Wreck of the Lady Mary, so many lessons
When I came across the New Jersey Star Ledger’s finely reported series on the sinking of the scallop dragger Lady Mary, I didn’t stop until I’d finished all five chapters, watched the video, and done some further research. It may not sound like a story in the holiday spirit, but aren’t we about to gather during the darkest days of the year to celebrate light and love? You’re not apt to forget the loving extended family at the center of this dark tragedy. And you’ll certainly be reminded about how so many SAR gadgets and systems might and might not work…
The mystery of the Lady Mary is how she sank so quickly, but I bet many of you will conclude as I have that it’s very likely she was struck from behind by the container ship Cap Beatrice. While I have no particular expertise in ship wreck forensics, I tend to agree with the experts quoted in the article that damage like that mangled rudder above — not to mention the bent down 5-inch prop shaft — could only have been caused by the ship’s bulbous bow moving at 20 knots. There are more photos of the Lady Mary’s damage here, as well as similar damage to another run-down dragger here.
Unfortunately this sort of story feeds the skepticism of those who think ships don’t care about running into boats, and therefore anti-collision gear like Class B AIS transponders aren’t worth the cost. Which seems especially true as it looks like the captain of the Cap Beatrice may get away with what looks like a hit, run, and cover-up operation. But note how his own AIS incriminated him, and that he may in fact have turned it off in his efforts to escape responsibility (all conjecture, mind you). If the Lady Mary had had a transponder would the collision have been avoided, or at least been more easily investigated after the fact?
And there are other questions. Would a DSC VHF alert have gotten the notice of nearby fishing vessels and saved a few lives? How about if the Lady Mary had had a GPS EPIRB instead of a standard issue model, which takes longer to geolocate? And if the mistaken registration number really did delay the search, isn’t that why through-satellite testing is so valuable? My hat is off to Amy Ellis Nutt and Andre Malok for their efforts covering this story, and my heart is out to Fuzzy Smith and all the other family members involved.
I knew a couple of those gentlemen. Good people, and sadly missed by those close to them.Happy holidays Panbo. Love your site.
This appears to be yet another case of two radar-equipped vessels colliding, apparently with no one on watch on either vessel. If it was the container ship that hit Lady Mary, it was probably not avoidable by them due to the amount of time and distance required to either stop or change course.
It also appears that the capt. of the smaller vessel was was more interested in taking hits off a bong than watching his screen…
And, there’s the whole thing about procedural errors with the EPIRB, and the fact that it was not a GPIRB…
Perfect storm.
Sigh…that’s what I mean about skepticism. How is it apparent that the container ship was doing 20 knots with no one on watch? That’s extremely unlikely.
Nor is it likely that the ship couldn’t have changed course to avoid the Lady Mary had it seen her on radar or by eye. I do not believe she was restricted by draft or traffic scheme in that area. I also believe she was the burdened vessel as the Lady Mary was restricted in her ability to maneuver because her dredge was overboard.
What likely happened, I think, was that the watch standers on the ship missed or got confused about the boat’s lights and/or radar target — there were other fishing vessels in the area — and then responded to the collision in ways they probably feel horrible about today.
I get very upset reading articles like this. It is stupid that these killings are not avoided by electronics. Fisherman and sailors alike get run over all too often because they or the crew of larger vessels are not seeing the danger. Time to make more things a Legal requirement when more than day sailing?
If we can convert the nation to HDTV, then AIS transceivers and GPS EPIRBs should be easy right? How about requiring them to be on all the time or face a fine? Homeland security should require them!
I’m confused about a couple of things:
– The Lady Mary had no AIS but was “automatically” transmitting its position to VTS. By what mechanism was it doing this?
– In Section 4 the authors use heading data to interpolate the ship’s position between AIS transmissions. Since Class A AIS transmits every 30 seconds, why are the AIS positions recorded as infrequently as every 6 minutes? Is this just a case of lost AIS transmissions due to the limits of VHF?
/afb
Hi Adam,
Here’s some info on VMS (Vessel Monitoring System) equipment. It looks like minimum reporting times for scallop boats within regulated areas is twice an hour:
http://www.nero.noaa.gov/nero/fishermen/multispecies/gom/VMSRegs.htm
And here’s some on the USCG NAIS system (Nationwide AIS monitoring):
http://www.uscg.mil/acquisition/nais/
Class A dynamic data is actually sent every 2-10 seconds when underway, depending on speed and rate-of-turn. I don’t know if NAIS captures all that data, or what.
