AIS, SART, and MOB SART Beacons

[Island Time 1,235]

I thought I'd just introduce a new product (for us) and outline some of the more recent changes in AIS for anyone who is interested.

 

AIS has been around for a while now. I'm sure you all know there are basically 2 types (for yachts), receivers and class B Transponders. Transponders send out your details, as well as receive those of other vessels. Typical range of an AIS transponder is 10-30 miles, sometimes more. They tell you where other equipped vessels are, their speed, course over ground, if they pose a collision risk, their callsign etc. All good, and well known so far? Oh yeah, and Transponders start at about $500 USD at the moment.

 

Now the newer bits. There are two new areas, SART and A2N. Sart is search and rescue transmitter (or Transponder). It is designed to locate vessels or persons in distress - like an EPIRB, but if you lose someone overboard with an EPIRB, how do YOU find them? Unless you have a 121Mhz RDF you are searching blind. So, if you have an AIS receiver or transponder compatible with SART, you can have a MOB SART in each lifejacket. The Man overboard triggers the beacon, and their position comes up on the AIS screen. Better units also have an alarm to bring the MOB/Distress to the watch keepers attention. No search, it gives bearing and distance to the person (or vessel), even making allowances for their drift. It's accurate to about 15m. See http://www.neptunes-gear.com/collections/electronics/ais-and-associated-products for our AIS products, go to page two for the MOB Sart. That's $180 USD, so way cheaper than a PLB. Also, if you have AIS that does not support the SART standard (or it does but the alarm is crap or non-existent) you can add the capability with the AIS SART Lifeguard.

 

The next thing to know about AIS is A2N or Aid to Navigation. A2N units can be on a bouy, light, wharf, whatever. They can give you all sorts of info - lights out, wind speed, state of tide - almost anything. For example, they are in use in the suez canal, and show the nav beacons on your plotter, with wind speed and dir. They are becoming more common, and, if buying a new AIS, you should make sure they are compatible with these now standards...

 

Cheers

Matt

[rigger 47]

Totally agree that people need to make sure that the unit they buy is up to date and complies with the latest standards.

 

Re AIS AtoNs

 

Screen shot taken today, the red diamonds are AIS AtoNs.

 

There are a good number of AIS AtoNs around NZ, the first were installed in Auckland on the Rangi Channel buoys when the new channel was altered (they were version 1 - some of the first in the world I was told). They had teething problems that ended in them being switched off for a year or so, reactivated in 2010 or 2011, memory gets fuzzy, after the issues were sorted.

 

Some Class B units cannot pick them up correctly.

 

If you are interested there are 3 main types last time I checked (ignoring the types of AIS method of

 

Real - an AIS AtoN in the actual place.

eg - Rangi channel buoys, Tauranga's A Beacon.

 

Synthetic - there is a marker there but the data comes from a transponder remote to the site

eg - an isolated danger mark that is prone to damage

 

Virtual - there is nothing marking the point and the data comes from a transponder remote to the site.

eg - a recent ship wreck, a place that cannot be physically marked say an underwater rock in an exposed location.

 

Note: a "base station" can transmit the data for a number of synthetic and virtual AtoNs so the distance that AtoNs can be detected from can vary greatly.

[idlerboat 116]

.....yep,

---and remember that AIS is not radar, and visa versa.

I am a bit disturbed to hear from some here that they are not going with radar because "why would they, they have AIS"..

They have very different abilities.

Dont get me wrong, I like AIS. It can take a lot of the guess work out of "situations".

But dont think it is without its problems.

Just like with radar, weather can play a part (but for differant reasons)

VHF radio which is what AIS uses can be shut down in severe thunderstorms.

That is, like with VHF the transmission and reception on those freq, can be limited for a short time. Not common, and becomes less as the vessels get closer, but dont treat it like a perfect video game where all the players are always displayed.

 

My sincere advice is to get radar first, get good at using it, and then add AIS....