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Pakistan’s submarine fleet expansion requires genuine submarine rescue capability


The core element of the Pakistan Navy’s long-term development efforts is the expansion of its submarine fleet, which is slated to swell to as many as 13 ships equipped with air-independent propulsion (AIP) from the three – i.e. Khalid-class (Agosta 90B) AIP submarines (SSP) – in service today. Pakistan signed a multi-billion-dollar deal in 2016 for eight new SSPs from China Shipbuilding Industry Corporation (CSIC). The first tranche of four SSPs is due for 2023-2024, while the remaining four – which will be constructed by Karachi Shipyard & Engineering Works (KSEW) – will be delivered by 2028. This is only the projected SSP fleet, the Pakistan Navy could also potentially add miniature diesel-electric submarines (SSK) for littoral operations. The prospect of a large submarine fleet – the largest in the history of the Pakistan Navy – could come to fruition, which will provide greatly improved anti-submarine warfare (ASW), anti-ship warfare (AShW) and land-attack capabilities. However, the effectiveness of this force will also necessitate infrastructure in the way of specialized support ships, such as a submarine rescue and salvage vessel.

Submarine Procurement

The Pakistan Navy’s submarine procurement plans outlined in detail in Quwa Premium’s Monthly Report for December 2017 (accessible here or Quwa Premium subscribers). Briefly, the Agosta 90B SSP upgrade – being headed by Turkey’s Savunma Teknolojileri Mühendislik A.Ş. (STM) and implemented at KSEW – program is worth $350 million U.S.[1] [2] Pakistan signed onto upgrading the lead-ship (PNS Khalid) in 2016, which will be delivered to the Navy in 2019 or 2020.[3] Pakistan has also issued subsystem contracts for the second ship (PNS Saad) in late 2017 – this will follow 12 months of PNS Khalid.[4]

Overall, the Agosta 90B upgrade program involves a thorough replacing of electronic subsystems, namely: electronic support measures (ESM); command and control (C2); combat management system (CMS), electro-optronics and sensors, such as radar.[5] The purpose of the upgrade is to equip the Agosta 90Bs with subsystems found on contemporary submarines, such as Naval Group’s Scorpene. Although this upgrade will not alter the structural qualities of the Agosta 90B, but it will enable Pakistan’s ships to have directly comparable ASW and AShW capabilities to its newer counterparts, such as the Scorpene.

The Agosta 90Bs will be joined by eight new SSPs from CSIC. Designated Hangor-class, it is unclear which CSIC model Pakistan will procure, but a mock-up shown by KSEW during the 2016 International Defence Exhibition and Seminar (in November 2016) suggested it could be the double-hulled S26. The S26 is the AIP-equipped variant of the S20. Displacing at 2,660 tons, the S26 has a maximum speed of 18 knots and maximum diving depth of 300 m.[6] The S26’s default AIP offering is a Stirling system.[7] While Stirling carries the risk of higher acoustic signatures (from vibrations caused by moving parts), but the S26’s double-hull design might help mitigate the effects. However, in contrast to the Thailand S26T contract, neither KSEW or CSIC have confirmed the model of Pakistan’s submarines. This is a worthwhile consideration as in November 2017, CSIC revealed a series of new single-hull SSPs.[8] Besides being closer in emulating the designs Pakistan had originally sought from Europe, such as the Naval Group Marlin and ThyssenKrupp Marine Systems (TKMS) Type 214, these new single-hull SSPs may also offer lower life-cycle costs – a key advantage when operating a large fleet.

Miniature SSKs are being sought to succeed the Navy’s Cosmos MG110 (SX756/W) for minelaying and frogmen (i.e. deploying special forces) operations. However, new mini-SSK designs can potentially deploy heavyweight ASW torpedoes and anti-ship cruising missiles (ASCM) as well. CSIC’s newly revealed 200-ton MS200 mini-SSK has two ASW torpedo tubes. Leveraging low procurement costs, Pakistan could consider adding a relatively sizable number of mini-SSKs to cement its littoral anti-access and area-denial (A2/AD) requirements. Turkey’s STM said it was engaging with Pakistan to develop an original mini-SSK design.