The Star Ledger series is a little weak on the tech stuff, stating, for instance, that AIS positions somehow don’t account for current. Not so. The GPS option for EPIRBs is also not a physical add-on, as the authors imply, but is built in (as I’m sure you know).
Good post, a heartbreaking incident. If fishing vessels were transmitting an AIS signal it would be an enormous help to the watch on ocean going vessels. Avoiding fishing vessels in poor weather is a very difficult task. A container ship at 20 kts is covering a mile each 3 minutes. In rough seas a fishing boat will typically be lost in the sea return once it is inside about 4 miles and are difficult to detect beyond 8 or 9 miles. That means the window of detection is from 8 to 4 miles, a distance that is covered in 12 minutes. An AIS signal on the other hand will be easily seen at all ranges from say 24 miles and less.
Another point, to me it seems unwise to place the responsibility for keeping a proper lookout entirely in the hands of the crew of another vessel. Apparently these fishing vessels lack the manpower to maintain a proper lookout. Large container vessels can be easily detected by their AIS signal while they are over an hour away. I would think an AIS device that provided an alarm when your vessel was being approached by a large, fast moving vessel would be a good investment.
Thank you, Cap; good points all. It will be interesting to see what type of AIS the USCG will mandate for vessels like this (I think the notice of ruling is due any time). With 2nd generation Class A at about $2,500 and fairly easy to install, it seems like the extra range and message frequency would be worthwhile.
Ben, thanks for that information. I too wondered about the technical points that you raised, but think I understand them in the following ways:
– When they say that AIS doesn’t take into account current, I believe they are saying that AIS dynamic data includes heading but not COG. This is how they seem to account for the variance between the two ship’s locations: the heading data used for the dead reckoning plot is off because a strong presumably northerly current is being ignored. However, I believe that AIS does include COG, so this portion of their argument (or more likely, of one of their experts) is wrong.
– As for the GPS EPIRB question, I think that the one Fuzzy bought in 2006 probably has an optical NMEA interface that allows it to be “prepped” with the boat’s current position so that it can broadcast those coordinates during the first transmission. Obviously subsequent transmissions would not contain coordinates unless the unit had an integrated GPS.
COLREGS: Rule 18
Responsibilities between vessels
Power-driven vessel underway keeps
out of the way of:
– A vessel not under command
– A vessel restricted in her ability to maneuver
– A vessel engaged in fishing
– A sailing vessel
The burden is on the merchant vessel to avoid a trawler “tied to the bottom” by its trawl. A visual lookout and radar watch are the means for avoiding a collision. Would an AIS transponder on the trawler have helped – yes. But, AIS is a recent invention and radar and eyeballs have been with us for a long time and should have been adequate IF a good radar watch was being maintained on both vessels.
An emphasis on fishing vessel safety is not the lesson to be learned from this incident. The prudent merchant master should avoid known fishing grounds on the approaches to Delaware Bay. Threading your way through vessels engaged in trawling to save some time and fuel is foolish. Saving a few hundred dollars buying an EPIRB without built-in GPS is foolish. A Class “A” AIS transponder might cost several thousand dollars and may be beyond the budget of most small fishing vessels. 100% of the fishing vessels that I have observed have radar onboard. If the watch stander on a fishing vessel sees a ship bearing down on his vessel, the ONLY thing that he can do is broadcast a warning to the ship – he cannot move out of the way.
We have the Coast Guard investigating itself and that is unacceptable – especially where they share part of the blame for the loss of life. The Coast Guard has become notorious for not adequately training their radio operators and this incident highlights that lack of training and inadequate supervision. The heroism of individual Coast Guard members is often used to cover up their poor training in what used to be their primary mission – Search and Rescue (SAR.)
The NTSB must be relied upon to render a definitive report on this incident. Such a report should include the examination of any paint scrapings remaining on the submerged hull. Such an analysis would be dispositive. Meanwhile, I will rely upon the shaft’s being bent downward. I would be interested in who contracts with the one firm which agrees with the Coast Guard’s preliminary findings. I would also look to see if they are competing for any government contracts.
My heart goes out to Fuzzy and the families of the crew. We are all saddened by the loss of life and recognize the dangers that commercial fisherman face every day.
Staying out of the fishing areas is not as easy as it may sound. The Elephant’s Trunk scallop zone that the Lady Mary was fishing is over 1,500 square miles, map here:
http://www.seatrade-international.com/map.cfm
I also learned at that site that the boat price for the 18,000 pounds scallop limit those guys had almost finished catching was about $7/lb, and now it’s nearly $10.
