# Kilo-class submarine

The Kilo-class submarines are a group of diesel-electric attack submarines designed by the Rubin Design Bureau in the Soviet Union in the 1970s and built originally for the Soviet Navy.
The first version had the Soviet designation Project 877 Paltus (Russian: Па́лтус, meaning "halibut"), NATO reporting name Kilo. They entered operational service in 1980 and continued being built until the mid-1990s, when production switched to the more advanced Project 636 Varshavyanka variant, also known in the West as the Improved Kilo class. The design was updated again by the Russian Navy in the mid-2010s, to a variant called Project 636.3, also known as Improved Kilo II.

## Role

The Project 877 attack submarines were mainly intended for anti-shipping and anti-submarine operations in relatively shallow waters. Original Project 877 boats are equipped with Rubikon MGK-400 sonar system (with NATO reporting name Shark Gill), which includes a mine detection and avoidance sonar MG-519 Arfa (with NATO reporting name Mouse Roar).
Newer Project 636 boats are equipped with improved MGK-400EM, with MG-519 Arfa also upgraded to MG-519EM. MGK 400E can detect submarines with 0.05 Pa/Hz noisiness in 16 km (9.9 mi) and surface vessels with 10 Pa/Hz noisiness in 100 km (62 mi). The improved sonar systems have reduced the number of operators needed by sharing the same console via automation.
Anechoic tiles are fitted on casings and fins to absorb the sound waves of active sonar, which results in a reduction and distortion of the return signal. These tiles also help attenuate sounds that are emitted from the submarine, thus reducing the range at which the submarine may be detected by passive sonar.
Project 636 and 636.3 submarines can launch Kalibr (and their Club export version) cruise missiles. It was reported in September 2022 that they can carry four Kalibr missiles, and can launch them through two of their six torpedo tubes.

## History

A single Project 877 submarine, B-871 Alrosa, is equipped with pump-jet propulsion, instead of a propeller. It has been retrofitted for the Kalibr missile.
It was planned for Project 636 (Improved Kilo) to be succeeded by the Lada class in Russian Navy service. However, by November 2011 it was apparent that the Lada class would be delayed because Sankt Peterburg (B-585), the lead boat of the class, had shown major deficiencies. On 27 July 2012, the Russian Navy commander-in-chief announced that construction of the Lada-class submarines would resume, having undergone design changes. Series production was reported to be underway in the latter 2010s.
The Russian Navy also moved forward in the late 2010s, with the construction of Project 636.3, also known as Improved Kilo II. The first-in-class was named Petropavlovsk-Kamchatsky (PPK) and was launched by the head of Admiralty Shipyard Alexander Buzakov on 28 March 2019, or some thirty months after commission. By November 2019, six units had been built for the Black Sea Fleet and further boats were proposed, but not funded, for the Pacific and Baltic Fleets.
In June 2022, an unconfirmed report from within Russia's defense industry suggested that a further tranche of six additional Project 636.3 vessels might be ordered to start construction in around 2024. The PPK class "is slightly longer in length — the sub's submerged displacement is around 4,000 tons — and features improved engines, an improved combat system, as well as new noise reduction technology; it can fire both torpedoes and cruise missiles, launched from one of six 533-millimeter torpedo tubes." The PPK class has a seven-bladed propeller, instead of the six-bladed propeller of the Project 877 class.

## Specifications

There are several variants of the Kilo class. The information below is the smallest and largest number from the available information for all three main variants of the boat.
* Displacement:
** 2,300–2,350 tons surfaced
** 3,000–4,000 tons submerged
* Dimensions:
** Length: 70–74 meters
** Beam: 9.9 meters
** Draft: 6.2–6.5 meters
* Maximum speed
** 10–12 knots surfaced (18–22 km/h)
** 17–25 knots submerged (31–46 km/h)
* Propulsion: Diesel-electric 5,900 shp (4,400 kW)
* Maximum depth: 300 meters (240–250 meters operational)
* Endurance
** 400 nautical miles (700 km) at 3 knots (6 km/h) submerged
** 6,000 nautical miles (11,000 km) at 7 knots (13 km/h) snorkeling (7,500 miles for the Improved Kilo class)
** 45 days sea endurance
* Armament
** Air defence: 8 Strela-3 or 8 Igla-1, but after sea trial it was rejected by the navy.
** Six 533 mm torpedo tubes with 18 53-65 ASuW or TEST 71/76 ASW torpedoes or VA-111 Shkval supercavitating torpedoes, or 24 DM-1 mines,
* Crew: 52
* Price per unit is US$200–250 million (China paid about US$1.5–2 billion for 8 Project 636 Kilo-class submarines)

