HMS Cardiff (F89): The Royal Navy's Next Submarine Hunter Takes Shape on the Clyde

A Ship Still Being Born

HMS Cardiff is being built by BAE Systems Maritime at the Govan shipyard on the Clyde, with first steel cut on 14 August 2019, the beginning of a construction process that reflects just how much has changed in shipbuilding since the earlier ships to carry the Cardiff name.

The yard she came out of is nearly as new as she is. BAE Systems has since opened the Janet Harvey Hall at Govan, a covered shipbuilding facility large enough to hold two Type 26 hulls at once and part of a three hundred million pound programme to modernise and digitalise naval shipbuilding on the Clyde. Building a warship indoors sounds like a comfort and is in fact a schedule decision: weather is one of the biggest single causes of delay in outdoor shipbuilding, and every week of painting, welding and outfitting that can be done under a roof is a week that does not have to be done afloat at Scotstoun, where it costs more and takes longer. The hall is named after Janet Harvey, who worked as an electrician in the Clyde shipyards during the Second World War. There is something quietly satisfying about the newest generation of British frigates being assembled in a building carrying the name of a woman who wired the last one.

She is the second of the Royal Navy's new Type 26 Batch 1 frigates, following the lead ship HMS Glasgow, and is part of a £3.7 billion contract covering three ships in total, with HMS Belfast to follow behind her.

It is worth knowing where the design came from, because the Type 26 had an unusually long gestation even by British standards. The requirement began life in the Future Surface Combatant studies of the 2000s, went through several changes of shape and name, and only became a firm order in 2017. Eight are planned for the Royal Navy, three in Batch 1 and five in Batch 2, replacing the eight anti-submarine Type 23s. That history, and the propulsion arrangement that came out of it, is set out in the article on the lead ship, HMS Glasgow (F88). What matters for Cardiff is that she is the second of eight rather than a one-off, which is the difference between a programme and a project: the second ship of a class is where the lessons from building the first one actually get applied, and it is usually where a shipyard starts to make money.

Unlike every previous HMS Cardiff, whose full service histories can already be written from beginning to end, HMS Cardiff's story is only just beginning: this account describes a ship still being fitted out rather than one whose career can yet be assessed in full.

A Purpose-Built Submarine Hunter

HMS Cardiff floated off her barge at the Glen Mallan jetty on 30 August 2024, moving to BAE Systems Maritime's Scotstoun shipyard for fitting out.

Progress since then has been steady rather than spectacular, which is what building a warship actually looks like. BAE Systems completed her first flood-up at Scotstoun in April 2026, which moved her out of the dry dock and into the afloat fitting-out phase: combat system integration, cable termination, machinery activation and harbour testing, all of it before she goes anywhere near a sea trial. She is a step behind her sister Glasgow, whose own trials are expected in late 2026 or early 2027. Five Type 26s are now being built at the same time on the Clyde, Glasgow, Cardiff, Belfast, Birmingham and Sheffield, which is a rate of warship construction Britain has not sustained in a very long time.

She is designed from the keel up as a multi-mission warship built around anti-submarine warfare, air defence and general purpose operations, fitted with 48 Sea Ceptor anti-air missiles across twelve quad-cell launchers, a 24-cell Mark 41 Vertical Launching System capable of firing Tomahawk cruise missiles, ASROC anti-submarine rockets and Long Range Anti-Ship Missiles, and hangar space for either a Wildcat helicopter, armed with anti-ship missiles or torpedoes, or a Merlin helicopter carrying anti-submarine torpedoes.

One capability on the list is a bigger change than it looks. The twenty-four-cell Mark 41 vertical launching system is the American standard silo, and it is significant because of what can be put into it rather than what will be on day one. The Royal Navy has fired Tomahawk from submarines since the late 1990s but has had no surface ship able to launch a land-attack cruise missile since the Second World War era of naval gunfire; a Mark 41 farm gives it that option for the first time. The same cells can take anti-submarine rockets, which extend a torpedo's reach to that of the sonar, and future anti-ship weapons. Strike length cells are also the currency of the moment in naval procurement: a ship with them can be upgraded by changing what is loaded rather than by cutting the deck open. For a ship expected to still be in service in the 2060s, that is the difference between a long career and an early one.

