AIS How do you use it? Vs Small vessles

Yeah I like watching the AIS targets go from 0 to 50mph from the boat ramp to the HWY.

Mark, If you think my comment in a a little hostile you are right. I’m the guy with the 12-4 watch. Some of your pals sail with the anchor light on so they look like a power boat. And when I call on the radio there is no answer. Maybe they are asleep. Maybe the radio is not even on. Maybe nobody speaks English. Maybe Mr Singlehanded is sailing with autopilot and now his course might turn into me when the wind shifts.

And to answer your question about the watchkeeper asking the captain about changing course: He or she is the office on watch. Part of their job is to keep the boat safe from others who do not understand or do not follow the rules. But the officer on watch has other jobs too. They take care of navigation and chart corrections. They maintain and test the GMDSS equipment. And when Mr Asleep At The Wheel is nearby they can’t do any of their other work because of the nearby WAFI.

And this is coming from someone who works on a sailing vessel.

[QUOTE=“wafinator;113231”]
7) 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.[/QUOTE]

The “law of gross tonnage” is in the rules…

Rule 2 says, “In construing and complying with these Rules due regard shall be had to…the limitations if the vessels involved”. Which means there are times when an 850ft ship is well within their rights to tell a small boat to get the fuck out of their way.

I like to reference part B of rule 9 when in most of the places I run into trouble with WAFi’s, emphasizing that it’s not just a narrow channel:

(b) A vessel of less than 20 meters in length or a sailing vessel shall not impede the passage of a vessel which can safely navigate only within a narrow channel [I][B]or fairway[/B][/I].

Sometimes its not a narrow “channel” but designated as fairway but there’s only so much room to go…knowing the fairway thing applies as well helps us be a bit more aggressive in standing on.

And to keep on topic with the AIS thing; no AIS isn’t going to do crap in a narrow channel. Coastwise I do appreciate vessels having AIS especially at night when their lights may or not be working. I tend to see AIS on small boats at 8 miles or so wheras on radar (tugboats) its usually way closer, probably <4. Thats for a range where I can get a good return and tell what they’re doing. My beef with AIS on smallboats is that i may have to scroll through 40 nonsense targets sitting at the dock or sailing in circles to get to the 2-3 targets I need to keep an eye on.

Use TCPA/CPA like its going out of style not really for collision avoidance but determining where we will meet when in close quarters. Very useful in that regard i think. Obviously course changes (think NY kills/Cape Cod canal) have to be factored in as the machine factors as the seagull flies but I find even with that its normally within a few minutes of reality.

Not sure if this is the argument that we should be making or that you intended to make, but it comes off as “you need to look out because I can’t all the time and have other stuff to do.” I know we’re all busy up there and have a lot on our plates, but maintaining a safe navigational watch is priority number 1, no? Ancillary duties can and should wait.

[B][U]The question being asked here is “Gee, is it worth my while to get an AIS transponder for my boat so I can send out a signal that I am under sail so I can sleep better?” [/U][/B]

And, yes, of course ancillary bridge duties have to wait.

Look at the last Vendee Around the World race where two sailboats collided with commercial fishing boats while in the Bay of Biscay. I have been out therein the Atlantic listening to the Channel 16 broadcasts telling vessels to keep a sharp lookout because the Vendee boats are somewhere out there. How about a broadcast to the racers telling them to maintain a safe watch?

[QUOTE=z-drive;113258]

no AIS isn’t going to do crap in a narrow channel. … I tend to see AIS on small boats at 8 miles or so wheras on radar (tugboats) its usually way closer, probably <4. Thats for a range where I can get a good return and tell what they’re doing. My beef with AIS on smallboats is that i may have to scroll through 40 nonsense targets sitting at the dock or sailing in circles to get to the 2-3 targets I need to keep an eye on.

[/QUOTE]
I did find it useful in the US Intra Costal Waterway to see tugs and barges well in advance around the next few corners. Some areas of the ICW are so tight and the barges so large one needs all the time available to find a spot to pull over.
A small vessel, like mine, is hull down to a 25 foot high radar at 6 miles… my freeboard is less than 6 feet… and if you add the sea state then even a much higher radar needs to be pretty good to get much more range. (BTW saw a test of radar reflectors and I dont put much weight on mine to be seen very far! The active ones are more than $2,000)
Re Colregs: Don’t forget we study them too :slight_smile: 9(a) and my size can be helpful too… theres places I can go that ships can’t. Up the middle is a good one, or up the side dependant on the depth of the outer edge. I’ve actually never really had a problem in a channel… Crossing Singapore Straits without AIS or Radar was a slightly traumatic experience! Inside the Great Barrier Reef was fine.
I agree with you about determining where and when we meet. I find it difficult to judge speed unaided. Very difficult to judge distance at night at water level.