Super sad story. Fair thoughts to the families of the sailors lost.
Regardless of tech, I think there is a back to basics element of this. Basic visual and radio watch standing, supplemented by radar if so equipped would go a long way to reduce this and other accidents (coast guard ran a boat down recently in SD). Captain should be sober, he/she is responsible for crew.
I’d hope they at least lit the boat up first, maybe go double red at the masthead before smoking. The difference in vis to other boats with and without deck lights is significant for all size boats.
Having used AIS and AIS with radar, while some returns are tricky, a containership such as the Beatrice will have a return that is clear. Waves of 6-9 feet are not excessive. MARPA with a closest approach alarm would generally pick this up even if set conservatively unless the containership is doing a big turn. At 4 mile radar range roughly 10 minutes of notice. Not a lot at all, but depends on watchstanding.
How in the heck though did the Beatrice not stop if they hit the Lady Mary? This is the part I don’t understand. If you are watchstanding you’d notice that. And her AIS going out. Very odd.
That said a class B AIS on Lady Mary probably would have popped her up on Beatrice! That + EPIRB for commercial vessels pulling in $100+K fishing loads seems a reasonable investment.
The ocean transit system with it’s large 24 kt container ships and precision GPS is analogous in some ways to the Interstate highway system in the U.S.. The Interstate highway, with it’s banked and shallow curves, the design of the exit and entry ramps and so forth is designed to be safe at high speeds. Unlike the Interstate, where pedestrians farm equipment, bicycles, mopeds and so forth are banned, at sea, these large fast ships must share the waterways with fishing and other small vessels. Suggesting that the risk to fishing vessels can be reduced by improving the level of seamanship is like saying the interstate would remain safe with pedestrians, cyclist and so forth if we simply raise the skill level of the drivers. It may be true in principle but it clearly is not a practical solution.
Given the skill level of the bridge watch stander, the technical limitations of radar in poor weather and other factors, encounters with fishing vessels are the weak link in the chain. Just as RACONs help the navigator interpreting a radar display identify aids to navigation, AIS would assist participants in our ocean transportation system identify small vessels who’ s crews are put at risk by large fast moving vessels in marginal conditions. To think that the solution lays in increasing the skill level of ship’s crews or by having captains become more prudent is wishfull thinking. That horse is out of the barn and long gone.
Capt Beck:
I guess when I look at the major deaths & accidents at sea I more often than not see user error rather than technical failure.
Countless pleasure boat deaths with crew falling in the water without something as basic as a PFD, even in cold waters. Even commercial deaths for this reason.
USCG Fast Patrol vessel in San Diego runs down a Sea Ray killing a child and injuring 12. This boat had the latest in everything, probably even thermal cams. Despite the latest and greatest (I’d be curious what these boats cost) it hit a lit boat while traveling perhaps 45mph.
I’m 100% for AIS and EPIRB’s. That said, in addition to technology, seamanship does seem to matter to me. How do you miss a containership on radar? If you smoke a bong and turn out your deck lights, and stop watching your radar or for lights you are making it significantly harder for a container-ship to avoid you.
It looks like the the rudder angle indictor is at hard to port, I think this rudder may have had a little help from another ship!
A few days ago two cargo ships collided in the North Sea in the beginning or just before the TE Traffic Separation Scheme, the 395 m (1200 ft) long CMA CGM Laperouse and the 90 m (300 ft) Thebe, luckily with little damage. Conditions were not great, 3m swell with a 40 – 45 knot wind, but not completely atrocious either.
You can see where the accident happened on MarineTraffic’s AIS log of the Laperouse’s track.
Here is a scanned recording of the VHF transmissions of the the Dutch Coastguard and rescue services (from scannernet.nl).
Now both of these vessels are mandated to have AIS on board, but that doesn’t say both had fully integrated AIS sets that would warn them about an upcoming collision. Even so, it’s hard to understand why these accidents still happen even with all this tech aboard.
It shows that although AIS is a great help to all parties there is apparently still enough room for error such that a large(ish) cargo vessel is able to collide with one of the largest container vessels in the world.
Kees,
This also shows what it sounds like when a trained, experienced professional coordinates a rescue with 3 sets of response assets and two casualties on VHF in two languages.
