Australia has lowered the requirements for its next class of submarines, cutting the risk and cost of a program that could carry a good deal of both.

The speed, range and endurance of the submarines will be similar to those of the current Collins-class subs that they will replace, the Australian Strategic Policy Institute reports, citing conference presentations by two top program officials. Australia’s 2009 defense white paper, which first set out the program for 12 submarines, required greater speed, range and endurance.

"Capability enhancements will instead focus on sensor capabilities and stealthiness, both of which will make the subs more effective and survivable in the decades to come," writes the institute’s director of research, Andrew Davies. The Collins class is capable of 20 kt. submerged and has a range of 16,700 km (9,000 nm) submerged at 10 kt.

The Collins replacement program is expected to cost AUD$20-40 billion ($22-43 billion), though the government could cut the requirement to fewer than 12 submarines. The final figure is hard to guess, since the driving force behind it is China’s growing strength. A cut in numbers this decade could easily be reversed in the 2020s as construction proceeds.

Since Australia has had great trouble with domestic construction of complex warships, including the Collins class, the prospect of locally building submarines of even more demanding specification has raised concerns about risk and cost.

The newly reduced capability requirement not only promises to alleviate those challenges, it also implies a reduction in displacement and propulsion power that could affect the impending competition to design the submarines and supply their technology.

The white paper did not specify a displacement, but at least 4,000 metric tons submerged was suggested by its call for better performance than the 3,400-ton Collins design, already among the world’s largest diesel submarines. By moderating the performance demands, the program office may be making one of the options, adaptation of the Collins design, more practicable. Government shipbuilder ASC, which constructed the six Collins boats to a design by Sweden’s Kockums, has backed that approach.

Even with relaxed requirements, the boats would still have to be larger than the Collins class. Air-independent auxiliary propulsion is likely, adding several hundred tons, and the improved sensors and stealth could also require a little more displacement.

Air-independent propulsion is already designed into another contender, the Soryu class, built by Mitsubishi Heavy Industries and Kawasaki Heavy Industries. That design displaces 4,100 tons submerged, though its surface displacement, 2,950 tons, is less than that of the Collins. Thanks to Tokyo’s newly relaxed rules on arms exports, Japan could largely alleviate Australia’s program execution worries by delivering mostly complete hulls or hull sections for fitting with U.S. combat and weapon systems.

A third option would be for DCNS, ThyssenKrupp Marine Systems or Kockums, now owned by Saab, to develop a new design of the size that Australia needs for construction by ASC in Adelaide.

Meanwhile, BAE Systems may acquire at least part of ASC. Both companies are building the Hobart-class air-defense destroyers, with ASC as prime contractor, but the government is not satisfied with the program’s performance. Local media say it is considering making BAE the prime contractor, possibly taking over that part of ASC that is handling the program.

This also raises the possibility of BAE taking charge of the submarine program, especially since the British company is more likely than continental European rivals to be allowed to handle U.S. submarine technology that Australia wants incorporated into the new boats. Submarine technology is an especially sensitive area of close cooperation between the U.S. and Britain.

In its report, the Australian Strategic Policy Institute quoted project head Rear Adm. Greg Sammut and the general manager for submarines of the Defense Material Organization, David Gould.