Container Ship and Saliboats

[Glenn.Brooks]

So one this I didn't see mentioned here, regarding AIS, is whether large commercial ships pay attention to AIS-B, or not. AIS-B is the frequency small boat transponders transmit on, versus AIS-A, which is reserved for large commercial ships - as I understand it.

Some time ago, a ships captain told me often they turn off the AIS-B And do not monitor it because of the Hugh number of signals and constant alarms going off.


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[MarkSF]

Originally Posted by Glenn.Brooks

So one this I didn't see mentioned here, regarding AIS, is whether large commercial ships pay attention to AIS-B, or not. AIS-B is the frequency small boat transponders transmit on, versus AIS-A, which is reserved for large commercial ships - as I understand it.

Some time ago, a ships captain told me often they turn off the AIS-B And do not monitor it because of the Hugh number of signals and constant alarms going off.


Sent from my iPad using Cruisers Sailing Forum

I had to turn the alarm off on receive-only AIS on my sailboat. Just too much traffic around. In fact, it will go off immediately when I turn it on, in my slip!

The alarm is useful for when you're in the ocean and there isn't much traffic around.

[captmikem]

Originally Posted by Lodesman

Mike, I assumed your comments were specifically about large ship's manoeuvrability in confined waters, but there is some ambiguity. What do you say about situations in open waters (assuming good vis, no complicating factors) - are you saying that pleasure boats should not stand on when the rules require them to?

So your interpretation of the rules is that in the open ocean when you see a ship on a collision course that the rules REQUIRE you to maintain your course and speed?

Here is basically what happens on two vessels:
Yacht: (doing 6 kts, can turn in 200 feet)
Ship: (doing 23 kts can turn in about a mile)

(By the way, at less than around 6 miles you can physically see a ship change course, more at night. Only way a ship can tell if a small boat is changing course is to track and plot him. unless he is right next to you.)

6 miles
Yacht, look at that ship, it looks like we are on a collision course.
We are a sailboat we have the right of way.

Ship.........

4 miles (about 2 minutes 30 seconds later)
Yacht, he is not altering, he has to see us.
calls on 16 “big ship big ship This is tweety bird do you see us?”


Ship,.........

2 miles (again, 2 minutes 30 seconds later or 5 minutes total time)
Yacht, He is not turning! There must be no one on the bridge, or they are asleep!

Ship, Lookout. “Sir, little boat off the starboard bow”. Watchofficer grabs his binoculars to look.


It sure would have been easier for both vessels (and to me prudent seamanship) to have altered at around 4 miles.

So let us look at the rules:

Rule 2(b) if I recall correctly says basically (not a quote, just my memory) Complying with the rules, Due regard to all dangers of risk of collision; circumstances, limitations etc may make it necessary to depart from the rules to avoid a collision.
To me, that means do whatever is prudent to AVOID a collision.

Rule 8 a, Take action early to avoid a collision
On ships at sea early is before the six mile ring.

Rule 17, (I forget if it is a or b) basically says as soon as it is apparent the give way vessel is not going to give way, the stand on vessel may take action to avoid a collision.

So to me on a sailboat, this says that my REQUIREMENTS should a risk of collision exist:
if they are not altering at less than six miles they probably do not see me, I need to be ready to take action.
3 miles to me is close, I will take action at 4 miles, if I see no course change on the ship.


Just my humble opinion, but I believe if you are on a small boat at sea, and at six miles you conclude you are on a collision course with a ship, the rules do NOT REQUIRE you to hold your course and speed.

Michael

[newhaul]

Only rule I have is biggest has right of way period

[a64pilot]

Originally Posted by newhaul

Only rule I have is biggest has right of way period

Long ago I was taught Mass X Velocity = Right of Way
Hasn't failed me yet, and that goes for boats, airplanes, ground vehicles whatever

[Exile]

Originally Posted by captmikem

So your interpretation of the rules is that in the open ocean when you see a ship on a collision course that the rules REQUIRE you to maintain your course and speed?

Here is basically what happens on two vessels:
Yacht: (doing 6 kts, can turn in 200 feet)
Ship: (doing 23 kts can turn in about a mile)

(By the way, at less than around 6 miles you can physically see a ship change course, more at night. Only way a ship can tell if a small boat is changing course is to track and plot him. unless he is right next to you.)

6 miles
Yacht, look at that ship, it looks like we are on a collision course.
We are a sailboat we have the right of way.

Ship.........