## Operational history

Kilo-class attack submarines originally began entering service with the Soviet Navy from 1980.
At the beginning of 2014, the Chinese PLA Navy held an emergency combat readiness test. The Kilo-class submarine Yuanzheng 72, deployed on a combat readiness voyage encountered a "cliff" caused by a sudden change in seawater density. Because the seawater density suddenly decreased, the submarine lost its buoyancy and rapidly fell to the seabed more than 3,000 metres (9,800 ft) deep. The pressure on the submarine increased sharply, and the main engine room pipeline was damaged and water entered. The vessel lost power due to a large amount of water entering the main engine room. The crew reacted quickly, the submarine resurfaced in three minutes, avoiding disaster. The voyage was notable for creating many firsts for PLAN's submarine service.
In 2015 five Kilo-class submarines were deployed to the Russian naval facility in Tartus, Syria. At least two of the units reportedly attacked land targets inside Syria with 3M54 Kalibr cruise missiles (NATO designation: SS-N-27A "Sizzler"). On 8 December 2015 marked the first time a Kilo-class submarine fired cruise missiles against an enemy. B-237 Rostov-on-Don struck two targets near the ISIS capital of Raqqa by the missile attack. The B-237 Rostov-on-Don transited the Dardanelles on its way back to the Black Sea on 12 February 2022.
B-871 Alrosa, a pump-jet Kilo class, which derives from the Project 877 hull, participated in the Russo-Ukraine War.
After the sinking of the Russian cruiser Moskva in April 2022, it was remarked that the Kilo-class subs were the only members of the Black Sea Fleet whose orders did not prohibit venturing into Ukrainian waters near Odesa during the Russian invasion of Ukraine. In September 2022, after the early 2022 Crimea attacks, the UK Ministry of Defence said that the Kilo-class submarines were moved from Sevastopol to the Port of Novorossiysk in Krasnodar Krai.
On 13 September 2023, B-237 Rostov-on-Don was severely damaged by a Ukrainian Storm Shadow missile strike while it was drydocked in Sevastopol. According to satellite images taken in June 2024, the submarine was moved to a lesser used dry dock within the port (at coordinates 44.609975029014116, 33.537496816089906). Camouflage nets were, at least initially, thrown up to disguise its presence and to make observation more challenging. According to reports, the submarine is under repair.
On 2 August 2024, Ukrainian Forces launched a strike against a Russian submarine and an S-400 air defense system in Crimea. Ukrainian sources claimed that the submarine B-237 Rostov-on-Don was "sunk on the spot" in the attack. Other sources claim that the submarine was only hit and not sunk. Satellite images showed the that camouflage nets were burned out by the strike.

## Operators

The first submarine entered service in the Soviet Navy in 1980, and the class remains in use with the Russian Navy today; around 11 original Kilo-class vessels believed to still be in active service with the Russian Navy (as of 2023), while new Improved Kilo–class subs are being delivered through the 2020s to replace them. About forty vessels have been exported to several countries:
* Algeria: 2 original Kilo (Project 877), 4 Improved Kilo (Project 636).
* People's Republic of China: 2 original Kilo (Project 877), 10 Improved Kilo (Project 636).
* India: 10 original Kilo (Project 877), 1 sustained major casualty – designated as the Sindhughosh class
* Myanmar: one boat transferred from Indian Navy by March 2020.
* Poland: 1 original Kilo (Project 877) – ORP Orzeł.
* Iran: 3 original Kilo (Project 877).
* Romania: 1 original Kilo (Project 877) – Romanian submarine Delfinul (not operational).
* Russia: 10–11 original Kilo (Project 877), 11 Improved Kilo (Project 636.3) and 1 additional Improved Kilo on order (636.3) for Pacific Fleet to be delivered in 2024. One further Improved Kilo ordered in August 2020, during the International Military-Technical Forum "ARMY-2020"; up to six additional boats of the class intended to replace Project 877 units; first three ordered in 2023.
* Vietnam: 6 Improved Kilo (Project 636) – Hồ Chí Minh City, Hà Nội, Hải Phòng, Đà Nẵng, Khánh Hoà, Bà Rịa-Vũng Tàu.

