How Large Ships Use Navigation Systems

Jan 20, 2012
Originally published on March 8, 2012 1:03 pm
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This is SCIENCE FRIDAY. I'm Ira Flatow.

Last week, a cruise ship carrying more than 4,000 people ran aground off the coast of Italy, resulting in the loss of numerous lives, not to mention damage to the ship. It struck a rocky outcropping clearly visible on the chart, tearing a gash in its hull, which leaves us wondering: How in this age of GPS, sonar, other high-tech navigational devices could such a tragedy occur? Did it veer dangerously off-course? What kind of technology does the crew of large cargo and cruise ships depend on?

Joining us to talk about this and answer some of those questions is Max van Norden. He's coordinator of the hydrographic science program in the Department of Marine Sciences at University of Southern Mississippi in Hattiesburg, Mississippi. Welcome to SCIENCE FRIDAY.

MAX VAN NORDEN: Thank you very much, Ira. I'm glad to be on your show.

FLATOW: You're welcome. Is this a common occurrence?

NORDEN: Not really, not really. I mean, this is - well, this is really a case of gross stupidity.

FLATOW: Why do you say that?

NORDEN: Well, because a modern navigational system, which would have been present on a ship like the Costa Concordia, would have definitely warned the crew, the bridge crew and the captain that they were - you know, had to make corrective actions. A modern navigational system, which is called an ECDIS, an electronic chart display and information system, really gives great improvement in navigational safety because, first of all, it gives great improvement in the situational awareness. It automatically plots the position of the ship, as you mentioned, with GPS.

It also automatically plots the positions of other ships within its radar range to - and, from that, project, from the course and the speeds, whether there's a problem with, you know, possible collisions with other ships. It also plots what we call AIS targets, automatic information - automatic identification system targets, which every major ship today has to carry an AIS transponder after 9/11 because. And these transponders give a ship's position, its course, its speed, what cargo it carries, where it's coming from, where it's going, what flag it flies, so forth.

But from the - from, say, the Concordia's AIS receiver, it could also have plotted all the AIS targets as well. So a active system gives greatly improved situational awareness of the water space the ship is going in and there to prevent collisions with other ships.

And then, in addition to that, the systems allow for voyage planning, where the navigator sets out the exact track that they want to follow at each course change based upon the electronic navigational chart. And if the navigator should set out a course or a planned course in this voyage planning that takes it over a hazardous area, the active system will tell him, you can't - this is a bad track. You know, change your voyage plan to a more safer track. So it's also a great improvement in voyage planning.

And then the third thing is the route monitoring part. It actually gives you warnings when you exceed the allowances for danger. In the voyage planning, you'll put in things like the ship's characteristics, its turning rate and things like that, its allowable draft. And if it gets too close - and the standoff allowances to navigational hazards, and if it exceeds those allowances, the system will give out warnings, you know?

Think of the Exxon Valdez, for instance, in 1989. That accident could have been prevented with a - with an ECDIS system. But they didn't have ECDIS at that time. But if you recall, there was a third mate, an inexperienced third mate on the bridge who failed to make a critical course change. And an ECDIS system would have warned him, say, you've got to make this turn at this time. And - or as the ship was going off towards a navigational hazard, the ECDIS system would have given him a warning, saying, you're getting too close to this navigational hazard. Or a depth sounder, which is interfaced with an ECDIS system, would have told him, you're - the bottom is getting too shallow. You need to make - take corrective actions. So all these are great improvements in navigational safety that these modern electronic chart display information systems provide to the mariner.

FLATOW: And the location of the underwater hazards are also well known, like the rock that it hit.