Overall, Pakistan could build a sizable submarine fleet through the long-term, certainly its largest in history and, arguably, by several multiples. This will translate into increases in AShW, ASW and land-attack thanks to the increase of platforms capable of deploying ASCM, ASW torpedoes and land-attack cruise missiles (LACM). On the surface, the loss of a submarine due to routine maintenance and servicing, wartime repair or – the worst-case scenario – attrition could be sustained thanks to a large fleet. The ‘distributed lethality’ doctrine enables navies to distribute the mainstay of their attack capabilities across many ships, instead of concentrating them in a few high-cost assets. The loss of one ship does not adversely impact the fleet’s effectiveness. However, operating a sizable fleet comes with higher operating costs and the necessity for a host of support platforms to supply forward ships and, if necessary, rescue crew and salvage ships.

Submarine Emergency Response (SMER)

Analysts who discuss non-NATO or non-Western submarine development commonly point to the relative lack of submarine emergency response (SMER) development to pair with submarine fleet development.[9] SMER assets basically enable navies to search for distressed submarines (DISSUB) and carry-out rescue operations of the crew and, potentially, recovery of the ship. Outside of China, Japan, Australia and South Korea (i.e. established naval powers), only Singapore in Southeast Asia can fully undertake SMER.[10]

Besides saving crew lives (especially that of well-trained submariners), Pakistan will have the added need to reclaim strategic – i.e. nuclear-tipped – munitions. Furthermore, a sophisticated ship is also a trove of valuable information, such as one’s threat-library for electronic warfare jamming, schedules for receiving messages from a land-based very-low-frequency (VLF) transmission site (i.e. PNS Hameed) and potentially the submarine’s missions, which would factually expose Pakistan’s wartime plans. Based on these risks, it would follow that the Pakistan Navy will build SMER capability in parallel with its submarine procurement. In its 2015-2016 disclosure, Pakistan’s Ministry of Defence Production (MoDP) listed the construction of a submarine rescue and salvage vessel for the Pakistan Navy at KSEW.[11]

The MoDP did not provide a specific timeline, but it would likely coincide with the induction of the Hangor SSPs. While unarmed, a submarine rescue ship can be a relatively sophisticated – and costly – suite, but a necessary expense for a large submarine fleet. Generally, a rescue ship would include: a system to survey large areas of sea floor; remotely operated vehicles (ROV)/unmanned underwater vehicles (UUV) to reach the DISSUB and prepare the site for the rescue process; and DISSUB crew rescue systems. The cost of each of these inputs will vary depending on the original equipment manufacturers (OEM) dealing with Pakistan.

The first component of a SMER is the base ship platform to house the necessary vehicles and subsystems for the role. In recent years, Pakistan has ordered auxiliary/support ships from Turkey and China, such as the STM Pakistan Navy Fleet Tanker (15,600 tons) and the Survey Vessel (3,000 tons), respectively. Hence, in terms of a SMER platform, the Pakistan Navy could procure a mothership (MOSHIP) platform from those countries. However, considering that it is not a combatant (in the direct sense, though it would obviously support Pakistan’s submarine fleet), the pool of prospective suppliers can include other countries. Besides regulatory/approval and political issues, Pakistan will also look to control cost – controlling the cost of the MOSHIP could provide greater flexibility in terms of the accompanying vehicles and subsystems.

Potential reference designs can include the TCF Alemdar, the Turkish Navy’s first SMER, commissioned in January 2017. With a displacement of 4,447 tons, the Alemdar has a range of 4,500 nautical miles at 14 knots and crew of 131.[12] The TCG Alemdar can undertake rescue operations for DISSUBs at a depth of up to 600 m. Besides being a newer and tested design, the Alemdar is also compliant with the standards set under the NATO Submarine Rescue System (NSRS). This allows the Alemdar to interoperate with NATO in rescuing DISSUBs. Although Pakistan would not be part of the NSRS, such standards could enable Pakistan to offer SMER services to others in the Arabian Sea, such as the Arab Gulf states (which could procure new submarines of their own in the coming years).[13] By regularly attending bilateral and multi-lateral exercises – including Pakistan’s own AMAN – the Pakistan Navy clearly has an interest in nurturing ties with other navies. Including the provision of substantively valuable services such as SMER would add to that work.