### Possible purchasers

The government of Venezuela expressed interest since 2005 in acquiring nine AIP-powered conventional submarines, either the German U214 or later the Amur 1650. There was a Russian counteroffer due to technical issues at the shipyards back then, for five Project 636 Kilo-class and four Amur 1650, but it hasn't gone through yet.
In 2017, the Philippine Navy showed interest in the Kilo-class submarine as part of its modernization program. Defense Secretary Delfin Lorenzana said the country was evaluating a Russian offer.

### Failed bids

The Indonesian Navy was interested in purchasing two used Kilo-class submarines, but the Chief of Staff of the Indonesian Navy Laksamana Marsetio cancelled the plans in 2014 after inspecting the two submarines in Russia with an Indonesian Navy team. He said, "The submarines look good on the outside, but the inside is filled with broken equipment, and the two submarines have been in storage for two years." Indonesia instead bought six Improved Jang Bogo-class submarines, later known as Nagapasa-class submarine, including a transfer of technology, where Indonesia will eventually build four of six of the submarines with South Korea. Actually, the bid for Kilo Russian submarines fell apart due to the lapse of the financing term of the Russian Federation.

## Gallery

* The Polish Kilo-class submarine ORP Orzeł, 26 June 2011
* Russian Kilo-class submarines in Polyarny, Murmansk Oblast
* An Algerian Kilo-class submarine
* A Chinese Kilo-class submarine being delivered from Russia as deck cargo in 1995.
* ORP Orzeł, the control room of an 877E-class submarine
* The Iranian Kilo-class submarine Yunes, during delivery in 1995.
* Indian Kilo-class submarine, INS Sindhughosh
* Diesel submarine Kilo-class Kaluga returns from a long voyage
* Russian Improved Kilo-class submarine Ufa during the Russian Navy Day parade in 2023.