Only one quick comment on this subject:
AIS is useless, UNLESS it is mandatory for every vessel (comercial AND recreational). But having said that, AIS would be useless due to info overlaod/conjestion on displays, IF it was mandatory for every vessel.
As one of the previous posters said, in almost ALL of these incidents, USER error is at fault. We need to fix the USERS, not the AIS rules.
Absolutely absurd statements, Birdman, as thousands of people who actually use AIS will tell you. Seriously, have you been to sea with it? Honest answer, please, with details. Also, did you read this entry? There are at least three ways AIS might have saved lives in this situation. Do you give a damn?
I have not used AIS on any of my boats. I have been on boats with AIS. Was it helpful? It was helpful to get the name or # of another vessel. Other than that, it served no purpose other than cluttering an otherwise un-cluttered display. Sorry, just an honest answer from a real life boater.
There is ABSOLUTELY no excuse for a small trawler to be hit by a large tanker, period. BOTH parties are at fault. The large for running them down if that is what occurred, and the small for not getting out of the way of a larger vessel. We are not talking about missiles or spaceships, these are boats moving at 25 knots tops, with a beam of 50′ max. So honestly, don’t you think you should be able to move 50′ (either vessel) to avoid a collision? If of course, they were paying attention which apparently they were not.
If Capt’s don’t pay attention to what’s on their radar now, what makes you think they will pay more attention to an AIS display?
I look at things from a realistic view, not a theoretical book view.
Birdman, if you look through the entries in Panbo’s AIS category you’ll find comments from cruisers all over the world who have found AIS to be an excellent safety tool. You’ll also learn that I started using Class B AIS offshore before it was even legal in the U.S. And it will be pretty obvious that most every marine safety organization on the planet has developed respect, if not downright enthusiasm, for the technology. But I guess we all missed the major shortcomings of AIS you saw with just a cursory look, right?
I would also surmise from your willingness to lay ABSOLUTE blame on a group of dead men and another crew who likely live with great guilt that you don’t have much experience with the realities of being offshore at night. Sorry, mate, I’m just right up to here with people of weak knowledge and strong opinions. I’m going to rest now.
Well, get a realistic view on this: THE TRAWLER IS ENGAGED IN FISHING AND IS EFFECTIVELY ANCHORED TO THE GROUND BY ITS TRAWL. It is moving, but slowly. This is why the COLREGS cited above give them a privileged status. BECAUSE IT CANNOT GET OUT OF THE WAY!
It is everyone’s responsibility to avoid a collision, but some vessels are better able to do so than others. Study your rules which you have onboard at all times – right?
Your assuming the Fishing vessel should have moved. Why couldn’t the tanker have moved?
OR ok, the fishing vessel was fishing/ AKA moving SLOWLY. I see a tanker of that size on my radar 10 or 20 miles away. I have a cheap, recreational Garmin 24″ dome. If they were PAYING ATTENTION to their radar, they would have had at least 30 minutues warning. They were offshore, not in a obstructed, congested passage.
I feel absolutely terrible for the crew and their families. I also feel terrible for the 20,000 people who died last year alone from drunk driving. Does that mean we shouldn’t talk frankly about what they did wrong? I for one think we need to learn from this kind of incident. Adn the CLEAR message is simply:
PAY ATTENTION when at the wheel. Or better yet, always keep somebody at the wheel!!!
You can read books and quote RULES all you want. But in this case, if EITHER capt was simply paying attention, the incident could have been avoided. It’s plain and simple.
You still havn’t explained HOW AIS would have avoided this? I repeat: If they were not paying attention to their radar, what makes you think they would pay attention to AIS?
One more thing Ben, if the crew of either boat is NOT to blame as you implied in your last post, who is?
You completely lost me there. It’s one or the other crews fault, or more likely BOTH of their faults. Nobody elses.
An interesting thing I learned from years of going to sea on all sorts of boats with all sorts of folks is that the people who are most experienced and wise about it are generally the first to forgive the mistakes of others. And they don’t SHOUT. And vice versa.
Everyone has acknowledged that maintaining a good lookout was the obligation of both parties. Interpreting radar return is an acquired skill and it is not always possible to identify a small vessel at 10 to 20 miles whereas the trawler probably had a better chance of seeing the tanker as a large target.
