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The Swedes have been building submarines in one shape or another for over a century for both themselves and international customers. The pedigree has string roots in the Baltic but Swedish submarines are literally all over the globe.

Given the geopolitical climate that Sweden faces, the government has taken the bipartisan decision to make two defence assets matters of national sovereignty: the design and production of both submarine and fast jets in country. In a nation that boasts 9.7 million people and a GDP of US$552 billion, this is a national security decision rather than a purely economic one. As a comparison, Australia has 22.5 million people and a GDP of US$1.448 trillion.

On the geopolitical front, a large sabre-rattling bear lies to the north, making incursions into Sweden’s airspace and waters on a semi-regular basis. Post cold war defence sites are not uncommon, and still functioning in many cases. The Baltic is one of the most crowded maritime areas in the world but submarine faring nations in the region are decreasing. As ADM has pointed out before, if submarines were easy, everyone would have them.

Sweden maintains a fleet of five submarines; three Gotland class boats and two Sodermanland boats. The Sodermanland boats were previously known as the Vastergotland class until they went through an extensive upgrade program that effectively made them new boats. The Swedish Södermanland class of diesel-electric submarines consist of the HMS Södermanland and HMS Östergötland. These two submarines were originally launched as Västergötland-class submarines in 1987 and 1990, and have been relaunched as a new class after extensive modernization 2003 and 2004 by Kockums AB.

The pressure hull had been cut in two after the sail and a 12 m long new section with an air-independent propulsion (AIP) system was inserted. It contains two Stirling engines which are coupled to electric generators and heated by burning diesel fuel with liquid oxygen stored in cryogenic tanks. Two submarines of similar modifications, known as the Archer class, are in service with the Republic of Singapore Navy.

Originally launched as the Swedish Navy Västergötland class submarines HMS Hälsingland and HMS Västergötland in 1986 and 1987, the two submarines were sold to Singapore in November 2005 and relaunched in June 2009 and October 2010 respectively after extensive modernisation by Kockums. This included a refit to Södermanland class standards, the insertion of a new hull section with a Stirling AIP system, and additional climatisation for use in tropical waters.

The Archer class submarines were designed and built by Kockums AB as single-hull, double compartment submarines optimised to reduce noise and magnetic signature. The two pressure-tight compartments also enhance safety and survivability of the crew. The submarines were designed to operate in the shallow waters of the Baltic Sea and are therefore also optimised for operation in Singapore waters, which have similar depth profiles.

To give you an idea of the performance the Swedish navy are able to get out of their Gotland class boats, the USN borrowed HMS Gotland for a year (extended the period out to two years) to practice hunting conventional AIP boats in both littoral and blue water environments. The USN learnt a lot during this time. Gotland sunk carriers, frigates and anything else thrown at them.

First submarine flotilla commander, Captain Jens Nykvist confirmed that much of this success was due to endurance and capability offered by the AIP system.

“AIP gives us an definite advantage,” CAPT Nykvist told an Australian media tour. “With AIP we have better endurance compared an ordinary SSK, reduced exposure of masts, and increased time at the area of operations. Plus it’s a cost efficient way to run a submarine compared to a nuclear or fuel cell operated boat. While nuclear boats have their benefits, the power source is a sensitive issue for many countries.”

CAPT Nykvist admitted that the technology in finding AIP and conventional boats is improving, but ‘the sea will never be transparent’.

Both Swedish submarine classes have almost identical physical characteristics (see table – get figures from Jens Niquvist slides). The Sodermanland class is due to operate until the end of this decade with the new A26 design from Saab Kockums due to take over from 2022. Saab and FMV (the Swedish equivalent of DMO but with the ability to sign off on programs without the minister) signed an agreement in March 2015 for SEK 8.5 billion (AU$1.27 billion) the first two boats, with another three expected down the track.

Saab and FMV signed a Letter of Intent in June 2014 regarding the Swedish Armed Forces’ underwater capability for the period 2015-2024. The Letter of Intent comprises support, development, design and production of submarines and other underwater systems, corresponding to potential orders of approximately SEK 11.2 billion (AU$1.67 billion), provided that necessary decisions are made.

“The majority of the design work on the A26 is already done,” Gunilla Fransson, Saab’s head of security and defence solutions, confirmed to ADM. “We are confident we can meet the 2022 timeframe from FMV. We will probably start cutting steel late this year if not early 2016.”

“The modular design of the A26 is part of the wider design philosophy of Kockums,” Dr Roger Berg, head of technology management at Saab Kockums said. “From the beginning of the design process, there are margins in place for future growth and to allow for customer adaptation.”

Note: The writer travelled to Sweden as a guest of Saab.

 
This article first appeared in Australian Defence Magazine VOL.23 No.4, April 2015 
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