AIS in the Clyde

[Gordonmc]

The weekend weather was decidedly iffy at the weekend with winds gusting to 30 Kts and, conversely, a mist bordering on fog.
I had to shift the boat out of Rothesay to the mooring and was a bit lary about doing it solo (nae mates).
So, the conditions got me thinking (again) about AIS.
I have Shipfinder on my mobile so I got that going and quickly picked up Calmac's Bute heading into Rothesay bay.
However, no sign of the grey funnel line or the others taking part in Joint Warrier.
The VHF was stacked with warship chatter including from a very pleasant sounding US Navy lady telling a trawler to naff off out of the way.
There were RFAs, submarines, Illustrious, Bulwark, Type 45s et all, but none showing on AIS.
Do they switch it off during exercises? Do they transmit AIS at all?
If so is there any merit in an investment in an AIS receiver when, apart from ferries on known routes, the main collision risk is military stuff?
Thoughts?

 

[BrianH]

Naval and fishing vessels, for obvious reasons, are exempt from regulatory AIS transmissions. I'm happy to see though, where I sail - the Adriatic - more and more fishing craft of any size, are showing up as targets.

 

[Bodach na mara]

I think that they do switch it off, or forget to switch it on at all, Gordon. (I can't talk, sometimes literally and am known for having my VHF either off or still on 86)

Listening to the grey funnel line on VHF is often an education in how not to do it. I once heard a lengthy "mayday" call on 16 with spurious locations given and improbably distress scenarios and showing a complete lack of normal protocol before Clyde Coastguard spoiled the fun by telling them to switch to a working channel or use a simulator for exercises.

To drift the thread a bit, I can understand why ships (commercial or naval) may need to turn off AIS when in an area with certain hazards (near the horn of Africa for example) but I cannot understand why it is even possible for the crew of a passenger aircraft to disable the equivalent equipment (radar transponders for example.) I also cannot understand why the smallest fishing boat must carry a floating beacon that is located so that it can float off and activate if the vessel sinks yet a large modern passenger jet has no similar device.

 

[ctva]

I find the AIS receiver plugged in to the chartplotter is great on the Clyde and West Coast with most vessels of a reasonable size showing up (smaller ones are easier to avoid in fog....hopefully). I note that you are using a mobile app so are reliant on the AIS signal being received by a station which then puts it on the web page and is then downloaded by 3G to your phone..... Whilst I was on the Clyde all weekend around Helensburgh, I did not have AIS on so cannot comment on whether the grey boats were transmitting or not.

 

[scottie]

Maybe they like to hide

A recent TV doc showed the trainee Sub commanders would sit under the Arran ferry to avoid detection so switching of AIS would seem basic.

When the Hebridean princess was chartered by HM a couple of years ago the ais was switched off

 

[scottie]

Looking at marine traffic just now I have never seen so many fishing boats on the clyde as now just south of Arran

 

[OGITD]

Switch it off?

Yes they do.

 

[Tidewaiter2]

Yes they do.

And off Portland, on Wargame Wednesday/Thursday nights, all their nav lights too, bar one small aft red for the budgie-wonderful with the big tankers and containers using the tide to swing through Lyme Bay.
Damn all radar signature too to help keep out of eveyone's way on a dark wet May night.

Shame we couldn't not go west that day, rather than before or after.

 

[markhomer]

I would imagine that they switch off when on exercise , but to fro etc they def had on at weekend , my ole finlaw of 93 was having a great time watching the ais of the grey fleet on his ipad as they tootled in and out the gareloch .

 

[wully1]

When close to warships it is alway good to call them up on VHF, 25 watts, by name and position. They like that.