Panbo

AIS, raves & rants

... written for Panbo by Ben Ellison and posted on Oct 9, 2009
ShipFinder_New_England_cPanbo.JPG

The iPhone AIS app Ship Finder got updated a few weeks back, and darned if it didn't add a large Eastern Seaboard feed that even includes the Penobscot Bay listening stations set up by the local pilots.  That feed hasn't been public for some time, and I'm tickled to have it in my pocket, even if the data is delayed an hour.  Ship Finder is improved in several other ways, too, and has become one of my favorites.  Red Sky, incidentally, is a handsome 30m Swan that's been hanging around Camden this summer.  Now I know she's at Lyman Morse in Thomaston, which is near enough to the Rockland listening tower that her 2 watt Class B transponder gets picked up.  The same tower doesn't see even 12 watt Class A's in Camden, largely because of the hills, but if I get down the Bay next week (hoping), maybe I can engage in some AIS-style navel gazing?  And, now, for more serious matters...

Last week I attended an NMEA seminar on AIS.  It was largely about installing and maintaining Class A transponders on mandated ships and was led by two gentlemen who have inspected radio equipment on thousands of ship bridges.  When asked about the 'rumor' that ships were filtering out Class B AIS targets, they literally guffawed.  An "urban legend" one said -- that's "not gonna happen" -- which corresponds to my research into the latest IMO bridge display regs.  But I know the filtering meme is still out there, and is paired with the flawed notion that even a channel switching AIS receiver is good enough for recreational boats.
   I was disappointed to see Tim Flanagan at NavaGear make this case recently, writing that though he carries a Class B, "nobody really cares where my boat is" and that "about 99 percent of the real-world AIS utility I have experienced so far comes from reception," which can be had from a receive-only unit "purchased for less than $200" versus "the more expensive Class B AIS units, which cost about $1,000."   It's great that Tim is encouraging AIS use, but gosh there's a lot left out of his analysis.  Plus, it's just not true that Class B costs $1,000.  Here's an ACR Nauticast B for $729 and here's a Digital Yacht AIT250 for $699.  Both come complete with both VHF and GPS antennas, can supply alternate GPS to some PC charting programs and plotters (not all recognize the messages), are built and tested to high specs, and listen to both AIS channels simultaneously.  None of which can be said for the $189 Smart Radio SR161 lauded at Navagear.
   Besides, we're in transition.  Class B AIS has been legal in the US less than a year, and there aren't many out there yet.  Yet I saw quite a few in Maine this summer and am sure there will be more next year.  Plus the USCG will soon mandate B on thousands of commercial vessels that frequently share coastal waters with us.  Shouldn't we anticipate that B-to-B AIS usage will increase a lot?  And shouldn't AIS shoppers be aware that Class B vessels only transmit position data every 30 seconds on alternate channels, and hence single-channel receivers like the SR161 will only plot a B target every 60 seconds at best?
   I also think that AIS attitudes will change.  Once we get beyond the it's-all-about-ships phase, won't it start seeming odd that some boats are full participants in the Identity System while others of similar size just listen?  I was struck by a story Bruce Kessler told when he arrived this Spring.  That day Spirit of Zopilote was hailed by name in thick fog, so as they spoke on the radio, Bruce started looking for a corresponding nearby AIS target.  Eventually he identified their radar target and the crossing situation was resolved fine, but he said the other vessel sounded a bit ashamed when confirming that they were just receiving AIS, not sending it.  Think about being on the receive-only side of that conversation. Doesn't the subtext go something like this:  Thanks for broadcasting your position so I can see you plotted on my chart and easily call you on my radio;  sorry I'm not doing the same thing for you, but I wanted to save a few hundred dollars by only installing an AIS receiver.

But if you still want just a receiver, do consider a true dual channel model, like the new AIS200 PRO that Digital Yacht was showing at NMEA.  This, I believe, is one of the super sensitive 2nd generation receivers SRT spoke of recently, and it has USB built in and will retail for $330.

Digital_Yacht_AIS_PRO_200_receiver.jpg

Comments

It is a pet peeve of mine that boaters purchase the receive only products.

I have budget reasons for not purchasing an AIS transiever just yet, a glaring hole in the high tech on my sailboat, but refuse to purchase a receiver product to fill the gap !

If a boater wants to benefit from the contribution of other boaters investing in this safety net, they should have to contribute their boat's position information to the AIS community as well !!

Posted by: Dan Corcoran (b393capt) at October 9, 2009 4:00 PM | Reply

While the receivers are nice for shore based receivers I agree and would hope most would go for the AIS Class B transciever. I have my N2K Navico 300L on it's own AIS antenna and GPS antenna. I don't understand why especially with the NMEA standards the GPS or position can't come from your navigation system where the addition of a position sensor might make the boats display more accurate when you loose GPS track or are anchored out.
Bill

Posted by: Bill Lentz at October 9, 2009 6:08 PM | Reply

Dan: If I read your comment correctly, it's sort of shockingly hypocritical. How can you have a pet peeve about others when you yourself don't transmit? You're certainly not the only boat owner with a budget.

Ben: To your point about being in transition, it's not clear to me that Class B is anything more than a transitional product. If a mfg set aside IMO requirements and made a class A "black box" for recreational customers, is there any reason it should be more than a $200 price premium? Aren't we right at the top of the B cost curve with dramatic drops likely in the next 18 months?

I certainly see the benefits of sending my position, but I've also spent enough time debugging the "bleeding edge" to know that it rarely makes sense to buy a first generation product.

Posted by: Russ at October 9, 2009 9:12 PM | Reply

Ben, shouldn't that be "naval gazing"?

The reason that Class-B transponders have built-in GPS receivers is because the rulemakers were afraid that the amateurs and pleasureboaters would misconfigure their Class-B units and thus send bad data. As they are designed now, they are fairly plug-and-play.

Russ, I installed the ACR Class-B unit within a month of it being released, and it has been trouble-free. I have heard that the Raymarine unit initially had a firmware bug (bugs?), but it is OK now.

Posted by: Paul at October 9, 2009 9:47 PM | Reply

Having a great fear of being run over at sea, we placed a Comair CSB-200 (Class B) transponder aboard s/v Horizons (our SC-39) last June before sailing from Hawaii on a 26 day passage to the Pacific NorthWest. The Comar was selected to avoid the �bleeding edge� of design � the CSB-200 has been in service for some time now overseas and is now available locally.

Information provided by AIS has not relieved our watch-standing effort, but it has forever changed the collision avoidance �game� aboard Horizons. Where we used to go to great lengths to stay out of everybody�s way, we are now active players in jointly resolving potential conflicts. In our experience, unintentional filtering is an issue, and often associated with older software.* But some level of filtering or temporary target suppression would be a very good thing.

Few sailboats, if any, run radar on passage except where visibility is greatly restricted as doing so for any length of time means also starting the engine or running a generator. While on passage, we normally don�t run a chart plotter full time either.

But on this passage, shortly after leaving the sight of land behind, we observed the incessant blinking of the CSB-200 �receive� LED first slow, then cease altogether indicating it was no longer receiving �hits� from other vessels. Running the CSB-200 alone (and probably any other Class B AIS unit), without plotter interface drew less than 0.2 amps, a very affordable price extracted from two 8D �house� batteries.

We would observe the �receive� LED to begin flashing as vessels got within roughly fifty NM giving the watch-stander ample time to boot up a plotter, and well before being able to acquire the approaching vessel visually.

Until AIS, I have never been able to raise shipping on the VHF � but with a vessel�s name and call sign now provided, ready communication is the norm. We encountered only one ship that would not pick up the mic and respond.

At one point, all three of us stood in the cockpit to watch a container ship approach, emerge from the fog at 2.4 NM, and then disappear again in less than a minute. We mused about how many ships may have passed in close proximity where neither party was aware of the other.

As we drew within range of the entrance to the Strait of Juan de Fuca (ingress/egress point for all Seattle/Vancouver shipping) around 2A, the AIS notified of traffic closing from astern. After watching the distance shrink to five miles, and having a �visual� on him, I flashed our search light several times with no apparent change. But with the vessel�s name and call sign, I got an instant response on the VHF. Horizons presence had not been noted, but once advised, the ship altered course and passed safely to starboard.

But half of the shipping was not able to pick up our Class B AIS transponder, and a few complained of only receiving our MMSI number. The only Class B vessel encountered (with an ACR unit) was able to receive all Horizons data.

AIS is in transition � but I cannot imagine anyone who has experienced the reality of AIS to operate routinely without it. Although there is less traffic offshore than along the coast, AIS is possibly of even more value to cruisers than coastwise boaters who often opt to remain in harbor when visibility is restricted.

Filtering: Much of the charting software in use today, including some still being sold* is not capable of displaying Class B targets.

But in congested areas, clutter is a problem and the ability to temporarily suppress �base stations� would be a good thing. They are likely already in the plotter�s database anyway. Another suppression candidate would be vessels riding at anchor. Suppressing anything with a speed of �0� would better enable detection of rapidly moving but unseen vessels on the far side of the anchored vessel.


* Note: �We recently were able to obtain some AIS data that we knew contained both Class A & Class B data. Upon working with this new data stream we discovered that The CAPN was not displaying Class B data. We are fixing that now and will have the fix incorporated into the 8.4 release which we anticipate by the end of August 2009.�

The above is from The Capn online �support forum� back in July � while the end of August has come and gone, still no fix.

Posted by: John Hallinan at October 9, 2009 9:52 PM | Reply

John, thanks for the report! Very informative, and makes the case for AIS on pleasure boats even more compelling. Your experience offshore varies in several significant ways from my inshore experience.

Unless I've misunderstood, it sounds like most of the genuine value you experienced from AIS was generated because you had access to other vessels' AIS data you had received. Were there instances in which the AIS data you were broadcasting contributed, as well?

Posted by: Tim Flanagan at October 9, 2009 11:31 PM | Reply

John: I have an AIS receiver and it's invaluable.

WRT transponders, your observation that half the ships couldn't see your Class B signal is the counter point to Paul's "trouble-free".

I think AIS is a great thing and long overdue since the underlying technology is ancient. But then so is data networking, and yet N2K seems to be a challenge for most marine equipment manufacturers.

My plotter (NN3D) does have the ability to suppress AIS targets beyond a specified distance, or below a specified speed. I suspect it's not the only plotter with that capability.

Posted by: Russ at October 9, 2009 11:33 PM | Reply

Russ, Class A and B communications are obviously asymmetrical. A Class B receiver is going to see a 12 watt Class A signal further away than the Class A is going to see its 2 watt signal. That's not a glitch; it's by design.

And I don't think Class B will transition away. Class A transponders that don't meet IMO specs are apparently going to get much less expensive, but I don't know where you get the $200 premium. There are still a lot of technical requirements to meet to be Class A at all, plus there may still be a royalty issue regarding SOTDMA. (Which is one reason why they changed Class B to CSTDMA somewhat late in the game, I think.)

Overall, though, Class B transponders are not "bleeding edge" in the same way a lot of other marine electronics are. That's because the core technology is tightly defined and tested, and because one company makes virtually all of it. Class B's almost always work fine right out the box, except for the failure of older Class A's to see the newish CSTDMA static data message (just an update issue, really), and some glitches in the NMEA 2000 AIS implementation. The latter -- which is completely managed by NMEA and the individual Class B manufacturers -- does have "bleeding edge" qualities.

Posted by: Ben at October 10, 2009 9:04 AM | Reply

Wow, lots of good info here... Currently we are in the middle of a total retro fit because of a lightening hit to our 40' Beneteau that took out everything. This vessel did not have AIS, will certainly add it. I will be attending the IBEX show to try to learn more specific details and try to determine which manufacturer and model to add into and build a totally new system. AIS transponder will be on board for sure, would never think of receive only. Hoping to take part in the 2010 Regatta del Sol al Sol XLII and we would very much want to be seen while out in the Gulf of Mexico.
We also have big questions to find answers to at IBEX this year as to what instruments to install, and from Ben's review of the new Simrad MFD NXe8 / 12 we are leaning that way, coupled with replacement of older Robertson Autopilot with a new model AP-28. Thinking of the Airmar Ultrasonic wind instrument at the top of the mast and CS4500 Ultrasonic for speed. We are hoping that these will interface with the Simrad IS20 and MFD. Still do not know what depth transducer to use as this is as critical for us as wind...being a sailboat that sails much of the time in shallow South Florida Biscayne Bay. If we go with the Simrad line vs. lets say Garmin I would choose the entire line vs. mixing and trying to match equipment. The last total or near total retro fit we did was with all new 2009 models Garmin equipment. I understand that Sim/Net is really NMEA 2000 with different cable ends. We would only want to do this total retro fitting with N/2000 compatible equipment so in the future we can add or change out equipment as necessary. Any specific thoughts on this, or if anyone wants to meet up at IBEX you can contact me at jeffrey54@comcast.net.

Posted by: Jeffrey at October 10, 2009 10:29 AM | Reply

Ben,
Has NMEA issued a final set of PGN's for AIS to use on N2K networks? I just returned from the Annapolis Boat show where I asked the rep from ACR if the next generation of AIS units will send out NMEA 2000 data. He said ACR has no plans on adapting N2K into their AIS class B transponders. I was also disappointed when one other vendor told me Com Nav will never change over their autopilots or instruments to N2K and, in fact, some manufacturers are dropping their plans for making this transition to N2K. Why so much resistance to N2K when it far exceeds the old 0183 in every way? I was anticipating and holding off on buying AIS Class B until one comes out using N2K and maybe a USB output for the computer. How difficult is it to engineer this modification that should have been here already?

Posted by: Richard C at October 10, 2009 10:54 AM | Reply

We are seeing some rather rapid development of marine electronics. These systems as a whole are quite expensive, what with wiring, antenna, and "language" problems, that is the absence of a true universal standard which all manufacturers have adapted. Then there is the problem of inserting new gear into older systems and losing some of the data because of communication issues. And finally there is the matter of installation of this equipment into nav station panels, cockpit instrument dashboards, instrument pods and bridge deck helms stations. This is a lot more complex than changing the dishes we use to eat on. And a lot more expensive.

The take away is that it's not easy to evolve a working marine electronics system to upgrade and take advantage of new features.

And from the manufacturer's POV they have to support older products for some time and need to take a longer view of their product line.

Then consider that some of this new technology is something many have no hands on experience with whatsoever. You have to believe the marketing because you can't take it for a test drive so to speak. Ben does that for us.

I was an early adapter of a receive only AIS. I can see the potential to transceive and expect to move to that in a while. Right now my sailing would hardly benefit from it so it amounts to a way cool gizmo. I suppose this may be true for many recreational boaters as well. We'll buy when we can afford it or when we really need it and it has a perceived measurable benefit.

I'm thrilled that AIS is here and it should save lives.

Posted by: SanderO at October 10, 2009 11:51 AM | Reply

While AIS is great and I use it, it does have limitations. One limitation should be engraved in large letters across any AIS unit:

AIS will show the tug, but it will not show the barge(s). It is not a substitute for radar.

Almost every year we have boaters who get into trouble by running between the tug and its tow. Ocean going tugs have their tow(s) a very long distance behind the tug. Running over the cable can be fatal. Add to this the fact that pleasure craft must cross shipping lanes at as close to ninety degrees as possible and you have a receipe for disaster -- especially if people are confident that the little boats on the screen represent reality.

Not to be a Luddite here, but used improperly AIS is going to lead to more "computer assisted collisions."

Posted by: George R at October 10, 2009 12:09 PM | Reply

I wonder why Apple posts a notice before downloading the "Ship Finder" app informing us it is only for those over the age of 17 due to mature content. What the heck is that all about? Since when are ship AIS positions obscene? Did anyone else see this or did they post it just for me :)?

Posted by: Richard C at October 10, 2009 12:27 PM | Reply

Ok, I found the answer to my own question above regarding the app "Ship Finder". Support for Ship Finder says that Apple requires the riot warning about mature content because the app has a breakout to Google. I guess that means it falls within a very strict rule Apple places on app's downloaded from iTunes.

Posted by: Richard C at October 10, 2009 1:29 PM | Reply

Russ, Tim �

Thanks for your thoughts & comments. I do indeed need to look at updated plotter and software capabilities to increase available AIS benefits. Ensuring Class B display is a big issue as is some level of target suppression. Sorting through AIS targets to find those of �high� value, i.e., those I really need to pay attention to, I often feel like a �homeless� guy going through a dumpster to find a cheeseburger. Suppression/Filtering, done right, would be a very good thing.

While I can state without hesitation that genuine value accrues aboard s/v Horizons through access to other vessels AIS data, it is not possible to assess or know exactly what goes on aboard the other guy�s boat without assuming facts not in evidence.

But a few assumptions, and a bit of logic would suggest that anyone who could receive our AIS (whether full capability or a �receive only� guy) would not hesitate to consider our presence during his navigation. The opposite needs no assumptions � no one is ever able to consider the AIS information of a boat that does not transmit.

AIS is indeed in transition � I believe its usage will increase as people come to be familiar with its safety and other benefits. Fifteen years ago, people were still navigating with LORAN. Try to find a boat today without a GPS.

Posted by: John Hallinan at October 10, 2009 4:08 PM | Reply

Richard: Head in the mud manufacturers will deliver what the market demands, or they will leave a nice fossil. N2K is not due a replacement any time soon, and proprietary networks are a manufacturer's pipe dream, blown away by morning.

I'm guilty of owning a class B AIS and not transmitting, I need to reconsider my reasons.

Posted by: Sandy Daugherty at October 10, 2009 4:48 PM | Reply

Richard C, the NMEA AIS PGNs were finished last summer, but as far as I know neither Navico/Simrad nor Raymarine has offered the software updates needed to make their N2K Class B transponders send the new Class B Static Data PGN out on the N2K network. Some MFDs may also need updates to understand that PGN (heck, some like Raymarine and Furuno need updates to understand any AIS PGNs).

I'm quite dubious regarding the statement, "some manufacturers are dropping their plans for making this transition to N2K." The latest MFDs from Garmin, Raymarine, Simrad, Lowrance, and Furuno all support NMEA 2000, and their latest small plotters and dual function machines do as well. In many cases, the latest sensors, autopilots, vhf radion, and instruments from the same leading manufacturers also use NMEA 2000, often exclusively.

This means that more and more installers, do-it-yourselvers, and regular boaters are learning how robust, easy, and flexible the Standard really is. I think that manufacturers who don't adopt N2K are taking a serious risk of getting left behind.

That said, an AIS transponder is one device where NMEA 2000 is less critical, particularly at the moment. The 0183 connections they all have work better with MFDs than N2K right now, and 0183 is the only route to a PC charting program. That will change.


Posted by: Ben at October 10, 2009 5:17 PM | Reply

To answer the questions about why AIS transmitters require a dedicated GPS, it is because an accurate time signal is required. The time signal is used to align the transmit time slots. The 0183 ASCII strings have lots of jitter so, GPS units for timing purposes have PPS (pulse per second) outputs accurate to 1 microsecond, or even 10 nanoseconds, of the start of the second.

Jon

Posted by: JonM at October 10, 2009 10:24 PM | Reply

Amen to George R's observation that AIS will show the tug but not the barge (and the danger is not obvious) .

My office overlooks central Puget Sound and tug/stern-tow barge traffic is continuous. Bringing up the local AIS feed from marinetraffic.com on the desktop confirms that the tug's ship icons seriously under represent the actual situation.

Its only a matter of time before a fog bound novice mariner with AIS is going to cut in behind a tug based on his chart display only to find himself hopelessly ensnared in a steel hawser with a massive barge coming up fast soon to run over him, his family and his boat.

Tugs underway with stern tows need a different icon.

Posted by: Bob at October 10, 2009 11:56 PM | Reply

Ben,

If my Furuno FA50 Class B AIS Transponder is using Ethernet to connect my system, what advantage does NMEA2000 offer? My dealer told me I don't need it with my Furuno vx2 system and there is no advantage. In fact, he told me it is actually more reliable this way and not dependpent upon an MFD to translate the data directly to my PC.

Let me know if I am missing something by not having NMEA2000 AIS PGNs in my network.

Richard

Posted by: Richard at October 11, 2009 6:38 AM | Reply

Richard, I think a Furuno FA50 will work fine with your vx2 system via Ethernet, but understand that Furuno is using Ethernet in a proprietary way. If you want to use something other than MaxSea on your PC, you'll have to use the FA50's 0183 output. Ditto if you want to use another manufacturer's MFD, even if it has Ethernet.

In fact, I think you could make a case that any Class B transponder would work pretty well. They all come with dual 0183 outputs -- one RS-422, one RS-232 -- so it's fairly easy to feed target info to independent MFD and PC systems. The MFDs typically bridge the data up to proprietary Ethernet to share with brethren MFDs on the boat.

NMEA 2000 is an extra and optional AIS interface at this point, but it sure is nice when, say, you plug a new Simrad NSE onto a backbone and it just gets the AIS data coming from a Raymarine AIS500, no friggin with little 0183 wires. It's also an easy way to get heading info to the transponder, which isn't mandatory, but will make your boat lay right on other AIS screens when you're anchored or docked (i.e. without realistic COG). I'm sure Furuno takes care of this via Ethernet, but on Gizmo it's happening across brands.

Finally, if and when we get a Third Party Gateway, PC software that takes advantage of it will be able to see AIS and all the other standard data on a backbone via one reliable pipe, no messing with multiplexors, multiple inputs, etc.

Posted by: Ben at October 11, 2009 9:21 AM | Reply

I agree that tugs with tows aren't well represented via AIS, but I wonder if IMO or others are working on it. I wrote once about how Jeppesen's river pushboat ECS deals nicely with this issue, changing a tug's AIS dimensions to correspond with the barges rafted in front of it.

http://www.panbo.com/archives/2006/12/jeppesen_ecs_ais_to_the_max.html

This is a tricky area. I think an adept tug captain could go into his Class A AIS and change the dimensions relative to the GPS antenna so his/her target scaled to, say, the 1,000' of water actually occupied by the tug and tow. But that might not be legal; plus every day we see info errors that have been entered on Class A's by professional crews.

Posted by: Ben at October 11, 2009 9:42 AM | Reply

Rats! I opened Ship Finder this morning and it's no longer showing AIS targets north of Cape Cod. This could be a temporary glitch or it could mean that what I thought was a private, subscription-only feed still is, and only got on Ship Finder by mistake. It's even possible that this Panbo entry caused the change!

At any rate, please treat the screen shot at top as an aberration until I know more. Also note that the data in the free version of Ship Finder is quite old; it's just a demo.

Posted by: Ben at October 11, 2009 10:08 AM | Reply

The AIS "Ship Type" field does include an entry for "Towing and length of the tow exceeds 200 m or breadth exceeds 25 m", but you would be foolish to rely on this being correctly entered in the static provisioning. You will be lucky if you see "Tug" in the shiptype field.

I have seen both tug and tow with their own AIS transponders, but this was probably not your standard barge.

You know, a tug and tow will show up as two separate targets on a radar screen, and the cable will be invisible. The moral here is that if you can't visually confirm a questionable AIS or radar target, you need to proceed with all appropriate caution. This is not a "problem" with AIS (or with radar), but with our training.

Posted by: Paul at October 11, 2009 12:47 PM | Reply

At least with radar you "see" the second target when you are close enough that it matters and no one in their right mind would consider trying to make it through that gap . . . sorry, did I say that? Anyway, good comment on putting transponders on barges. I wonder if a cheap, generic ais transmitter could be developed for barges? Tugs that do stern tows could have a few in inventory and then just toss them onto the barge before getting underway? Or perhaps the owner or loader of the barge could handle it? The device wouldn't need receive functionality and could likely be an unregistered class B type device? Essentially a dumb beacon?

Posted by: Bob at October 11, 2009 1:18 PM | Reply

Ben: My $200 premium for Class A is an educated guess. If we assume that the cost of goods is about 50% of retail, then $200 buys $100 in cost of goods.

The difference between a black box Class A and Class B is software, compute power and RF power. There are no displays, no additional connectors and no UI components. Black box units don't have fancy industrial design or hard tooling, they can use off the shelf packaging. Other than a few analog components for the RF and power supply, we're mostly talking about silicon and software.

Software gets amortized over all the units and may well be available from a third party (like most comm protocol stacks). Let' say that the additional s/w and increased analog components costs $25 / unit. $75 buys an awful lot of incremental silicon compute power and Moore's Law says it buys twice as much 18 months from now.

There may be business or marketing reasons for more than a $200 premium, but I don't see it as a product cost issue.

Posted by: Russ at October 11, 2009 1:38 PM | Reply

"The difference between a black box Class A and Class B is software, compute power and RF power."

I think there's more to the differences than that, Russ, and more to overall AIS technology than most people realize. Without more research into what's actually required inside a transponder, I believe your speculations are quite speculative.

Posted by: Ben at October 11, 2009 1:51 PM | Reply

Russ: I think you misread my comment when you wrote I was "shockingly hypocritical". I refuse to purchase an AIS receiver to fill the gap until I afford a transiever.

I was going to purchase a transiever this winter, but now I lust for the new Raymarine HD radar Ben evaluated, lighting, and other upgrades for my entire mast.

Posted by: Dan Corcoran (b393capt) at October 11, 2009 11:36 PM | Reply

Ship Finder is great, in theory, but it's full of bugs. The feed and even the app itself is prone to crashing. I plan on waiting for a true AIS solution for my iPhone, not one using hobbiest's data.

Posted by: Aaron at October 12, 2009 12:44 AM | Reply

Dan, I agree that the usefulness of AIS will be enhanced as more vessels become equipped with transponders (ignoring the "too many AIS targets" argument for now). This is one reason that I ultimately removed the receive-only unit and installed the transponder.

It's like radar and radar reflectors. If we all had radar reflectors, but nobody had a working radar, the reflectors would be pretty useless. If we all have AIS receivers, but nobody transmits, then the receivers are also useless.

Of course this analogy breaks down a bit, given that the big ships are mandated to have AIS, but I think the golden rule (the "do unto others" one) isn't a bad principle here.

However, if you can't see spending for a transceiver, you really ought to consider a receiver. You can re-use much of the installation once you do get the transponder, and in the meantime you will have the significant advantage of having AIS, and just as important, learning how to use AIS effectively. This is one of those technologies where practice and time spent with the system can make a big difference.

There's no reason, other than budgetary, for you to deny yourself a valuable safety tool just because your philosophy suggests that a transponder is preferred. If you install nothing, the other vessels still won't be receiving your (non-existant) AIS transmissions. Installing a receiver hardly makes that situation any worse.

Posted by: Paul at October 12, 2009 4:11 AM | Reply

Paul, excellent analogy !! (aside that many radar reflectors spend the entire season deep in a locker)

Right on about the golden rule!

