The UK Royal Navy’s most expensive combat ships must have their engines refitted at a cost of tens of millions because they keep breaking down.

Problems with the Type 45 destroyer’s specially-built advanced generators have plagued the ships since they were first commissioned in 2009.

Engine refit of UK Royal Navy’s combat ship to cost tens of millions (Video)

Image: The Royal Navy Type 45 Destroyer, HMS Defender / Wikipedia

The six ships, which cost the taxpayer £1bn each, are the backbone of the Royal Navy’s combat force at sea and among the most advanced missile destroyers in the world.

A fault in the engine design, however, means that running all of the ship power-hungry systems at once can cause its generators to trip out, leaving the vessels completely without electricity and defenceless, writes the FT’s Sam Jones and Peggy Hollinger in London. The problem was first identified several years ago shortly after the first vessel – HMS Daring – entered service, but was previously dismissed by the Ministry of Defence as a teething problem.

A senior Royal Navy officer said the problem would be “catastrophic” in a combat situation, and was not a rare occurrence aboard the Type 45s. “It happens whenever we try to do too much with them at once,” he said. News of the decision to refit the ship’s power systems was first reported by the BBC on Friday morning.

A spokesperson for the MoD said: “The Type 45 destroyers are hugely capable ships and have consistently made a difference to our safety and security, including HMS Defender’s support to US carrier operations against Daesh in the Gulf. In our defence review last year we committed to improving the Type 45’s power and propulsion system through a series of machinery upgrades during planned maintenance, which will ensure increased availability and resilience over the life of the ships.”

The ship’s WR21 gas turbines were built by Rolls Royce and the electric propulsion motors by GE. The Type 45 project as a whole was led by BAE Systems.

A spokesperson for BAE said the company had “met its obligations as the design authority,” but was actively engaged in developing improvements. Rolls Royce has been working with the company to develop a solution to the issue.

“We have presented a range of upgrade options to the MoD, including a preferred solution,” BAE said. “The MOD has since asked the company to investigate some additional options and represent its findings. It is now up to the MOD to down-select its preferred option and instigate the detailed design process.”

The WR21 design was not the first choice of power and propulsion system for the destroyers. As the cost of building them began to spiral out of control – driven largely by their top-of-the-range air defence systems – Whitehall officials opted for a cheaper alternative to the original proposals.

The process of refitting the Type 45’s will also prove costly for the Royal Navy’s operational stance. Senior naval officers have already long-warned that the fleet is stretched thinly and has the minimum number of combat ships it requires to adequately perform its duties.

The commissioning of the UK’s two new aircraft carriers will further complicate the picture. Having at least one Type 45 out of action at any one point for an extended refit will make defending the carriers in the future a difficult if not impossible task, said one senior officer.