Crossing Shipping Lanes (again)

Sections 1.9 & 2.5 of this MAIB report are quite interesting as it deals with the actions of a third party that identified both its own risk of collision with one vessel involved and also the risk of collision developing between both of them.

https://www.gov.uk/maib-reports/col...essel-timor-stream-off-the-dominican-republic

Interesting and disturbing reading, thanks for that. What I learn from it is that I cannot rely on other traffic paying attention and that, as master of a fairly vulnerable vessel, I need to maintain vigilance. Puts me in mind of a quote used by Douglas Bader in Reach for the Sky...

"Rules are for the guidance of wise men and the obedience of fools"
 
Details for a channel crossing are her, Rule 10 Traffic separation schemes:

The OP asked this:

Imagine motoring in your sailing boat from UK to France (outside the TSS) crossing first the westbound and then the eastbound shipping lane.

None of the discussion here relates to crossing a TSS. Rule 10 is therefore a total irrelevance. (The rest of that document is relevant, and is what people on this thread have been discussing. Just not the rule you highlight).
 
One of the many weaknesses of the IRPCS is that they assume that only two vessels are ever involved and completely ignore the possibility that a vessel could be simultaneously give-way and stand-on to two others.

I've just completed & passed my YM Offshore theory. The training materials and the IRPCS exam paper included some very complex multi-vessel situations including one that had 5 vessels simultaneously. It was intellectually pretty challenging.... :) finding this thread very interesting.
 
What do you do when simultaneously give-way and stand-on?



The trouble is that "shall not impede" is just not defined anywhere. Is there a legal obligation for pedestrians not to impede vehicular traffic?

Please don't get me wrong - the IRPCS do work very well, most of the time. However, the mindset which says "just follow the rules and everything will work out" is a bit too simplistic - and a bit too smug - to be as safe as it good be. Sensible people acknowledge ambiguity and work round it.

The first question is really very simple.

To stand on for a vessel while simultaneously a give way for another vessel would clearly be dangerous so priority is given to the obligation to give way.
Ordinarily this would be an alteration to starboard which would be turning away from the vessel you would other wise stand on for.
On the rare occasion where vessel you are the give way for is also on the port side slow down to minimum steerage way or stop until they are past and clear.

The second question about not impede. I am to tired right now:)
 
Interesting and disturbing reading, thanks for that. What I learn from it is that I cannot rely on other traffic paying attention and that, as master of a fairly vulnerable vessel, I need to maintain vigilance. Puts me in mind of a quote used by Douglas Bader in Reach for the Sky...

"Rules are for the guidance of wise men and the obedience of fools"

I always find that quote very disturbing because fools generally consider themselves wise, whereas a wise man knows that we are all fools.
 
I'm anxious when I'm under sail and a ship approaches on my port side. I'm the stand-on vessel, but I'd much rather take avoiding action.
 
Interesting and disturbing reading, thanks for that. What I learn from it is that I cannot rely on other traffic paying attention and that, as master of a fairly vulnerable vessel, I need to maintain vigilance. Puts me in mind of a quote used by Douglas Bader in Reach for the Sky...

"Rules are for the guidance of wise men and the obedience of fools"

Maybe if he'd obeyed the rules he'd have kept his legs and played for England as a fly-half ;-)
 
I've just completed & passed my YM Offshore theory. The training materials and the IRPCS exam paper included some very complex multi-vessel situations including one that had 5 vessels simultaneously. It was intellectually pretty challenging.... :) finding this thread very interesting.

That sounds impressive. I don't remember situations as complex as that when I did my theory exam but it was a while ago. Congrats on passing.
 
I'm anxious when I'm under sail and a ship approaches on my port side. I'm the stand-on vessel, but I'd much rather take avoiding action.

I think there is much confusion over terms in this discussion.
If I have another vessel on a constant bearing, on my port side, I monitor it. If the other vessel doesn't alter course at a point where I would have expected it to, I may choose to alter course to avoid a collision situation developing. I don't call that "avoiding action". If I elect to continue until our vessels are so close that there is a risk of collision, the other vessel hasn't changed course and I am the stand-on vessel there will come a point where I decide I must take action to avoid a collision. That will be "avoiding action". The term could also apply to a give-way manoeuvre if I am the give-way vessel and have left it too long to make a move. If we are not in a collision situation, a change of course is just that. Having another vessel on a constant bearing is not in itself a collision situation, if you are monitoring it carefully from an appropriate distance (as soon as you become aware of it by whatever means!).
I may be being pedantic here but I find these clear definitions help me to understand a quite complex set of rules.
 
Last edited:
I'm anxious when I'm under sail and a ship approaches on my port side. I'm the stand-on vessel, but I'd much rather take avoiding action.

We all feel that. But what makes him anxious is when you, as stand-on vessel, fail to exercise your duty which is to maintain your course and speed. He still has the duty to keep clear of you, which should be easy, but by behaving unpredictably you’re making it hard - and risky.
 
I think there is much confusion over terms in this discussion.
If I have another vessel on a constant bearing, on my port side, I monitor it. If the other vessel doesn't alter course at a point where I would have expected it to, I may choose to alter course to avoid a collision situation developing. I don't call that "avoiding action". If I elect to continue until our vessels are so close that there is a risk of collision, the other vessel hasn't changed course and I am the stand-on vessel there will come a point where I decide I must take action to avoid a collision. That will be "avoiding action". The term could also apply to a give-way manoeuvre if I am the give-way vessel and have left it too long to make a move. If we are not in a collision situation, a change of course is just that. Having another vessel on a constant bearing is not in itself a collision situation, if you are monitoring it carefully from an appropriate distance (as soon as you become aware of it by whatever means!).
I may be being pedantic here but I find these clear definitions help me to understand a quite complex set of rules.

We've discussed this many times before. In the days before AIS it seems to be accepted wisdom that you are in a collision situation as soon as you actually take a bearing from the other vessel and recognise that is is not changing. This could be 2 or 3 miles out.

With AIS I'm happy to note a collision situation at much greater distances. That doesn't mean that it will still be a collision situation 15 minutes later because one of us might well have changed course for reasons which are totally outwith the collision situation, but it does no harm to observe it from 10 or 20 miles out as all knowledge is good knowledge. :)

Richard
 
We've discussed this many times before. In the days before AIS it seems to be accepted wisdom that you are in a collision situation as soon as you actually take a bearing from the other vessel and recognise that is is not changing. This could be 2 or 3 miles out.

With AIS I'm happy to note a collision situation at much greater distances. That doesn't mean that it will still be a collision situation 15 minutes later because one of us might well have changed course for reasons which are totally outwith the collision situation, but it does no harm to observe it from 10 or 20 miles out as all knowledge is good knowledge. :)

Richard

Agreed, but I would call a vessel on a constant bearing a potential collision situation. Pedantic, I know, but it makes a difference to me at least.
 
I think there is much confusion over terms in this discussion.
If I have another vessel on a constant bearing, on my port side, I monitor it. If the other vessel doesn't alter course at a point where I would have expected it to, I may choose to alter course to avoid a collision situation developing.
I get on the radio to him, ask if he has seen me and what course of action he intends to take.
Then you know for sure, no guess work involved.
 
Clearly the vessels that use busy shipping lanes like the Straits of Gibraltar dont have a copy of that. VHF radio can often have a continual stream of conversations between vessels avoiding a risk of collision by talking to each other.
 
Top