The Danes have given up on their best warships: Lessons for the Royal Navy

Telegraph

08-06-2025

Building warships is hard. To those who have been in one this will come as no surprise but for the majority who have not, and who see them like one's phone or car, then this is not well understood. A warship is a complicated assembly of many different complicated things, most of which need to be networked and connected to each other.
Any given class of warship tends to be made in small numbers, too, and there may be major differences even between warships of the same class. The first Arleigh Burke class destroyers in the US Navy, for instance, were 8,400 tons: the latest are 9,700. To some extent, every warship is custom built. And they're so expensive that there isn't usually much scope for prototypes and extensive tests on them before building the actual ship.
The Danes, however, do know all this, having lately found out just how difficult it is to get right. The Danish Chief of Defence recently announced that ongoing attempts to repair and upgrade the Royal Danish Navy's Iver Huitfeldt-class frigates will be abandoned. This is painful for the Danes as these three ships are the most modern in the Danish navy: and, on paper at least, they are the most capable.
The reality, dramatically exposed in the Red Sea last year, is rather different.
In the case of the Iver Huitfeldt herself, an integration failure between different weapons and sensors caused the ship's crew to lose the use of their air defence missiles for up to half an hour during a Houthi attack. They rebooted the command system and subsequently fired more missiles but in the hottest missile environment of recent times, this could have ended very differently. Their fallback option for shooting down drones – twin 76mm cannons – had similar command and control issues with 'up to half' the shells detonating too close to the ship to be effective.
The then Chief of Defence was relieved of his position and the ship removed from theatre: red faces all round (which was better than the alternative).
The problem was that a ship's detection and fire control radars, other sensors, command system, weapons and power delivery train all need to work as one and all at once. The search radar must find the incoming threat, it must then pass the information to the fire-control radar, the fire-control radar needs to get a lock on the threat, the missile system then needs that information – usually a human gets briefly involved here. Then a missile must launch and acquire the threat itself at some point, either using the reflections from the fire-control radar or its own active radar, or both at different times: or it may be guided initially by networked commands, possibly using information provided from a completely different ship, or an aircraft. Meanwhile the ship's installed generation must be powering and cooling all this kit reliably and in many modern cases driving the propulsion too.
Good ships – the US Navy's Arleigh Burke destroyers and the Royal Navy's Type 23 frigates, for example – do all this well. Bad ships – the US Littoral Combat Ships and our early Type 45 destroyers before they were partly fixed – do not.
One of the issues is that all the various systems may not originally have been built to work together. The Arleigh Burkes use Mark 41 missile launch tubes, originally built to work with the Burkes' Aegis combat system and its accompanying, hugely powerful radars: that configuration is proven and reliable.
The Iver Huitfelts use Mark 41 tubes too, but connected to different, European made radars and command systems. In this case of the Red Sea failure, many fingers point at the Thales phased array radar's ability to talk to the command system, but the detail isn't as important as noting the complexity. The problem is obviously a deep-seated one, as it has evidently proved uneconomic to fix.
One lesson that is crystal clear is that no feasible amount of laboratory work, peacetime testing and training can replicate the stresses and strains of combat. Whilst the gun issue was known about before, the missile fire control system problem was not, and only became exposed when real weapons were in the air.
Our Type 45 destroyer operating in the Red Sea, HMS Diamond, had the opposite issue when it shot down a ballistic missile previously thought to be outside its capabilities. This is a nice surprise, but it was a surprise, and it shows again that you don't know until you do it for real. Looking back in time, we had terrible problems in the Falklands and in the Gulf with our old Sea Dart and Sea Wolf missiles. (The sole Sea Dart engagement of 1991, in which an antique Silkworm missile was shot down, was claimed as a success. It should be noted that the Silkworm had already – luckily – missed HMS Gloucester and carried on past before the destroyer managed to shoot it down.)
The difficulty of weapons systems integration is also why I get a little nervous when plug-in or containerised systems are cited as a more flexible way of fighting ships in the future. On paper they can appear to be but if they don't integrate into the command system properly then you quickly end up with the Iver H problem. And by the time you've spent enough money to get around this, then maybe you should have just made that system part of the ship in the first place.