Class B AIS waste of money

[Jim Cate]

Originally Posted by StuM

Are you talking about trolls?

After serious analysis of the statement, Stu, I'm left with the impression that he is referring to himself.

Jim

[Exile]

[QUOTE=Littlechay;2293788]

Originally Posted by Exile

Apparently many AIS systems are tied into instruments or gps w/o separate switches to turn on/off./QUOTE]

It is legal to turn off AIS class B and for this reason most class B transceivers have a silent mode built in (RTFM its in the menus); therefore it matters not whether the AIS is tied into other instruments or not.

True enough, so maybe some people who like to leave their instruments on when they leave their boats in the slip forget to flip the switch on their AIS silent mode. And I'm sure there's some who leave their transponders on intentionally for reasons already mentioned. Who cares? I thought the discussion was about whether Class B transmissions in general justify big ships filtering them out in busy harbors? Personally, if I'm leaving my boat for more than a day I turn everything off except the battery charger, but could really care less what others do.

"RTFM"??? Now is that any way to bring in the New Year? WTF??

[Exile]

Originally Posted by Paul Elliott

El Pinguino, I understand your point, I really do, and in the short term having berthed boats turn off their transponders would reduce the clutter. I turn mine off for just that reason.

But some people are also complaining that we are running Class-B while we are underway in the harbor -- apparently we are cluttering the plotter displays on the big ships.

You say this:
And there's your problem.

The proper solution to all this is not to disable Class-B transmissions, but for the ships to not be running "at sea" AIS alarm configurations in the harbor. There is no good reason for watchstanders to have to disable individual AIS target alarms under these conditions. If the software doesn't provide for a reasonable alarm setting then the software needs to be improved.

The gcaptain article referenced in the first post mentioned that the Furuno was also capable of minimizing (rather than filtering) the on-screen appearance of Class B signals. That, and maybe modifying the AIS proximity alarms when navigating harbors, may be a better answer than filtering them out altogether. But then I've never been on the bridge of a big commercial ship!

[Paul Elliott]

Originally Posted by Exile

The gcaptain article referenced in the first post mentioned that the Furuno was also capable of minimizing (rather than filtering) the on-screen appearance of Class B signals. That, and maybe modifying the AIS proximity alarms when navigating harbors, may be a better answer than filtering them out altogether. But then I've never been on the bridge of a big commercial ship!

It's an evolving system. And I do realize that the ships crew have to work with the tools they have, and my saying "fix the software" is not immediately useful to the people who are trying to pilot their ship through crowded waters.

But, long-term, "fixing the software" is the only way to solve the problem. Class-B is here in a big way, and people will be using it. AIS equipment manufacturers like Vesper have been providing flexible and powerful alarm configurations for some time now, and programs such as the free OpenCPN have flexible AIS alarm options.

Furuno and other providers of IMO EDCIS-compliant equipment are perhaps constrained by the standardization process, but I understand that progress is being made, and we shouldn't hobble the very valuable AIS technology because some old equipment hasn't kept up with the current needs. Class-B has been around for ten years now, and we need to look forward, not back.

[CarinaPDX]

Just a small correction: AIS equipment is properly considered a transceiver, not a transponder. A transponder reacts to received signals by transmitting, which is not how AIS works. AIS transceivers transmit location/course/speed etc every few seconds - more frequently for Class A than Class B. They also transmit ship's identification/description information on a longer cycle. So they are more like a beacon than a radar transponder.

Greg

[StuM]

Originally Posted by Jim Cate

> Are you talking about trolls?
After serious analysis of the statement, Stu, I'm left with the impression that he is referring to himself.

Jim

Or to put it another way, the answer is Yes.

[StuM]

[QUOTE=Exile;2293809]

Originally Posted by Littlechay

I thought the discussion was about whether Class B transmissions in general justify big ships filtering them out in busy harbors?

Nope the discussion is about the ludicrous assertion by some Able Seaman (Engineering) that Class B AIS is a waste of money because some ships turn off Class B recognition in busy harbours.

[StuM]

Originally Posted by CarinaPDX

Just a small correction: AIS equipment is properly considered a transceiver, not a transponder. A transponder reacts to received signals by transmitting, which is not how AIS works. AIS transceivers transmit location/course/speed etc every few seconds - more frequently for Class A than Class B. They also transmit ship's identification/description information on a longer cycle. So they are more like a beacon than a radar transponder.

Greg

Good catch! Apparently our OP, the Able Seaman (Engineering) doesn't know the difference.

"I'm hoping to prompt some discussion on what a total waste of money purchasing and installing a class B transponder on your please craft is"

I'm seriously starting to doubt that "Able" part

[Littlechay]

Originally Posted by CarinaPDX

Just a small correction: AIS equipment is properly considered a transceiver, not a transponder. A transponder reacts to received signals by transmitting, which is not how AIS works. AIS transceivers transmit location/course/speed etc every few seconds - more frequently for Class A than Class B. They also transmit ship's identification/description information on a longer cycle. So they are more like a beacon than a radar transponder.

Greg

Yea I long ago gave up pointing out the difference between the two and let it wash over me

But as soon as I see it in an article or discussion I know that the writer is not as well informed as they think they are; it's one of those little warning flags that the person is on the first step of on the competence ladder - the unknowingly incompetent -

[Paul Elliott]

An AIS transmit/receive unit (Class-A and Class-B) is properly called a "transponder". They can indeed be remotely interrogated and I guess that makes them transponders.

