Cure for Royal Navy destroyers engine woes in sight

This evening HMS Dauntless sailed from Portsmouth, heading to Birkenhead. She will arrive on Merseyside on Tuesday morning and be the first Type 45 to undergo work to cure the propulsion problems that have plagued these ships.

The RN has paid a high price for pioneering Integrated Electric Propulsion (IEP) in a major warship. In simple terms, the gas turbines can sometimes fail when propelling the ship and the sudden load on the diesel generators can become too great. This causes them to ‘trip out’ resulting in complete power and propulsion failure. Although temporary fixes have reduced the frequency and severity of these occurrences, this is clearly an unacceptable situation and the remedy is overdue.


£280M of funding was set aside in the 2015 SDSR for the Power Improvement Package (PIP) which will finally cure the problem. In March 2018 BAE Systems, BMT Defence Services and Cammell Laird signed a contract with the MoD to deliver the PIP. The competition for the contract was split into two parts, comprising procurement, design and integration of the solution, and the physical installation and replacement of equipment onboard the Type 45 vessels.

BAE Systems has sub-contracted Cammell Laird to cut open of the hulls to remove the old generator sets and insert the new plant at their shipyard in Birkenhead, this will sustain more than 100 jobs. CL has large dry docks and years of ship repair and conversion experience appropriate to this kind of work.

Rolls-Royce is to supply new MTU Series 4000 diesel generator sets which will substantially increase the resilience of the power and propulsion system. The two existing Wärtsilä 12V200 diesel generator sets are to be replaced by three new MTU sets per vessel.

Despite the Pandemic crisis, HMS Dauntless sails. (Video: PortsmouthProud)

Key points

  1. The choice of the WR21 was made by the (Labour) government in 2000. (Geoff Hoon was Defence Secretary at the time). This was against the advice of the shipbuilder BAE Systems. BAES has subsequently made healthy profits sustaining these ships in service but cannot be blamed for the propulsion issue.
  2. Although a mistake in hindsight, it was not an unreasonable risk to select the WR21 over the proven US-made LM2500. It supported British workers and industry who had a strong track record of design and development of aero and marine gas turbines.
  3. The problem is with the intercooler which is designed to improve the engine’s thermal efficiency, not the gas turbine itself.
  4. Replacement of the GTs would be an enormously complex engineering challenge and it is simpler to supplement them with more powerful diesels. Once given the PIP, the Type 45 will change their mode of operation so they primarily cruise on diesel power and use the GTs for sprinting at higher speeds.
  5. Some media coverage has given the impression that all the Type 45s have been permanently stuck in port for years, but this is far from the truth. Sailing with some workarounds and operating restrictions, developed under the Equipment Improvement Plan (EIP), has allowed them to successfully deploy, including to the warm waters of the Arabian Gulf.
  6. Inexplicably the staff requirement for these vessels did not mandate strictly enough their ability to operate in high ambient air temperatures, despite it being obvious the ships would be deployed in warm climates.
  7. It has taken nearly 5 years since the PIP was agreed to start work on the first ship – a dismal lack of urgency. Cammell Laird was ready to start work on HMS Dauntless in September 2019 but BAES took another 6 months to prepare the ship which had already been in refit for almost two years.

In purely air-defence terms, Type 45 is regarded as perhaps the finest combatant in the world. This has been demonstrated by the US Navy welcoming them to co-ordinate air defence around its aircraft carriers in the high threat environment of the Arabian Gulf. The propulsion issue and their high unit cost resulting from the reduction from 12 to 6 ships has sadly marred their reputation. Let us hope the work on HMS Dauntless proceeds smoothly and at pace allowing her to be fully operational by mid-2021. The PIP should finally see an improvement to Type 45 availability and the potential of these vessels fully realised.