Australia's ''future submarine'' could be a super U-boat built by a German company that made many of the submarines that nearly brought Britain to its knees in World War II.
HDW has released details of a concept design, designated the Type 216, for a long-range conventional submarine.
Experts say the design, based on the successful Type 214, is specifically targeted at Sea 1000 - Defence's future submarine program.
Rex Patrick, a former submariner and the director of Acoustic Force, said yesterday the information available indicated Type 216 would meet the requirements spelt out in the 2009 Defence white paper and there was no reason the submarines could not be built in Adelaide.
''I think they [HDW] have been working on the Type 216 for some time with candidates like Australia, India and Canada in mind,'' he said.
Another HDW design, the Type 209, is the basis for three submarines Indonesia is buying from Korea's Daewoo Shipbuilding Marine Engineering.
The $1billion contract for the three, two of which will be built in South Korea and one in Indonesia, was signed on December 20.
Defence has been considering a number of European submarines, including the HDW 214, the Spanish Navantia S-80 and French DCNS Scorpene, as replacements for the trouble-plagued Collins for some time. It has confirmed ''requests for information'' are to be sent to the three manufacturers.
Defence has also signed a contract with Babcock to research a land-based submarine propulsion test facility and a ''Future Submarine Industry Skills Plan'' is being prepared.
While Defence has acknowledged the European vessels offer proven designs and shorter delivery times than an Australian-designed submarine, the concern is they are too small to meet Australia's broad needs as outlined in the 2009 white paper.
The ''supersized'' HDW Type 216 may change that. It is more than twice the size of the three submarines that have just been commissioned by Indonesia.
Designated the Type 1400, the Indonesian boats will still be very capable. The first is expected to be in use by 2015 with the second scheduled for delivery in 2018.
There is grave concern delays in the Government's decision making process means there is no longer sufficient time to design and build an ''evolved'' Collins class boat by the 2025 deadline.
Former ASC chief executive officer, Greg Tunney, is on the record as having said ''serious concept work and definition studies'' should have begun in 2010.
HDW's Type 216 concept, the subject of a special report in the current edition of Jane's International Defence Review, overcomes the shortcomings of small European submarines and would take less time - and money - to build than a ''son of Collins'' analysts claim. At almost 4000t, 89m long and with an extendable minimum range of 10,400 nautical miles (19,240km), it outclasses the existing Collins in every way.
The evolved 216 would come with air-independent propulsion giving it a nuclear submarine-like ability to linger underwater in choke points such as the Straits of Malacca for weeks on end. It would have the ability to launch cruise missiles, carry a ''swimmer delivery vehicle'' for special operations and be extremely quiet thanks to propulsion design parameters and an outer shell that absorbs sound.