In September 2022, the Russian Navy’s SS-750 underwater support vessel was observed near the Nord Stream pipeline just four days before the undersea conduit became the target of sabotage. This renewed interest in the little known SS-750, which is billed as a submarine rescue and salvage ship. It carries an AS-26 mini deepwater submarine and a deepwater crane, both of which have the potential for use in subaquatic sabotage operations. It is a member of the Kashtan (ASR) class of auxiliary ships.
Images Sourced From: Viktor Maksimenko, Alex Omen, Press Service of the Western Military District, George Chernilevsky
1 Organisation
1.1 Place within broader Russian Military
The SS-750 is one of the Russian Navy’s tactical marine vessels. It carries a submarine that allows for a greater range in underwater operations. The Russian Navy controls the movements of the SS-750.
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2 Equipment
2.1 SS-750 Ship Commission
The SS-750 was launched in 1998 and commissioned in 1990 under the name “KIL-140.” It is the product of Soviet Navy Project 141, which produced eight Kashtan class vessels at Rostock’s Neptun Werft in East Germany. The SS-750 is classified as a salvage vessel. All the Kashtan class ships are crane ships. Today, they are tenders of the Russian Navy. The other seven ships are: KIL-926, KIL-927, KIL-143, KIL-158, KIL-164, KIL-498, and KIL-168.
2.2 SS-750 Specifications
The SS-750 has a complement of 47 persons. The ship contains a diesel-electric propulsion system (diesel engines connected to an electrical generator that drives the propellers).
- The ships have five 775 kW diesel generators, three 400 kW diesel generators, and two 1500 hp electric motors which power two pitch propellers.
- Length of 97.83 meters
- Draught of 5.7 meters
- Beam of 18.2 meters
- Top speed of 13.5 knots
- Range of 3,700 kilometers
- The SS-750 has a displacement of 4200 tons with a standard load and a displacement of 6200 tons with a full load.
- Ice-breaking prow
- Hyperbaric chamber.
The Kashtan class vessels have large working area amidships with a hundred ton capacity gantry located at the stern. The SS-750 also contains a twelve ton electro-hydraulic crane, which is capable of lifting a hundred tons, on the starboard side and a sixty ton boom amidships. Through modernization efforts, the SS-750 now contains an MR-231 Pal-N navigation radar.
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2.3 AS-26 Submarine
The AS-26 is a priz-class deep-submergence rescue vehicle (DSRV) that was commissioned in 1987.
- Length of 13.5 meters
- Height of 4.6 meters
- A maximum speed of 3.3 knots
- A range of 39 kilometers
- Depth range of 1,000 meters
- Manipulator arm capable of lifting 50 kilograms.
The mini-submarine can function for up to one hundred and twenty hours. The crew on this submarine consists of four people but an additional twenty individuals can be on board. If twenty four individuals are on board then the submarine has an operational capacity of ten hours.
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3 Tactical Operations
The SS-750 has been primarily spotted operating in the Baltic Sea. In terms of its militaristic operations, it has been near Bornholm, Denmark. For a closer look at the movements and operations of the SS-750, refer to these video link sources:
3.1 Nord Stream Gas Pipeline
On 26 September 2022, explosives damaged three of the four Nord Stream gas pipelines. These are natural gas pipelines that link Germany to Russia and traverse the Baltic Sea. Four days earlier, the Russian SS-750 ship was spotted in the vicinity of the pipelines. The SS-750 ship set off from the Baltiysk naval base on 21 September 2022 and may have been accompanied by the Aleksandr Frolov and SB-123 tugboats. At this time, the SS-750 was travelling with its Automatic Identification System (AIS) turned off. The two other boats kept their AIS turned on until they approached the northeast area of Bornholm.
Later on 21 September 2022, the Danish military sent the P524 Nymfen patrol vessel to investigate the possible movement of the vessels. The Danish Defence Command later confirmed that the SS-750 was at the scene. While there was speculation by Scandinavian authorities that Russia was behind the attack, Russia has denied the claim and the Scandinavian authorities have not assigned blame to any particular party. The United Nations Security Council meeting, which convened on 26 September 2022, yielded no further results as to the origin of the explosion. Germany’s investigation into the matter focused on other suspects as of late 2024.
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3.2 Sea Trials
A sea trial is the testing of marine vessels on open water in order to determine the vessel’s capacities and functionality. The Kashtan class SS-750 has accompanied other ships during their sea trials in the capacity of a rescue ship since 2021. The SS-750 has ensured the safety of a variety of submarines, including the Mozhaysk, Ufa, and Kronstadt. These trials have taken place primarily in the Baltic Sea.
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4 The Future
The underwater and tactical capabilities of this ship allow it to complete open water maneuvers and tactical operations. Its presence around the Nord Stream pipelines has increased interest in its possible use as a sabotage vehicle for the Kremlin’s covert action (hybrid warfare) efforts. It is likely that the SS-750 will continue to be utilised in a variety of missions due to its unique capabilities. There were seven other ships commissioned with Project 141. While there have been sightings of the other ships after their commission, their current and future operational capacities remain unclear. The extent that these ships will be used for tactical operations will depend on the actions of the Russian government and its military plans.
5 Conclusion
The SS-750 is a submarine rescue ship with a small submarine and crane. It is part of Russia’s Navy and is designed for underwater rescue and salvage operations, but is also capable of sabotage of submarine infrastructure, such as pipelines, cables, etc. This ship was spotted near sabotage operations against the Nord Stream pipelines within four days of the attack. The SS-750 disabled its electronic identification system while in the area, but investigations have not confirmed any involvement in the sabotage operation.