4 miles (about 2 minutes 30 seconds later)
Yacht, he is not altering, he has to see us.
calls on 16 “big ship big ship This is tweety bird do you see us?”


Ship,.........

2 miles (again, 2 minutes 30 seconds later or 5 minutes total time)
Yacht, He is not turning! There must be no one on the bridge, or they are asleep!

Ship, Lookout. “Sir, little boat off the starboard bow”. Watchofficer grabs his binoculars to look.


It sure would have been easier for both vessels (and to me prudent seamanship) to have altered at around 4 miles.

So let us look at the rules:

Rule 2(b) if I recall correctly says basically (not a quote, just my memory) Complying with the rules, Due regard to all dangers of risk of collision; circumstances, limitations etc may make it necessary to depart from the rules to avoid a collision.
To me, that means do whatever is prudent to AVOID a collision.

Rule 8 a, Take action early to avoid a collision
On ships at sea early is before the six mile ring.

Rule 17, (I forget if it is a or b) basically says as soon as it is apparent the give way vessel is not going to give way, the stand on vessel may take action to avoid a collision.

So to me on a sailboat, this says that my REQUIREMENTS should a risk of collision exist:
if they are not altering at less than six miles they probably do not see me, I need to be ready to take action.
3 miles to me is close, I will take action at 4 miles, if I see no course change on the ship.


Just my humble opinion, but I believe if you are on a small boat at sea, and at six miles you conclude you are on a collision course with a ship, the rules do NOT REQUIRE you to hold your course and speed.

Michael

Hopefully that's a given for most, as a matter of the Rules & common sense (although the two usually go hand in hand). If you want to go pedantic, you could go further & say the Colregs aren't even applicable until a risk of collision arises. In any event, the rules re: stand on & give way are there to promote predictability & consistency, and always subject to Rule 2(b)'s allowance for rule departures to the extent they may be required to avoid collisions.

As a matter of safety, common sense, professionalism, and courtesy, recreational vessels should always stay well clear of large merchant vessels, and do it early. Imho . . . .

[Exile]

Originally Posted by Glenn.Brooks

So one this I didn't see mentioned here, regarding AIS, is whether large commercial ships pay attention to AIS-B, or not. AIS-B is the frequency small boat transponders transmit on, versus AIS-A, which is reserved for large commercial ships - as I understand it.

Some time ago, a ships captain told me often they turn off the AIS-B And do not monitor it because of the Hugh number of signals and constant alarms going off.


Sent from my iPad using Cruisers Sailing Forum

As MarkSF commented, it may make sense for large commercial ships to filter AIS-B and maybe longer range AIS-A signals when they are trying to maneuver in & out of port, for example, but there wouldn't be much need for such filtering in the open ocean.

For the past few years I've only had an AIS-B receiver on my boat, on the assumption that large, fast-moving commercial ships probably pose the greatest potential threat to my small sailboat in open waters, it's easier for me vs. them to both spot them & to maneuver, and so it's therefore my job to stay out of their way. In other words, having a receiver, along with radar & a lookout, helps put collision avoidance more under my control, whereas I can't control whether another vessel can see me, whether electronically or physically. As I undertake longer voyages, however, especially if short or singlehanded, then I'll install an AIS transponder on the theory that it's increases my odds by having my vessel as visible as possible.

[newhaul]

This thread brings to mind a line from hitchhikers guide to the galaxy ( the container ship is the dozer). Have you any idea how much damage that bulldozer would suffer if I just let it roll straight over you?"
"How much?" said Arthur.
"None at all," said Mr. Prosser.

[Dockhead]

Originally Posted by captmikem

So your interpretation of the rules is that in the open ocean when you see a ship on a collision course that the rules REQUIRE you to maintain your course and speed?

Here is basically what happens on two vessels:
Yacht: (doing 6 kts, can turn in 200 feet)
Ship: (doing 23 kts can turn in about a mile)

(By the way, at less than around 6 miles you can physically see a ship change course, more at night. Only way a ship can tell if a small boat is changing course is to track and plot him. unless he is right next to you.)

6 miles
Yacht, look at that ship, it looks like we are on a collision course.
We are a sailboat we have the right of way.

Ship.........

4 miles (about 2 minutes 30 seconds later)
Yacht, he is not altering, he has to see us.
calls on 16 “big ship big ship This is tweety bird do you see us?”


Ship,.........

2 miles (again, 2 minutes 30 seconds later or 5 minutes total time)
Yacht, He is not turning! There must be no one on the bridge, or they are asleep!

