Invincible-class submarine
The Invincible-class is a class of submarines with air-independent propulsion ordered by the Republic of Singapore Navy from ThyssenKrupp Marine Systems. Type 218SG is based on the design of Type 216 concept submarine from Howaldtswerke-Deutsche Werft. Four submarines were ordered and the lead vessel RSS Invincible was launched in February 2019. These submarines, along with the previously acquired Archer-class, will replace Singapore's Challenger-class submarines.
Design
The customised design is oceangoing and larger than the Challenger-class and Archer-class submarines operated by the Singapore Navy. The design is expected to be influenced by the export Type 214 submarine or Type 216 submarine, which have been designed for the potential needs of several other navies. Features will include AIP and a combat system designed by both Atlas Elektronik and ST Electronics. The Invincible class also features an "X" rudder "which offers enhanced manoeuvrability in confined littoral waters, as opposed to the Type 214's cruciform rudder arrangement." The X rudder is used on the Type 212 submarine and its larger and newer derivative, the Dolphin 2 submarine built for the Israeli Navy which is almost identical in size to the Invincible-class submarine.They are believed to have Horizontal Multi-Purpose Airlock, which can be used to launch either torpedoes, divers, or special forces assault teams, and also have the capability to launch cruise-missiles while submerged with an option for Vertical Multi-Purpose Airlock, for launching missile vertically, like the Tomahawk or Naval Strike Missile
Competitors
competed to supply 3 submarines to the Singapore Navy for $1.8 billion.Orders
The initial deal for two submarines was valued at €1.6 billion, including logistics and crew training.On 16 May 2017, Singapore defence minister Ng Eng Hen announced an order of 2 more Type 218SG submarines for a total of 4. The first 2 will be delivered in 2021 and 2022, while the remaining 2 will be delivered from 2024.
The first Type 218SG submarine, named RSS Invincible, was officially launched during a ceremony in Kiel on 18 February 2019.
Ships in class
| Hull Numbers | Name | Launched | Commissioned | Builder | Status |
| RSS Invincible | 18 February 2019 | ThyssenKrupp Marine Systems, Kiel, | Launched | ||
| RSS Impeccable | ThyssenKrupp Marine Systems, Kiel, | Under construction | |||
| RSS Illustrious | ThyssenKrupp Marine Systems, Kiel, | Under construction | |||
| RSS Inimitable | ThyssenKrupp Marine Systems, Kiel, | Under construction |