NORDEN: Well, in this case, yes. But you bring up something - there are some pitfalls to these navigational systems, particularly, I think, in my opinion, in fact, the cruise line industry because these displays, these are all very colorful, you know, computer monitors and displays

...navigational systems, particularly, I think, in my opinion, in fact, the cruise line industry, because the - these displays, these are all very colorful, you know, computer monitors and displays that sort in complacency(ph) the fact the - OK, the database for these active systems is the electronic navigational chart, and it looks very colorful as well. But in many cases that information on that chart is based on very old data. NOAA, for instance, is responsible for charting U.S. waters.

I've seen the presentation where they say that 50 percent of the data on their charts were collected by hydrographic surveys before 1940, old technology. And so in areas that are well travelled by, say, container ships or tankers, whatever, these well-travelled routes are well charted. But these cruise liners, they like to go off the beaten path and show, you know, pristine areas, picturesque areas to the passengers. So they're going off the beaten path into areas that are not well surveyed.

Or maybe they've been surveyed many, many years ago with old technology, even by - perhaps by Captain Cook even. But in any case, these areas in fact may not have ever been surveyed, in some cases of Alaska, where the glaciers have receded and these cruise liners going to these areas and watching these beautiful glacier areas may have never - the waters, however, may have never been surveyed.

So for these cruise ships, they're going off the beaten path and putting these half-a-billion-dollar ships at some risk with the passengers, of course, by going into these areas that are not well surveyed. Even though the chart might look very fancy and colorful and - a very colorful display in this modern, integrated bridge, but that underlying data would have been collected, in many cases, with very old technology.

FLATOW: Mm-hmm. But the case of last week, this was not that case, was it?

NORDEN: No, it was not. This is just really a case where - well, from my readings, the Costa Concordia had a modern navigation system, modern (unintelligible) system. It was given a number of warnings that he's getting too close, I'm sure, but I guess in his case, the captain's case, he just turned off the warnings and ignored them.

FLATOW: Would there not be other members of the crew on the bridge there?

NORDEN: There would. And I was wondering why the chief mate would not have jumped in and say, Captain, you're doing, you know, you're taking the ship into dangerous waters here. But, you know, that's - I'm just speculating.

FLATOW: Right. So there's enough electronics on the ship to let you know, at least in that case, to let you know where you are exactly...

NORDEN: Exactly.

FLATOW: ...and to let you know exactly what is around you. And it's up to you to decide whether to listen to it or not.

NORDEN: Yes. And in the case of the Costa Concordia, of course I mentioned every large ship has to have an AIS receiver these days. Nowadays, I mean, it was constantly transmitting those AIS transmissions, and there are stations ashore that pick that up and can simulate exactly where that ship was through that whole ordeal. And in fact, there's a very good website that show – it gives some explanations of where the ship went.

FLATOW: What website is that?

NORDEN: One that I saw that was really good is, where they show, using the AIS data, exactly where the ship travelled. And the narrator gives very good explanation what he thought happened.



FLATOW: Let me go to the phones to Matt in Alexandria, Virginia. Hi, Matt. Welcome to SCIENCE FRIDAY.

MATT: Oh, hello.

FLATOW: Hi there. Go ahead.

MATT: Yeah. I was curious. I used to be a second mate. And I was wondering if the voyage data recorder info had been recovered. And if so, would it ever be made public?

NORDEN: I saw a picture of them recovering the voyage data recorder.

FLATOW: Is that like the recorder on an airplane when it goes down?


MATT: Yeah.

FLATOW: So it's been recovered. And that would have the record of where - exactly where it went.


FLATOW: Matt, does this surprise you as a second mate?

MATT: Yeah. Yes. I mean, the ships I've been on have all had one. We never had to do anything with it, I mean it was sort of a passive thing. But we were under the instructions or understanding that if something happened, it would be one of the first things recovered, and the data it records would be used to recreate what happened prior to the incident.

FLATOW: All right. Thanks for calling. 1-800-989-8255. Talking with Max van Norden. So you're saying that there's a lesson here about the future of cruise shipping and knowing where you are and the ancient charts that - and you were not joking that some of these go back to Captain Cook.

