KIEL, Germany - Singapore has launched its final Invincible-class submarine, marking a new era in the Republic’s submarine journey.

The 70m-long Inimitable is the last of four Type 218SG submarines that the Republic of Singapore Navy (RSN) had commissioned thyssenkrupp Marine Systems (TKMS) to build as far back as 2013.

Like its sister vessels, the Inimitable was launched at the TKMS shipyard in the German port city of Kiel. The April 22 ceremony was officiated by Senior Minister and Coordinating Minister for National Security Teo Chee Hean and attended by German Defence Minister Boris Pistorius.

In his speech, SM Teo said the Inimitable is a product of the longstanding and strong relationship that Singapore has with Germany in the naval domain. This stretches back to the RSN’s first missile gunboats acquired in the 1970s, which were built in Germany, he noted.

He also hailed the strong bilateral and defence relations between the two countries that stretch across multiple domains, and which have expanded in recent years to digital and other sectors.

SM Teo said the new submarines will enhance the RSN’s ability to fulfil its mission of protecting the sea lines of communication in the region.

He noted that the Republic sits astride a focal point of international shipping routes: Close to 90,000 ships pass through the Straits of Malacca and Singapore each year, while the port of Singapore handled 39 million containers in 2023.

In comparison, about 74,000 ships passed through the same waterways and Singapore handled 30 million containers in 2011, the year the RSN commissioned its first Archer-class submarine.

The launch of the Inimitable marks the latest milestone in a journey that began in the late 1980s, when the RSN recognised that developing its own submarine capability would be critical for its mission of protecting vital sea routes and securing Singapore’s access to the seas.

The early years saw Singapore acquire and adapt second-hand submarines from the Swedish Navy, first with the Challenger-class, then the Archer-class.

“Now, with the help of our German friends, we have delivered a submarine which is uniquely Singaporean – specially adapted for our waters, and fitted with advanced digital systems,” said SM Teo.

As the lady sponsor for the launch, his sister, Ms Teo Swee Lian, pressed a button which triggered mechanisms that smashed a bottle of champagne against the submarine’s hull.

Officials in attendance at the ceremony included Senior Minister of State for Defence Heng Chee How, chiefs of navy from Germany and Singapore, and senior defence officials from both countries.

The four submarines are progressively being brought to Singapore, and will be operational in Singapore’s waters by 2028.

Since its launch in 2019, Invincible has remained in Kiel for training purposes. Illustrious, launched in 2022, is undergoing sea trials in Kiel.

Impeccable, also launched in 2022, arrived in Singapore in July 2023 and is undergoing local sea trials and working towards full operationalisation and commissioning later in 2024.

The return of the Invincible-class submarines means the four Challenger- and Archer-class submarines that the RSN has operated for more than two decades will be progressively decommissioned.

The earlier generations of submarines had to be retrofitted to operate in warm tropical waters, which included replacing steel pipes with copper nickel iron ones to reduce corrosion, and installing a system to minimise barnacle growth on the submarine surface.

The Invincible-class vessels, on the other hand, were designed from the get-go for operations in Singapore’s shallow and busy waters. They also possess longer endurance and higher payloads than their predecessors, said the Ministry of Defence without revealing specifics.

Lieutenant-Colonel Xander Lim, who is the head of operations and training at the submarine project office, said the RSN had learnt through years of operations the challenges faced in local waters, and incorporated new designs into the Invincible project to better operate in this environment.

For instance, the new rudder drive system in the Invincible-class provides better manoeuvrability – LTC Lim likened the difference to operating a bus or large car in a multi-storey carpark, versus driving a small car with power steering.

The new vessels also maximise manpower efficiency, a necessity given Singapore’s declining birth rate, said LTC Lim.

A submarine of the Inimitable’s size typically needs about 50 to 60 personnel, but through automation the RSN has cut this to 28 submariners.

SM Teo said that while the Inimitable’s launch is the last in the series of Invincible-class submarines, the partnership with TKMS will continue.

The German shipbuilder will continue to provide technical training and in-service support for the RSN and ST Engineering to operationalise these boats.

The RSN’s submariners will also continue to have professional exchanges through Singapore and Germany’s submarine affiliation programme, launched in 2022 for both sides to share best practices on submarine training.

SM Teo said: “The Invincible project and the launch of Inimitable mark a new era for Singapore’s submarine journey. This is the culmination of hard work by capable and dedicated people who persevered through the challenging years of the Covid-19 pandemic.”

Singapore’s submarine journey

With Singapore sited at a focal point of international shipping routes, the RSN plays an important role in keeping vessel movements in the country’s waters safe. Here is how it has used submarines from the 1990s till now:

1995: RSN begins submarine development by acquiring a refurbished Sjoormen-class submarine built in the 1960s from the Swedish Navy. It acquires another three in 1997. The boats are relaunched as the Challenger-class.

2005: In November, Singapore signs an agreement with Kockums of Sweden to supply the RSN with two Vastergotland-class submarines to replace some of the Challenger-class ones. They are relaunched as Archer-class vessels in June 2009 and October 2010 after extensive modernisation.

2013: A deal is signed with TKMS to buy two new submarines. In 2017, Defence Minister Ng Eng Hen announces the purchase of two more, bringing the total to four.

2019: The first Type 218SG submarine, or Invincible, is launched in Kiel, Germany. Sea trials and crew training are carried out there.

2022: Invincible-class boats – Impeccable and Illustrious – are launched in Kiel with Prime Minister Lee Hsien Loong officiating.

2023: In July, the first of the four Invincible-class submarines, Impeccable, arrives in Singapore.

2024: The final of the four Invincible-class submarines ordered from TKMS is launched in Kiel. The Inimitable is launched by Senior Minister Teo Chee Hean on April 22.

The Ministry of Defence says the Impeccable is working up to full operationalisation and commissioning in 2024.

2028: All four Invincible-class submarines will return and be operational in Singapore waters by 2028.