Ship, Lookout. “Sir, little boat off the starboard bow”. Watchofficer grabs his binoculars to look.


It sure would have been easier for both vessels (and to me prudent seamanship) to have altered at around 4 miles.

So let us look at the rules:

Rule 2(b) if I recall correctly says basically (not a quote, just my memory) Complying with the rules, Due regard to all dangers of risk of collision; circumstances, limitations etc may make it necessary to depart from the rules to avoid a collision.
To me, that means do whatever is prudent to AVOID a collision.

Rule 8 a, Take action early to avoid a collision
On ships at sea early is before the six mile ring.

Rule 17, (I forget if it is a or b) basically says as soon as it is apparent the give way vessel is not going to give way, the stand on vessel may take action to avoid a collision.

So to me on a sailboat, this says that my REQUIREMENTS should a risk of collision exist:
if they are not altering at less than six miles they probably do not see me, I need to be ready to take action.
3 miles to me is close, I will take action at 4 miles, if I see no course change on the ship.


Just my humble opinion, but I believe if you are on a small boat at sea, and at six miles you conclude you are on a collision course with a ship, the rules do NOT REQUIRE you to hold your course and speed.

Michael

Certainly you are required to hold course and speed, and this is fundamental to collision avoidance. You are supposed to "hold still" to give the give-way vessel a chance to sort out the situation. if you don't do this, then he can't know which way or how much to turn -- think about it.

When you are allowed to presume that is not going to maneuver, and do it yourself, is not written in the Rules. My rule is -- after I've given him a decent chance. Most ships, where I sail, maneuver at about 10 miles out (which by the way is impossible to perceive for boats without AIS), and the maneuver to give a CPA of 1 mile. But sometimes they don't maneuver until about 5 miles. In open water, good viz, etc., I try to wait until about 4 miles before I start to maneuver myself. I think 6 miles is too early, unless it is a higher speed vessel (18 -- 24 knots), or if I'm sailing slowly in light winds, in which case you need a greater margin of error. Relative speeds are very important to collision avoidance -- the greater the difference, the less you can do to open up the CPA. It is a common myth that "our boats are much more maneuvrable than big ships" -- bullocks. Only in close quarters. Other than in close quarters, the ability to turn and change the CPA of an encounter is a direct function of your relative speed compared to the other vessel. The faster you go, the more power you have to do this, and thus the more control you have over the crossing.

Which brings me to very high speed vessels -- like the fast cat ferries in the Channel making 40 knots. The relative speed is so great, that your maneuver is meaningless. Don't bother. He will steer around you like you're standing still. If he fails to, then there's nothing you can do -- you're dead. The COLREGS system of collision avoidance doesn't work at all in an encounter between a 6 knot vessel and a 40 knot vessel -- only he can do any avoiding, so just hold your course and speed.

[Dockhead]

Originally Posted by Exile

. . . If you want to go pedantic, you could go further & say the Colregs aren't even applicable until a risk of collision arises. .

That's not pedantic at all -- that's absolutely correct.

If you can calculate a CPA with a vessel more than 10 miles away (for which you need AIS), then you not only MAY, but really, following Rule 2, you MUST, maneuver to prevent a risk of collision from ever arising. This is good seamanship, and applicable when crossing shipping lanes where you know where the ships will be. Pick a time to cross so that NO ONE HAS TO MANEUVER. Missing an opportunity to do that which then forces the ship to maneuver for you is very bad form.

Being the stand on vessel does not mean you just blithely sail along expecting everyone to just get out of your way.

[Exile]

Originally Posted by Dockhead

That's not pedantic at all -- that's absolutely correct.

If you can calculate a CPA with a vessel more than 10 miles away (for which you need AIS), then you not only MAY, but really, following Rule 2, you MUST, maneuver to prevent a risk of collision from ever arising. This is good seamanship, and applicable when crossing shipping lanes where you know where the ships will be. Pick a time to cross so that NO ONE HAS TO MANEUVER. Missing an opportunity to do that which then forces the ship to maneuver for you is very bad form.

Being the stand on vessel does not mean you just blithely sail along expecting everyone to just get out of your way.

I'm not great with estimating distances on the water, but the most common scenario for me in open water is when a vessel first gets close enough that, either by sight or electronically (generally both), I can conclude that a course deviation to pass under its stern is prudent. It is often at this point in time that I'll make the deviation rather than waiting, and make the deviation more pronounced than it needs to be to communicate it clearly to the other vessel. After that I can always slowly come back to my original course as the vessel draws nearer, but all the while maintaining my intent to pass behind its stern. I think it's just a matter of prudence & courtesy not to force a larger commercial vessel to give way, regardless of whether I am stand on (i.e. under sail) or not. Among other things, it requires an assumption that the big ship sees you, one which may all too often be incorrect.

