AIS, Receiver or Transmitter

[TJ D]

Originally Posted by roland stockham

Fitted a transceiver before my last ocean passage and am now sold, it is on my must have list. I was amazed to watch commercial ships altering course 10-15 miles out by a few degrees to gain the ideal clearance. Biggest advantage is that you see the course change so no more "are they clearing or not? Have they seen me or not?"
I also imagine big ships love them because they can see you reliably and see your course, speed and heading. All those things are quite difficult to get from radar when you have a week intermittent signal from a small boat hidden in the wave clutter and with (relative to a ship) poor course holding.

Exactly this. To borrow a phrase from a previous post, we commercial guys regard small boats operating in the same area as us without ais as a pain in the a@@.

As I mentioned before, AIS is simply FAR superior than ARPA or an EBL or especially an eyeball for determining the risk of collision.

It's not that the old ways don't work. It's that this way works so much better.

There will always be those who reject the new. Even if it's better than the old way. I have no issue with it, but we should also recognize it for what it is.

How many people here, in all of these posts, have come out against AIS who have spent any amount of time actually using it? I don't remember seeing any.


TJ

[El Pinguino]

Originally Posted by skipmac

Secret barges and freighters running the Chesapeake at night with no lights and yet they transmit an AIS signal? If they are secret and mysterious and trying to hide why would they transmit an AIS signal?

Barges, whether pushed or pulled, are notorious for having crap sidelights... and of course no steaming lights.....

Good luck on seeing this combo's lights or the tug seeing yours....

[anacapaisland42]

It's about time someone (i.e. Me) posted this old joke to remind everyone about the best safety system: Being a Canadian this version has a Canadian slant..besides we don't have any aircraft carriers, or destroyers...or cruisers...or 6 ships...oh, never mind...they're even trying to get rid of our lighthouses now!

ACTUAL transcript of a US naval ship with Canadian authorities off the coast of Newfoundland in October, 1995. This radio conversation was released by the Chief of Naval Operations on 10-10-95.

Americans: "Please divert your course 15 degrees to the North to avoid a collision."

Canadians: "Recommend you divert YOUR course 15 degrees to the South to avoid a collision."

Americans: "This is the captain of a US Navy ship. I say again, divert YOUR course."

Canadians: "No, I say again, you divert YOUR course."

Americans: "THIS IS THE AIRCRAFT CARRIER USS ABRAHAM LINCOLN, THE SECOND LARGEST SHIP IN THE UNITED STATES' ATLANTIC FLEET. WE ARE ACCOMPANIED BY THREE DESTROYERS, THREE CRUISERS AND NUMEROUS SUPPORT VESSELS. I DEMAND THAT YOU CHANGE YOUR COURSE 15 DEGREES NORTH. THAT'S ONE-FIVE DEGREES NORTH, OR COUNTER MEASURES WILL BE UNDERTAKEN TO ENSURE THE SAFETY OF THIS SHIP."

Canadians: "This is a lighthouse. Your call."

[hsi88]

Has anyone heard of:
dAISy Open Source AIS Receiver
I haven't seen anything posted about this so I thought I would.

A fellow named Adrian Studer has designed an open source AIS receiver and is selling them at a pretty low cost ($55). You can find them here on Tindie (recently back in stock)
https://www.tindie.com/products/astu...-ais-receiver/

I bought one of these. Works fairly well. I use it with OpenCPN. The reason I bought it was because I was "caught" by darkness one time and was almost hit by a "dark" 200' barge being pushed by a tug. And yes, it was just outside Baltimore harbor.

I was just outside the shipping lane (which was on my starboard side headed North) when out of nowhere a spotlight came on, pointed right at me. I thought it was the coast guard. I waved and the light went out. At that point I noticed the dark shape of a huge barge as it passed me on the port side, about 100 feet away. Took a while to pass and sort of freaked me out to see something so large that close. Didn't see any lights on the barge itself. Was just lucky I wasn't in front of it. Don't think at 4 knots I could have gotten out of the way.

Sure, transmit would have been nice, but a receiver would have let me know the barge was there long before it got there and would have provided me with some options that I certainly did not have at the time. And had the tug not turned on their spotlight. I'm not really sure I would have noticed the barge until I saw the faint running lights on the tug itself. A little too close for my comfort.

Its funny, back in the 80's I sailed at night several times. No GPS, no Loran, no AIS, no Radar. Almost hit an unlit buoy (I thought they all had lights), used a spotlight a LOT when close in. Also, learned never to head directly towards a blinking buoy. The blinking messes with your depth perception, so almost hit a blinking buoy as well. And to watch the depth gauge like a hawk. Especially in the Chesapeake. We have come a long way since then.

[DotDun]

Originally Posted by TJ D

Exactly this. To borrow a phrase from a previous post, we commercial guys regard small boats operating in the same area as us without ais as a pain in the a@@.

As I mentioned before, AIS is simply FAR superior than ARPA or an EBL or especially an eyeball for determining the risk of collision.

It's not that the old ways don't work. It's that this way works so much better.