For the second part about installing a receiver "hardly makes it worse", well I feel I don't have a choice as it is a pet peeve of mine that people buy receivers (especially when they buy it for reasons like "I don't want big brother watching me", "I get most of the AIS benefits at a fraction of the price", and "I'll buy a transiever later when more people use Class B in my local waters") and I would agree with Russ (if he would had read my comment correctly) that it would be "shockingly hypocritical" (See first Russ comment above) if I used a reciever to fill a budget gap.

In the meantime I actually do use a nifty radar reflector, and you will be able to read about it if I ever find a print magazine to publish it.

Cheers

Posted by: Dan Corcoran (b393capt) at October 12, 2009 8:59 AM | Reply

I installed my FA30 receiver before Class B was available. I'm not throwing out a $1,000 box after one season.

If it was just a matter of swapping out black boxes, I might be tempted to install a Class B. Unfortunately even staying with Furuno, upgrading to the FA50 requires running new wires up the mast for the GPS antenna. If I go with another brand, I have to run the GPS antenna cable up the mast, and then NMEA183 back to 183 Pas-Thru box. Upgrading to a transponder is yet another project.

Given the work involved, I'll wait and hope someone is makes a Class A black box with an N2K connection, lower price and lower power consumption. The next 12 months will be receive only, then 6 months to sit out cyclone season. 18 months is a full product cycle in the semiconductor world, perhaps good things will come to those who wait.

Posted by: Russ at October 12, 2009 12:51 PM | Reply

Russ, I don't think there's any need to put a GPS antenna high on a mast. They can get plenty of sky view from a cabin top or rail or spreader.

Posted by: Ben at October 12, 2009 1:49 PM | Reply

Sorry for the misunderstanding, I would use the Furuno combined antenna on my first spreaders where the FA30 antenna is currently located. But it's still a new wire to feed up the mast and out to the spreaders.

No cabin top or push pit antennas allowed on New Morning.

Posted by: Russ at October 12, 2009 6:59 PM | Reply

Last Monday nite going into Newport RI a very large cruise ship (over 1000 ft) was going out as I was coming in. Lots of chatter over ch 13 at to where she was and me in my little 37 ft and AIS transponder on calls the ship and says do you see the Sally W. He says yup and I say we will keep to the far right in the narrow Newport channel and he says thanks for the info. So I know one big ship that is seeing class B.

Posted by: Allan Seymour at October 17, 2009 10:33 AM | Reply

Ben the Iphone app is working up the New England coast again! It is a good way to see if your boats AIS transponder is really putting out a signal. I had some fun while going from Portsmouth to Haddam CT last few weeks. It seems the Cape Cod Canal controller couldn't see the boat name and later a tug couldn't see it either. West Marine says their software needed updating. But there was the boat name on the Iphone app....go figure.

Posted by: Allan Seymour at October 20, 2009 9:49 AM | Reply

Right, great to have the feed working again. I can see my brother-in-law (M/V Brilliant) in his slip in Barrington, RI, almost ready to go south.

The tug and the CCC controller need their AIS software upgraded; yours is fine. Hope that's what you or West meant by "their" software.

Posted by: Ben at October 20, 2009 11:02 AM | Reply

Here is my translation: If a vendor says "Our products will never support NMEA2000 and everyone else is canceling their plans to", this is business speak for, "We don't have any NMEA2000 ready to sell, so we have to tell you something to convince you to buy the old stuff we do have." It is sales 101.

Just look at this thread and you will see the demand for NMEA2000 abounds. A vendor who cancels their 2000 plans would be canceling their business plans. It's FUD. Don't reward them with your money to deliver out of date technology.

Posted by: Andy at December 17, 2009 3:08 AM | Reply

Russ:
I've been involved with the design of both Class A and Class B transponders and I can tell you that the bill-of-materials cost of a current Class A is about double that of a Class B. The hardware differences between the two ARE substantial.


...and the software is considerably more complex too...

Posted by: del at December 17, 2009 4:20 PM | Reply

Leave a comment