Under many other scenarios, however, e.g. congestion, confined waterways, confusing lights, channels, etc., maintaining course & speed as the stand on vessel is plainly the most prudent & seamanlike action.

In both cases, you are communicating your intentions clearly & early so as to avoid confusion, but also remain prepared to depart from the Rules should circumstances warrant. Of course, strictly speaking this "departure" from the Rules isn't a departure at all, since the Rules explicitly instruct you to do this as needed to avoid a collision.

[Dockhead]

Originally Posted by Exile

I'm not great with estimating distances on the water, but the most common scenario for me in open water is when a vessel first gets close enough that, either by sight or electronically (generally both), I can conclude that a course deviation to pass under its stern is prudent. It is often at this point in time that I'll make the deviation rather than waiting, and make the deviation more pronounced than it needs to be to communicate it clearly to the other vessel. After that I can always slowly come back to my original course as the vessel draws nearer, but all the while maintaining my intent to pass behind its stern. I think it's just a matter of prudence & courtesy not to force a larger commercial vessel to give way, regardless of whether I am stand on (i.e. under sail) or not. Among other things, it requires an assumption that the big ship sees you, one which may all too often be incorrect.

Under many other scenarios, however, e.g. congestion, confined waterways, confusing lights, channels, etc., maintaining course & speed as the stand on vessel is plainly the most prudent & seamanlike action.

In both cases, you are communicating your intentions clearly & early so as to avoid confusion, but also remain prepared to depart from the Rules should circumstances warrant. Of course, strictly speaking this "departure" from the Rules isn't a departure at all, since the Rules explicitly instruct you to do this as needed to avoid a collision.

Indeed.

It should be -- but maybe isn't -- obvious, that preventing a risk of collision from ever arising is far preferable to sorting it out with COLREGS maneuvers.

It means that in bays and harbour entrances and busy inshore areas, just stay out of the bloody channels and lanes, until there's no traffic.

It means if you can predict the crossing more than 10 miles out, alter to pass astern, with a large change of course so that it is obvious.

But if for whatever reason you find yourself on a constant bearing at less than 10 miles, and more than say 4, you need to hold course and speed (if you are under sail, or if he is to port of you) for a while to give him a chance.


One collision avoidance trick which I love, which predates all electronics, and maybe even predates hand bearing compasses, is to flip the pilot off and just steer for the stern of the ship you are tangling with. What's good about this is that if everything goes to hell -- say you've just dodged two other ships and find yourself face to face with a third which you hadn't figured on -- this is foolproof, dead simple, muscle memory move which requires zero electronics, calculations, or thought, and is guaranteed to prevent a collision -- provided, of course, you can see his stern to steer towards Used to be taught back in the day, but is becoming a lost art I think these days.

[Exile]

A very recent event which makes for an interesting read and is most pertinent to the current discussion. Among other lessons, it teaches how dangerous making assumptions can be out in open water. Hard to believe a large US naval vessel wasn't aware of the presence of the small sailboat.

A midnight encounter with a Navy ship and what we learned from it. | Sailfeed

[Lodesman]

Originally Posted by captmikem

So your interpretation of the rules is that in the open ocean when you see a ship on a collision course that the rules REQUIRE you to maintain your course and speed?

Where rules 13, 15 or 18 would require it, yes, you are required to maintain your course and speed.

Originally Posted by captmikem

Just my humble opinion, but I believe if you are on a small boat at sea, and at six miles you conclude you are on a collision course with a ship, the rules do NOT REQUIRE you to hold your course and speed.

Out of curiosity, what are your professional qualifications, and what type of ships have you "driven" in what capacity? And what to you sail for fun?

[markpierce]

Originally Posted by MarkSF

Yesterday I heard the Vessel Traffic Service (VTS) make an announcement on 16, that a ship was southbound and would be heading under the Bay Bridge, bound for the South Bay anchorage, and would all the sailboats south of the western section of the Bay Bridge please get out of the way! I've not heard one of those announcements before. ...

I heard a conversation between a ship and SF VTS yesterday about the ship complaining about a sailboat cutting it too close for comfort.

...

Another day... This ship made a prolonged signal approaching a Bay-to-Stockton regatta:



A ship can function as a good "blocker" through a fleet if one follows behind: