Channel Ribs
New member
Crikey, this is an old thread!
I have just fitted a class B unit both for receive and possible assistance that I can get from the broadcast side. I accept it may not be perfect but who knows - it might help a merchant ship see me even if late in the day.
. . . . . Three years on and we have still not fitted it to any of our boats, as I said back then there are other things above it on the list.
I agree power drain is not a major issue but the average transceiver uses about 0.5 Amps in transmit mode and 0.2 Amps in receive only mode.
More to the point a friend of mine is a Thames pilot so he sees the bridges of more big ships than most and he confirms that only a minority of ships have their AIS receiver linked to their Radar/Nav screens. For most it is a minimum keyboard device at the back of the bridge which they consult only when they want the MMSI of a target they have aquired on radar.
If you can afford both an AIS transceiver and a radar transponder fine. However, if its a question of one or the other why spend money on a transceiver you know will only be seen by a minority of ships when you could spend less on a radar transponder that will will be seen by the majority?
Agree for the time being. But then, where would you put it on a sliding scale versus a See-Me?
who was talking about narrow waters - not me - and yes I would hazard a guess that 14 years of watchkeeping at sea all round the world would probably give me some knowledge.
So you don't bother switching your lights on because so long as you can see other vehicles, there is no need for them to see you?My philosophy on a boat is much the same as in a car.
One of the most fundamental of the colregs is the one that requires all vessels to keep a proper lookout by all available means. For a ship's watchkeeper to arbitrarily choose to ignore his AIS just because it's "one o' they 'lectronickery things" is unprofessional -- criminal, even. I don't disagree that some do -- but AIS has been around for a good few years now: bridge displays are getting better, and watchkeepers are gradually getting used to it. A growing proportion of watchkeepers will never have been to sea without it: for them, it is as much a part of standard bridge equipment as radar.I am sure some merchant ships are well manned but bloody sure some aren't too! AIS B is the latest whizz bang.
At least it doesn't rely on smoke and mirrors like radar reflectors! AIS B does work. Radar reflectors do not. Even the MAIB, after the Ouzo collision, failed to find a single commercially-available radar reflector that met the basic minimum performance standards.It relies on many assumptions that are not particularly well founded
There is no such thing as "right of way" at sea. Telling people "I am here" is not the same thing at all.rather than broadcasting "this is me and I have right of way" In fact I have always thought that was an ideal tombstone inscription.
There is no such thing as "right of way" at sea. Telling people "I am here" is not the same thing at all.
My choice would therefore be (and is) AIS receiver only plus SeaMe. No one device does everything and its an individual choice what you invest in, but the original point that Talbot made was that it's far better to have really good information yourself to know how to aviod trouble than to rely on others seeing you.
Lets do a side by side comparison then....
AIS B:
Cost - c420 including backup VHF antenna.
You always seem to need an NMEA mux to interface to your plotter, which is another £100+ on top.
On another issue, would a timer on the 'transmit' function be an idea on class B Units? So e.g. it only transmits for an hour or so after pressing a button, to stop overwhelming numbers of tracks.
MD
Most now have NMEA out which goes straight into NMEA in on the plotter. Most class B's I think have an on and off button so you can stop broadcasting when there is no need.