think that can lead to very strange consequences. I don't think the courts would interpret the rules as literally as you suggest.
So how do you see this interacting with the "not to impede" regulations?
In particular I don't see how your reading of the rules can be reconciled with Rule 8(f) which clearly suggests that "risk of collision" may develop as the vessels approach - otherwise (iii) does not make any sense at all.
15-10-09, 16:22 #75
Anyway, I'm rather afraid that the annoying tendency of my vessel "to yaw a few degrees to port" at medium range is unlikely to get fixed very soon. Bu**er. Just hope the purists don't sit on the examination panel for my YM ticket.
15-10-09, 16:40 #76timbartlett Guest
For one thing, I'm finding it really interesting, and would be delighted to come back early next week to find it still going.
For another, having let the genie out of the bottle, it's quite beyond my powers to put it back.
And finally ... this thread has generated so much interest that I'm trying to think of some way in which I might persuade one of the magazines to use something like it as a feature.
15-10-09, 16:45 #77
Following on from my 'change of bearing' post, this is the strategy I suggest. It doesn't involve ignoring colregs but takes into account the relative speeds of the vessels, plus my ability to stop or turn far quicker than any ship.
1. Stand on until the approaching ship is approx 1 mile away
2. Then start taking bearings
3. If by around 1/2 mile there is still a constant bearing, assume the ship is not going to turn. His ARPA may be telling him he'll miss you but he might also be watching a video or being bloody-minded.
4. Stop and wait until the ship is approx 45° off my bow (still approaching). At this point his superior speed will ensure he passes ahead.
5. Get under way again.
I can stop without altering course on any point of sailing. Others will need to make a turn if sailing with the wind free. When turning, turn enough to show him a different sector of light.One hull good, two hulls better.
15-10-09, 16:53 #78I'm trying to think of some way in which I might persuade one of the magazines to use something like it as a feature
15-10-09, 16:54 #79Registered User
- Join Date
- May 2001
That is particularly the case as it may not be readily apparent to him that you have stopped.
IMHO the only action you should consider taking when he is that close is turning signficantly - either showing him your stern or doing a 180.
In my view if you as stand on vessel decide to take action yourself it must involve a change of course large enough to be immediately apparent to the other vessel, and it must be early enough that should he take action at about the same time there is still time to sort things out before the crunch
15-10-09, 16:56 #80