## List of submarines
### Project 877

| Operator | # | Name | Shipyard | Project | Laid down | Launched | Commissioned | Fleet | Status |
| Russia | B-248 | x | Komsomolsk-on-Amur | 877 | 16 March 1980 | 12 September 1980 | 31 December 1980 | | Decommissioned 2001 |
| Russia | B-260 | Chita | Komsomolsk-on-Amur | 877 | 22 February 1981 | 23 August 1981 | 30 December 1981 | PF | Decommissioned 2013, sank partially on way to scrap in 2019 |
| Russia | B-227 | Vyborg | Komsomolsk-on-Amur | 877 | 23 February 1982 | 16 September 1982 | 23 February 1983 | BF | Decommissioned 2018 (exhibit patriot park Kronstadt) |
| Russia | B-229 | x | Komsomolsk-on-Amur | 877 | 23 February 1983 | 15 July 1983 | 30 October 1983 | | Decommissioned 2002 |
| Russia | B-404 | x | Komsomolsk-on-Amur | 877 | 7 May 1983 | 24 September 1983 | 30 December 1983 | | Decommissioned 2002 |
| Russia | B-401 | Novosibirsk | Nizhniy Novgorod | 877 | 6 October 1982 | 15 March 1984 | 30 September 1984 | NF | Decommissioned 2012 |
| Russia | B-402 | Vologda | Nizhniy Novgorod | 877 | 24 August 1983 | 29 September 1984 | 30 December 1984 | NF | Decommissioned 2016 |
| Russia | B-405 | (ex Tyumenskiy Komsomolets) | Komsomolsk-on-Amur | 877 | 20 April 1984 | 21 September 1984 | 30 December 1984 | | Decommissioned 2002 |
| Poland | 291 (ex-B-351) | Orzeł | Nizhniy Novgorod | 877E | 29 September 1984 | 7 June 1985 | 29 April 1986 | | Active as of 2010 |
| Romania | 581 (ex-B-801) | Delfinul | Nizhniy Novgorod | 877E | 1984 | 1985 | August 1985 | | Unknown (in reserve since 1995) |
| India | S55 | Sindhughosh | Saint Petersburg | 877EKM | 29 May 1983 | 29 July 1985 | 25 November 1985 | | Active as of 2010, modernized to project 08773 in 2002–2005 |
| Russia | B-470 | x | Komsomolsk-on-Amur | 877 | 6 May 1985 | 27 August 1985 | 30 December 1985 | | Decommissioned 2005 |
| Russia | B-806 | Dmitrov | Nizhniy Novgorod | 877EKM | 15 October 1984 | 30 April 1986 | 25 September 1986 | BF | Active as of 2018 |
| India | S56 | Sindhudhvaj | Saint Petersburg | 877EKM | 1 April 1986 | 27 July 1986 | 25 November 1986 | | Decommissioned on 16 July 2022. |
| Algeria | 012 | Rais Hadj Mubarek | Nizhniy Novgorod | 877EKM | 1985 | 1986 | 29 November 1986 | | Upgraded in 2010, able to launch Kalibr/Club missiles |
| Russia | B-439 | x | Komsomolsk-on-Amur | 877 | 4 April 1986 | 31 July 1986 | 30 December 1986 | | Decommissioned 2005 |
| India | S57 | Sindhuraj | Nizhniy Novgorod | 877EKM | 1986 | 1987 | 2 September 1987 | | Active as of 2010, modernized to project 08773 in 1999–2001 |
| Algeria | 013 | El Hadj Slimane | Nizhniy Novgorod | 877EKM | 1986 | 1987 | 25 November 1987 | | Upgraded in 2011, able to launch Kalibr/Club missiles |
| Myanmar | 71 | UMS Minye Theinkhathu (ex-Sindhuvir) | Saint Petersburg | 877EKM | 15 May 1987 | 13 September 1987 | 25 December 1987 | | Modernized to project 08773 in 1997–1999, transferred to Myanmar Navy in 2020 |
| Russia | B-445 | Svyatoi Nikolai Chudotvorets | Komsomolsk-on-Amur | 877 | 21 March 1987 | 26 September 1987 | 30 January 1988 | PF | May have decommissioned 2020; listed as still in service by one source |
| India | S59 | Sindhuratna | Nizhniy Novgorod | 877EKM | 1987 | 1988 | 14 August 1988 | | Active as of 2010, modernized to project 08773 in 2001–2003 |
| India | S60 | Sindhukesari | Saint Petersburg | 877EKM | 20 April 1988 | 16 August 1988 | 29 October 1988 | | Active as of 2010, modernized to project 08773 in 1999–2001 |
| Russia | B-808 | Yaroslavl | Nizhniy Novgorod | 877 | 29 September 1986 | 30 July 1988 | 27 December 1988 | NF | Decommissioned 2022 |
| Russia | B-394 | Nurlat | Komsomolsk-on-Amur | 877 | 15 April 1988 | 3 September 1988 | 30 December 1988 | PF | Active 2018 |
| Russia | B-800 | Kaluga (ex-Vologodskij komsomolets) | Nizhniy Novgorod | 877LPMB | 5 March 1987 | 7 May 1989 | 30 September 1989 | NF | Refitted in 2009–2012, active 2022 |
| India | S61 | Sindhukirti | Saint Petersburg | 877EKM | 5 April 1989 | 26 August 1989 | 30 October 1989 | | Active, modernized to project 08773 |
| Russia | B-464 | Ust'-Kamchatsk | Komsomolsk-on-Amur | 877 | 26 May 1989 | 23 September 1989 | 30 January 1990 | PF | Active 2018 |
| Russia | B-459 | Vladikavkaz | Nizhniy Novgorod | 877 | 25 February 1988 | 29 April 1990 | 30 September 1990 | NF | Refitted in 2011–15, active, entered Baltic Sea 3 July 2018 to take part in Main Naval Parade in St Petersburg on 29 July. |
| India | S62 | Sindhuvijay | Saint Petersburg | 877EKM | 6 April 1990 | 27 July 1990 | 27 October 1990 | | Active as of 2010, modernized to project 08773 in 2005–2007 |
| Russia | B-871 | Alrosa | Nizhniy Novgorod | 877 | 17 May 1988 | September 1989 | 30 December 1990 | BSF | Refitted in 2014–2022 |
| Russia | B-471 | Magnitogorsk | Nizhniy Novgorod | 877 | 26 October 1988 | 22 September 1990 | 30 December 1990 | NF | Active 2018 |
| Russia | B-494 | Ust'-Bolsheretsk | Komsomolsk-on-Amur | 877 | 5 May 1990 | 4 October 1990 | 30 December 1990 | PF | Decommissioned 2023 |
| Iran | 901 | Taregh | Saint Petersburg | 877EKM | 5 April 1991 | 25 September 1991 | 25 December 1991 | | Active as of 2012 Upgraded in Iran shipyard |
| Russia | B-187 | Komsomolsk-on-Amur | Komsomolsk-on-Amur | 877 | 7 May 1991 | 5 October 1991 | 30 December 1991 | PF | Active 2018 |
| Russia | B-177 | Lipetsk | Nizhniy Novgorod | 877 | 3 November 1989 | 27 July 1991 | 30 December 1991 | NF | Active 2018 |
| Russia | B-190 | Krasnokamensk | Komsomolsk-on-Amur | 877 | 8 May 1992 | 25 September 1992 | 30 December 1992 | PF | Decommissioned 2023 |
| Iran | 902 | Noah | Saint Petersburg | 877EKM | 30 April 1992 | 16 October 1992 | 31 December 1992 | | Unknown (probably in modernization in Iranian shipyard) |
| Russia | B-345 | Mogocha | Komsomolsk-on-Amur | 877 | 22 April 1993 | 6 October 1993 | 22 January 1994 | | Decommissioned 29 May 2021 |
| People's Republic of China | 364 | Yuan Zheng 64 Hao | Nizhniy Novgorod | 877EKM | ??? | 1994 | 10 November 1994 | | Decommissioned 2021 |
| People's Republic of China | 365 | Yuan Zheng 65 Hao | Nizhniy Novgorod | 877EKM | ??? | 1995 | 14 August 1995 | | Decommissioned 2021 |
| Iran | 903 | Yunes | Saint Petersburg | 877EKM | 5 February 1992 | 12 July 1994 | 2 September 1996 | | Active as 2011 (probably in modernization in Iranian shipyard) |
| India | S63 | Sindhurakshak | Saint Petersburg | 877EKM | 16 February 1995 | 26 June 1997 | 2 October 1997 | | A munitions accident caused an explosion and fire while at berth in 2013. It was later scuttled. |
| India | S65 | Sindhurashtra | Saint Petersburg | 877EKM | 12 December 1998 | 14 October 1999 | 16 May 2000 | | Active as of 2010 |

