Class warfare: The frigates and corvettes debate

What's in a name?

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As with other free and open nations, a discussion is taking place in Australia regarding ship classes such as frigates and corvettes, and their utility to Australia’s interests at sea. So, what’s in a name? Does a designated ship class affect a vessel’s utility to the nation?

Frigates are important to a fleet. The accounts of Admiral Horatio Nelson’s Mediterranean campaign in 1798 illuminate his desire to have more frigates, as these ships were his principle on-water reconnaissance capability. Their mission? To find the French battle force so Nelson could destroy it on the high seas. While history reveals that the subsequent Battle of the Nile provided an operational advantage to Britain, the value of the frigate to a nation’s navy should not be underestimated.

The term ‘frigate’ originated in the Mediterranean – the French class frégate and Italian class fregatta was a term applied to a galleass class of ship of about 250 tonnes. However, since the 17th century, the term ‘frigate’ has never had a precise definition.

Between the 17th and 19th centuries, the Royal Navy maintained a rating system to categorise their ships. Vessels with between 60 and 100+ guns were considered ‘ships of the line’ because of their lethality and survivability to stand in the line when opposing fleets came together. Frigates were given a sixth rate, essentially because they only carried between 20 and 28 guns.

Napoleon is said to have lamented that if you can find a fathom of water you would find the British – and their frigates. Perhaps the reason for his anguish was that frigates could remain at sea without provisioning for six months and were deployed globally on independent duty to undertake the business of the British state. Frigates, with all their armaments on one deck, were built for speed. In the age of sail, communiques occurred at the speed of the prevailing wind. Accordingly, their superior sailing qualities were considered essential to a balanced fleet as they provided the necessary intelligence for successful fleet action.

Unsurprisingly, other classes of frigates emerged to accommodate a state’s requirements. In 1794, the United States (US) ordered six frigates; they were known as the ‘big frigates’ as they carried between 44 and 56 guns. While the American frigates were larger, their duties were not dissimilar to those of other nations. The American frigates deployed from the Caribbean to the Mediterranean and the Pacific to protect shipping and commercial interests.

Frigates gained their reputation for independent duty, detached from any specific squadron. From this, the term ‘cruising’ emerged, which was essentially the meaning of the function, not a ship type. However, during the transition from sail to steam, and due to maintaining many of the frigate’s duties, cruisers became their own class by 1880. During World War I, they grew considerably in tonnage (up to 16,000 tonnes) and capability.

Early in World War II, frigates re-emerged as a class of medium-sized warship designed for anti-submarine warfare and convoy escort duty. Notably, these warships displaced around 2,000 tonnes. Since that time, the class of frigate has been universally adopted to describe a small-to-mid-sized warship capable of missions involving anti-submarine warfare, anti-aircraft warfare, shore bombardment and general-purpose duties such as trade protection and maritime security-themed stabilisation.

Notionally, a small-to-mid-sized warship can also be a corvette. This class of ship was also used in the 17th and 18th centuries, serving as the communications link between the ships of the battle fleet. The corvette, with only 20 guns, proved to be fast and weatherly, and its design – which enabled the free circulation of air, for example – made them suitable for service in hot climates such as the waters around Bermuda.

The changing character of war at sea during World War II – particularly the Battle of the Atlantic – ensured the re-emergence of the corvette as a ship class. The Battle of the Atlantic would not only be the war’s longest campaign, but one of the most vital to Allied success. The Atlantic provided the principal shipping supply route between the US and Britain. Simply put, without successfully contesting German sea control, Allied shipping and sea communications would have been lost and the Axis powers would have prevailed.

The vital stakes in defending Atlantic shipping and sea communications required quick production of the chosen ship class. The British Flower class emerged, based upon a ‘whale catcher’ design. This class was considered to have good seakeeping qualities and exploited commonality of commercial machinery to hasten production and technical training. It is hard to argue that the Flower class was the perfect design, yet it remained in service and was modified across nearly 300 ships built during the war.

During World War II, Australia, with a wartime budget and a mobilised nation, undertook its largest ever shipbuilding programme. Pursuing an uncomplicated design philosophy, it delivered 60 Bathurst-class corvettes from across eight shipyards. 33 ships of this class were delivered in 1942 alone. These corvettes undertook duties in Allied maritime theatres of operations, which included the Mediterranean, the Indian Ocean, the Pacific Ocean and the Atlantic Ocean.

Most recently, informed discussion highlighted the 1986 idea of a ‘three tier’ system to approximate surface combatant fleet duties, which ranged from oceanic high-end capability to domestic sea short-term contingency, then devolved further to benign coastal activity. This tier idea came from an internal naval study.

Following the tabling of the Defence Review in March 1986, Admiral Michael Wyndham Hudson, the Australian Chief of Naval Staff, wrote plainly to the Royal Australian Navy, illuminating what was ‘effective national defence’, albeit through a maritime lens. Firstly, Australia’s lifeblood is from the sea, and trade is invaluable. Secondly, Australia must assume responsibility for its own security. Thirdly, Hudson highlighted the value of maritime capability, especially a ‘balanced maritime force’ which underpins foreign policy options.

Hudson spoke to three levels of ships. Level one was the high-end oceanic capable ships, level two was envisaged as general-purpose ships deployed regionally to lower-level operations and level three ships would focus upon constabulary duties in the domestic seas. Hudson’s key point was that neither in peace nor in war is a capability as versatile as a surface warship.

Small-to-mid-sized warship classes evolve and are interpreted differently by each state depending upon their requirements. Some constants will prevail; attributes such as seakeeping qualities, combat role flexibility, endurance and range, which afford poise and persistence, will remain vital to any maritime state confronted with maritime discontent, on-water ambiguity and strategic complexity. In 1972, the Australian strategic thought leader T. B. Millar highlighted the Royal Australian Navy’s penchant for larger ships, deducing that distance and interoperability with American and British navies was an important requirement.

Australia’s geography is maritime; irrefutable interests at sea are the maintenance of access and the rule of law. Australia’s geography illuminates what tasks a navy must do, which in turn determines the character of the naval and maritime force required. The equally irrefutable fact is the capacity of the Department of the Treasury to fund Australia’s oceanic liabilities; an enduring tension for the foreseeable future. More challenging is that a nation’s navy should be viewed for its value rather than its binary cost.

Dr Sean Andrews is the founder and director of the Deakin Room. He was most recently the Senior Maritime Fellow at the National Security College, Australian National University, and he returns as a Visiting Fellow at the Changing Character of War Centre at Oxford University in September 2025. He is an Associate Member of King’s College London, former Director of the Sea Power Centre – Australia and the founder of the Indo-Pacific’s Six Nation Maritime Working Group.

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