Steffan Watkins 😷+ Your Authors @steffanwatkins Steffan Watkins is a OSINT research consultant mostly focused on debunking #disinformation about planes, ships, & the #OpenSkiesTreaty [email protected] Jul. 19, 2019 5 min read + Your Authors

What are the limits to what we can discern by monitoring their AIS transponders?

🇬🇧 The Royal Navy has a disdain for transparency and (arguably) poor understanding of what is needed for #OPSEC in 2019. I can easily justify this by comparing their posture to every other Navy on the high seas.
I call this poor maritime domain awareness.

🇨🇦 While the #RCNavy uses their assigned MMSI, and usually broadcast their commissioned name, or other friendly name that makes it clear who they are. They turn off their public transponder when they are conducting operations which require it for #OPSEC.



It's easy!

You can watch many of the world's navies using web sites like , and see the difference between how their Navies conduct operations.
Some Navies hardly use AIS on any warships at all (🇷🇺).
Some use fake MMSIs across most of their Navy (999999999 🇫🇷).

🇺🇸 Some have different policies between different fleets and types of ships that aren't immediately clear, but do seem to be used consistently, but even the #USNavy (most of the time) uses unique MMSIs to keep their ships separate.

🇬🇧 The Royal Navy uses the on/off button, but to keep you at home, sitting on the loo, on your toes (figuratively), they play a shell game with their unique MMSI#; the number assigned to any ship that's used by the transponder to identify them to all nearby ships, or satellites.

Familiar with the OSI model? I haven't made a new diagram re: how AIS can be displayed in layers; but at level 1 you have a physical transmitter on a ship, transmitting their location pulled from GPS. At level 7 we have you, on the loo, looking at an app showing a little arrow.

Whatever app you're using to see that little arrow, the data has already travelled from the ship, over VHF to a terrestrial receiver, or satellite receiver, through several networks and servers, to be interpreted by an application pulling the data from a database.

How that data is interpreted, when one MMSI is being used across multiple ships, is often confusing because of that top application layer trying to make sense of something which is impossible by anyone sticking to the AIS standard.

As a result, you'll see "jumps" where a ship is (say) in the English Channel one moment, and (say) in the Persian Gulf the next; suggesting one ship turned off their transponder, and another ship lit theirs up with the same MMSI.
(similar to using a cell phone with a cloned IMEI)

🇬🇧 To demonstrate how this doesn't accomplish anything related to increasing the operational security of British warships in the Persian Gulf, let's review what we can determine from their ops in the Persian Gulf, using the past ~30+ days; info that's available from many sources.

This isn't a new gripe, BTW.


Naval Support Activity Bahrain (#NSABahrain) is the major US Navy base in the area; home to U.S. Naval Forces Central Command & United States Fifth Fleet.

(side note: this is why protests in Bahrain are allowed to be violently put down with no condemnation from the West)

🇬🇧 All British ships in the area will make stops there, #RoyalNavy Bay-class landing ship RFA Cardigan Bay (IMO:9240782|MMSI:232779000|CS:GCID) is no exception, and last transmitted their location 2019-07-15.

#RFACardiganBay #L3009 

We can also see their standard operating procedure #SOP is to turn on their AIS when entering or exiting ports, or crossing the Strait of Hormuz; and have it off the rest of the time.

Surprisingly, they were using their usual MMSI! 👏👏👏

Remember the (fantastic!) infographic; that's 1 of 6 ships the British have in the Persian Gulf today.

🇬🇧 #RoyalNavy Type 23 frigate HMS Montrose (IMO:8949642|MMSI:234618000|CS:GCOD) was at one time 234618000, and we can see them sitting by the pier 2019-05-17; where they last transmitted their location as 234618000.

#HMSMontrose #F236 

🇬🇧 #RoyalNavy Type 23 frigate HMS Montrose is believe to be the one showing up in the strait of Hormuz w/ MMSI 232002833. We see they are frequent visitors to Qatar & Bahrain - they don't cycle numbers, that's just their new number.

#HMSMontrose #F236 

MMSI 232002833 is used by (at least) 5 Royal Navy ships, generally at the same time. MarineTraffic has implemented measures to try and keep them apart, but ultimately this isn't how AIS is supposed to work, so the results aren't always consistent; but there's only one in the Gulf

There is also a Royal Navy squadron of MCMVs in the Persian Gulf; could any of them be using the same MMSI as HMS Montrose? ABSOLUTELY! I haven't heard much about them, and wonder if they're patrolling with AIS off, or just using 232002833? The Iranians know, but I can't tell.

🇬🇧 #RoyalNavy Hunt-class mine countermeasures vessel HMS Brocklesby (IMO:4906616|MMSI:234577000|CS:GBPQ) was still reporting to be in Bahrain by AIS up to 18 hours ago, but I can't be sure it was them, or if they are still there.

#HMSBrocklesby #M33 

For all I know 234577000 could be used by all four MCMVs in The Gulf.

The point I try to make repeatedly is, while this confuses the British public who are using rudimentary tools, it does far less to confuse the Iranians who can use binoculars to see which ship is which.

I believe if any 🇬🇧 oil tanker is being followed or led by any Royal Navy vessel, the Iranians are not going to intercept them. Which MMSI/which ship is largely irrelevant. Confrontation between Iranian gunboats and Royal Navy vessels of any size ends poorly for the Iranians.

The Iranians will also *see* the difference between HMS Brocklesby, Cardigan Bay, or Montrose - visually or on radar. Does this sow doubt? Does this ruse fool them? ...,maybe? But only for minutes, maybe hours, not days.
It seems like a waste of time; security theater for optics.

🇬🇧 #RoyalNavy Type 45 guided missile destroyer HMS Duncan (IMO:4907880|MMSI:235053411|CS:GMIC) departed Naval Support Activity Souda Bay on 2019-07-17, so they're well on their way to the Persian Gulf via the Suez by now.

#HMSDuncan #D37 #NSASoudaBay 

🇬🇧 #RoyalNavy fleet auxiliary RFA Wave Knight (IMO:9168594|MMSI:235491000|CS:GWBU) is well on her way to the Persian Gulf as well, presently crossing the Mediterranean.

#RFAWaveKnight #A389 

🇬🇧 #RoyalNavy Type 23 frigate HMS Kent (IMO:8949719|MMSI:234606000|CS:GDIR) is also supposed to head to the Persian Gulf.. eventually, and it last beaconed on 2017-07-12 from port.

#HMSKent #F78 

RFA Wave Knight left 2019-07-15.

That they wouldn't send HMS Kent with her is surprising, to me anyway.

You can follow @steffanwatkins.


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