sailorman
Well-Known Member
this is for a passive reflector
AIS transponder
- Thread starter Daydream believer
- Start date
Rivers & creeks
Well-Known Member
Thank you, that's very helpful, I had assumed it was on re-coding but I see it's only on new RADAR fitting after 2008. I think I'll revert back to that 90% plus figure then! Honestly, anyone who thinks an AIS transponder will show them as a nice big blip on a ship's display is deluding themselves. What it does do is show you on some yachts' AIS screens and I have a suspicion that it forms the main reason for buying an AIS transponder - sort of "look at me and my cool kit", apologies if that is disingenuous but as there's almost no practical reason for fitting one, I'm struggling to understand why people do.
pvb
Well-Known Member
I think people fit transceivers for the reason you've highlighted - they mistakenly think their yacht will be seen on some mystical AIS display on a ship's bridge. There's probably a bit of showmanship involved too; why else would so many yachts in places like the Solent have their transceivers on?
sailorman
Well-Known Member
The Orwell is becoming cluttered too
prv
Well-Known Member
I do think that's unfair. I think most people buy them because they believe in good faith that it will make them highly visible to all ships.
It's a good idea for a magazine article, as long as they are able to collect some real data rather than just yet more yottie hearsay and opinion (yours and mine included). Maybe ask the pilots if they'd be willing to keep simple stats on the ships they bring in - categorise it as "AIS on primary displays" / "AIS available in usable form, but not a primary instrument" / "MKD only" - although I think this would be a skewed sample at least in Southampton as I don't think they pilot many small coasters in compared to large modern container ships and cruise liners.
Pete
prv
Well-Known Member
You misunderstand - what I posted is the display, the transceiver is a separate box. This display unit satisfies the legal carriage requirements for the vast majority of ships out there, they do not have to display the data on any kind of plotter or radar screen or graphical monitor. This is why your assertions in post 40 that all ships over 300 tons must display AIS by law, while not incorrect, are a huge red herring.
Pete
Tintin
Well-Known Member
Thanks ITHtop of the mast it is then. Also gives me the reason the replace the suspect vhf coax.
The advice i received from echomax was NOT to fit up the mast, but on a pole on the pushpit.
Koeketiene
Well-Known Member
I am asked quite regularly to go and brief crews who will be transiting high-danger areas (piracy).
Every time I am given a tour of the ship and I get to chat to the crew so I can get a clear idea of their standard practices (and the equipment they have) and then - if required - advise them how them might improve on them.
I dare claim that I have a fairly good idea of the navigation equipment most larger merchantmen carry these days and the standard of training of their crew.
(Almost) all had their AIS transponder linked to a radar/plotter display. Which is why the figure quoted by Lazy Kipper seems so at odds with my own personal (and fairly recent) experience.
This is the last I post I will make on the subject.
We can argue about this till we're both blue in the face, and you're entitled to your opinion but all I can say is that I know what I know.
Storyline
Well-Known Member
That sounds easier
Just checked the site and it says both mast top and pushpit mounting is OK. ranges of 25 miles and 6 miles
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savageseadog
Well-Known Member
I've used an AIS transponder with a plotted display and can confirm this advice to be spot on. Without electronics it's basically up to us to stay out of the way, the situation is no different with electronics whatever you decide to have. I would, as a minimum buy an AIS receiver and plot it where it can be monitored and stay out of the way. I see no reason to put reliance on ships to keep clear of us, they may or may not avoid running us down I think I prefer to make my own decision about where I need to be. The AIS is extremely useful for identifying contacts and calling them if necessary as already pointed out.
I have a transponder for offshore racing rules compliance, I wouldn't have bothered otherwise and got a receiver only.
sailorman
Well-Known Member
Line of sight of the transmitter & receiver
#56 :encouragement:
ShinyShoe
Well-Known Member
Does that answer part of the question for why so many yachts have it...
It has an alarm function. If they have it on that's enough to tell someone I'm about to hit them...What if your AIS looked like this?
So my understanding is that a large proportion of vessels will need ECDIS by July 2018 for international voyages (the setting the OP was considering) - so 4.5 years away. Two things strike me - is the OP wanting a solution that will be appropriate in 5 years time? Clearly he needs to bear in mind its limitations for the next 4.5years... ...but likewise if I was a ship needing to replace my plotter or whatever for any reason would I replace it now and again if 4 years or would I just make the jump...?
Ships 3,000 - 10,000 GT won't need ECDIS.
BrianH
Well-Known Member
As my AIS receiver is of an older generation and not simultaneous dual-channel receive, I decided to upgrade for next season. Prices have dropped considerably since I was last in the market and I have abandoned my fervent receive-only principles and bought a transponder for only $400.
I can suppress the transmissions when really not required but whilst I am quite aware that even when enabled there will be no guarantee I will be seen and will not change my practice of active evasion assisted by the target list and any CPAs generated by them, it is, however, another plank in the safety aids armoury.