:slight_smile:

Mark

[QUOTE=PMC;113279]

Look at the last Vendee Around the World race where two sailboats collided with commercial fishing boats while in the Bay of Biscay. I have been out therein the Atlantic listening to the Channel 16 broadcasts telling vessels to keep a sharp lookout because the Vendee boats are somewhere out there. How about a broadcast to the racers telling them to maintain a safe watch?[/QUOTE]

That’s a valid point of course and I agree to a point but rule 2 “the limitations of the vessels involved” works both ways. In the Bay of Biscay a watch officer on a 24 kt container ship, with AIS & ARPA etc and a 100 foot height of eye can more easily stay clear of a small sailing vessel while on the other hand the watch on the sailing vessel can not even easily or reliably determine if risk of collision exists until it’s practically too late to do anything. The opposite is true in confined waters where the smaller vessel is at advantage.

Thanks for the excellent replies to my questions. The great replies have given me some good stuff to think about! :slight_smile:
Some others think I may be intimidated by a post on the internet, but I’m sorry, I’ve been round the traps a bit :slight_smile: Suffice to say any argument is not won by vitriol like a day-time TV Dallas or Days of our Lives.
Of course we all hold different viewpoints according to our ‘place’ on the seas, we all do know little about how the other people at sea operate. So with that I will hang about here and learn from some folks here… I will, of course, not let you off without knowing the other side of the coin. And I can tell you that some of the well meaning sailors of my ‘type’ are as ill informed, an example from just this week where the container ship snapped in the Indian Ocean with some folks saying thats 8,000 extra containers floating the seas trying to sink sailing boats… Of course the facts don’t get the same weight as the fantasy when a ding-a-ling grabs hold.

Its not been a good year for the cruising sailors or the professional sailors… we have both lost many from our ranks… 2 sail boats in the Atlantic, one overdue in the Tasman nearly 20 crew in just those, and they are only the ones we know about. Professional crew deaths this year I am not aware if they are higher or lower. But I dont think it shows a complacency on either ‘side’. Certainly cruising sailors heading out for a passage know it can be a life and death situation. Then there is the third side (?) where the whole of the tall ship industry may be on the brink of full scale imposed change.

There is only one constant: That we all love the sea but we can never claim to be its superior.

Thanks for the discussion! :slight_smile:

Mark

[QUOTE=MarkJ;113158]Hi,

This could sound like the most basic question to fall out of the sky in a while…

I am a cruising sailor with a circumnavigation under the belt on this cruise. I sail solo because all women hate me :wink:

Theres some specific questions about how ships use AIS that cruising sailors argue about…

  • What is a ships prime avoidance system: Radar or AIS? Yes I know you have both, but what is used mostly in a practical sense?
  • At 2.33am is the watch keeper allowed to alter course of a ship with an AIS target or does he need to wake the captain? How long does that take? More generally how long does a ship take from target acquisition to change of course?
  • It appears to me (and overhearing VHF conversations) that many shipping lines have a set minimum CPA. Is that correct? Is 1nm normal?
  • Do ships filter out Class B signals at all? Or in harbours? etc.
  • I appear to have some ships start to divert at 10nms. Is that likely or some aberration?
  • Do ships ‘click’ on a target to determine if the target is a sailing vessel, or is it assumed all vessels are motor vessels?
  • My boat normally is doing about 6 knots (erratically). In practice, does a ship doing, say, 15 knots divert or stand on if they are the Stand On vessel.
  • What range do ships normally first get an AIS contact and does a Class B contact first appearing so much closer give surprise/irritation?
    [FONT=Helvetica][SIZE=2]* What range would a ship see a sailing boat thats not equipped with AIS? Or would you see us at all!

Any other advice for sail boats, small vessels?

Thanks for your help :slight_smile:

Mark[/SIZE][/FONT][/QUOTE]

A vessels prime collision avoidance system is the officer on watch. He/she will use radar, AIS, or whatever other equipment available to them as an [B][U]aide[/U][/B] to safe navigation.

The officer on watch may alter course to avoid close quarter or collision situations at any time of day.

As a rule of thumb only, many captains will set 2 nautical miles as a minimum safety zone around their vessel at sea. Of course this size zone is impractical on most Inland Routes.

I don’t filter out any AIS Targets, Class B or otherwise.

There isn’t a policy that I’m aware of that assumes all vessels are power-driven at night. However, if is isn’t easily apparent at night, sailing vessels captains would be smart to assume this scenario. I refer you to Rule # 2 of the Rules of the Road, Part A and B.

The range of AIS signals from vessels vary greatly, don’t assume you are visible, AIS is only an [B][U]aide[/U][/B] to safe navigation.

