Navy and AIS

vyv_cox said:
There are many warships patrolling the waters between Greece and Turkey. Many do not transmit anything on AIS but we have seen one or two that do, using the code 9999999
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They also seem to have shared MMSI which the admiralty share out Willy Molly. Nothing unusual to see an aircraft carrier jump overnight from Malta to Arab Emirates and shrink to destroyer dimensions . Maybe they use Black Holes ;) The aircraft carrier Queen Elizabeth was parked 5 Miles up the M90 for over a week a one point!
 
AIS transponders and receivers use two VHF radio frequencies: 161.975 MHz (AIS1, or channel 87B) and 162.025 MHz (AIS2, or channel 88B)
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But we all knew that, didn't we?

And it's not at all unlikely that a bored Sensors Operator has simply set a 'device' which scans multispectra to simply 'bugrup' such signal as is being pushed out by a leisure vessel. It's not at all unlikely that another 'warship' is spoofing transmissions of the AIS frequencies, during an exercise, in expectation of receiving position/course/speed data from some of its exercise 'foes'.
 
Makes you wonder how many non military vessels have foundered, collided, lost cargo and killed people over the same period. seems like almost a daily occurence somewhere in the world.
 
There were 53,415 Convention merchant ships (over 500 tons, engaged on international voyages) in January last year. I don’t know of figures for non-Convention ships, such as third world ferries, coasters, and so on, but the evidence of one’s eyes suggests that there are rather a lot of them.

Very few of them turn their AIS equipment off, although they are permitted to do so if their Masters consider that they may be under threat from pirates or insurgents.

Merchant ships tend to be at sea more than they are in port. It’s how they make money.

The US Navy seems to have 415 ships, other NATO members have fewer, and some of these occasionally venture out to sea, although most of them are alongside for most of the time.

Do a few simple sums in your head.
 
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RichardS said:
Which post by the Captain was the one where he was making a fool of himself? :confused:

Richard
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This one, in which your ‘Captain’ asks how many crew are needed to operate 24 hours a day for weeks or even months.

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Quote Originally Posted by capnsensible
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Operate 24 hours a day for weeks or even months. With no nipping back for a beer. How many people do you need then? Unquote

I’d respectfully advise you, as an enthusiast for the Royal Navy, not to pursue that line of argument. You may find yourself looking silly.

Read more at http://www.ybw.com/forums/showthread.php?528563-HMS-Pembroke/page3#MjGsk7uQxhdiFuqG.99
 
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bedouin said:
I can't imagine the Navy deliberately jamming AIS, what would that achieve?

I suppose it is possible they had other electronic equipment that was causing interference.
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Apart from not seeing any strategic or tactical benefit from jamming AIS its seen as a critical safety system and I'd be very surprised if the the Navy were jamming it. (I wouldn't be surprised if they had the ability, though).

All military electronic systems have to have a tightly controlled EMC profile and these are tested regularly, not least because they could interfere with each other. That would also extend to systems like AIS. (OK, I assume its still the case from when I served)

The same goes for anything that transmits. They have a tightly controlled transmit profile which includes protecting adjacent and co-channels as well as spurious transmissions. These are set out at the apex by the World Radio Conference which is part of the ITU although in practice responsibility belongs to local offices of communication.
 
RichardS said:
What? A post in a different thread? You've got to be pulling our plonkers? ;)

Richard
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It would seem so. A vessel that operates with a small crew for 12 hours will
clearly need a larger crew to operate for extended periods. It's so simple I am surprised it can be so misunderstood.....
 
It's shocking the things you can find out if one digs a little.

For example between 2011and 2017 the European Maritime Agency report that there were incidents on 23264 vessels. According to a poster on here that's over half of the worlds fleet.

6812 casualties. 683 deaths.

This seems to be an industry in an atrocious state. They don't look well placed at all to be finger pointing.
 
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