On Feb 18, 2009, at 5:03 AM, 'bella wrote:
> if nothing else, its like google earth
(sorry to pull up an old thread, out doing some deliveries and just
dug this up) Umm, not sure I get the analogy. AIS (Automatic
Identification System) is, in a grossly simplified explanation, a
collision avoidance system that transmits on VHF freqs (Wiki link at
the bottom). What you're linking to is a mashup that misses most of
the good stuff (heading, SOG, COG, ROT, etc), and, ironically,
something that makes the IMO cranky (internet availability of AIS data
citing vessel security). There's Class A required by IMO for ships
with GT >300T and passenger ships, and Class B for everyone else
that's optional.
There's a lot of information/misinformation floating out there about
AIS (especially the newer B variant), but now one of my most preferred
bits to have on a boat especially in interesting weather. Hopping
from boat to boat and sailing some crappy routes/weather, you learn to
quickly miss it, if nothing else than having a name to hail some of
the big ones by (improving the odds of them actually responding from
zero to a coin flip). There's Class B receiver only and receiver
+transponder types available, including usb powered ones that plug
right into the laptop (receive only); the upside is they use very
little juice and provide a good bit of information. Not a golden BB,
but another tool in the toolbox. From talking to some pilots in
Brisbane, makes their life a little easier when they can hail us
"dinghies" by name. Have a usb powered receiver that's in my delivery
kit ever since using an onboard one in a cyclone near a shipping
channel (long story) when radar was effectively 'blind' due to weather/
sea state. For something the size of a pack of cigarettes and almost
no power, it's got a lot of bang for the buck and really good range if
hooked into the mast-mounted antenna. Ships show up on AIS long
before most radar out there. There are limitations, but nice to have
on board. YMMV of course...
http://en.wikipedia.org/wiki/Automatic_Identification_System
(more information out there, used as a summary)
Regards,
Dan
Singapore
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