The transponder term is used throughout the IMO, IEC, USCG, and other standards for AIS. For example, here's an overview webpage from the IMO with the title "AIS Transponders": Automatic Identification Systems (AIS)

[Littlechay]

Originally Posted by Paul Elliott

An AIS transmit/receive unit (Class-A and Class-B) is properly called a "transponder". They can indeed be remotely interrogated and I guess that makes them transponders.

The transponder term is used throughout the IMO, IEC, USCG, and other standards for AIS. For example, here's an overview webpage from the IMO with the title "AIS Transponders": Automatic Identification Systems (AIS)

You may be right in the instance where the unit responds to a position request but otherwise they are not operating as transponders in the classic sense.

Just because a term is widely used does not make it correct, just like popular music is not necessarily good

[CarinaPDX]

Originally Posted by Paul Elliott

An AIS transmit/receive unit (Class-A and Class-B) is properly called a "transponder".

The IMO calling it such doesn't make it so. It is not technically a transponder.

[/QUOTE]They can indeed be remotely interrogated and I guess that makes them transponders. [/QUOTE]


That would make them transponders if it were so. But I find no indication that it is so. Unless the DSC integration counts (I don't think so). There is an ability for shore stations to transmit messages to specific MMSI numbers (Class A only), but that still isn't a transponder (transmit responder).

Greg

[CarinaPDX]

Originally Posted by Littlechay

You may be right in the instance where the unit responds to a position request

A DSC radio responds to a position request; AIS does not. AIS repeatedly broadcasts the position, un-requested.

Greg

[Watermann]

Originally Posted by SV Enough

I am one of 2 ETs serving aboard most USNS vessels. If you are under the miss impression that any bridge crew are electronics technicians, you need to get your MMC and walk bridge deck plates. USNS ships are manned by CIVMARS, civilian mariners with US Merchant Marine Credentials as are all US flagged vessel commercial or otherwise. It goes downhill from there for foreign flagged vessels. If you think Liberian Merchant Marine Credentials meet the same level of rigor for competence as US MMC, I have a bridge for sale in Brooklyn. Good luck reading the Colregs, SOLAS, USCG, or any other documents in a Liberian admiralty courtroom over an AIS or any other maritime complaint.

For US Navy USS and its USNS vessels there is a letter of understanding with the USCG allowing them to secure their AIS transponders at will. The Master and or MOW (Mate on Watch) determine what is set or not set when or where on bridge instruments and to do that the ET IS CALLED.

And I repeat, what are your professional MMC qualifications and what deck plates in any capacity you have walked for a living? You really need to get a grip on how the real wold operates.

Mark Fay MMC Jr. Engineer QMED AS-E / MSC ET

I was going to stay out of this until I read that bolded line...

If you think the MSC world is typical of a commercial ship operating environment (and given that you were formerly AD Navy, you probably do), then you're the one who needs to get a grip on how the real world operates.

So long as were posting credentials, I'm a USMMA grad, Master AGT & Master of Towing, Oceans with some First Class pilotage thrown in. Been sailing on a variety of vessels (tugs, container, tanker) for over 15 yrs since graduating, the last 5 or so as Master. I also have a QMED rating for deck engineer, electrician, junior engineer, pumpman and oiler, though I haven't sailed in the engine department since my cadet days (and never with MSC).

The engineers on the vessels I've worked on would never know how to operate the ECDIS, much less fool around with its settings. At best, they might might be able to diagnose a hardware issue but that's more a function of the individual having moderate computer skills (the thing is basically a hardened computer with multiple serial inputs, eg. Moxa PComm Terminal Emulator or something similar) and not necessarily expected because of their credentials. I can't ever imagine a time when an engineer, especially an un-licensed one, would ever work on the software end of things.

In addition to their regular credentialing, your deck officers have taken a type-specific 40-hour course on ECDIS and should know how to access every user setting, what they do and why they should be set a certain way. They should also know the radars like the back of their hand. There are really not that many types in the big ship world.

I understand that if you're an electronics tech and do work on the bridge equipment, then good for you. But, you're basically unemployable in a sailing role outside of MSC if those are your only skills. In the "real world" of commercial shipping, QMEDs are down below working for the 1AE. In fact, one of my best friends/classmates is a 1AE on one of the T-AKE ships. I'll ask him how many of his QMEDS work on the ECDIS in between rebuilding pumps, changing strainers etc...

My experience with MSC is limited to riding along on pilotage observation trips and a couple of pierside ADT's I did when in the MMR, but even from that glimpse, I know that it's a completely different world than most commercial shipping. The mission is different so it's understandable, but this is why you received the earlier retorts that you did from other current/former ship's officers.


Really didn't want to bring this back up, but that last line from you bothered me a bit...

[Paul Elliott]

Originally Posted by CarinaPDX

The IMO calling it such doesn't make it so. It is not technically a transponder.

That would make them transponders if it were so. But I find no indication that it is so. Unless the DSC integration counts (I don't think so). There is an ability for shore stations to transmit messages to specific MMSI numbers (Class A only), but that still isn't a transponder (transmit responder).

Greg

Take a look at Standard AIS Message #15:
Interrogation -- Request for a specific message type (can result in multiple responses from one or several stations)

And message #16 is an "Assignment mode command", which changes the "reporting behavior" of a mobile station (the transponder).

When received, these two messages (and others) result in a response by the transponder. This response may be one or more messages in reply, or a change in channel usage. I would say that the name "transponder" is quite appropriate.

These message descriptions come from the IALA Guideline 1082, "An Overview of AIS". You can download it from the USCG here: http://www.navcen.uscg.gov/pdf/IALA_...iew_of_AIS.pdf