Rule 17 -- Vid of a close encounter....

[bedouin]

6 knots is ~3 m/s. For a cargo ship with a 30 m beam, that's 10 seconds to cross side to side, and about a minute to get a cable-length clear. In a narrow channel, where the ship's course is clear, a cable or two away is often sufficient. In open water I'd not want to be anywhere near that close, so assuming I consider a half mile as a "safe" CPA, then that means I'm deciding at least 5 minutes out (more, accounting for closing speeds).

Below is another example, this time for a crossing with perpendicular headings. Note that at ~7 minutes out the distance would be down to 2.5 miles. At that time, to maintain a half mile CPA, you'd need to turn at least 65° (indicated by OsM1 in the third image).

However, these are simple calculations with nice precise numbers. If my idea of the other ship's course was off by 5°, then instead of that 65° turn opening up the CPA, it might return it back to 0! And here's the kicker... while the ship has an aspect of red 17° on course 270, it's only red 12° on course 265. Can you tell that by eye?

View attachment 195770View attachment 195769

That is rather over complicating things.

It is much simpler to rely on bearings. Constant bearing with range decreasing means you are at risk of collision.

So monitor the bearing of (bow of) the ship from say 10 minutes out. If the bearing is clearly increasing you will cross ahead. Anything else and you are going to want to go round the stern.(let's not play chicken with the big guys). Depending on wind etc I would stand on until say 5 minutes out then turn sufficiently to show my other bow to the ship (or turn parallel to show the stern - technically the more correct action). No need to act any earlier

I am not a particularly experienced sailor when compared to many on this board - I don't claim my approach is superior to anyone else's.

 

[sfellows]

Looking at the video then, unless the cruise ship is in a narrow channel, or restricted in its ability to manoeuvre, then the sail boat is the stand on vessel, and the cruise ship should have given way.

1) Having said that, the sail boat should have never got that close
2) If the sailing boat had AIS then they should have called all up the ship on VHS when it was clear they were on a close CPA and requested they alter course. I've done this on a number of occasions when 5 miles away and the ship has always altered course.

For me anything less than 0.5 miles CPA is a reason to call up.

 

[LittleSister]

Looking at the video then, unless the cruise ship is in a narrow channel, or restricted in its ability to manoeuvre, then the sail boat is the stand on vessel, and the cruise ship should have given way.

1) Having said that, the sail boat should have never got that close
2) If the sailing boat had AIS then they should have called all up the ship on VHS when it was clear they were on a close CPA and requested they alter course. I've done this on a number of occasions when 5 miles away and the ship has always altered course.

For me anything less than 0.5 miles CPA is a reason to call up.

I disagree.

The Maritime and Coastguard Agency's Marine Guidance Note 'Navigation: Watchkeeping Safety – Use of VHF Radio
and AIS' states:

'3.1 There have been a significant number of collisions where subsequent investigations have found that at some stage before impact, one or both parties were using VHF radio in an attempt to avoid collision. The use of VHF radio in these circumstances is not always helpful and may even prove to be dangerous.

3.2 . . . Uncertainties can arise over the identification of vessels, correlation and interpretation of messages received. Even where positive identification has been achieved there is still the possibility of a misunderstanding due to language difficulties however fluent the parties concerned might be in the language being used. An imprecise or ambiguously expressed message could have serious consequences.

3.3 Valuable time can be wasted whilst mariners on vessels approaching each other try to make contact on VHF radio instead of complying with the COLREG. . .

3.8 Although the practice of using VHF radio as a collision avoidance aid may be resorted to on occasion, for example in pilotage waters, the risks described in this Note should be clearly understood and the COLREG complied with to their best possible extent.'
[emphasis added]

https://assets.publishing.service.g...keeping_Safety_-_Use_of_VHF_Radio_and_AIS.pdf

 

[capnsensible]

That is rather over complicating things.

It is much simpler to rely on bearings. Constant bearing with range decreasing means you are at risk of collision.

So monitor the bearing of (bow of) the ship from say 10 minutes out. If the bearing is clearly increasing you will cross ahead. Anything else and you are going to want to go round the stern.(let's not play chicken with the big guys). Depending on wind etc I would stand on until say 5 minutes out then turn sufficiently to show my other bow to the ship (or turn parallel to show the stern - technically the more correct action). No need to act any earlier

I am not a particularly experienced sailor when compared to many on this board - I don't claim my approach is superior to anyone else's.

I like compass bearings too. Plus an A4 sized whiteboard and some non permanent markers in the cockpit are very useful. Great too for pilotage plans.
Even more simple in coastal waters is to watch for the vessel moving relative to the shore.