Her sensor suite includes the Type 997 Artisan 3D radar and the Sonar 2087 towed array, among the most capable anti-submarine sonar systems in service anywhere in the world, driven by a combined diesel-electric and gas turbine propulsion system designed specifically to keep her exceptionally quiet while hunting for enemy submarines.

Sonar 2087 deserves rather more than a name-check, because it is the reason the ship exists in the shape she does. It is not one sonar but two working together. A low frequency active transmitter is lowered on a cable to whatever depth the water conditions favour, and it pings; a very long passive array is towed behind the ship and listens, both for the returning echo and for whatever noise the submarine is making on its own account. Working the two together, bistatically, and putting the active transmitter below the layer of water that would otherwise bend the sound away, is what gives the system its reach. Thales describe it as letting a frigate hunt modern submarines at considerable distances and find them beyond the range at which the submarine could launch an attack, and that phrase is the whole argument: in anti-submarine warfare the ship that detects first usually decides whether there is going to be a fight at all.

The quietness is not a refinement, it is the primary design driver, and it buys two separate things. The obvious one is that a quiet ship is harder for a submarine to find. The less obvious one matters more: a ship's own machinery noise is the main thing degrading her own sonar, so a quieter hull hears further. The Type 26 goes after this with some determination. The propulsion machinery sits on rafts, isolated from the hull structure rather than bolted to it. The engines have isolated mounts. Pipework is isolated with rubber and the brackets holding it are designed so that vibration does not travel into the structure, which is why one description of the class ran under the heading that even the plumbing is quiet. The propellers are shaped to delay cavitation. All of it is aimed at a single requirement, which is to keep Russian submarines in the North Atlantic permanently uncertain about whether they are being listened to.

One feature of the design deserves more attention than it usually gets, because it is the thing that will define what she actually does. Amidships, below the flight deck, the Type 26 carries a large flexible mission bay with its own side and stern access, and it is deliberately empty. It can take boats, containerised equipment, unmanned surface or underwater vehicles, disaster relief stores, or a mix of all of them, changed over in a matter of days. A frigate built in 2026 will still be in service in the 2060s, and nobody knows what will need to be carried by then. The mission bay is the design admitting that.

A Name With a Proud Naval History

HMS Cardiff carries a name already well established in Royal Navy service, following the First World War light cruiser HMS Cardiff, which famously led the surrendered German High Seas Fleet into internment in 1918, and the Type 42 destroyer HMS Cardiff, which served in both the Falklands War and the Gulf War before decommissioning in 2005.

The two Cardiffs before her each did something worth remembering, and neither of them was quiet about it. The first was a C-class light cruiser that on 21 November 1918 led seventy warships of the German High Seas Fleet into internment in the Firth of Forth, the largest surrender of a navy in history and a scene nobody who saw it ever forgot; her story is told in the article on HMS Cardiff (D58). The second was a Type 42 destroyer that went south in 1982, took the surrender of the Argentine garrison at Port Howard, and was also involved in one of the worst incidents of the campaign; that is set out in HMS Cardiff (D108). A name that has been present at the surrender of one navy and the surrender of an enemy garrison is carrying a reasonable amount of history into a ship that has not yet been to sea.

As she completes her fitting out and moves towards sea trials and eventual commissioning, this newest HMS Cardiff inherits a name with a properly significant legacy to live up to, and a design built to keep the Royal Navy's submarine-hunting capability at the leading edge of naval technology for decades to come.

The wider programme is the most successful piece of British warship exporting since the Leander class, and it happened almost by stealth. Australia is building six as the Hunter class. Canada is building up to fifteen as the River class. In September 2025 Norway committed to at least five, a deal worth something like thirteen and a half billion dollars and the largest warship export in British history, and unlike the Australian and Canadian variants, which share roughly seventy per cent of the design, the Norwegian ships will be built on the Clyde and will be very close to the Royal Navy's own. Add the Royal Navy's eight and the total comes to upwards of thirty ships across four navies, all descended from a design drawn up for a submarine problem in the North Atlantic.

This is a live article which will be updated when more information is available.