NORDEN: No, I wasn't. Another example, the QE2 grounded off of Martha's Vineyards a couple of years ago. I think 1992. They went off the beaten path and grounded off on - in an area they hadn't been surveyed since 1939. So, I mean, these things happen.

FLATOW: And you say they go off the beaten path because the captain may want to get the passengers a special look at something or get close to a glacier in Alaska?

NORDEN: Right. That's part of the deal for these cruise lines, to take you into picturesque, you know, pristine areas of Alaska and other areas and have the, you know, the passengers see some very beautiful scenery. But in a number of cases, these are unsurveyed or very bad or very old surveyed areas.

FLATOW: Mm-hmm. And the alarms could be going off in the ship, literally off the chart when they do these things.

NORDEN: Well, you see, in that case the alarms wouldn't necessarily go off because the ship relies or the active system relies on the known data of the electronic navigational chart. And so if there's nothing to tell or nothing in the data to say that there's, you know, there's a danger, if the rocks haven't been discovered that will ground the ship, if those shoals have not been discovered, there's no - the alarms wouldn't necessarily go off.

FLATOW: But in the normal course of a cruise, we would expect that this is - if you stay on course, this cruise has taken - the captain and his crew have taken this trip a hundred times at least and know exactly where everything is, and they're quite safe.

NORDEN: Right. If they follow, you know, the normal shipping lanes or have taken these cruises along that line before, then it should be safe, yes.

FLATOW: I'm Ira Flatow. This is SCIENCE FRIDAY from NPR. Talking with Max van Norden, who is coordinator of the Hydrographic Science Program at the University of Southern Mississippi in Hattiesburg, Mississippi. So what is your recommendation here, Dr. Van Norden?

NORDEN: Well, of course one recommendation would be to, you know, follow the advice of your ecto(ph)-system and not overrule it. But the other thing is that we need, you know, more hydrographic surveys in those areas where these cruise liners are going.

FLATOW: Yeah. And...

NORDEN: Modern surveys.

FLATOW: And we need to have captains take less risk.

NORDEN: Absolutely.

FLATOW: What is the normal sequence of an investigation that would go on now?

NORDEN: Well, I - that's really out of my area. I, you know, I'm sure the Italian version of their coast guard would be following that investigation, and they would have to present the evidence to a maritime court of some type. And generally these things follow some sort of maritime law.

FLATOW: And as far as knowing where you are in the water and what's around you, would not sonar on your own ship tell you that there were these rocks right next door to you, where you're going?

NORDEN: Well, most ships do carry a depth sounder. But in a case of a ship like the Concordia, which has a great mast behind it, it would be - they don't have the type of sonar, probably the forward-looking type of sonar that, say, a warship would have. They would have a more, you know, commercial, down-looking sonar. And there was probably no way they would detect something in time like that. They can only see a prevailing trend, say, in the bottom, but on all of a sudden type hazard that's in the way, no. They would have to depend upon the charts to tell them there's a hazard. And they need - and, of course, in this case, you need to follow the charts instead of just thinking that you could get away with what he did.

FLATOW: If you have the chart, you got to use it.

NORDEN: That's correct.

FLATOW: And the charts that he used, there's no reason to believe these were ancient charts. And as we talked about before, he had been over - I mean this is just a normal course that this cruise liner took all the time.

NORDEN: Well, no, not in this particular case, though. I mean in this sail-by that he did, he had done it, I believe, one time before but with slightly different headings. And so what he did was actually, you know, unauthorized and unusual. Now, what I meant was normally ships would stay, you know, farther away from an island like that on - in the normal shipping lanes. And that would've been the safe course of action.

FLATOW: Dr. Van Norden, thank you very much for taking time to be with us.

NORDEN: Oh, my pleasure.

FLATOW: Max van Norden of Southern - University of Southern Mississippi in Hattiesburg. Transcript provided by NPR, Copyright NPR.