There will always be those who reject the new. Even if it's better than the old way. I have no issue with it, but we should also recognize it for what it is.

How many people here, in all of these posts, have come out against AIS who have spent any amount of time actually using it? I don't remember seeing any.


TJ

I agree that AIS is far superior to radar in 'most' situations, but certainly not 'all' situations.

Situations where radar is superior:

1) Vessels not transmitting AIS (obviously).
2) Class B AIS transmits dynamic data every 30 sec. A sport fishing boat doing 20kts, that's an update every 1000 feet. Furuno ARPA scans every 1.25 seconds (spinning @ 48rpm). ARPA has the advantage of faster/more updates in close situations compared to Class B AIS.

Don't discount radar/APRA, the right units work well.

[Mike OReilly]

Originally Posted by Ann T. Cate

...Sometimes even ships who are supposed to be transmitting, aren't. In the case I have in mind, VHF traffic revealed that it's AIS had malfunctioned, and they needed to fix it while in port.

Further to Ann's point here, I used to live overlooking a fairly busy shipping port (Thunder Bay). It is the terminus of the St. Lawrence Seaway, so receives a large amount of traffic, both local (lakers) and international (salties). It was entertaining to pull up the ship's AIS signals to see where they were from.

A surprising number of these ships showed no signal, and occasionally were just plain wrong. By surprising number I mean a small percentage (2-3% perhaps). So not huge, but enough to make me appreciate some of the limitations of AIS.

I'm impressed with the posters who say a cargo ship altered course based on their AIS transmission. On the Great Lakes and the Seaway, freighters do not alter course. They travel in well defined shipping lanes. If you're in their way, they tell you with the 5-blasts. I've also heard coming over the VHF (in a strong east European accent): "Little sailboat, little sailboat off of xxxx. GET OUT OF OUR WAY!" I suppose with AIS transmit they could call the boat directly, so that would be a benefit. But they do not alter course (unless they had no other choice, I suppose...)

AIS, like chartplotters, are fine tools. Use them wisely and they're a great addition to the navigation arsenal. But for dog's sake, keep your head off of the screens and look up. Eyeballs are still your best navigational tool.

[rwidman]

Originally Posted by Ann T. Cate

I agree with Mike OReilly about the receive being adequate unless you frequent busy sea lanes frequently. The ships generally go about their business.

This gets to people evaluating their own needs, and desires and telling the difference between the two. To disparage and denigrate someone because he or she chooses something different from what you would choose for yourself, that's purely bad manners, and rather unbecoming.

Ann

Thank you for being one of the few to understand that all of us do not boat in the same areas or conditions and do not have the same needs.

I think some folks just get caught up in trying to win an argument and lose sight of the big picture.

[rwidman]

Originally Posted by Mike OReilly

........ I'm impressed with the posters who say a cargo ship altered course based on their AIS transmission. On the Great Lakes and the Seaway, freighters do not alter course. They travel in well defined shipping lanes. If you're in their way, they tell you with the 5-blasts. I've also heard coming over the VHF (in a strong east European accent): "Little sailboat, little sailboat off of xxxx. GET OUT OF OUR WAY!" I suppose with AIS transmit through could call the boat directly, so that would be a benefit. But they do not alter course (unless they had no other choice, I suppose...).

Yep. Impressed? Remember this is the Internet and as Abe Lincoln used to say "Don't believe everything you see on the Internet."

For the most part, those commercial ships cannot or will not alter course for a 30' recreational boat. It's our duty to stay out of their way. It's a "no brainer".

[barnakiel]

We have seen countless ships changing their course to avoid passing too close to our boat. Open waters, not restricted passages. These tend to act very early and make a small adjustment only.

But we have also seen a handful of ships that did not bother. Those that did not, refused to respond to our VHF calls, also to our DSC placed calls.

I do not have any explanation. My guess their crew were either asleep of ignorant jerks.

b.

[rwidman]

That's not a very good guess.

[Mike OReilly]

Originally Posted by barnakiel

We have seen countless ships changing their course to avoid passing too close to our boat. Open waters, not restricted passages. These tend to act very early and make a small adjustment only.

But we have also seen a handful of ships that did not bother. Those that did not, refused to respond to our VHF calls, also to our DSC placed calls.

I do not have any explanation. My guess their crew were either asleep of ignorant jerks.

I don't doubt you or the others at all. I'm sure this is the case. I wish my waters were so friendly. But this just reinforces the point that there isn't one right answer for everyone, all the time.

Barn, a question here (an honest question, not a challenge): how do you decide to remain the stand-on vessel in these distant encounters in open water? Presumably you can see them on AIS just as well as they can see you. Why don't you alter course? And maybe that's the answer to your question; maybe those who don't alter course just figure it is you who should alter course, not they.

[barnakiel]

No.

It is not a good guess, but I do not have other guesses.

Or they cannot hear/see you (fog, no look-out, heavy seas, your AIS switched off, etc.) or else someone on the bridge wants to scare you.

I do not think anyone of them is out there to kill me.

b.

[rwidman]

No, nobody is out there to kill you, there would be too much red tape.