In general, it is a wise mariner who will stay out of the way of vessels much larger and/or more burdened than your own vessel. I would keep Rule #2 in mind before I challenged a loaded 90,000 ton Tanker to alter course for my small sailing vessel.

Remember, your best [B][U]aide[/U][/B] to safe navigation lies between your ears.

Hoist a radar reflector and stay clear of larger vessels.

[QUOTE=Lookout;113424]A vessels prime collision avoidance system is the officer on watch. He/she will use radar, AIS, or whatever other equipment available to them as an [B][U]aide[/U][/B] to safe navigation.

The officer on watch may alter course to avoid close quarter or collision situations at any time of day.
[/QUOTE]

He and the other solo sailors need to realize they they also need to provide someone on watch 24/7 and that sleeping is unacceptable.

To my mind, AIS is far superior to ARPA or M ARPA for both avoidance and sheer information.

AIS give vessel derived navigation data directly into my display. I don’t have to ‘hope’ the ‘other guy’ is understanding my intentions, or he mine. I see what he is doing, and how it effects me. I see the electronical position predictor and where mine is meeting. Some of the better Plotter programs actually show CPA meeting points on the heading line.

ARPA is inefficient because it is subject to the need for constant heading, speed from both vessels involved. It ‘may’ look accurate, but ARPA plots do more bad than good in “RADAR aided collisions.”

Bottom line, If I am out to sea, pushing my 500’ tug and barge along in a 15’ sea, your little 40’ sailboat is going to be IN the troughs about 70% of the time. I ‘may’ get an occasional RADAR return off your mast or RR. But if you are transmitting AIS That usually works within 3 to 15 miles.

I think wafinator mentioned the AIS unpredictability. It is pretty odd sometimes. I recall a coastwise self propelled barge that had such a crappy antenna installation that they only got most of their AIS targets when the target was abaft the beam! So just because you HAVE AIS does not mean you are invincible. BUT, I would have to say AIS is better than NO AIS.

And don’t even start about improperly lit vessels ‘Demanding’ the ROW because they are lit so. An IMPROPERLY lit vessel is as wrong as the vessel not following Colregs.

Here is a link to a more appropriate forum: http://www.cruisersforum.com/forums/f57/colregs-puzzle-89609.html and this http://www.cruisersforum.com/forums/f90/freighters-vs-sailboats-89285.html

[QUOTE=cappy208;113467]To my mind, AIS is far superior to ARPA or M ARPA for both avoidance and sheer information.

AIS give vessel derived navigation data directly into my display. I don’t have to ‘hope’ the ‘other guy’ is understanding my intentions, or he mine. I see what he is doing, and how it effects me. I see the electronical position predictor and where mine is meeting. Some of the better Plotter programs actually show CPA meeting points on the heading line.

ARPA is inefficient because it is subject to the need for constant heading, speed from both vessels involved. It ‘may’ look accurate, but ARPA plots do more bad than good in “RADAR aided collisions.”

Bottom line, If I am out to sea, pushing my 500’ tug and barge along in a 15’ sea, your little 40’ sailboat is going to be IN the troughs about 70% of the time. I ‘may’ get an occasional RADAR return off your mast or RR. But if you are transmitting AIS That usually works within 3 to 15 miles.

I think wafinator mentioned the AIS unpredictability. It is pretty odd sometimes. I recall a coastwise self propelled barge that had such a crappy antenna installation that they only got most of their AIS targets when the target was abaft the beam! So just because you HAVE AIS does not mean you are invincible. BUT, I would have to say AIS is better than NO AIS.

      • Updated - - -

And don’t even start about improperly lit vessels ‘Demanding’ the ROW because they are lit so. An IMPROPERLY lit vessel is as wrong as the vessel not following Colregs.[/QUOTE]
Effective as long as the other vessel has it and it is functioning and being used correctly. If it is a choice, I want a good ARPA.

Ditto, AIS is secondary to me, ARPA would be by first choice. Many times I noticed the CPA info on AIS not being all that accurate. A great tool to be sure! All tools, AIS for long range, and great for knowing another vessel is out there, Arpa to be used closer for more refined solutions, and eye ball for " when in sight" should all be used together…

Hello,

So, I’ve had this discussion before. In fact, I had an argument with a PILOT about this in Alaska.

All small vessels and yachts must ensure they have an effective radar reflector up, if they want to arrive alive. Cargo ships can’t see you.

The key thing to understand re AIS/smaller vessels, is that AIS uses vhf. That means the reliable range, is to the visible horizon / vhf horizon. Big ships may be able to see them on AIS, but not on radar, quite early. As such, they will not take action until later.

At any rate, number one aid to collision avoidance is not so high tech.