SMER MOSHIPs are equipped with towed side-scan sonar (TSSS) systems, which enable the MOSHIP to survey large areas of the ocean floor. TSSS use acoustic emissions to build a visual picture of the sea floor. TSSS solutions are widely available on the commercial market, Pakistan should not be short of options in terms of an affordable and high-quality systems. Cost will vary based on the TSSS’ depth range and imaging resolution. The Klein Marine Systems D3500TF, which is marketed as a solution for SMER (along with other operations, such as oceanographic surveys, searching for mineral mines, etc), has a diving depth of 3,000 m. However, for optimal image capture, the D3500TF would operate at 200 m (at 400 kHz) and 600 m (at 100 kHz). The D3500TF is built from stainless steel and has an underwater weight of 47.7 kg. [14]

To initiate the submarine rescue process, the MOSHIP would deploy its remotely operated vehicle (ROV), an unmanned undersea vehicle (UUV) to survey the DISSUB’s vicinity and to prepare the site for additional rescue inputs. The ROV can provide essential functions such as lighting, hatch clearing, guiding incoming emergency supplies for the DISSUB crew and even connecting an emergency ventilation system (providing fresh oxygen) to the DISSUB crew. Using an emergency life-saving support (ELSS) system, the MOSHIP can send medical supplies, food and water to the DISSUB. The MOSHIP could also send a diver to the DISSUB (e.g. to directly connect an emergency ventilation system) using atmospheric diving suits (ADS). An ADS enables a diver to operate under the very high-pressure environment of the deep sea. OceanWorks’ HARDSUIT ADS can reach a depth of 365 m.[15] The TCG Alemdar was equipped with both an ROV and ADS.[16]

In terms of recovering crew, the lowest-cost method is to deploy submarine rescue chambers (SRC). These are basically derived from the McCann SRC, an early 20th-century DISSUB rescue method involving the use of a pear-shaped – but high-pressure resistant – pod to extract crew. OceanWorks’ SRC can reach a depth of 600 m.[17] While benefitting from a low upfront cost, thanks to its relative simplicity and lower integration requirements to the MOSHIP. However, for the SRC to connect to the DISSUB hatch, the MOSHIP must send a supporting ROV or ADS. Furthermore, the MOSHIP must be directly above the DISSUB for the SRC to reach the DISSUB – there is limited flexibility in the lateral or sideways range. Complementing the SRC, several new SMER MOSHIPs use remotely operated rescue vehicles (RORV) or submarine rescue vehicles (SRV) to extract 12-18 DISSUB crew at a time.

The SRV/RORV is essentially a miniature ship-launched submarine. If pursued, this would be the costliest element of the SMER MOSHIP. However, having one can provide the advantage of enabling the MOSHIP to begin the crew extraction process sooner (i.e. without needing to be in its immediate lateral proximity). Moreover, considering the strategic value of the SMER and the fact that it is (or should be) a long to very-long-term purchase, it would be wise to equip it such that it has maximum possible utility. Finally, the Pakistan Navy would likely require only one ship. While one ship could be costly, it would offer the totality of Pakistan’s SMER capability. This is unlike trying to build a sea-based air defence presence, which would require multiple expensive ships to build capability. Because it only requires one ship, Pakistan could look at investing sizably in that one ship, which would not – in the absolute sense – scuttle its budget.

In 2016, India ordered two such systems from the U.K.-based James Fisher & Sons for $273 million U.S.[18] Besides two RORV, the Indian order also includes the launch and recovery systems (LARS), which is the machine handling system to deploy and recover RORV/SRV, ADS, ROV and ELSS, along with the transfer-under-pressure (TUP) systems. The LARS is essentially a hoist through which rescue systems can be lowered to the ocean floor. The TUP is an integral system. It connects to the RORV, SRV and/or SRC housing rescued DISSUB crew and then provides decompression to that crew in the MOSHIP.[19] Thus, while the Indian Navy order is expensive, it includes several integral components necessary for a complete and effective SMER system.


Besides building a large submarine fleet, the indicators of a navy intent on building a robust sub-surface warfighting capability are its procurement of supporting assets. This includes the means to communicate with submerged vessels, which necessitates a VLF transmission site on-land. The second is to build SMER capabilities for recovering the crew of disabled submarines. Pakistan has its own VLS transmission site in PNS Hameed. Regarding SMER, Pakistan has put a submarine rescue and salvage ship on its procurement roadmap (with plans for KSEW to construct the vessel as well), though there are no details as to when this will occur, much less the procurement avenues or cost/budget goals of the program.

