Yesterday I fired up this sample Simrad AI50 Class B AIS transponder and found it to be pretty much as self-contained and impressive as I'd hoped. I attached one of my boat's VHF antennas, deployed the AI50's included GPS antenna, gave the unit a little 12v juice (just 8 watts at 100% screen brightness), and, voila, Gizmo was transmitting its position and plotting other AIS targets, including another Class B I had set up as "Panbo.com Lab". A full AI50 entry will follow, but first I'll report on its SimNet/N2K output. I was excited about how easily NMEA 2000 could feed the AI50's target and GPS info to all devices on the network, but nervous about that how well 2000 currently handles the data (nobody has yet tried it much). Both feelings were justified...
After METS 2007, I wrote about how many new AIS products Comar had in the pipeline. Well, this U.K. company hasn't slowed down, and has even developed a snappy new logo and Web site. Comar's latest is this AIS-Multi, which seems like quite an able AIS listener at $399 (from U.S. distributor Milltech Marine). It features true parallel receivers, so slow Class B updates will plot as well as they can; an amplified VHF splitter, so you don't need to add another antenna; USB data output, so you can connect it to a modern PC without needing a serial converter; and, finally, the ability to multiplex in NMEA 0183 data at 4800 baud (GPS most likely), so the unit's 38,400 baud data output can be easily used with a plotter whose NMEA 0183 port was already in use (and the PC will get it, too). But...
Ever since I realized that the free Siitech.com AIS pro web viewer can count and/or filter AIS types, I've been using it occasionally in an attempt to gauge the spread of Class B in the USA. You may recall the day last October when my Li'l Gizmo was the only Class B to show up on the whole East Coast (or at least within range of a certain mix of listening towers). And, frankly, I haven't seen many B transponders in US waters since then...until today when there were six in the general New York area, almost all underway. And, surprisingly, some were being seen well offshore, in fact way offshore...
Thanks to Sandy Daugherty over on the Forums, I now know that JRC has introduced a VHF radio series that can easily make direct DSC calls to AIS targets. They are most definitely big ship radios (see diagram below), and they do AIS calling in a way I hadn't anticipated, but still...
I wished I'd clicked on one of those AIS targets before I took this screen shot, so you could see how CE 2009 displays their properties, but our focus (after the reboot affair) was on crossing the Boston shipping lanes in pitch dark and with enough true wind on the beam (reported right at the boat icon from the PB 200) to bounce us around a bit and deposit salt on our windows. Thank goodness for AIS. The 277 meter S/S Explorer was lit up like a Walmart super store, and would have been intimidating if we weren't confident that she was anchored or moored. It was also nice to easily speak with the bridge of the Haruna Express and learn that they could see us fine on their AIS display. But the best AIS moment came a little later, when a passenger ship exiting Boston hailed us by name on channel 16 to discuss our passing situation. So what the hell are cruisers talking about when they presume that Class B AIS has little value around big ships?...
In the screen above I was testing Coastal Explorer 2009 with AIS target data coming in from a shore receiver network via an IP feed. It was neat to watch the pilot boat rendezvous with a ship inbound to Narragansett Bay, and it showed off CE's ability, like NavSim's, to dead reckon targets (note how it's using COG, not heading), as well as track them and pop up useful info with a mouse click (or finger tap). But good data and good data presentation like this could be used for very bad purposes. Despite all the discussion of Somali pirates last week, I didn't hear anything about whether or not they use AIS to rendezvous with their targets...but I'm not surprised that they do, and that the crews thus exposed are pretty pissed off about it!
At the Miami Boat Show, NavSim Technology was showing some neat AIS plotting features, and yesterday I got them to send some illustrative screen shots. In the lower right "secondary chart view" above you can see how NavSim uses yellow, green, and red target icons to show moored, moving, and dangerous vessels (a full explanation of AIS icons here, and special Class B icons are coming soon). You can also see how a user can set an AIS Filter Range, which doesn't actually eliminate any targets but does reduce them to dots (sort of like IMO "sleeping" and "active" targets). In the main chart window, you can see what happens if a target's CPA and TCPA violate user set minimums; the Alert pops up along with red and purple "ghost" icons depicting the target and your vessel in the worse case scenario (i.e. at the Time of Closest Point of Approach). And there's more...
If I understand the timing correctly, about when Raymarine starts shipping its new AIS 500 Class B transponder in May, it will also offer software updates for A, C, E, and G Series MFDs that provide some AIS plotting improvements. On top of the list is "buddy tracking", which I consider a valuable feature, though the term -- used by several manufacturers -- is a bit misleading. The idea is that when you see an AIS target that you might see again, and care about -- be it a friend, or a local fishing boat that sometimes seems like it's driven by zombies -- you can save its name and MMSI in a little database kept by your MFD or charting software. Then...
Thanks to an angelic Panbot, I've now read pertinent sections of IEC 62388, a.k.a. "Maritime navigation and radiocommunication equipment and systems -
Shipborne radar - Performance requirements, methods of testing and
required test results." It's a hundred pages (preview PDF here) laying out in great detail the minimum requirements for how all new radars going on SOLAS ships will perform and present data. Perhaps most important among many mandated enhancements is the treatment of AIS targets, Class B included, putting them on essentially the same level of safety value as radar targets. I think these standards are good news not only for the bridge teams on big ships, but also us little guys who sometimes travel amongst them (despite the consternation that came up yesterday)...
Given the new C Series Widescreens and ST70+ displays, and my mid-week absence (moms happen!), let’s just call this Raymarine New Stuff Week. Behold the AIS500, which just may be the easiest-to-integrate-into-your-system Class B transponder yet. That’s because, like Ray’s AIS250 receiver, it has an NMEA 0183 multiplexer and a VHF antenna splitter built right in. Note that splitting 25w VHF and 2w AIS transceivers is more complex than just sharing a VHF with a receiver, and to date only the Digital Yacht SPL250 claims the ability (and seems to work well in my testing). And that’s not all…