  1. Mark 1 eyeball. Visual lookout is paramount.
  2. Situational awareness. Decision to call master will be dependant on the experience and confidence of the watchkeeper. What is the traffic [I]likely[/I] to be doing? Is the AIS heading facing the right way? If the watchkeeper [I]is ever in any doubt,[/I]ever he should always call the master. The experienced watchkeeper will always take action to avoid collision as early as possible once ‘risk of collision’ has been established.
  3. Radar vs AIS? Radar, obviously, is less prone to error than AIS. Purely because so many AIS transmitters have been installed incorrectly. However, visual lookout is number one. Every other aid, is just that. An aid to situational awareness. So read the manuals, train the crew, and interpret accordingly.

I’m sure you know all the technical points by now.
However, I feel your question was directed at how ‘wise’ it is to rely on AIS, and the wisdom of letting watchkeepers base decisions on AIS data.

The safest bet, is to encourage a culture where the watchkeeper is never afraid to call the skipper.
That means having a restrained skipper. That means, a skipper who doesn’t lose his temper and shout all the time, for trivial reasons.
That means no bullying on board. That means training and leadership, based on help instead of sarcasm etc.

You want every situation where the watchkeeper has any doubt or has any lack of confidence at all, to call the skipper.
If he is unsure whether to call the skipper, he should already have called the skipper.

And that is it, I think. It takes time, reading and discussing the colregs over and over, and reading equipment manuals.
And lots and lots of patience.
Stay safe. Arrive alive, and don’t worry about anything else.

Also, I think determining ‘risk of collision’ should not be just based on CPA.
If the vessel approaching is 12nm away, but CPA 0.4nm, you still cannot say risk of collision exists yet.
However, if she’s approaching you at 35kts, and is now 6nm away, and the Watchkeeper is playing candy crush on facebook, you’d best alter course without hesitation.

Develop your watchkeepers instincts over time, but no one aid to collision avoidance can take absolute priority.

Anyway, I don’t mean to state the obvious. Just alter early, make your intentions clear, don’t rely on radio, or AIS, or radar, or ARPA (CPAs), in isolation. And never hesitate to take bold alterations of course ON THE SIDE OF CAUTION, whether you are give way vessel or not.

Also, 1nm CPA is usually fine, but this distance should always increase if weather is deteriorating, or you are prone to steering or propulsion failure, etc.

I hope this was of interest to you.

Also, Just to state the obvious again,

Never assume that other vessels are aware of your presence. If you are stand on vessel, you still have a responsibility to keep a proper lookout, and full situational awareness.

You should have AIS on, and functional. (try calling someone periodically to test it)
You should have radar reflectors in place.

But there are older, poorly maintained ships out there, who do not have AIS. Or AIS is not functional, and they have old or damaged radars. It’s the one in a million encounter that will catch you out, that you need to be scanning for. If they don’t seem to be giving you a wide enough berth, signal them visually, on the radio, and with everything you’ve got. And call the skipper. And alter boldly.

[QUOTE=cappy208;113467]

ARPA is inefficient because it is subject to the need for constant heading, speed from both vessels involved. It ‘may’ look accurate, but ARPA plots do more bad than good in “RADAR aided collisions.”

[/QUOTE]

Not sure what cappy means here. When the other ship changes course the ARPA takes some time to update. But when I change course the other ships new data (CPA/TCPA) is updated as I turn. In other words if I am on relative vectors and I make a big course change I can watch the vectors rotate as I turn. However on an older ARPA set I used a few years back that was not the case. If I made a big course change the relative vectors would stay the same until the ARPA updated same as if the other guy had turned.

As a result if you have a vessel with a 0 CPA and you make a big course change and have another look it will still read 0. Then slowly 0.1. 0.2 etc as it updates.

Well yes, You have to know what’ the limitations of the arpa are. Arpa needs at least three minutes of steady state tacking, that means both vessels on a steady course and speed for 3-4 min. But, if you are seeing a close CPA and use trail maneuver to determine your course to clear , then come to that course ( normally with a bit more course change for safety) the arpa will indeed catch up. While arpa is a good tool it’s not the end all, and for that matter no tool is. If you are a qualified radar observer and understand relative motion you can certainly make a very educated deduction for a course to steer even without arpa and AIS. As pointed out, there is no tool that replaces the eye ball and experience.

[QUOTE=Xmsccapt(ret);113483]. Arpa needs at least three minutes of steady state tacking, that means both vessels on a steady course and speed for 3-4 min.[/QUOTE]

What I am saying is with my current ARPA is that it does not require own ship steady 3-4 minutes but computes new CPA/TCPA continuously based on heading/speed data it receives from the GPS. Other ship turns, yes, but not own ship, not with the gear I am using now at least. I wonder if that is what Cappy is dealing with?