A country’s Merchant Navy are the commercial vessels under its flag, able to be requisitioned during crises. Australia once had a Merchant Navy, and the 2023 Strategic Fleet Report proposes (without using the term Merchant Navy) just such a body of vessels. It argues for 12 (and ideally 50) larger ships, with these commercially owned and operated, and Canberra paying some A$8 million per ship annually to cover Australia’s higher operating costs. While the report doesn’t mention arming such vessels, there’s a history of doing so from Defensively Equipped Merchant Ships (DEMS) equipped for limited self-defence to Armed Merchant Cruisers (AMC) with heavier weapons to guard convoys. A Merchant Navy of 50 ships (though Canberra’s only agreed to 12) optionally armed with easily removable weapons as DEMS and AMC has great merit.
DEMS could mount Phalanx gun and SeaRAM missile systems atop minorly modified 20- and 40-foot shipping containers. These systems together can address the most probable threats, and have self-contained sensors, computers, and weapons – minimising integration risks. For convoy protection, an AMC could equip Mark 70 launcher units, each with four large missile cells in a 40-foot container. The 1500-square-metre cargo surface area on a modestly sized AMC could notionally provide 50 launchers with 200 ASCM to hold Chinese ships at bay (Beijing’s most potent Type 55 destroyer holds at most 112 ASCM), with this arsenal remote-controlled by RAN escorts, again minimising integration risks.
This approach offers huge cost savings. Phalanx and SeaRAM are each A$25-40 million, and while the AGM-158C ASCM for the Mark 70 costs some A$5.5 million apiece, 200 fit on an AMC that costs Canberra nothing to buy versus 32 on a Hunter frigate that’s A$3.7 billion. Also, as containerised weapons could be easily added or removed, fewer units could be bought and then swapped between vessels. Further, 50 vessels at A$8 million each would cost A$400 million annually, noting eight ANZAC Frigates were A$374 million.
Finally, the RAN crewing impact is favourable. DEMS ships had a few naval personnel to operate their weapons, while AMC replaced their regular staff with military crews. So, DEMS would likely need some three RAN personnel and AMC around 20-30. For 50 ships this means 150-1,500 personnel; in contrast, a single Hunter has 183.
So an armed Merchant Navy has enormous potential, though it wouldn’t replace warships. The Hunters (and others) cost so much, including due to their exquisite sensors, computer systems, and damage resistance. But DEMS and AMC offer a cheap, crew-friendly way to enhance Australia’s supply lifelines. As such, they deserve a close look.