On 2008-05-25 11:55:34 -0400, " said:

Assuming the chart on this page
http://www.shinemicro.com/AISoverview.asp is right, B looks ideal for
small boats. The cost is rumored to be 1/3 that of A which seems
significant, too.

The "A"-only items on the chart couldn't be useful on boats our size:
Destination, ETA, rate-of-turn....

--
Jere Lull
Xan-à-Deux -- Tanzer 28 #4 out of Tolchester, MD
Xan's pages: http://web.mac.com/jerelull/iWeb/Xan/
Our BVI trips & tips: http://homepage.mac.com/jerelull/BVI/

Tom,
I'm not sure what the B has, but the point I am making is the A is approved
the B is not. The A transmits 25 watts the B 5. The A has its own dedicated
GPS. I don't know if the B does as well. Just because the A can xmit those
data items that are related to large vessels, does not mean you have to
include them. I believe it is also possible to xmit at slower time intervals
as well, but I will have to check the manual. I bought a new demo model
Simrad A for $1200 lst year on eBay.
Steve

wrote in message
...
On May 24, 10:27 pm, "Steve Lusardi" wrote:
My position is that if
you think you need AIS, Class B makes no sense at all. Class A gear is
not
that much more and is much better plus Class A is approved everywhere and
although discouraged for yacht use, it is not prohibited.

Steve,

If you're right about the FCC approval the question is moot. Still,
class B gear looks ideal to me. What does A do that B doesn't? I've
looked at some web pages but don't really have a great understanding
of the differences. Assuming the chart on this page (http://
www.shinemicro.com/AISoverview.asp) is right B looks ideal for small
boats. The cost is rumored to be 1/3 that of A which seems
significant, too.

-- Tom.

On May 25, 11:23 am, Marc Heusser
BTW: Here is a website with live AIS tracking - tankers, passenger
vessels, rescue boats, pleasure yachts etc

http://familjenhakansson.se/html/ais_live_kiel.html


Thanks! Also, since I'm in the bay area new (http://www.boatingsf.com/
ais_map.php). There are others, too. Just looking at the sf one I
notice that some vessels are showing bogus data. That's a little
worrying...

-- Tom.

On May 25, 12:28 pm, "Steve Lusardi" wrote:
Tom,
I'm not sure what the B has, but the point I am making is the A is approved
the B is not. The A transmits 25 watts the B 5. The A has its own dedicated
GPS. I don't know if the B does as well. Just because the A can xmit those
data items that are related to large vessels, does not mean you have to
include them. I believe it is also possible to xmit at slower time intervals
as well, but I will have to check the manual. I bought a new demo model
Simrad A for $1200 lst year on eBay.
Steve

Thanks. All good points and that price is in w/in my pain threshold.
For us low power use is a major so 5w every 15 seconds is going to be
better than 25w every 10. A bit more googling has brought up the
possibility that B units might not be received by some older AIS's or
might be filtered out. Also, B seems stalled at the FCC... Which
leaves me thinking of spending say $800 on a receive only system, or
~3.5K list for an A system (plus power issues) or seeking out a deal
on eBay... The mind boggles. But thanks again for the input.

-- Tom.

On May 25, 9:58 am, jmr wrote:
Hi Tom,

You probably already know this, but even with a class B transponder
you'll still need some way to display received info.

Good point. The Verper unit plus a pc for close calls is what I'm
thinking of now.


The multiplex receivers work well and work much better than the single
channel units. But they may only deliver every other message (if the
ship is transmitting every two seconds, they deliver data every four).

Right, but I'm worried a little that they need to get a complete
sentence/packet (not sure of the system details) and I wonder if they
couldn't find themselves missing many packets because of bad timing.
Does the protocol take care of that somehow?
....
When looking for a display I'd recommend seeing if it computes CPA, how
many targets it can handle and whether its AIS receiver can be upgraded
later to a class B transponder when they become available.

Yes CPA/TCPA are the big selling point for me. One reason I don't
like the NASA AIS Radar is that you get to plot that on a tiny PPI.
Not all the units I've looked at mentioned the number of targets they
could track. I think the AIS system has some kind of filtering built
in. Is there a problem w/targets getting dropped?

Cheers,

-- Tom.

" wrote in news:29390dea-fb19-4e8c-
:

Yes, we're in the Bay Area right now. Planning to go to Mexico in the
autumn and the rest of the S. CA coast in between now and then.

-- Tom.



Very nice!

These cheap AIS transponders are, most of them, still awaiting FCC
approval for US sales. I don't know what would happen if you were a US
Flag vessel and had an unapproved unit transmitting aboard, but I suspect
it wouldn't be cheap if FCC found out, assuming you have a Ship Station
License, of course.

The USA is dragging its collective ass very hard on AIS because it's a
European invention forced upon them by the ITU by the other nations.
There's still no real CG response to AIS and I don't think any fixed
station AIS installations I know of in the USA to put emergencies, notice
to mariners, etc., which all should be broadcast from every harbor in the
country.

It's really too bad, too, as the whole marine community would benefit
from seeing the REAL location of all those bouys they moved because of
the sand bar shifting last month.....instead of the useless charts which
never get updated for years. An AIS shore installation could be sending
you the exact location of every hazard and all changes to navigation you
need to know about in the area.....but they don't. How stupid.

"Steve Lusardi" wrote in
:

I think I have mentioned this before, but it is not at all certain
that Class B AIS will ever be approved in the US. Perhaps Larry has a
better insight to this, but that's the rumor I keep hearing. My
position is that if you think you need AIS, Class B makes no sense at
all. Class A gear is not that much more and is much better plus Class
A is approved everywhere and although discouraged for yacht use, it is
not prohibited. Steve


I've been told the commercial shipping interests are trying their best to
keep all the non-compulsory boats off the AIS system, what there is of it
in the technology backwater the USA has become. I think this is why all
the footdragging is going on at the FCC and USCG. They don't WANT to see
your 40' sloop on their AIS displays.

