Why Saab-Kockums Excluded? Australia doesn't trust it.

Following Australia's Collins-class Submarine Program by Sub Brief of April 20, 2021, GhalibKabir commented/asked:

"To this day I cannot wrap my head around why Kockums and RAN went with Hedemora Diesel instead of a Pielstick or the go to workhorse good ol' MTU..."

A support group in Australia, without any real knowledge of Kockums' troubled Collins history, frequently ask why Australia doesn't cancel the Naval Group submarine contract and return to Swedish Kockums (now absorbed into Saab) instead. 

Sweden imposing the Hedemora diesel motor (on the Collins) is one of the primary reasons Australia did not/does not want to return to Saab-Kockums. Supporters regularly advocate building a "Collins 2" aka "Son of Collins". 

Some History - in the mid-2010s Kockums was a poor risk, in corporate turmoil, for Australia to buy its submarines. Kockums from 1999 was owned by the Germans and in no position to build submarines.

In 1999, following the acquisition of Celsius AB by Saab, Kockums was sold to the German shipbuilding company HDW. In 2005, HDW was bought by the German industrial conglomerate Thyssen Krupp.^[2] The time after 1999 was rife with conflicts between Kockums' only Swedish customer, the Defence Materiel Administration (FMV), and Kockums' German owners. ThyssenKrupp insisted that Kockums ought to discontinue large submarine construction and to focus on the development of small submarines. Meanwhile, anonymous sources from inside Kockums claimed that ThyssenKrupp's goal in acquiring Kockums was never to reach synergies with HDW, but only to eliminate its main competitor.^[2]

On 14 April 2014 about 200 employees had left Thyssen Krupp for Saab and it was reported that Saab and Thyssen Krupp had started to negotiate about selling Kockums.^[32] In June 2014 Thyssen Krupp agreed to sell Kockums to Saab.^{[33 ]}During a visit to Kockums facilities on 30 June 2015 the Swedish defence minister, Peter Hultqvist, announced that two submarines will be ordered for a cost of 8.2 billion SEK (US$ 867 million).^[36] The two submarines will be delivered to the Swedish Navy in 2024 and 2025 ^[37]

Technical experts have demonstrated Kockums' actions and corporate instability was far deeper and more significant than Swedish cop-outs that "Kockums didn't deserve the "dud sub" tag".

In the 1990s Kockum's mishandling of the then Swedish company Hedemora's diesel problems, perhaps the main continuing defect of the Collins, was reason enough to exclude Sweden from the mid 2010's SEA 1000 shortlist. Also in the mid-2010s when Australia was compiling its shortlist Saab had never managed an order for new submarines - not even from its own Swedish Navy.  

A submarine's diesel motors are a major propulsion component that can kill a submarine. Efficiency and reliability are key. Submarine motors are thus expected to be tried, tested and mature pieces of technology - built to handle a customer (like Australia's) mission conditions. Diesels need to be big business, for the builder to have the money and expertise to tailor the diesels to customer needs.  

Simply put - Hedemora, when under Swedish ownership, had built submarine diesels for the Swedish Navy's Baltic Sea conditions. This was more than unhelpful for the Australian Navy's warmer, saltier and rougher, Indian and Pacific oceanic conditions.

See https://www.jstor.org/stable/10.7249/j.ctt3fh0pr.12?seq=2#metadata_info_tab_contentshttps://www.jstor.org/stable/10.7249/j.ctt3fh0pr.12?seq=2#metadata_info_tab_contents which explains:

"The Collins boats are the only diesel submarines [in the world with this particular 18 cylinder Hedemora] engine....In 1998 a liaison with ASC visited Hedemora [in Sweden] to try to resolve some of the problems with [these] engines and was shocked to see [Hedemora] only had 35 employees and was up for sale. Hedemora's ability to assist [the Australian Submarine Corporation] ASC was minimal, and Australia had to deal with the responsibilities of operating and supporting a unique engine that was a key to the submarines' success."  

Someone had to buy Sweden's Hedemora, the only builder of the Collins' diesels, before Hedemora went broke. 

Furthermore, Peter Yule's and Derek Woolner's 2008 book The Collins Class Submarine Story: Steel, Spies and Spin on page 225 explains, in part:

"The problems with the [Hedemora] diesels led many to question the choice of Hedemora engines...[As early as 2008 Hans Ohff] believes Hedemora should never have been involved in the project because it was a small and declining company that lacked the resources to develop and support submarine engines of the size required for the Collins, or to remedy any defects." 

