THE CONTENDERS FOR AUSTRALIA'S NEW SUBMARINES:

TKMS: ThyssenKrupp Marine Systems of Germany is proposing its new Type 216, a 4345-tonne 90-metre boat. The Type 216 doesn't yet exist but will be more than twice the size of Type 212 and 214 designs on which it is based. TKMS is a prolific builder of submarines, supplying 163 diesel electric subs to 20 navies since 1960, 51 built in customer shipyards.

The company is offering advanced air independent propulsion and lithium battery technology to enhance range. Early on, TKMS declared it could build all 12 subs in Australia for $20 billion. The company says that promise still stands. Heading the company's bid in Australia is Dr John White who led the Anzac ship project, which delivered 10 frigates for Australia and New Zealand on time and on budget.

DCNS: Direction des Constructions Navales Services, majority owned by the French government and defence company Thales, is offering the Shortfin Barracuda, a conventionally-powered version of its new Barracuda nuclear attack sub. Vessel number one will be launched next year. The Aussie Barracuda will be slightly smaller at 4500 tonnes and 97 metres.

DCNS is proposing power by familiar lead-acid batteries, but with propulsion from its advanced top secret pump jet instead of a conventional propeller. DCNS is the only bidder which builds both conventional and nuclear boats. It points to its extensive experience building nuclear subs for the French navy and diesel electric subs for Malaysia, India, Chile and Brazil.

JAPAN: The Japanese government, with Mitsubishi Heavy Industries and and Kawasaki Shipbuilding Corporation, is offering its Soryu (dragon) class boats. Unlike other contenders, the 4200-tonne 84-metre Soryu boats actually exist, with seven in service in Japan's navy.

This is close to what Australia wants but it still requires modification to improve range. Had former PM Tony Abbott had his way, Australia could have purchased Japanese boats built in Japan with no competition at all. The prospect of a political backlash prompted the competitive evaluation process.

Up to now, Japan's pacifist constitution meant it never exported any defence equipment, let alone something as complex as a submarine. Indisputably Japan builds good gear but it has no practical experience of the all important technology transfer needed to build in Australia.