Of course, they'd rather you never left the dock, either....(c;

" wrote in
:

On May 24, 10:27 pm, "Steve Lusardi" wrote:
My position is that if
you think you need AIS, Class B makes no sense at all. Class A gear
is not that much more and is much better plus Class A is approved
everywhere and although discouraged for yacht use, it is not
prohibited.

Steve,

If you're right about the FCC approval the question is moot. Still,
class B gear looks ideal to me. What does A do that B doesn't? I've
looked at some web pages but don't really have a great understanding
of the differences. Assuming the chart on this page (http://
www.shinemicro.com/AISoverview.asp) is right B looks ideal for small
boats. The cost is rumored to be 1/3 that of A which seems
significant, too.

-- Tom.


http://uscg.mil/nais/description.asp
I just stumbled onto this government monstrosity....as usual.
CG says it should be implemented by 2014 after AIS has been replaced by
the next generation of navagational electronics from some other
simpletons.

The contractors must be very proud. It'll buy them houses and cars and
vacations in exotic places for another decade or two......while mariners
die who could be saved by a SIMPLE AIS shore station setup like:
http://www.shipais.com/index.php
which now covers ALL OF ENGLAND, SCOTLAND, WALES and about half of
IRELAND. The software ALREADY exists, but let's not let that bother our
bureaucrats spending millions to reinvent what's ALREADY UP AND RUNNING!

http://www.shipais.com/currentmap.php?map=folkstone
Wow! Look at the CHANNEL TRAFFIC!

" wrote in news:d88f5712-bcf7-4aba-
:

What does A do that B doesn't?
http://www.panbo.com/archives/cat_ais.html
Panbo has an excellent handle on current AIS tendencies to answer your
question.


But, if you're very adventurous, the FCC can addle your brain in minutes:
http://fjallfoss.fcc.gov/edocs_publi...-07-2597A1.txt

And, of course, you ALREADY have a copy of:
http://www.access.gpo.gov/nara/cfr/w...7cfr80_07.html
as required by your Ship Station License.....right?
.....and you've read it all, carefully, and are in full compliance, as
required by law with heavy penalties.....right?


To see lots of the political wrangling and foot dragging going on,
including the little problem of the FCC bureaucrats ALREADY selling one
of the AIS channels to Maritel Communications they shouldn't have, look
on this list:
http://search2.fcc.gov/search/index.htm?
job=search&site=fcc_all&q=AIS&Submit+search+reques t.x=0
&Submit+search+request.y=0&Submit+search+request=S ubmit

or better yet:
http://tinyurl.com/5noy3x

The political nonsense involved didn't help the Capt Joe's survival,
which was credited, partially, by her AIS transmissions even before the
crew called for a Mayday. Panbo quotes APA.com saying:

"“The fishermen had an ‘automated identification system transponder’
aboard their boat. While that transponder system sunk with the Captain
Joe, the signals it gave out before the vessel went down helped the
rescue crews find the boat's last position.” We don’t normally think of
AIS being used that way, and I don’t know the details, but I can easily
imagine how the rescue center could use some sort of Internet based AIS
tracking system, or maybe their own receivers, to get good position data
before the fishermen even fired off their EPIRB.
For me, this news was ironic on several levels. Just last week I
learned that Class B AIS isn’t even on the FCC’s March 19 agenda, meaning
that this Capt. Joe type rescue aid remains unavailable for most boaters.
(However, I also heard that at least one commissioner has already signed
the ruling—a meeting isn’t even necessary—so maybe this FCC travesty will
actually end soon.) Second, before hearing about Capt. Joe (thanks,
Jim!), I was already into an amazing book called Dead Men Tapping, and
hardly slept last night plowing towards it inevitable conclusion. The
book is not only an excellent profile of New England fishermen and
salvors, but also a wrenching tale of what can happen out there, and
hence why Class B AIS could be such a valuable collision avoidance tool.
(One reason the USCG wants reasonable-cost Class B expedited is so that
it can mandate them on commercial fishing boats.) But the book is also a
stinging indictment of the Coast Guard’s failure to perform well in this
and several other somewhat unusual rescue situations. I’d like to think
they learned something from author Kate Yeomans fine work. But whether
that’s true or not, you’ll likely approach disasters at sea a little
differently once you’ve read Dead Men Tapping."

.....once again showing the multi-bureaucratic bungling between CG and FCC
and other Federal bureaucrats and we STILL don't have an AIS transponder
for your boat, whether the big ships like it or not....

" wrote in
:

On May 24, 10:27 pm, "Steve Lusardi" wrote:
My position is that if
you think you need AIS, Class B makes no sense at all. Class A gear
is not that much more and is much better plus Class A is approved
everywhere and although discouraged for yacht use, it is not
prohibited.

Steve,

If you're right about the FCC approval the question is moot. Still,
class B gear looks ideal to me. What does A do that B doesn't? I've
looked at some web pages but don't really have a great understanding
of the differences. Assuming the chart on this page (http://
www.shinemicro.com/AISoverview.asp) is right B looks ideal for small
boats. The cost is rumored to be 1/3 that of A which seems
significant, too.

-- Tom.


The S/V "Dragonfly" is at sea doing 8.3 knots under sail, tonight.
Here's what you MIGHT look like, at some point years and years from now
in the USA:
http://www.shipais.com/showship.php?mmsi=235005213

Oops...got an update. She's up to 9.1 knots, now!

HEY, COAST GUARD! YOU WATCHIN' DIS BO'?!!