AIS B

[SolentPhill]

anyone got this is it any good, is it worth having? am told most bigger ships filter out clutter inc AIS B.

will it show on standard AIS receivers or do you need a separate receiver?

Cheers

Phill

 

[Hurricane]

I have a Comar one.

I believe that most AIS receivers will pick up a Class B signal but dont forget that Class B is given a much lower priority than the Class A stuff.

The only time that we have any experience of ours working was when we were passing Cabo de Gata last autumn. Our VHF DSC went off. It turned out to be the Spanish Coastguard calling us - they had obviously seen us on the AIS and wanted to know who we were. Class B AIS has only bee out for about 18 months so they had probably never seen one before. We had a fairly quick VHF conversation with them and that was it. A patrol boat was nearby so maybe we would have been boarded if we hadnt been transmitting AIS - who knows?

There is obviously no immediate need for everyone to rush out and buy one of these systems but it does give you a good feeling that you've done just a bit more to help the big traffic see you.

BTW - to install a full Class B transponder, you need a separate GPS feed dedicated to the AIS and you will also need a good (preferably separate) VHF antenna. Also these units operate as an AIS receiver so it would be a bit silly if you didnt incorporate a NMEA feed to your plotter for your own use.

 

[gjgm]

I ve looked into this a bit- as in transmitting too?
I think it depends just how often you are likely to be caught out in poorer weather. Of course, it can spring upon you, but if you hope to avoid being pranged by a rib in the Solent in fog, it probably isnt going to help.
I think receivers are quite popular with saily types bcz, of course, moving slower,they have less time to get out of the way of fast moving commercial shipping, so any advance warning helps.
I ended up wondering who would be receiveing my signal, and what would they do about it, and concluded my concern was large shipping, and to that end, receiving AIS was enough for me. If I spent my life blatting across the channel , maybe I d reconsider, but most of my boating is isnt offshore, and in poor weather, and I wasnt convinced transmitting was such a big step up from receiving only.
I mean, its mainly of use when you cant see a vessel, and in that situation, is another leisure vessel, say, receiving AIS anyway?
So having yesterday ordered a Comar unit, I was told, out of stock /forums/images/graemlins/shocked.gif

 

[Ballistix]

I've got the Digital Yachts one and it's brilliant. Hooked in to my Garmin 525.

 

[Tallulah]

Just fitted one, it seems a good idea to me given that anything that increases the visibilty of your boat to other vessels has to be a good idea. I notice an increasing number of leisure boats in the Solent with AIS B transponders. Some boats leave them on all the time as a means of monitoring their own boats position (I note for eaxample there is a Princess V42 in Haslar Marina "Charlie 2" that transmits constantly) You can monitor both AIS A & B transmissions on the free WEB site at:

http://www.ais-live.co.uk

Not sure how busy the plotter screen will get when we've all fitted one though! (I use a Raymarine plotter to display AIS data)

 

[Ballistix]

They only usally populate the immediate stuff around you 1.5-4 miles or so thus preventing saturation.

 

[jfm]

I too have the comar one.

1. The comar has a pair of terminals for a remote switch to turn off the transmit function. So you can hide the unit away, and fit your own OEM looking switch on the dash. This is handy, cos they're ugly units and you wouldn't want to see them. The digital yachts one is also ugly but I think it doesn't have the remote switch terminals, in which case the comar is the better one to buy imho

2. I plan to have my transmit turned off 99% of the time. On the delivery trip Essex-Soton of my boat last week we went in convoy with a phantom 40 and he left his comar on transmit. He was called by Dover and Solent coastguard (by name on ch16, rather than DSC) and asked to say who he was and where he was going etc. Totally pointless disturbance, better to turn the thing off except in poor vis, offshore, or when you want to let your mates know where you are in a busy anchorage.

 

[Hurricane]

The comar unit also comes with some PC software that mimics the front panel of the Comar unit.
This means that you really can hide it awaqy and plug in a PC when you want to see what its doing.

I've gone a step further and prmanently wired it into the boats fixed PC. The interface also provides an entirely separate NMEA GPS feed into whatever you want. I use it for logging position etc. during a long passage.

 

[jfm]

Mimic software? That sounds like a solution looking for a problem

You are much more computer-understnading than me so I'm being tongue in cheek, but a luddite like me is happy with the Comar tucked away out of sight, never seeing its LEDs, and just an OEM switch on the dash to disable the tx function!

I agree with you that the GPS is useful though as a back up. I use it in a more simpleton way than you: it just goes to the Raymarine gear via a switch, which I'll operate if the mushroom GPS on the mast fails. Actually I think you can select/deselect if from the menus, and if you leave it all activated the Raymarine gear listens to the Seatalk position in priority to the NMEA0183. So yes, a good back up arrangement.