UNDER AUSTRALIAN OWNERSHIP HEDEMORA HAS IMPROVED - BUT THE COLLINS' PROBLEMS ARE NOT OVER

Some history - Hedemora Diesel is a trademark to the Swedish company Hedemora Turbo & Diesel AB [which] used to produce diesel engines for ships, locomotives, and oil rigs along with backup generators to hospitals. The company later shifted its focus to supply existing engines with spare parts and service. In February 2006 Hedemora Diesel was bought by the Australian company Coote Industrial Ltd.^[1] The Collins' diesels are now called Garden Island-Hedemora HV V18b/15Ub (VB210) 18-cylinder diesel motors.

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SOME CONTEXT - SWEDISH KOCKUMS' PROPULSION PROBLEMS

Regarding the Collins submarines trials in the 1990s:

The fuel tanks were backfilled with seawater (as intended) BUT some of that seawater leaked into the Hedemora diesel engines, stopping compressed diesel fuel from igniting. But cylinders and pistons did compress, wrecking them. The whole process, of course, stopped the engine(s). This problem has never been completely fixed. Major “sun-roof” cutouts of top rear Collins hulls to remove the diesels for regular Total Overhauls (to remove rust-corrosion, salt, water) has weakened the pressure hulls of the whole Collins class thus reducing diving depth. This contributes to the total overall, overhaul, cost for the Collins submarines being about A$700 million per year.

“During trials of the first [Collins] submarines, the propulsion system was found to be prone to failure for a variety of reasons.^[93] Most failures were attributed to the fifteen-tank diesel fuel system: the tanks were designed to fill with salt water as they were emptied to maintain neutral buoyancy, but water would regularly enter the engines due to a combination of poor design, gravity separation of the fuel and water being insufficient, and operator error resulting from poor training.^[93] Problems were also caused by bacterial contamination of the diesel fuel, which, along with the salt water, would cause the fuel pumps to rust and other components to seize.^[94] The fuel-related issues were solved by installing coalescers, improving training and operational procedures, and adding biocides to the fuel.^[94]”

Shaft seals did not align properly during construction, causing seawater leaks in of up to 984 liters per minute in a deep test dive, almost sunk a Collins sub, perhaps  HMAS Dechaineux. Quick action by a crewman permitted this sub to rapidly move to surface to remove the pressure on onrushing water. 

“Propeller shaft seals were a significant problem on Collins and Farncomb.^[95] Although designed to allow for a leak of 10 litres per hour, during trials it was found that the seals would regularly misalign and allow hundreds of litres per hour into the boat—during one deep diving test the flow rate was measured at approximately 1,000 litres a minute.^[95] ASC claimed that solving these problems could be done by manually adjusting the seals as the submarine dived and rose, but this would have required a sailor dedicated solely to that task, affecting efforts to minimise the required number of personnel.^[95] It was found that the problem could be temporarily alleviated by running the propeller in reverse for 100 revolutions, pulling the seal back into alignment, although a permanent solution could initially not be found, as ASC refused to accept responsibility for the problem, and the original manufacturer of the seals had closed down.^[95] New suppliers were found, with modified seals fitted to the first two submarines in late 1996, before completely re-designed seals were fitted to the boats in late 1997, solving the problem.^[96] 

“The propellers themselves were also found to be poorly manufactured, having been shaped by hand, with at least one cast at the wrong pitch.^[97] This was rectified by using a five-axis milling machine for future shaping work and replacing the miscast propeller.^[98] The material used for the propellers was also found to be weaker than expected, developing fatigue cracks after only a few years of use.^[97] Instead of going to Kockums, which had started to go into decline after the end of the Cold War, the submarine project office sent the propeller to the United States Navy for redesigning.^[99] Despite the Americans fixing the problems with the propeller design, resulting in significant performance improvements, the Swedish company was dissatisfied with the Australian actions; the dispatch of the propellers was one of the points of contention in the [SWEDISH] company's legal action in the mid-2000s against the Australian government over ownership of the intellectual property rights to the submarine's design.^[100]

“Other propulsion problems included excessive motor vibrations at certain speeds which damaged various components (which was attributed to the removal of a flywheel and to corrosion caused by the fuel problems), and excessive fuel consumption in Collins at high speed (found to be caused by manufacturing problems with the turbines and turbochargers).^[101] The propulsion system was also found to be a secondary source of noise: poor design of the exhaust mufflers, weight-saving measures in the generator mountings, and an incorrect voltage supply to the battery compartment exhaust fans were noise-creating factors found and eliminated during studies by the Defence Science and Technology Organisation.^[102]