I do think it's foolish though to expect the QE II to alter course for a 30' recreational boat when that boat can stop or turn on a dime. Sure there are "rules" but sometimes we need to add a bit of common sense.

[Dockhead]

Originally Posted by barnakiel

No.

It is not a good guess, but I do not have other guesses.

Or they cannot hear/see you (fog, no look-out, heavy seas, your AIS switched off, etc.) or else someone on the bridge wants to scare you.

I do not think anyone of them is out there to kill me.

b.

You're obligated to stand on for a while to give the ship a chance to resolve the crossing itself, if the ship is the give-way vessel. This is required by the COLREGS and is not a joke.

It may be that there is special practice in the Great Lakes, and I can imagine if the shipping lanes are very well defined, this could work ok -- just stay out of them like we do with channels in harbors. It may be that they are working with an expanded idea of Rule 9, which is fine if everyone knows how it works. But in the ocean, 99% of ships follow the COLREGS (as they are obligated to) and will maneuver when they are required to. Many recreational sailors are not able to discern that this is happening, because it happens far outside of their horizon of awareness (typically 10 miles out in open water). The fact that you cannot discern that ships are maneuvering to make a safe crossing with you, does not mean that they are not doing it.

Ships may not maneuver and may have good reasons not to -- for example, there is other traffic they would be coming into conflict with. At about 5 miles out, if I still have an unacceptable CPA with a ship, then I consider myself free to maneuver myself, and do so. Just be sure to alter to starboard in order not to put yourself into the zone where the ship will pass in case he alters at the same time. It is silly to wonder WHY he doesn't maneuver -- who cares? The main thing is to manage the crossing safely and do the right things at the right time -- stand on when that's required, then maneuver yourself at the right moment, if he does not.

Forget all ideas about precedence, right of way, etc. -- collision avoidance at sea is all about maneuvering in an orderly way to keep everyone safe, and 99% of professional mariners are very well trained to do it, and do it scrupulously. So you must not ignore your obligation to stand on during that phase when it's required. While at the same time being ready to maneuver yourself in case he can't or doesn't maneuver.

One thing you should be very careful about, however, is getting caught in a trap if you're hard on the wind on a starboard tack and so can't alter course to starboard. If you wait too late, as I did once recently, and the ship doesn't maneuver, then you can be stuck in a very dangerous situation since you can't alter course to starboard, and altering to port will put you in the zone through which the ship will maneuver, if he wakes up and starts maneuvering itself. In this case you have to agree by VHF that one or the other of you will stand on, since you don't have a safe maneuver without being sure that he will stand on.


In ports and approaches to ports, collision avoidance with ships is much simpler. Just follow Rule 9, and stay out of the channels and fairways until there's no traffic. What makes this far easier is that unlike in open water, you know where the ship will be at any given time, so it doesn't require any coordinated maneuvering, like is required in open water.

[Dockhead]

Originally Posted by Mike OReilly

. . . Barn, a question here (an honest question, not a challenge): how do you decide to remain the stand-on vessel in these distant encounters in open water? Presumably you can see them on AIS just as well as they can see you. Why don't you alter course? And maybe that's the answer to your question; maybe those who don't alter course just figure it is you who should alter course, not they.

A bit presumptuous of me to answer a question directed to Barny, but . . .

Prior to a risk of collision arising, you are free to maneuver as you like. In open waters I consider that to be about 10 miles. If you can altogether avoid a crossing which invokes the Steering & Sailing Rules, then this is an optimal result. But it's not always possible, because you may have other traffic to deal with or something you can't easily maneuver around.

Once a risk of collision arises, if you are the stand-on vessel, then you are OBLIGATED to stand on. This is crucially important. The whole purpose of the COLREGS is to provide an orderly procedure for fixing a dangerous crossing. Someone has to stand on, or it doesn't work. Vessels maneuvering simultaneously and maneuvering into each other is a classic cause of collisions which has sunk probably thousands of ships.

Once you have a reasonable doubt that the give-way vessel is going to maneuver, then you get the freedom to maneuver yourself, but only then and not sooner. I consider this to happen at about 5 miles, but in crowded waters could be as little as 3, if the crowded conditions are moving up the horizon of maneuvering for everyone. It is important that when you do this, that you (a) turn to starboard if possible, and never to port; (b) never do small and repeated changes of course but a big and obvious one; and (c) in general maneuver to stay out of the zone where the ship will go if he wakes up and maneuvers himself.

You should avoid VHF calls unless it is really necessary. If you have a safe maneuver to starboard which creates a safe CPA, then all is good and the crossing is a success, and you can wave at him as he goes by. Only if you have real doubts about his intentions or you must have for some reason some cooperation from him, should you call him. Obviously with AIS it's much easier to be sure you're calling the right vessel.


You don't need any of this if you're dealing with defined channels or fairways, and maybe not if you have very well defined shipping lanes as it sounds like you have in the Great Lakes. Just stay out of them. Note however that even in a TSS, if something happens (including you just screwed it up) and a risk of collision does arise, Rule 10 does not trump the Steering & Sailing Rules, and on the contrary, you may be obligated to stand on for some time.