Based on Pakistan’s procurements thus far, it is likely that one of China or Turkey will lead the program. The latter has the advantage of engaging Western suppliers for key subsystems and vehicles, shown in the Agosta 90B submarine upgrade program (which involves Hensoldt and Kelvin Hughes). In fact, STM has a tangible and current design (i.e. TCG Alemdar) for the Pakistan Navy to examine. Moreover, critical design aspects of the ship, such as its pool test simulation, subsystem suite/integration and experience in constructing it have already been addressed. This is a key consideration as China, which would be the leading candidate to offer a design, last built a SMER vessel in 1975. In other words, a Chinese design would certainly be a riskier proposition unless it is also benefitting from wide-scale People’s Liberation Army Navy (PLAN) induction. Considering the age of the PLAN’s SMER assets today, this too is plausible.

The fact that Pakistan has slotted an uncommon maritime capability into its procurement roadmap shows that it intends to build a strong maritime presence. Having committed to eight new SSPs along with plans for new frigates and corvettes, the intent is evident. Unfortunately, the challenge of sustaining that with what is generally the smallest allocation of Pakistan’s defence budget is difficult to overcome, especially with an uncertain near-fiscal outlook. That said, the SSPs are a priority in the Pakistan Navy’s strategy, and in turn, supporting assets for these SSPs – like the SMER – will likely come to fruition.

[1] “Defense Industry Focuses on Quality and Quantity to Step-up Turkey’s Exports.” Defence Turkey. 30 September 2016. URL: (Last Accessed: 21 January 2018).

[2] Press Release. “STM Breaks New Ground in Pakistan.” STM. 22 June 2016. URL: (Last Accessed: 21 January 2018)

[3] Press Release. “STM Breaks New Ground in Pakistan.” STM. 22 June 2016. URL: (Last Accessed: 21 January 2018).

[4] Press Release. “SharpEye Radar for Pakistan Navy Submarine Upgrade.” 21 November 2017. URL: (Last Accessed: 21 January 2018).

[5] The Agosta 90B SSP upgrade is outlined in detail, including the make and model of new subsystems, in December’s Quwa Premium Monthly Report: Bilal Khan. “Monthly Report: Pakistan Defence Review 2017.” Quwa Premium. 31 December 2017. URL:

[6] Richard D Fisher Jr. “IDEX 2017: China offers S-26 conventional submarine with Stirling engine AIP.” Jane’s Defence Weekly. 22 February 2017. URL:

[7] Ibid.

[8] Gordon Arthur. “D&S 2017: Chinese floats whole submarine family for export.” Shephard Media. 06 November 2017. URL: (Last Accessed: 21 January 2018).

[9] The Geobukseon. “Opinion: Indo-Pacific submarine proliferation affects safety.” Shephard Media. 24 January 2018. URL: (Last Accessed: 21 January 2018).

[10] Geoffrey Till, Collin Koh Swee Lean. “Naval Modernisation in Southeast Asia, Part Two: Submarine Issues for Small and Medium Navies.” Palgrave MacMillan. 2018. p. 128-129.

[11] Ministry of Defence Production (MoDP) Yearbook 2015-2016 Part II. Government of Pakistan. p.86

[12] “Alemdar Class.” Bosphorus Naval News. URL: (Last Accessed: 21 January 2018).

[13] Ibid.

[14] Promotional Material. “D3500TF.” Klein Marine Systems. URL: (Last Accessed: 21 January 2018).

[15] Promotional Material. “Submarine Rescue Intervention.” OceanWorks International. URL: (Last Accessed: 21 January 2018).

[16] “Submarine Rescue Ship MOSHIP TCG “Alemdar” Delivered to Turkish Navy.” Defence Turkey. 28 January 2017. URL: (Last Accessed: 21 January 2018).

[17] Promotional Material. “Submarine Rescue Intervention.” OceanWorks International. URL: (Last Accessed: 21 January 2018).

[18] “India acquires two submarine rescue systems.” Naval Today. 23 March 2016. URL: (Last Accessed: 21 January 2018).

[19] Promotional Material. “Submarine Rescue Intervention.” OceanWorks International. URL: (Last Accessed: 21 January 2018).

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