What would AIS have done? It would have clearly told the watch on the tanker that they were bearing down on some trawlers. If visible, the tanker watch would then see the trawlers lights saying that they were pulling a trawl. Then the tanker would know to give the trawler a wide berth. If they were on the ball, they would use their AIS to call the trawler by name and ask if her intention was to hold her course. If the trawler only had an AIS receiver, she would see the danger posed by a high speed tanker constant bearing, decreasing range, and she could call the tanker by name and request that she give her a wide berth. If she got no response, she might be able to emergency slip her trawl and escape the collision.
There is also the problem of believing that the tanker wasn’t going to conform to the COLREGS. If you call her by name and you do not get an answer, that would tell you that no one was there or no one was awake.
Absent AIS, I had the same problem near the entrance to Cape May. I was being run down by a tug/oil barge combination and no one was answering me. I had been calling beginning at 6 miles on radar. I did not know the tugs name. I was lucky that I had an old Icom that could broadcast at full power on 13. In addition, her measured output was 30 watts. Switching to high power, I blasted the lone watch keeper awake and he went hard left out to sea. Had I been calling by name, I might have been more successful, earlier.
AIS enhances the tools a well-equipped boat normally has available. It’s up to the user to employ it intelligently. Homeland Security may end up requiring AIS in certain ports and sensitive areas. There has been talk about this in the last few years.
Lastly, I understand a previous post about the size of this fishing area and have cut through that area with such a fleet at night with radar in my small boat. It was a nightmare as several trawlers were making big circles while others appeared to trawl slowly in a straight line. The most I could make was 8 knots. I got through by switching to sail and the guys making circles got out of the way by going straight. These trawlers were manned by Koreans and were based in Cape May at the time. I was en-route to Cape Cod.
Thanks for answering the question Ron.
To be clear, I’m not saying AIS isn’t an effective safety device. What I’m saying is, and I maintain my 1st statement here: unless AIS is mandatory on ALL vessels, it’s useless. Oh, you might see the guy with AIS, but you still won’t see the Trawler that doesn’t have it. And secondly, if they did make it mandatory for all vessels, there would be so many of them in the high traffic areas, it would end up useless.
So unfortunately, I don’t find it useful. Sorry, that’s my opinion. I often tend to go against the grain with my opinion. And more times than not, I end up right. The obvious answers (in this case AIS is good!), is not always the final answer.
The ocean is a dangerous place. AIS is a safety device, by all means add it if you have the means to do so. But in the meantime don’t assume cases like this one, with presumably/allegedly nobody at the helm on one or both vessels, will be avoided. Sadly, it won’t. For that reason, when I’m at the helm offshore I take defensive actions to stay clear of all other vessels, as I do on the road.
Amazing! Birdman, while you’ve already stated that you don’t actually own an AIS yourself, please let readers know about the experience that your novel — but purportedly “realistic” — opinion is based on. For instance, how many nights of your life have you spend offshore in command of a vessel? How many nights as a watch stander on a vessel? Do you hold any level of captain’s license or other certification?
And for some balance to your opinion, here’s Steve Dashew: “Even though AIS B is not 100% foolproof, we suggest that it is a highly valuable safety feature, and would choose it and a good radar before a life raft, if there was a budgeting conflict.”
Steve wrote about his real world AIS experience here: http://goo.gl/9LS9T
and writes about all sorts of boat stuff here: http://setsail.com/category/dashew-blog/
I can quote 100 “experts” all over the place(books, trade publications, magazines, periodicals on the subject, and CG employee’s) stating the exact oposite opinion of “Steve’s”. I still have my opinion, and you still have yours. That’s how the world works.
How about simply answering my question on the subject matter instead of trying to divert the discusion? My lack of experience has no affect on that answer.
How will AIS change the outcome of this accident, when either nobody was at the helm and/or the Capt was not paying attention at the wheel?
It likely would not have.
So, Birdman, zero nights at sea in command of a vessel? Zero nights as a watch stander? And your “right more-times-than-not” opinions are based on “a realistic view, not a theoretical book view”? Man, have you been drinking tigerblood?
AIS specifics regarding the Lady Mary tragedy:
* The most likely scenario is that the bridge crew of the Cap Beatrice somehow missed the Lady Mary on their radar screens. If the Lady Mary had been sending out AIS signals, it’s quite possible they would have been seen, possibly alarmed, on the Cap Beatrice. Simple as that.
* If the Lady Mary had just had an AIS receiver, especially a good one like the Vesper Watchmate, it could have been set up to fire alarms all over the boat when it saw a large ship bearing down fast, even when it was many miles away. (Multiple alarm parameters let you set up rules like “CPA less than .25nm, Target Speed greater thnn 15 knots, range = unlimited” that avoid most unnecessary alarms, but can catch the nasty surprises.)
