AIS - essential kit these days for channel crossing?

We are finishing the fourth season in our present boat. Prior to that we had no chartplotter, AIS or radar (or electric windlass for that matter...).

While we had years of great sailing with our old Roberts 34, I really would not want to go back to doing without these "luxuries". Like the OP, we tend to sail in fairly light shipping areas, but both radar and AIS are more or less indispensable for us nowadays. After experiencing thick fog on a recent passage across the North Sea, and, again, most of the way from Sumburgh Head to Fair Isle, we decided to go the extra mile by upgrading from AIS receiver to tranceiver.

As the MAIB report on the Priscilla's grounding in the Pentland Firth shows, there is no absolute protection against being run over by a badly managed ship, but radar and AIS transmission and reception certainly helps.

See and be seen!
 
Last edited:
awol said:
We've been here before. A transponder is a device that responds to a received signal by transmitting its own. Examples are the Echomax that transmits when wiped by a suitable radar beam and a SART that does the same.
A transceiver is a device like a marine VHF radio or an AIS that can transmit and receive signals
Your own definition may vary but that's your problem.
Click to expand...

Errrrrr ..... your definition is the same as mine so if it's my problem, then it's also yours. ;)

Richard
 
Pete7 said:
I would have thought IRPCS Rule 5 would suggest at least AIS Rx.

Pete
Click to expand...
How do you mean? Nobody is obliged to fit anything to any typical size, private yacht, and a means of keeping a lookout is only 'available' if it is fitted, working and useable, and there is a spare crew member trained to use it.
For example, you might not want to flatten your battery by using radar, so it would not be 'available', and switched off.
Or, you might be doublehanded in rough conditions, and not want to have a person on watch, for the sole purpose of fiddling with gadgets, so the AIS would not be 'available'.
 
Last edited:
I have a JRC Vigil II radar, digital so a very short warm up and standby mode so I can turn it on for short bursts for a look around - no way could my boat power it to run constantly but it's nice to have an active sensor.

Of course I've never been caught in fog since I bought it, so money well spent !

Ohlin Karcher,

message received, I will probably go for RTE though I like the Wacky Races ' they're over there ' display of AIS.
 
awol said:
So you believe that an AIS transceiver responds to a message from another transmitter by automatically transmitting? I and the relevant standards think otherwise.
Click to expand...

Errrrrrr ..... nope, and I've never said as such. What I said was "An AIS device that receives and transmits IS a transponder".

(Do we hear the sound of pennies dropping yet? ;))

Richard
 
boatmike said:
I always work on the basis that I would rather take appropriate action to avoid others than rely on them missing me. I drive a car the same way. If you assume all other drivers are idiots you will be prepared when you meet the one that is! On that basis I have radar and a 12" chartplotter with AIS receive only. Unfortunately you need a decent chartplotter to make AIS useful and it won't be much use on a tiny cheap one but if your buddy has a decent chartplotter he can buy a receiver quite cheaply. Don't forget to budget for a decent antenna splitter or separate antenna though or it won't work!
Click to expand...

I really really hope that your first sentence doesn’t mean you alter course for any ship that looks as though it might come anywhere near you.
 
awol said:
No more a transponder than you are. The transmitted message has nought to do with the received. Or have you just invented a new device?
Click to expand...
Just as easy to add to ignore rather than point out black isn't white, thread killer as he's like trump and will never ever admit to being wrong..
 
awol said:
No more a transponder than you are. The transmitted message has nought to do with the received. Or have you just invented a new device?
Click to expand...

It's getting rather painful now Awol, so I think we need to draw this to a close but I'll try once more to reach that "tipping point". :)

AIS transponders and AIS transceivers belong to the subset of AIS devices which are able to both receive and transmit AIS data, although the two devices operate differently in the way the receive/transmit function is implemented.

Kerching ..... hopefully. ;)

Richard
 
awol said:
No more a transponder than you are. The transmitted message has nought to do with the received. Or have you just invented a new device?
Click to expand...

It's kind of open to debate.
It's a transponder in a sense because the transmitted message is sort-of controlled by the message(s) it receives, in terms of the timing. But it's not an immediate response to every message.
SRT use the word 'transponder' particularly wrt class B units, that's good enough for me.
Define:
transponder
/tranˈspɒndə,trɑːnˈspɒndə/

noun: transponder; plural noun: transponders

a device for receiving a radio signal and automatically transmitting a different signal.


'Different signal' often means the same data or content, at a different frequency.
 
GHA said:
Just as easy to add to ignore rather than point out black isn't white, thread killer as he's like trump and will never ever admit to being wrong..
Click to expand...

If there is a "thread killer" here, surely that's the pedant Awol telling us that we're all "ignorant" when we all know exactly what we mean by the use of the terms "transceiver" and "transponder" in this thread.

It's all very well trying to be a "Mr Smarty Pants" but to do that, one really has to be smart to start with. ;)

So, on that point GHA, please tell us all why you believe that an AIS transponder does not receive and transmit AIS data. :rolleyes:

Richard
 
Last edited:
Back to the subject in hand, what you have never had you don't miss. I did channel crossings for thirty odd years without AIS and preferred to cross at night so I could see when I had crossed the path of a ship when his port and starboard lights switched colour. When I fitted an AIS receiver I knew for sure how far away a ship would cross and when I learned how to use it in more depth I could see that ships that were on a collision course actually changed course to avoid me and the odd one that didn't I could contact on VHF. After a few years with a receiver and the price of transceivers came down, I felt guilty that I could see what others were doing but they couldn't see what I was up to so replaced the receiver with a transceiver.
Another advantage of a transceiver is that other small boats with a receiver but no RADAR could also see me. That is also an advantage of AIS over an RTE, where other boats have an AIS receiver but no RADAR.
 
lw395 said:
Define: transponder /tranˈspɒndə,trɑːnˈspɒndə/
noun: transponder; plural noun: transponders

a device for receiving a radio signal and automatically transmitting a different signal.

'Different signal' often means the same data or content, at a different frequency.
Click to expand...

Which despite RichardS's assertion does not describe an AIS transceiver as presently used by ships and other craft.
Pedantic, indeed yes, but if words are used wrongly, credibility in the message is diminished as is that of the sender. Arguing that "we all know exactly what we mean" is just another of the dumbing down, anti-expert attitudes that is only too prevalent in present times.
 
LadyInBed said:
...
Another advantage of a transceiver is that other small boats with a receiver but no RADAR could also see me. That is also an advantage of AIS over an RTE, where other boats have an AIS receiver but no RADAR.
Click to expand...
Yes that's true, if it's either/or (AIS or radar).
However..I care less about them than ships, which mainly use radar.
 
You must log in or register to reply here.

Share this page

Top