### Project 636

| Operator | # | Name | Shipyard | Project | Laid down | Launched | Commissioned | Status |
| People's Republic of China | 366 | Yuan Zheng 66 Hao | Saint Petersburg | 636 | 16 July 1996 | 26 April 1997 | 26 August 1997 | Active as of 2006 |
| People's Republic of China | 367 | Yuan Zheng 67 Hao | Saint Petersburg | 636 | 28 August 1997 | 18 June 1998 | 25 October 1998 | Active as of 2006 |
| People's Republic of China | 368 | Yuan Zheng 68 Hao | Saint Petersburg | 636M | 18 October 2002 | 27 May 2004 | 20 October 2004 | Active as of 2006 |
| People's Republic of China | 369 | Yuan Zheng 69 Hao | Saint Petersburg | 636M | 18 October 2002 | 19 August 2004 | 2005 | Active as of 2006 |
| People's Republic of China | 370 | Yuan Zheng 70 Hao | Saint Petersburg | 636M | 2004 | May 2005 | 2005 | Active as of 2006 |
| People's Republic of China | 371 | Yuan Zheng 71 Hao | Saint Petersburg | 636M | 2004 | 2005 | 2005 | Active as of 2006 |
| People's Republic of China | 372 | Yuan Zheng 72 Hao | Saint Petersburg | 636M | 2005 | 2005 | 2006 | Active as of 2006 |
| People's Republic of China | 373 | Yuan Zheng 73 Hao | Nizhniy Novgorod | 636M | July 1992 | 8 May 2004 | 5 August 2005 | Active as of 2007 |
| People's Republic of China | 374 | Yuan Zheng 74 Hao | Severodvinsk | 636M | 29 May 2003 | 21 May 2005 | 30 December 2005 | Active as of 2006 |
| People's Republic of China | 375 | Yuan Zheng 75 Hao | Severodvinsk | 636M | 29 May 2003 | 14 July 2005 | 30 December 2005 | Active as of 2006 |
| Algeria | 021 | Messali el Hadj | Saint Petersburg | 636M | 2006 | 20 November 2008 | 28 August 2009 | Active |
| Algeria | 022 | Akram Pacha | Saint Petersburg | 636M | 2007 | 9 April 2009 | 29 October 2009 | Active |
| Vietnam | 182 | Hà Nội | Saint Petersburg | 636.1 | 25 August 2010 | 28 August 2012 | 3 April 2014 | Active as of 2014 |
| Vietnam | 183 | Hồ Chí Minh City | Saint Petersburg | 636.1 | 28 September 2011 | 28 December 2012 | 3 April 2014 | Active as of 2014 |
| Vietnam | 184 | Hải Phòng | Saint Petersburg | 636.1 | | August 2013 | 1 August 2015 | Active as of 2014 |
| Vietnam | 185 | Khánh Hoà | Saint Petersburg | 636.1 | 2013 | 28 March 2014 | 1 August 2015 | Active as of 2015 |
| Vietnam | 186 | Đà Nẵng | Saint Petersburg | 636.1 | | 28 December 2014 | 28 February 2017 | Active as of 2016 |
| Vietnam | 187 | Bà Rịa-Vũng Tàu | Saint Petersburg | 636.1 | 28 May 2014 | 28 September 2015 | 28 February 2017 | Active as of 2017 |
| Algeria | 031 | El Ouarsenis | Saint Petersburg | 636.1 | 2015 | 14 March 2017 | 9 January 2019 | Active as of 2019 |
| Algeria | 032 | El Hoggar | Saint Petersburg | 636.1 | | 18 June 2018 | 9 January 2019 | Active as of 2019 |

