IMDEX 19: Singapore’s new generation sub-surface fleet

By Luca Peruzzi

The Republic of Singapore Navy (RSN) is one of the Asia-Pacific service introducing an expanded and enhanced sub-surface capability into its fleet. The service launched the first of its four Type 218SG AIP-equipped submarine at ThyssenKrupp Marine Systems’ (TKMS) yard in Kiel, Germany on 18 February. The RSN awarded an order for two Type 218SGs in 2013, followed by a second contract for two additional boats announced in 2017.

With a first steel cut occurred in 2014, the lead boat was christened Invincible and after the launch will be subjected to sea trails before being delivered to Singapore in 2021. In the meantime, the RSN crew will start operational training on board the boat, being based in Germany for up to two years for intensive training. In addition to the boats, the RSN will also develop a new simulators suite to train the submariners on the new unit type.

During the launch ceremony, the Singapore Ministry of Defence, Dr.  Ng Eng Hen, unveiled the following boats will be named Impeccable, Illustrious and Inimitable. The second-in-class will be delivered in 2022 and together with the first boat will replace the two older Challenger-class SSKs, while the second-batch submarines will follow from 2024 to replace the Archer class.

With a 70 m length and a 6.3 m pressure hull diameter, the Invincible-class AIP submarines displaces 2,000t on the surface and 2,200t submerged. Having been designed for operations in the Singapore’s shallow and busy tropical waters, the new submarines will be manned by a crew of 28, similar to the RSN’s existing submarines. The combat management system (CMS) of the Type 218SG was developed by ST Engineering Electronics and Atlas Elektronik.

The advanced automation and sense-making systems, which include data analytics and decision support engines developed by the Defence Science and Technology Agency (DSTA), will allow faster and sharper decision-making. The sophisticated automation and sense-making systems on board will also allow the new boats to be run on three four-hour watches or shifts (instead of two six-hour watches), allowing the crew more rest to endure longer underwater missions.

The agency has also worked closely with TKMS to ensure the design of the new submarines is ergonomically tailored for Asian physiques, as well as suitably climatised for tropical operations. According to the Singapore Ministry of Defence documentation, the new boats will have better situational awareness thanks to advanced sensors, particularly in the shallow and congested waters around Singapore. No details have been released, but EDR online understood the Type 218SG are expected to be equipped with latest-generation Atlas Elektronik’s Integrated Sensor Underwater System (ISUS 100) which can be configured for specific customer’s needs including the large acoustic aperture long-range sensors such as the Expanded Flank Array (EFAS) and the reelable thin line extended towed array sonar (ETAS), as well as the intercept and ranging sonars, the mid-frequency range ECAS (Enhanced Cylindrical Array Sonar), in addition to navigation aid acoustic equipment.

The TKMS-built Type 218SG submarines can stay underwater longer and have more firepower than the RSN’s existing submarines. The new boats are equipped with an Air Independent Propulsion (AIP) system based on fuel cells, which allow to stay underwater 50% longer than the RSN’s current submarines. Moreover, the Type 218SGs will have greater firepower through bigger payload capacity, although the RSN has not revealed exact numbers. Each boat is armed with eight forward-facing 533 mm tubes, likely to be used by the Leonardo’s Black Shark heavyweight torpedoes, that are reported to be in service with current fleet of submarines.

The new boats are indicated to be stealthier without giving details. However, in addition to the fuel-cell AIP, the other signature-reduction features include the propeller boss vortex diffuser to minimize propeller noise and increase efficiency. Moreover, the Type 218SGs are expected to be more maneuverable in littoral waters thanks to the X-rudder stern like the Type 212A boats, as opposed to boats with cruciform rudder arrangements.

Prior to the launch of the Republic of Singapore Navy’s first Invincible-class submarine on 18 February, Singapore’s Defence Science and Technology Agency (DSTA) and thyssenkrupp Marine Systems signed a Memorandum of Understanding (MOU) in Kiel to collaborate on new technologies such as additive manufacturing and data analytics for naval applications. Under the agreement, DSTA and thyssenkrupp Marine Systems will explore the use of additive manufacturing as an innovative, cost-effective method for producing submarine spare parts. Both parties will work together on the design, engineering, and qualification of additive manufactured components, which could be tested and trialled on Singapore submarines. This will add to the sovereignty and independence of the RSN from outside the country.

Photos by Luca Peruzzi