The loss of any submarine should be a catalyst for countries with submarines to review the likely causes and responses to determine if any lessons can be learned, in much the same way that airlines seek to learn from air disasters.

The tragic sinking of the Indonesian submarine KRI Nanggala 402 with its 53 crew has added significance for Australia because of our proximity, being between Australia and the highly contested South China Sea. What submarine search and rescue capability does Australia have and what is available in the region?

Although the Australian frigate HMAS Ballarat arrived early in the area where the Nanggala went missing, its sonar isn’t optimised for searching for wrecked or disabled vessels on the seabed. The wreck of the Nanggala was first detected by Indonesia’s KRI Rigel hydrographic survey vessel and confirmed by Singapore’s MV Swift submarine support and rescue vessel.

For the crew to escape or be rescued from a submerged submarine, the vessel must be lying intact on the seabed with survivors in at least one watertight compartment.

While accidents such as fires, floods and power failures do occasionally occur in submarines, an accident rendering a submarine incapable of surfacing is extremely rare. If a submarine sinks irretrievably, it’s even rarer that there are survivors to escape or rescue. More than 90% of the seabed is deeper than the crush depth of combat submarines, as was the case with the Nanggala.

The Royal Australian Navy’s six Collins-class submarines are based at HMAS Stirling, south of Perth, as are its two submarine rescue ships, MV Besant and MV Stoker. A rescue submersible ^[1], LR5, owned and operated by JFD Australia, is located nearby.

Considering the time required to install the LR5 system and the transit speed of the Besant and Stoker, it’s unlikely that the ships would be able to respond meaningfully to a disabled submarine any further away than Adelaide or Broome, and even that would require survivors to be contained in good conditions until a rescue could be attempted.

This raises a question of how the Australian Defence Force would respond to a RAN submarine that was disabled on the seabed further away.

The LR5 rescue system is air-transportable in the ADF’s C-17 transport aircraft, so it can be deployed to suitable ships that happen to be in the right place and are available to respond to disasters under the Vessels of Opportunity (VOO) program ^[2]. Offshore oil and gas rig support vessels, for instance, typically have the necessary deck space and systems for the submarine rescue equipment. There are many such VOOs to the northwest of Australia and in Southeast Asia.

Australia could also seek the assistance of other nations such as Singapore with its Swift rescue craft.

Unfortunately, with the occasional exception of a vessel in Bass Strait, suitable VOOs are rare on Australia’s east coast. If a RAN submarine got into trouble off the east coast, where they frequently exercise, there probably wouldn’t be a rescue ship available in time.

We could not afford the cost of having dedicated submarine rescue ships ready on the east coast or in most other areas where RAN submarines might operate, nor should that be necessary.

A better option would be to require certain ships designed for other duties to be able to embark and use the submarine rescue system. For example, an ability to embark and operate the full deployable submarine rescue system could be a capability requirement for the replacement for the landing ship HMAS Choules.

Until a few years ago, a ship was located at Western Port in Victoria tasked with RAN recruit sea training. It was also capable of supporting the deployable submarine rescue system. The RAN would benefit from a new recruit sea training vessel that could support diving and salvage operations, and submarine rescue. Such a vessel could provide the close escort for submarines doing sea trials off Adelaide following construction or maintenance, while simultaneously conducting recruit sea training.

In a Strategist post last year ^[3], I suggested that a support ship as a base at Manus Island would provide more value and flexibility than fixed infrastructure. Such a ship could be designed and built to accommodate the deployable submarine rescue system. A large fleet support ship need not be overly expensive; it could be built to commercial standards and operated by a core civilian crew as are current navy support ships Sycamore, Besant and Stoker. Navy and contractor personnel needed to support RAN ships could be embarked as ‘special personnel’, not crew, on a fly-in, fly-out basis.

I suggested that a Manus Island-based support ship should be optimised to support the Attack-class submarines that are being built for the RAN, but it should also be able to support destroyers, frigates and small vessels.

As the submarine force grows from six to 12 vessels, it’s likely to have a permanent presence on both coasts of Australia. A support ship, with submarine rescue compatibility, could be based on the east coast, offering flexibility to relocate as operational situations demand.

If Australia’s security situation continues to deteriorate, the government might recognise that nuclear-powered submarines are considerably more effective than conventional submarines and offer better value for money. Nuclear-powered vessels are not authorised to enter Sydney Harbour. A fleet support ship optimised for submarine support could be based in Sydney for conventional submarines or located elsewhere if nuclear-powered vessels are acquired.

The nuclear question is vexing when it comes to expenditure on submarine rescue systems. Why should Australia spend significant funds on world-class rescue systems and yet expect submariners to go to war in conventional diesel boats against superior nuclear-powered submarines?

Is nuclear power the right choice for our submarines, but not politically popular? As ASPI’s Peter Jennings wrote ^[4] last week: ‘When it comes to defence and security, governments need to do what is right for Australia’s interests, not necessarily what is popular, but it’s clear that public opinion has been ahead of government on the big strategic issues for some time.’

To encourage discussion on the nuclear issue, the Submarine Institute of Australia will convene a seminar ^[5] in Canberra on 15 July, ‘Might submarines lead a nuclear industry in Australia? Continuing the conversation’.

Regardless of whether we opt for nuclear or conventional submarines, Australia’s defence policymakers and capability developers need to consider the geographic limitations of our current rescue ships and whether there are relatively low-cost, flexible options that might increase the chances of a successful rescue if disaster strikes one of our submarines.