* Even if the Lady Mary somehow sank on its own, an AIS transponder might have helped the SAR people get to the scene faster, and thus might have save lives. (If you read the reports, you’ll see that a much less frequent VMS position was used to locate the victims, and that AIS for that area was being tracked on shore.)
There you go, Birdman, three real ways AIS might have been useful in this situation, and note that not one required that all boats be equipped with AIS transponders.
Ben 1 – Birdman 0
Actually, make that:
Ben 5 – Birdman 0
Although I welcome an informed different opinion, I for one don’t appreciate the kind of outright uninformed and opiniated slamming of AIS that Birdman seems to think is appropriate here.
Allot of “ifs and buts” type of conjecture in there.
Both vessels had Radar, correct? Both vessels Radar had MARPA functionality, correct? Neither of them used it. So again, what makes you think they would use a more sophisticated system like AIS if they had it?
See where I’m going with this? Again, I’m not saying AIS isn’t useful, it is. BUT, it’s useless if it’s installed, just like their Radar units were, and not used. Unfortunately, that is “REALITY”. The guys motoring most vessels out there, are not techies like you and I. They are fisherman….
I install marine electronics from time to time. I can’t tell you how many boats I’ve been on where the owner did not know how to turn on the radar. I had a request 2 summers ago to install radar on a boat. When I arrived, I noticed the Raymarine 24″ dome on the hardtop. He didn’t know he had radar. True story.
Just bringing a bit of reality to a theoretical discussion, that’s all.
Actually, Birdman, what you wrote emphatically, and more than once, is that AIS as it’s used now is “useless”, and that it can’t be fixed. Which was like a red cape tease to a guy who’s been researching, testing, and writing about AIS for years. It’s also the sort of confidently spoken misinformation that could mess up a reader trying to understand an important safety technology.
But I think it’s clear now that your understanding of AIS is mostly based seeing one on somebody’s boat at a dock. And is similarly light in regard to the realities of commercial fishermen and ships. I think we’re done the discussion.
The Dashew article links to a complimentary article by a merchant master who focuses on AIS and “seeing” small craft. It also starts with a very funny rules of the road rhyme with a small vessel punch.
http://www.powerandmotoryacht.com/boat-electronics/from-a-ships-bridge/
He comes from an 873 foot perspective.
Ron, That sidebar was written by John Konrad, founder of GCaptain: http://gcaptain.com/
He acquired a cruising sailboat recently and — surprise, surprise — installed a Class B AIS transponder.
“An interesting thing I learned from years of going to sea on all sorts of boats with all sorts of folks is that the people who are most experienced and wise about it are generally the first to forgive the mistakes of others.”
So true Ben, I’ve been going to sea for a while and have had a couple close call with fishing boats. When I see cases like this I think “there but for the grace of God go I.”
I am a recreational boater and a pragmatist. I have been offshore and have stood night watch on a 174 footer. What I see as the take-away from this discussion are a few points.
The first and most important is that standard, procedural watch-keeping is vital to safety at sea. That includes a basic understanding of how to “properly” use the tools that are available to keep it safe, particularly one’s own senses; his eyes and his ears.
All boats should be prepared before setting out to insure that they can be seen and heard. To be “seen” a proper radar reflector should be installed if the vessel isn’t made of a reflective metal. Additionally, at least two working VHF’s should be aboard and MONITORED; one of which is AIS-capable.
Onboard electronics can be PRE-programmed to sound audible alarms if either a collision-course is anticipated or if it appears that a vessel’s safety perimeter will be violated by an approaching vessel. ARPA, MARPA and CPA provide for this safety feature and modern electronics, software and user interface make it practical, it just needs to be used by ONE of the two vessels.
AIS is truly an awesome tool when combined with the radar-like collision avoidance features of commercial radar equipment. When overlayed on Radar, it has proven to prevent collisions. Many VHF radios have this now built-in or it can be fed to either a chartplotter or laptop to achieve the same benefits. I prefer to keep it simple and go for the one that is packaged as a collision avoidance VHF radio. One excellent product that does this better than any I have otherwise seen is the Standard Horizon Matrix GX2100 VHF radio. (No, I don’t work for them :-))
Given that the GX2100 is available for less than $300, only a fool would venture into shipping lanes without one – and the knowledge to use it properly.
My condolences to the families of the lost.