May 31, 2017

On April 27th 2017 the Russian Navy Moma-Class AGI Liman|Лиман had a really bad day.

Photo Credit: Alper Böler‏ @alperboler
October 21, 2016
On April 27th the Togo-flagged livestock vessel "Youzarsif H" (also referred to as "Youzar Sif.H"), IMO 7611547, and the Russian Navy Moma-Class AGI Liman|Лиман collided, between 08:30Z and 08:43Z, in thick fog, outside Turkish territorial waters, in the Black Sea. A breach below the water line caused the Liman to sink, reportedly after several hours. All crew were rescued in an orderly fashion from the pictures that were released by the Turkish coast guard. It was reported that the Youzarsif H headed back to port to check for damage and out of concern for the livestock; sheep.

Pretty much everything beyond that is speculation.

You should really read this excellent in-depth analysis by Tony Roper, a frequent contributor to IHS Jane's publications, before reading further, to get up to speed.

Sharing speculation; refuting, proving, discussing, and arguing points, makes for very good banter on Twitter, Reddit, or any social media platform where you can get people with different views together and crowd-source information and experience. I'm not sure if that friendly banter and respectful exchange of ideas was lost on Mr Roper, but for professing to not be an "Expert", he sure does seem to condescend when he portrays those who would speculate about the ships' purpose, and circumstances of it's demise, as idiots, conspiracy theorists, stupid, ignorant, and stubborn. Well,

  • Any ship could have an accident while at sea, in the fog, early in the morning. But, this wasn't "any" ship; just by being a Russian Navy AGI (a "Spy Ship") it makes me +1 suspicious. There is no good rational basis for that suspicion, except it's a Russian Navy AGI, it definitely has sensitive gear aboard, and having it sink leaves a gap in whatever task it was doing, on the deployment it was on.
    This is a seemingly inadvertent win for NATO, and a loss for the Russian Black Sea Fleet.
  • There have been no reports regarding who ran into who; or if it was a mutual effort. The news media is making it sound like they were both moving and collided in the fog. I'm not sure that's correct.
    Was this a "T-Bone" collision while both were moving?
    Was this a T-Bone collision, while the Liman was stationary?
    Was this a glancing bow-on-bow strike?
    We know the Youzarsif H was moving at 11kn before the collision, and suffered superficial damage to its bow, but we don't know if the Liman was stationary or not, since it conducts its operations without using an AIS transponder.
  • While the Liman does not transmit its location with an AIS transponder, can it receive AIS?
    Could it not "see" the other ship coming?
    AIS-T uses VHF marine frequencies
    87B (161.975 MHz)
    88B (162.025 MHz)
    Could these frequencies have been "jammed" intentionally, or accidentally?
    Likely not; any disruption to those frequencies should have affected all VHF maritime communications in the area. No such issues were reported, and most ships were beaconing fine on AIS.
  • The Liman was not a "stealth" ship, and as far as I understand, should have shown up on the navigational radar of the Youzarsif H; isn't that why navigational radar exists?
    How didn't the captain or navigator of the Youzarsif H see it?
    ...or did they, and dismissed it as noise because it didn't transmit AIS?
    Shouldn't there be a collision alarm built into the system?
    They were in thick fog, only navigating by instruments, and didn't see a ship directly in front of them on radar?
    Isn't that weird?
    I don't think it reflects well on the Youzarsif H's crew, unless the operations of the Liman were causing issues for the radar of the Youzarsif H. Yes, that's wild speculation, because it makes no sense how a ship doesn't notice a giant hulk of floating steel in front of it on radar. Make up your own crazy theory! It's better than what we have now, which is nothing.
  • The Youzarsif H's AIS signal was being received by terrestrial based AIS receivers, which Mr Roper described in his blog post with excruciating detail. The signal was very spotty before the collision, and crystal clear after the collision. This is the thing that really draws my eye and triggers my curiosity; it is the basis for much of my suspicion regarding this event. On the day Mr. Roper and I were discussing this he specifically dismissed my speculation that the issue could be related to the sender and insisted the gap in reception must be related to the receiver, or environmental conditions.
    "This totally depends on the receiver not the sender! The receiver may have been off."
    -Tony Roper, 6:29 PM EST, May 4 2017

    I tried to convey that my interest was less with the gap before the collision, and more with the immediate change to the signal quality (seemingly crystal clear reception) instantaneously after the collision, which Mr Roper had no explanation for at the time. It seems after reflection, he now theorizes the sender, may have had their antenna(s) facing away (blocked by the ship's superstructure?) from the shore-based receiver when travelling Southbound (toward the Liman) and immediately after the collision turned around and faced their AIS antenna(s) toward the shore-based AIS-T receiver. This is fantastic speculation, and would explain how the signal went from terrible, to perfect, immediately, while other ships in the area had AIS-T signal all along.
    Can we prove this theory with the available data? Well, it's certainly not as clear as I would like it to be. It is still crystal clear that immediately after the collision the AIS transmissions went from random times between successful transmissions to a steady stream at 3-4 minutes. (please refer to the spreadsheet snippet below)

    2017-04-27 06:55 (UTC)Terr-AIS11.441.8230828.98331177
    2017-04-27 07:02 (UTC)Terr-AIS11.441.7988128.984571770:07
    2017-04-27 07:05 (UTC)Terr-AIS11.341.7893528.984861780:03
    2017-04-27 07:26 (UTC)Terr-AIS11.241.7242328.984521820:21
    2017-04-27 08:20 (UTC)Terr-AIS11.141.5529528.974521850:54
    2017-04-27 08:22 (UTC)Terr-AIS11.141.5529528.974521850:02
    2017-04-27 08:30 (UTC)Terr-AIS1141.5276928.968051940:08
    2017-04-27 08:41 (UTC)Terr-AIS9.541.4994528.959211940:11
    2017-04-27 08:44 (UTC)Terr-AIS0.741.4973128.958231990:03
    2017-04-27 08:48 (UTC)Terr-AIS0.241.4969628.957552530:04
    2017-04-27 08:51 (UTC)Terr-AIS0.541.4968928.957322410:03
    2017-04-27 08:55 (UTC)Terr-AIS0.741.4965428.956732280:04
    2017-04-27 08:59 (UTC)Terr-AIS0.741.4968528.95632190:04
    2017-04-27 09:02 (UTC)Terr-AIS0.941.4971828.95667450:03
  • When did the collision occur?
    At 08:30Z, as you can see, the Youzarsif H was moving at 11kn on a course of 194 degrees.
    At 08:41Z, 11 minutes later, it was doing 9.5kn, still on the exact same course of 194 degrees. Could they have hit the ship, and shoved it aside, keeping the exact same course? I don't think so. They had significantly reduced speed by then; did they see the Liman coming and reduce speed, or were they in the middle of colliding with it at that moment?
    At 08:44Z, only 3 minutes later, they had dropped to 0.7kn and changed course to 199 degrees; the collision had already happened.
    I suspect the collision happened between 08:41 and 08:44, based on the course and speed.
    You'll notice the AIS-T problems cleared up at that exact moment too; they were at 3-4min intervals from then on.


The left hand line of dots (and gaps) are the locations where the AIS-T signal from the Youzarsif H was received by a shore-based receiver while headed South, the right hand line of dots represents the return trip where AIS was crystal clear. You might notice there was a spot where it turned around and didn't seem to have any problem transmitting it's position too. Proof of anything? Not really. (data courtesy of

Photo Credit: Yörük Işık‏ @YorukIsik
October 21, 2016

There is supposed to be an investigation underway by the Turkish authorities regarding this incident, and I look forward to hear what their conclusions are.


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