I've been lucky to have sailed across the shipping lanes in the Gib Straits many hundreds of times. Great for practicing this stuff. It's like sailing across to France from the UK but only takes 3 to 4 hours and has the N - S ferries plus willy nilly fishing boats too.

 

[Chiara’s slave]

I like compass bearings too. Plus an A4 sized whiteboard and some non permanent markers in the cockpit are very useful. Great too for pilotage plans.
Even more simple in coastal waters is to watch for the vessel moving relative to the shore.

I've been lucky to have sailed across the shipping lanes in the Gib Straits many hundreds of times. Great for practicing this stuff. It's like sailing across to France from the UK but only takes 3 to 4 hours and has the N - S ferries plus willy nilly fishing boats too.

We have our race course board, and whiteboard markers for taking down bearings if needed. But yeah, a convenient shoreline is a very sure way of telling. Clearly that’s the go to method of telling how you’re doing against other boats in a race.

 

[Never Grumble]

I'm just amazed at how complex this can be made.

 

[DFL1010]

Final try. I said, above, "...To clarify, some people are ignorant of the consequences of ignoring/violating the Colregs because, when they Google "Colregs" they don't get linked to the local legislation. They are sent to the original International Colregs which make no reference to penalties. However ignorance of the law is no defence as they will likely find out if they keep ignoring/violating." You may think it unimportant but for someone who goes looking for "the Colregs" after hearing others speak/write about it, the first site that Google throws up is this IMO page: Convention on the International Regulations for Preventing Collisions at Sea, 1972 (COLREGs) and I maintain that it is unlikely that, without prompting, that person might then look up The Merchant Shipping (Distress Signals and Prevention of Collisions) Regulations 1996 to learn about the associated penalties under that legislation for UK vessels.

I understand your point, I just don't buy it.

I agree that it's unlikely that someone will do a deep dive on the law to find the legislation and whatnot. However, I find it hard to believe that someone would go to the trouble of looking up/buying a book about the colregs, read and learn them, then think, 'hang on a mo, there's no penalty listed here. I guess I don't have to follow these.'

 

[requiem]

It is much simpler to rely on bearings. Constant bearing with range decreasing means you are at risk of collision.

I very much agree! (The question that spawned the scenarios was indeed assuming only a compass available.)

Running examples just helps give a better idea of the timing involved as well as what may be needed to ensure a safe passing distance. For example, in that last scenario if the crossing ship was indeed on a course of 265 instead of 270, then after 6 minutes her bearing would have increased from 73° to ~78°, a subtle but meaningful shift, and a reminder of the importance of careful observation.

 

[capnsensible]

I'm just amazed at how complex this can be made.

K.I.S.S

 

[Jmacd]

Regardless of context, Pretty aggressive driving by cruise ship. Probably drives a white van near where I live on their days off.

 

[Jmacd]

For my own edification, may I ask for responses to the following taken from an actual sailing event?

I am sailing from Channel Islands Nothwards to Britain.

On the horizon (that is about 5miles isn’t it ? - yes I know I should know) or a little closer I can see a large unknown ship to starboard. Big thing.

I have no AIS or radar.

I take compass readings over few minutes and see collision course, so if wind allows I alter course to starboard to avoid him.

Have I broken colregs?

Are my actions sensible or should I have carried on until we were much closer?

I think I did right, but I am not a master mariner.

Quite sensible and reasonable. 5 ish miles? Probably much appreciated. If action is taken early and large enough to be easily seen by OOW on the other vesel.
As in show him or her a clear R to R.
If distance was closer. Altering course to Port or Away from the Big Vessel might be a safer option for you. JIK the big vessel decides to alter to pass astern of you.

In the clip,
The sailboats decision to turn away, leaving the ship astern was probably the best use of discretion. and safest for the sailboat at this point in the proceedings, regardless of how they got there.
While one might wonder if the cruise ship OOW even saw the sailboat.

 

[sfellows]

I disagree.

The Maritime and Coastguard Agency's Marine Guidance Note 'Navigation: Watchkeeping Safety – Use of VHF Radio
and AIS' states:

'3.1 There have been a significant number of collisions where subsequent investigations have found that at some stage before impact, one or both parties were using VHF radio in an attempt to avoid collision. The use of VHF radio in these circumstances is not always helpful and may even prove to be dangerous.

3.2 . . . Uncertainties can arise over the identification of vessels, correlation and interpretation of messages received. Even where positive identification has been achieved there is still the possibility of a misunderstanding due to language difficulties however fluent the parties concerned might be in the language being used. An imprecise or ambiguously expressed message could have serious consequences.

