AIS
I'll jump in on John's question about what exceeded equipment
expectations - AIS. The AIS receiver allows us to see the big guys at
great distances so we can focus the radar (more of the time) in closer
to see the little stuff better. We still scan in and out with the radar
range on a regular basis during watches, but AIS allows us to keep the
radar range shorter - great for limited visibility situations. We spent
the summer cruising in Maine and Nova Scotia, and the use of the
AIS/Radar as I've described made all those pea-soup foggy miles much
less stressful. (We have an AIS receiver only.)
I don't intend to offend anyone, but IMHO pleasure boats have no good
reason to clog the airwaves an AIS transmitter. Busy harbors fill the
screen with AIS targets and VHF 13 or the local VTS is swarming with
traffic, and the LAST thing people need to see is one more target. The
commercial folks are out there because they have to be, and their
tonnage and draft grossly exceeds the pleasure boat crowd. It's our job
to stay away from them, and not make their task more complicated and
dangerous by cluttering up their screens with 50' pleasure boats.
We're seeing a disturbing trend of more small (relative to commercial
ships) pleasure boats getting AIS transmitters and it's not a good
thing. Stick with the receivers only, please!
Robin Roberts
MV ADVENTURES - DeFever 49 RPH
On Oct 25, 2008, at 7:05 AM, Robin Roberts wrote:
We're seeing a disturbing trend of more small (relative to commercial
ships) pleasure boats getting AIS transmitters and it's not a good
thing.
Actually I'll have to disagree with you on this one. When I did my
trip up to New England last summer, like you I had a Class C AIS
receiver and thought it was awesome and at that time thought like you
did. But after following a few other "Pleasure Boats" I heard
nothing but compliments by the commercial ships about how they LIKED
the smaller boats having AIS. Later when we were going through the
fog in Long Island sound I really wished I was transmitting as well.
So when we built the new "Feisty Lady" a Class A or B transmitter was
on our wish list. Now after using my new boat for just a few short
months I can tell you that I have had more then a DOZEN commercial
ships hail me and ask me about my transmitter if I was A or B(I have
the Furuno Class A unit) and thanked me.
I'm sure some captains will become frustrated with the ever increasing
number of AIS transmitters out there, but I have yet to have heard
from one yet. My single biggest frustration though is the number of
boats that are transmitting the wrong information. Beam that is
interchanged with Length, People thinking they are entering things in
feet when it's in meters, Boats always pointing north, etc.
John Ford
KK44 Feisty Lady
Annapolis, MD
I have a Class A Furuno AIS transponder, and after a couple of years of
cruising the PNW with it on, I would agree with John Ford... it lowers the
stress level for the big guys given they know exactly what I'm doing and
where I'm going.
That said, the issue of programming the unit properly is key. At the start,
I didn't have my length info inputed, and VTS kept calling me and trying to
gather me up into their fold, even when I didn't need or want their help.
But once I set up all the parameters correctly, and they could see that I'm
only 18 meters and a pleasure craft, they rarely initiate contacts with me.
I make sure I always update my destination and always enter the right date
and approximate time of arrival. (The latter two items are only useful to
ensure that the guy who is reading my data on their screen knows its fresh
and not some junk I entered a week ago.)
I always monitor the VTS frequency and Channel 13 because piloted cargo
ships do frequently contact me on those channels to negotiate passage, which
keeps the stress level lower for both of us. They'll be a dozen boats
clogging the way in front of a ship, some of those boats bigger than me, but
I'm the only one they are talking to. I've had container ships look at my
transmitted destination (say, Pier 66 Seattle) and then make an assumption
of where I might be making a course change (turning into Elliot Bay in
Seattle) and call to ask specifically where I was going to make my turn,
given they were overtaking me. (They'd obviously had boats turn across their
bow as they made a left turn out of the lanes and into the bay.) Again,
stress reduction for them if they know my intentions.
The only danger of using a Class A transponder is that you can fall into the
habit of 'finessing' your passage, given that both you and the big guy know
the exact computed CPA (Closest Point of Approach). In other words, passing
closer to the cargo ship than you otherwise would have, given that you both
have such detailed and rapidly updated data.
John Marshall
----- Original Message -----
From: "John Ford" johnpford@mac.com
To: "Passagemaking Under Power List"
passagemaking-under-power@lists.samurai.com
Sent: Saturday, October 25, 2008 5:38 AM
Subject: Re: [PUP] AIS
On Oct 25, 2008, at 7:05 AM, Robin Roberts wrote:
We're seeing a disturbing trend of more small (relative to commercial
ships) pleasure boats getting AIS transmitters and it's not a good
thing.
Actually I'll have to disagree with you on this one. When I did my
trip up to New England last summer, like you I had a Class C AIS
receiver and thought it was awesome and at that time thought like you
did. But after following a few other "Pleasure Boats" I heard
nothing but compliments by the commercial ships about how they LIKED
the smaller boats having AIS. Later when we were going through the
fog in Long Island sound I really wished I was transmitting as well.
So when we built the new "Feisty Lady" a Class A or B transmitter was
on our wish list. Now after using my new boat for just a few short
months I can tell you that I have had more then a DOZEN commercial
ships hail me and ask me about my transmitter if I was A or B(I have
the Furuno Class A unit) and thanked me.
