The claim

Defence Minister Richard Marles attacked the Coalition in Question Time yesterday, blaming the previous government for the state in which it left the navy.

"When the Albanese government came to power, we inherited from the Liberals the oldest surface fleet that the Royal Australian Navy had operated since the end of the Second World War," he said.

Mr Marles made similar comments upon the release of Australia's 2024 National Defence Strategy in April, during an interview with Channel Seven's Sunrise program.

Asked if he accepted that "both sides of politics should be judged harshly here", the deputy prime minister responded:

"Well, I think we certainly have a lot of challenges. I mean what we've inherited as a government was the oldest surface fleet for our navy that has been operating since the end of the Second World War."

"That's what the Coalition did," he added.

Was the Coalition responsible for leaving the government with the oldest surface fleet since World War II? RMIT ABC Fact Check investigates.

The verdict

Mr Marles's claim is not watertight.

Data from the Royal Australian Navy website, supplemented by other historical publications, shows there have been periods since the Second World War when the average age of the surface fleet was older than that recorded at the 2022 election.

This applies to the surface fleet whether defined narrowly as major surface combatants only or defined broadly using a wider definition adopted by the US Navy.

However, it's important to note that there may be other valid methodologies available to the navy which are not publicly available. Nonetheless, the data shows there are holes in Mr Marles's argument.

The publicly available data does show the current fleet is still relatively old in historical terms. But experts told Fact Check this situation could not be attributed solely to the Coalition, given that Labor did not bring into service any new major surface combatant ships when last in power and only commissioned one ship that met the broader US definition.

Moreover, the data is an imperfect measure of Australia's naval capability. That's because the decommissioning of an older ship without a replacement would reduce the age of the fleet but, at the same time, its size.

What is the surface fleet?

Fact Check contacted defence industry experts for help in assessing the age of Australia's surface fleet.

They agreed that there was no single way of defining the term "surface fleet", other than by excluding sub-surface vessels such as submarines.

Given this ambiguity, Marcus Hellyer, a defence analyst and the head of research at Strategic Analysis Australia, argued for assessing Mr Marles's claim using two separate definitions: major surface combatants, and something akin to the US Navy's Battle Force classification.

"Since he was speaking in the wake of the release of the 'surface fleet review' … I suspect he was referring to major surface combatants," Dr Hellyer said, discussing Mr Marles's April claim.

That fleet review, or the Independent Analysis into Navy's Surface Combatant Fleet, referred to destroyers and frigates as "major surface combatants".

Dr Hellyer added that in the past this definition would include Australian ships that had been classified as destroyer escorts, battle cruisers and cruisers.

In making his latest claim, Mr Marles noted that HMAS Anzac, the oldest of the Anzac class frigates, was "on its last legs" and that this meant Australia "had 11 coming down to 10 surface combatants".

Indeed, shortly before the May 2022 election, an archived version of the navy's website showed there were eight Anzac class frigates along with three Hobart class air warfare destroyers.

With the decommissioning of HMAS Anzac (III) in May this year, the number of these major surface combatants was reduced to 10.

Fact Check takes Mr Marles to be talking about major surface combatants when he talked about Australia's "surface fleet", but experts said there were also broader definitions of which ships might count as surface combatants.

Broader definitions

Jennifer Parker, an adjunct fellow in naval studies at UNSW Canberra with more than 20 years of experience in the Royal Australian Navy, told Fact Check that, in the broadest sense, the combatant fleet would include "all surface ships in the [navy], including auxiliary ships".

"The surface combatant fleet in my view is made up of destroyers, frigates and corvettes. But there is no strict definition, [so] you could argue it also includes aircraft carriers."

Jack McCaffrie, a retired naval officer and visiting fellow at the University of Wollongong's Australian National Centre for Ocean Resources and Security, said mine warfare ships and replenishment vessels, such as oil tankers, should also be included: "the former because they are combatants and the latter because we don't get far without them".

Peter Jones, an adjunct professor with the University of New South Wales's Naval Studies Group and a former vice admiral and chief of the Royal Australian Navy's Capability Development Group, also recommended the inclusion of the post-WWII Bathurst class corvettes, which are referred to as Australian minesweepers.

He agreed with the inclusion of oil tankers and added patrol boats and amphibious assault vessels to the mix.

Meanwhile, the US Navy's Battle Force classification includes a "combatant ship category" covering major surface combatants, aircraft carriers, mine warfare vessels, amphibious warfare vessels and support and logistics ships, along with "littoral" (coastal) combat ships.

To account for the range of definitions, Fact Check will assess the age of the surface fleet on the narrower definition of major surface combatants, as articulated by Dr Hellyer, and on the broader US Navy Battle Force definition (excluding submarines and submarine support vessels), which includes most of the vessel types mentioned by other experts.

Source of the claim

Fact Check contacted Mr Marles's office to ask for the source of his claim but did not receive an on-the-record response.

It is possible that Mr Marles has relied on internal government documents that are not available to the public and that could adopt valid methodologies which differ to those used above.

The recent surface review said it "concurred with the [Defence Strategic Review]'s findings that the current and planned surface combatant fleet is not appropriate for the strategic environment we face, noting it is the oldest fleet Navy has operated in its history".

As an example of what might be covered by different methodologies, Ms Parker speculated that ships often undergo upgrades that may affect the way the age of a ship is viewed.

However, she said that such changes were not worth including in Fact Check's analysis, because while they might affect the capability of the equipment on board, such as missiles and radar, they would not affect the age of the hull, "which is one of the most important elements".

Fact Check has not incorporated data on ship upgrades into this analysis but has sought to take account of when a ship has changed roles, as was the case for River class frigates HMAS Diamantina (I) and HMAS Gascoyne (I), which ended their service as survey vessels.

It should be noted, however, that any analyses are sensitive to which vessels are included and how they are classified.

Where is the data?

A comprehensive dataset of all warships that have served in the Royal Australian Navy does not exist online.

However, the navy's official website contains a list of currently serving vessels, while the Sea Power Centre, which sits within the navy, provides a list of past ships (and their histories).

Both sources contain information on when each ship entered into service in the Royal Australian Navy (its commissioning date) as well as when each ship left service (when it was either decommissioned or lost in battle).