The Turkish navy formally commissioned its first air independent propulsion (AIP) equipped Type-214 Reis-class diesel-electric submarine (SSK) Piri Reis in late August 2024. Türkiye had appointed German based Thyssenkrupp Marine Systems (TKMS) for this project in 2008 and the submarine was constructed at the Golcuk shipyard with support from local industries. On this occasion President Erdogan informed that Piri Reis has completed over 380 factory, harbour and sea acceptance tests. He mentioned that Türkiye plans to fit their national submarines with indigenous systems, devices and weapons such as guided anti-ship missile (ASM) Atmaca, Gezgin cruise missile (Turkish version of Tomahawk) and Akya torpedo. All these weapons are in various stages of development. Initially, the submarine will be equipped with heavyweight torpedoes like MK48 Mod 6AT, DM2A4 & anti-ship missiles like Harpoon. This submarine is expected to perform missions like littoral water operations, anti-surface and anti-submarine (ASW) operations, ISR tasks, and special forces operations. Eventually Türkiye is expected to operate six similar SSKs by 2029.

Features of Piri Reis:

Piri Reis is a single hull and compartment design-based submarine with fuel cell and high battery capacity. It is 67.6 meters long, weighs 1860 tons and can accommodate a crew of 37. Its speed is 10 and 20 knots on the surface and underwater respectively. It has a range of 12,000 nautical miles at 6 knots (surface) and 420 nautical miles at 8 knots (submerged). It has eight torpedo tubes with a diameter of 533 mm. Two BZM120 Proton-Exchange Membrane/ Polymer Electrolyte Membrane (PEM) fuel cell modules having 120 kw capacity powers AIP system. The service life these PEM is estimated between 2,000-4,000 hours. The PEM enables the submarine to achieve a cruising speed of 2-6 knots and stay underwater for about three weeks. The technical support and technology transfer for this AIP is provided by TKMS.

Türkiye’s naval aspirations and regional geopolitics:

Türkiye’s need for the construction of domestic SSKs stem from reasons like maritime rights, regional security, geopolitics and indigenous naval aspirations. President Erdogan while commissioning Piri Reis stressed “We are aware that to live peacefully in our lands, we must have a strong and effective navy both in our blue homeland and in distant geographies”. In 2019 he had stated “With the policies our country follows, we seek establishment of rights, which have been delayed. The works we carry out in the eastern Mediterranean, Syria and Libya are in this context. We have no intention to seize anybody’s rights. We do not have the luxury to pursue this silenced and shy policy. If we give up on the process we started with Turkish Cyprus and Libya, they will not let a seashore to even cast a fishing line. We will not comply with an order in which Turkey will gain 1 percent from fishing”. He had also accused Israel and Greece of hampering Türkiye’s fishing rights. Türkiye also felt the need to bolster its underwater capabilities and shift the regional balance of power because in the Eastern Mediterranean Sea, navies of Greece and Israel already operate AIP submarines. While Greece operates four Papanikolis-Class (Type 214 developed by German TKMS) and one HS Okeanos AIP submarine, Israel has Dolphin-II class AIP submarines.

Under project MILDEN (Türkiye’s national submarine project), Türkiye desires complete autonomy and indigenisation. MILDEN project was conceived in the year 2008. In 2009, a contract was signed by Howaldtswerke-Deutsche Werft GmbH (HDW), Kiel, a company of German TKMS, and Marine Force International LLP (MFI) London for the construction of Type-214 submarines for Türkiye. Türkiye’s leadership hope that Türkiye’s 80% industry participation can be realized through local subcontractors which can produce and integrate some systems and equipments. While HAVELSAN is the main sub-contractor responsible for developing submarine data distribution system (DBDS) & combat management system (CMS), other local industries are also involved, the other subcontractors are Aselsan, Milsoft, Ayesas, Koc Information and Defense Technologies, TUBITAK-MAM state-owned research institute and Roketsan which will deliver the Atmaca, Gezgin and Akya heavy torpedo of 533 mm.

German made submarine flaws:

German designed submarines have various flaws and limitations. Its stealth capabilities have been questioned as Type-214 uses a magnetic steel for the hull, which unlike non-magnetic steel hull can’t reduce magnetic signature. Also its claim of maximum speed without transient switching noises due to low-revolution, permanently excited motor is not validated. It also can’t launch cruise missiles due to its design, which was the reason India sided with the French Scorpene group for its Project-75i. It had been anticipated that there will be challenges for the Golcuk naval shipyard and TKMS to integrate Turkish subsystems in Piri Reis effectively. The flawless integration of Atlas Elektronik’s ISUS-90/72 CMS with Havelsan’s Sonar integration and Control system (SEDA) and Torpedo fire control system (TorAKS) was recognized as an issue.

TKMS built Type-214 submarines have faced various technical faults in other navies. The South Korean navy (ROKS), which operates similar TKMS developed SSKs had detected major defects on nine Son Won-il class submarines which are modified versions of the German Type-214 submarines. There were functional defects detected in the inverter module cabling. Three submarines had suffered problems due to a known method. The repair process was very long and affected the combat readiness of the entire fleet. Without necessary repairs, incidents of inverter module failure occurred which abruptly led to stranding of a submarine ROKS An Jung-geun in the middle of the East Sea. Another submarine ROKS Jeong Ji sufferedleakage from its cooling system which damaged the inverter module. National leaders have pointed that these problems are most probably due to depolymerization of the cables outer coating instead of structural defects in the cables themselves, since they have three layers of protection.

Greece possessing four AIP equipped Papanikolis-class SSKs built by German HDW had also detected 400 defects in the past, major one being such as excessive rolling when the submarine surfaced in high seas. The AIP system also didn’t function as promised. The output power was less than what was specified. The fuel cells got overheated and had to be shut down after several hours of operation. One reason could be the warmer Mediterranean, rather than the cooler waters of the North Sea in which the Germans used their AIP system. The propellers were noisy, the periscope vibrated when the submarine was traveling faster than 5 kmph. There were leaks, some equipment didn’t work, or function as specified. The Germans felt that some of these problems couldn’t be fixed.

Challenges ahead:

Technologies keep evolving and there are ongoing revolutions going on in submarine propulsion technology. French Naval group are TKMS are already planning to adopt lithium-ion batteries for its next-generation submarines which are considered better than fuel cell AIP systems. ASW tactics are also improving and there exists non-acoustic means of detecting even AIP based SSKs, such as analysing the effects of bioluminescence. As quoted by US Navy Cdr. Rob Brodie and retired Rear Adm. Tom Donaldson, “light produced by disturbed bioluminescent plankton is an ocean signature; a submarine cannot prevent the ocean from glowing.” Hence ASW operators can deploy low-light sensors and advanced processors with AI technology to decipher potential submarine contacts.

Türkiye wants to position itself as a formidable naval force in the global and regional security dynamics. It wants to extend its reach beyond the Black Sea and Eastern Mediterranean and someday wants to become a maritime power in the Indian ocean too. Türkiye’s own security needs imply that its resources are primarily meant to defend its own waters rather power projection elsewhere. Turkish navy doesn’t possess the resources for significant deployments to far-off waters. Already there were concerns with the shortened and accelerated harbour acceptance and sea acceptance trials for Piri Reis, which was launched on March 2022, in order to reach the timeline. This kind of hurried induction can spell trouble for the vessel in future. Türkiye’s commissioning of its first Reis class submarine could be a mega event for its leadership, but the technical issues faced by other navies in using TKMS/HDW made AIP submarines should not be ignored. In conclusion, Turkey’s commissioning of Piri Reis doesn’t alter the balance of power significantly in the Mediterranean.