3.3 Valuable time can be wasted whilst mariners on vessels approaching each other try to make contact on VHF radio instead of complying with the COLREG. . .

3.8 Although the practice of using VHF radio as a collision avoidance aid may be resorted to on occasion, for example in pilotage waters, the risks described in this Note should be clearly understood and the COLREG complied with to their best possible extent.'
[emphasis added]

https://assets.publishing.service.g...keeping_Safety_-_Use_of_VHF_Radio_and_AIS.pdf

It's interesting that the quote above is in relation to the para. 3 "Use of VHF to Aid Collision Avoidance". My advice was use AIS to determine CPA and if I am the stand on vessel, call up the other vessel if the CPA is less than 0.5NM when over 5 miles away and request them to alter course to increase CPA and avoid any potential collision. How calling up on VHF to request this is covered by your quote is beyond me. What would you prefer? That as the stand on vessel I ignore the VHF, stand on and do exactly what the video shows? AIS is a fantastic aid to safety. I'm not going to ignore the value of AIS, I'm not going to ignore the COLREGs, but I am going to ignore the "advice" quoted.

 

[requiem]

Regarding VHF, I recall running across (I believe one judge's comments) that we have little idea of how often VHF was successfully used to avoid a collision, as it's only the unsuccessful cases that tend to make it to the courts.

But, based on such cases, a few general rules of thumb regarding VHF use can be derived:

1. VHF should never be used to arrange a crossing contrary to the ColRegs, i.e. it should only be used to shed light where there is uncertainty.
2. Action should never be delayed simply because a VHF interaction is expected or in progress.
3. Positive identification of the involved vessels should be considered mandatory.

 

[john_morris_uk]

Quite sensible and reasonable. 5 ish miles? Probably much appreciated. If action is taken early and large enough to be easily seen by OOW on the other vesel.
As in show him or her a clear R to R.
If distance was closer. Altering course to Port or Away from the Big Vessel might be a safer option for you. JIK the big vessel decides to alter to pass astern of you.

In the clip,
The sailboats decision to turn away, leaving the ship astern was probably the best use of discretion. and safest for the sailboat at this point in the proceedings, regardless of how they got there.
While one might wonder if the cruise ship OOW even saw the sailboat.

At five miles the ship might already be taking action. Your action won’t be appreciated…!

Turning to port to avoid rusk of collision is strongly discouraged in IRPCS unless special circumstances dictate otherwise. (Eg rocks to Starboard.)

 

[Chiara’s slave]

At five miles the ship might already be taking action. Your action won’t be appreciated…!

Turning to port to avoid rusk of collision is strongly discouraged in IRPCS unless special circumstances dictate otherwise. (Eg rocks to Starboard.)

In the vid, clearly the yacht is taking last minute desperate action on risk of death. What we don’t know is if he’d taken avoiding action long before, possibly at the same time as the ship…… and this is the possible result of it.

 

[Mark-1]

In the vid, clearly the yacht is taking last minute desperate action on risk of death. What we don’t know is if he’d taken avoiding action long before, possibly at the same time as the ship…… and this is the possible result of it.

That doesn't look like a yacht that was aware of the ship's presence to me. It looks more like someone who was dozing behind his sprayhood facing backwards and turned around to find his horizon full of ship. (I haven't zoomed in to see who was in the cockpit.)

 

[john_morris_uk]

In the vid, clearly the yacht is taking last minute desperate action on risk of death. What we don’t know is if he’d taken avoiding action long before, possibly at the same time as the ship…… and this is the possible result of it.

That may or may not be true. I thought we’d moved on to discuss actions on applying IRPCS generally.

We have no information as to how the yacht in the OP’s video got into that position. Nor do we know the circumstances as to whether it’s in confined or open waters. Therefore it’s very difficult to draw accurate conclusions as to how and why the yacht ended up there.

 

[flaming]

We have no information as to how the yacht in the OP’s video got into that position. Nor do we know the circumstances as to whether it’s in confined or open waters. Therefore it’s very difficult to draw accurate conclusions as to how and why the yacht ended up there.

You talk as if that would prevent people from damning the yacht and/or ship.

 

[Muddy32]

Having ploughed my way through this post, I find 35mins of my life has re-affirmed my view to avoid the Brown waters.

 

[capnsensible]

That may or may not be true. I thought we’d moved on to discuss actions on applying IRPCS generally.

We have no information as to how the yacht in the OP’s video got into that position. Nor do we know the circumstances as to whether it’s in confined or open waters. Therefore it’s very difficult to draw accurate conclusions as to how and why the yacht ended up there.

Why would facts ever matter on here?