Battleships, Cruisers, Destroyers, Frigates--What's the Difference? And Why Should We Care Anyway in 2022?

The terminology denoting warship types can, at a glance, seem bewildering--in part because old usages have become profoundly muddled over time.

The term "battleship" derives from "line-of-battleship," the vessels topmost in size, protection and armament (i.e. the biggest ships with the thickest armor and biggest guns) and so intended to "stand" in the line of battle during head on fleet clashes like Trafalgar or Jutland, because they could take and give the heaviest of beatings.

Cruisers were different. They were supposed to "cruise" independently, whether scouting for the fleet, or commerce raiding. (Indeed, it was once common to refer to submarines as "submarine cruisers," precisely because they were submersible vessels that did the cruiser's job of scouting and commerce raiding.) The premium on mobility meant that while they could be "light," "medium" or "heavy," or even "battle cruisers"--packing an armament that could compete with a battleship, but in each and every case less well-armored, and reliant on superior speed and agility to chase down their prey or escape pursuers rather than their ability to endure punishment.

The term destroyer derives from "torpedo boat" destroyer. As the name implies these were intended to fend off attacks against a fleet by the smaller vessels, which could most certainly not stand up to a battleship in a fight, but which nonetheless threatened even the biggest ships with the torpedoes they carried. Of course, torpedo boats only proved to be the beginning in that respect, with those "submersible cruisers" and the advent of aircraft translating to comparable threats to naval and civilian vessels, and in the process, what destroyers were more likely to be fending off in action.

Finally the term "frigate" was originally used in the "age of sail" to refer to swift, agile vessels too small for the line of battle. Fairly general, it had fallen out of favor in the age of mechanical, fossil fuel-driven fleets, and one might add, their more precise classification. However, the Second World War, with its submarine and other attacks, and the emergence of convoys in response to them, saw a vastly increased need for ships fulfilling the destroyer's protective function--to such a degree that there was call for smaller (cheaper and more easily and quickly produced) vessels that did the job. In American usage at the time these were "destroyer escorts," but the British term "frigate" has since become more commonplace.

Increasingly over the course of the Second World War and Cold War, with the carrier assuming the central role in naval warfare over the battleship; missiles supplanting guns in shipborne and aerial armament; with physical armor decreasingly utilized as a way of protecting vessels; and aerial, electronic and even space surveillance coming to the fore; the old combination made less sense. Given their vulnerability and the limited reach of their guns armored, big-gun battleships increasingly increasingly seemed pointless aside from a very few, limited uses for which few navies could not justify keeping them, with the few remaining examples curiosities (like America's battleships, utilized primarily for shore bombardment rather than fighting other ships). Big surface cruisers made less sense as a way of performing the commerce raiding and scouting missions, and so, especially as time wore on, such anomalies as the Soviet Union's Kirov-class vessels aside, "cruisers" were really just big destroyers or frigates. Indeed, the usage of one term or another mainly an indicator of size and armament--with cruisers particularly large and heavily armed, frigates representing the low end of the spectrum in that regard, and destroyers somewhere in the middle.

As all this happened ships of all types got bigger, with destroyers and even frigates becoming cruiser-sized vessels, while designated cruisers became something of a rare anomaly, in part because they seemed superfluous. Certainly the U.S. Navy has been an obvious example. The Ticonderoga-class cruisers (21 of which still serve) were not much bigger than the Arleigh Burke-class destroyers that came along by the late 1980s (9,600 to 8,000 long tons), with the latest edition of the Arleigh Burke class about the same size (9,500); and the Ticos considerably outmassed by the Zumwalt-class destroyers (15,600 tons), with the DDG(X) vessels likewise to also outmass them in their turn (10,000 tons+).

And thus does it even go with frigates. Australia's new Hunter-class "frigates," with their 8,800-ton displacement, 7,000-mile cruising range and AEGIS combat systems (with anti-ballistic missile capability), look not unlike the "Ticos" in size, reach and function--the more so if one compares them with the preceding ANZAC class of frigate (3,600-tonner vessels, closer to the stereotype of such vessels), or even the country's relatively new Hobart-class destroyers (which displace 6,900 tons).

As the Australian example should make clear a country's replacing even a frigate with "another frigate" may well indicate that what the country in question is really buying is a cruiser--and that much greater an increase in capability, less obviously dramatic than the country's shift to a nuclear submarine fleet and Tomahawk cruise missiles, but still significantly indicative of aspirations to a far more formidable naval position, with all it implies for its connections with the U.S. and Britain, the general balance of power in what it is increasingly fashionable to call the "Indo-Pacific," and the sharp acceleration of the already years-long trend of increased militarization and global rearmament in the wake of the war in Ukraine.