But there is another reason. I go off for a summer's cruising alone, leaving my wife, who does not share my sailing passion, happily with her cat and garden. When in Italian waters we can communicate daily with Skype with me using a 3G USB adapter on board but that is Italy only - further afield and we resort to occasional sms texts. However, she will worry less when she logs onto marinetraffic.com to see a live update of my position. Two receiver stations subscribe 24/7 to the site in Koper, Slovenia, and Venice, Italy and easily cover my usual cruising area.
Okay, a bit 'big-brother' but if it keeps my worry-pot of a wife happy, it's worth it - I am, after all, usually single-handed and in my upper 70s so I guess she has her reasons.
Daydream believer
Well-Known Member
having read the posts with interest i am glad I posted the thread in the first place
I am extremely grateful for the comments about how a ship views the signal
I did think that ships would have a screen
I then decided that a receiver & an active radar reflector was the way to go & I had virtually made my decision
But you sir have b..gered that up because it had not occurred to me that it could be viewable by those at home
& am planning a second SH trip round UK & often spend the summer cruising ( I am 67 years ,the cat died & the wife plays golf --so not a dissimilar situation to yours)
So now I need to know -
If I go back to the transponder option will the wife get to track me in the UK?
anyone know?
Would I be better off with one of those garmin trackers ( spot is it called?)plus an AIS receiver, or just a transponder - but i will certainly get an active reflector
Dunno about Skype though - you have me there!!-- another thread perhaps
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BrianH
Well-Known Member
Oh dear, sorry to have upset your plans. But you should really take your time to become familiar with the principle and review the best for your circumstances. You have enough time not to jump - try to talk to other users and see their installations.
As for UK tracking of Class B transmissions - easy peasy, look here: http://www.marinetraffic.com/ais/home?level0=100
Zoom in to your area by centering it and scroll up - and it's all free!
Tintin
Well-Known Member
This summer I had a very worried call from the wife of a sailing friend. He was going from turkey to italy in october when it was rather windy. She tracked him via the ships ais with marinetraffic.
Her desperate panic was because the yacht had disappeared off marinetraffic, she assumed that it received every where, ergo the yacht had sunk along with hubby.
She truly thought he had gone.
in fact the internet ais tracking sites can only track you if you are in range of one of their volunteer aerials, and so the usual vhf limits apply.
in my friends case he was just out of range.
Her desperate panic was because the yacht had disappeared off marinetraffic, she assumed that it received every where, ergo the yacht had sunk along with hubby.
She truly thought he had gone.
in fact the internet ais tracking sites can only track you if you are in range of one of their volunteer aerials, and so the usual vhf limits apply.
in my friends case he was just out of range.
Daydream believer
Well-Known Member
So are we saying that on my yacht with limited transmission range I am unlikely to be tracked in the channel, Irish Sea or East coats of UK?
Tintin
Well-Known Member
If you go out of vhf range then yes. So cross channel in some parts and irish sea is possible.
Or if you are on receive only.
BrianH
Well-Known Member
Clearly your friends and relatives have to be informed of the system's limits and that your visibility is dependent on the subscribing receiver sites. There are probably areas around the northern UK coastline where there are no contributors to the service.
However, despite the AIS Class B transmission being only 2W, reception is dependent on the height of the receiving antenna and can still be reported at amazing distances. In the northern Adriatic the two Slovenian receivers (station 44) must be high up on the adjacent mountains as they consistently report Class B targets well down in Istria and Class A targets over 400nm distant, well down to central Italy.
http://www.marinetraffic.com/en/ais/details/stations/44
rgarside
Well-Known Member
An interesting thread. I have an AIS receiver [integrated into the VHF set] which displays on my chart plotter in the cockpit, plus a passive radar reflector [I don't spend much time in shipping areas]. However, I am very happy for yachts to fit AIS transceivers, especially the yacht that passed quite close this year on a dark and stormy night crossing of the Thames back from Sheerness. With all the other lights about, it was quite difficult to keep track of his masthead tricolour - especially when it altered course to change from showing green to red - the AIS information he was transmitting helped in identifying how close it was [difficult to determine on a bouncy night from a tricolour] and whether my course alteration was sufficient to avoid him.
The AIS integration into the VHF makes it very easy to make a DSC call to an AIS target. You don't have to transcribe the MMSI into the VHF, just press a button on the VHF AIS page. I haven't had the need to do this yet, but it is conceivable that it would be possible even singlehanded.
I'm sure there are quite a few AIS equipped boats within striking distance of Southminster you could have a look at - though many may be ashore at the moment.
The AIS integration into the VHF makes it very easy to make a DSC call to an AIS target. You don't have to transcribe the MMSI into the VHF, just press a button on the VHF AIS page. I haven't had the need to do this yet, but it is conceivable that it would be possible even singlehanded.
I'm sure there are quite a few AIS equipped boats within striking distance of Southminster you could have a look at - though many may be ashore at the moment.