I'm sure some captains will become frustrated with the ever increasing
number of AIS transmitters out there, but I have yet to have heard
from one yet. My single biggest frustration though is the number of
boats that are transmitting the wrong information. Beam that is
interchanged with Length, People thinking they are entering things in
feet when it's in meters, Boats always pointing north, etc.
John Ford
KK44 Feisty Lady
Annapolis, MD
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I have read somewhere that in the heavily trafficked English Channel,
Commercial skippers have the ability in software to clear their AIS screens
(radar or chartplotter screen) of vessels less than "X" in length. I don't
know if the traffic control stations keep track of all AIS transceivers. I
assume that some commercial ships can do this and, therefore, it would be
wrong to assume that in comparably heavy traffic, some of the big boys are
not reading your AID signal on purpose. Still, you can call them.
Ron Rogers
-----Original Message-----
From: John Ford
I'm sure some captains will become frustrated with the ever increasing
number of AIS transmitters out there, but I have yet to have heard
from one yet
I installed a Class B AIS on my boat at the beginning of this past
summer's cruising season in the PNW. I also added an ARPA board to my
Simrad radar. I could not be happier with both of these tools. They
serve similar functions but each have advantages over the other. The
AIS literally allows us to "see" around land masses which in the PNW
with its many narrow passes, heavy cargo, tug, cruise ship and ferry
traffic is extremely helpful. The ARPA helps us track non-AIS targets
which is invaluable.
For those that are concerned that too many pleasure boat AIS
transmitters are a problem, you should know that the Class B system is
intentionally designed to automatically degrade out of the system when
it becomes overly crowded. There is also the concern that large ships
being unconcerned with the pleasure boat crowd will just filter us out.
This may eventually happen, but in my mind anything that makes me, or
may make me, more visible to other traffic is a good thing. I also
figure that if I have a concern, I can call up the vessel I'm concerned
about and ask if they see my AIS transmission, alerting them to my
presence and prompting them to turn off whatever filters they have so
that they can get a bearing on me. I had cause to do this in the
Johnstone Strait this summer and the cruise ship I was hailing
eventually made adjustments to their AIS to confirm that I was indeed
showing up on their screen.
Whether you get, a Class A system or Class B system (bought mine in
Canada, because the FCC had not yet approved it at the time, and paid
about 30% of the cost of the Class A system), I think that the AIS
transceiver is a wonderful enhancement to boating safety and peace of mind.
Stan Heirshberg
CrossRoads N50
Stan,
Interesting comment on the Class B "degrading" out of the system. If I
recall, the Class B units transmit far less frequently, and at lower power,
so if there are many Class A's in the area, then all the time slots may be
taken by the A's. I think that's what you are referring to. In that sense,
it won't prevent an A from getting its signal out.
However, even if that happens, the guy with the B will still see everything,
he just might not get his own 'voice' out.
My Furuno FA150 Class A unit denotes Class A versus B units in a target's
data field. It would be easy to have a chart plotter program filter the B's
out.
That said, I haven't seen any filtering software options on Furuno, Nobeltec
or Coastal Explorer yet. Not sure what software the big guys use and whether
its different. But I'm assuming its a given that if the screens get
cluttered, the big guys will filter things out somehow.
Lastly, not everyone is willing to pay the huge premium for a Class A
transceiver, or even the 2x for a Class B transceiver, when a simple AIS
receiver gives you 90% of the benefits. (At least, given that your strategy
when dealing with large ships is to take responsibility for avoiding them,
all on your own, regardless of right of way rules.) But if you want to
routinely run in the shipping lanes under VTS control with the big guys,
then buy an A).
John
----- Original Message -----
From: "Stan" crossroadsn50@yahoo.com
To: "Passagemaking Under Power List"
passagemaking-under-power@lists.samurai.com
Sent: Sunday, October 26, 2008 9:33 AM
Subject: Re: [PUP] AIS
I installed a Class B AIS on my boat at the beginning of this past
summer's cruising season in the PNW. I also added an ARPA board to my
Simrad radar. I could not be happier with both of these tools. They
serve similar functions but each have advantages over the other. The
AIS literally allows us to "see" around land masses which in the PNW
with its many narrow passes, heavy cargo, tug, cruise ship and ferry
traffic is extremely helpful. The ARPA helps us track non-AIS targets
which is invaluable.
For those that are concerned that too many pleasure boat AIS
transmitters are a problem, you should know that the Class B system is
intentionally designed to automatically degrade out of the system when
it becomes overly crowded. There is also the concern that large ships
being unconcerned with the pleasure boat crowd will just filter us out.
This may eventually happen, but in my mind anything that makes me, or
may make me, more visible to other traffic is a good thing. I also
figure that if I have a concern, I can call up the vessel I'm concerned
about and ask if they see my AIS transmission, alerting them to my
presence and prompting them to turn off whatever filters they have so
that they can get a bearing on me. I had cause to do this in the
Johnstone Strait this summer and the cruise ship I was hailing
eventually made adjustments to their AIS to confirm that I was indeed
showing up on their screen.
Whether you get, a Class A system or Class B system (bought mine in
Canada, because the FCC had not yet approved it at the time, and paid
about 30% of the cost of the Class A system), I think that the AIS
transceiver is a wonderful enhancement to boating safety and peace of
mind.
Stan Heirshberg
CrossRoads N50
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Passagemaking Under Power and PUP are trademarks of Water World
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