### Project 636.3

Italics indicate estimates.
| Operator | # | Name | Shipyard | Project | Laid down | Launched | Commissioned | Fleet | Status |
| Russia | B-261 | Novorossiysk [ru] | Saint Petersburg | 636.3 | 20 August 2010 | 28 November 2013 | 22 August 2014 | BSF | Active |
| Russia | B-237 | Rostov-na-Donu | Saint Petersburg | 636.3 | 21 November 2011 | 26 June 2014 | 30 December 2014 | BSF | Damaged by the cruise missile strike on Sevastopol drydock on 12 September 2023. Currently completed repair in dry dock. |
| Russia | B-262 | Stary Oskol [ru] | Saint Petersburg | 636.3 | 17 August 2012 | 28 August 2014 | 25 June 2015 | BSF | Active |
| Russia | B-265 | Krasnodar [ru] | Saint Petersburg | 636.3 | 20 February 2014 | 25 April 2015 | 5 November 2015 | BSF | Active |
| Russia | B-268 | Velikiy Novgorod [ru] | Saint Petersburg | 636.3 | 30 October 2014 | 18 March 2016 | 25 October 2016 | BSF | Active |
| Russia | B-271 | Kolpino [ru] | Saint Petersburg | 636.3 | 30 October 2014 | 31 May 2016 | 24 November 2016 | BSF | Active |
| Russia | B-274 | Petropavlovsk-Kamchatsky [ru] | Saint Petersburg | 636.3 | 28 July 2017 | 28 March 2019 | 25 November 2019 | PF | Active |
| Russia | B-603 | Volkhov [ru] | Saint Petersburg | 636.3 | 28 July 2017 | 26 December 2019 | 24 October 2020 | PF | Active; carried out land-attack cruise missile tests in January 2022 |
| Russia | B-602 | Magadan [ru] | Saint Petersburg | 636.3 | 1 November 2019 | 26 March 2021 | 12 October 2021 | PF | Active; deployed in the Pacific fleet late 2022 |
| Russia | B-588 | Ufa [ru] | Saint Petersburg | 636.3 | 1 November 2019 | 31 March 2022 | 16 November 2022 | PF | Active |
| Russia | B-608 | Mozhaysk | Saint Petersburg | 636.3 | 23 August 2021 | 27 April 2023 | 28 November 2023 | PF | Active |
| Russia | B-??? | Yakutsk | Saint Petersburg | 636.3 | 23 August 2021 | 11 October 2024 | 2024 | PF | Under construction |
| Russia | B-??? | Petrozavodsk | Saint Petersburg | 636.3 | 2022 | | 2025 | BF | Ordered in 2020, improved design |
| Russia | B-??? | Mariupol | Saint Petersburg | 636.3 | Autumn 2024 | | 2027 | NF | Ordered in 2022 |
| Russia | B-??? | | Saint Petersburg | 636.3 | 2023 | | 2026 | BF | Ordered in 2022 |
| Russia | B-??? | | Saint Petersburg | 636.3 | 2025 | | 2028 | BF | Ordered in 2022 |