HMS Dauntless has completed sea trials as the first ship to undergo a major upgrade to resolve the propulsion problems that have plagued the Type 45 destroyers. As part of our series covering these issues, here we report on progress and some of the technical aspects of the work.
The guinea pig
After serving for just 6 years HMS Dauntless was laid up in early 2016, ostensibly due to the shortage of sailors, she then started a major refit in Portsmouth in early 2018. This project included major refurbishment of the ship’s hull, hotel services and sensor systems. The Sampson Multi-Function Radar was removed and taken to the BAE Systems facility on the Isle of Wight for obsolescence management and overhaul. The S1850M Long Range Air Surveillance Radar was also removed and refurbished at Thales’ radar facility in the Netherlands.
Thousands of metres of cabling were replaced together with hundreds of minor works to repair fittings. Deep fat fryers, fridges, freezers and other galley equipment was refurbished or replaced. The two propellors we inspected and overhauled along with more than 200 underwater valves, motors and pumps before the hull was completely repainted. The propulsion system that had not been run for several years was recommissioned and trials were conducted to provide baseline data against which to compare performance following the upgrade.
The Power Improvement Project (PIP) to rectify the Type 45’s serious propulsion deficiencies is being delivered under a £160M design and manufacture contract between the MoD and BAE Systems, delivered in collaboration with ship designers BMT Defence Services. The dry docking and work to install the new machinery was subcontracted to Cammell Laird in Birkenhead and Dauntless, selected to be the PIP lead ship, left Portsmouth to head north under her own power in May 2020.
Dauntless initially retained a full ship’s company as it was expected the PIP would take about a year and would not require the ship being ‘non-fleet date’ as would normally be the case for a ship in upkeep. Unfortunately, the project took more than double the time expected and she did not leave CL until June 2022, after 770 days spent in Birkenhead. She subsequently conducted an extensive range of machinery trials, it being particularly important to thoroughly test the new system as it will be applied to her five sister ships. The ship’s engineers and civilian contractors embarked during this period say the trials have gone well and “PIP is delivering exactly what it set out to do”. While at sea, software and hardware was further fine-tuned to get the most out of the enhanced power plant.
Despite the time already spent in refit, there is yet more work to be done. Now back in Portsmouth, Dauntless went into 15 Dock last week for additional maintenance and upgrades to her weapon systems which are expected to take just under 3 months. (The RN will have to wait until 2026 before the first Type 45 receives the Sea Ceptor upgrade). She should emerge in the Spring for additional trials, work up and certification by FOST. She will be finally ready to deploy by summer 2023, after being absent from the frontline fleet for more than 7 years.
The view from the engine room
The PIP is best characterised as a ship conversion project that will deliver far greater redundancy, returning full confidence to the command in the propulsion system while also providing a margin of additional electrical power for future upgrades. Changing engines presented a very significant challenge to fit them within the constraints of the machinery spaces and involved a complex design effort to ensure new equipment fully integrated with existing systems. PIP affects nearly all marine engineering aspects of the T45, with minor impacts identified ship-wide and on elements of the combat system. Digital modelling was used to de-risk some of the issues but in practice, the work proved more complex than expected. Not helped by COVID, the work on Dauntless over-ran by a year but the lessons learned should see subsequent vessels complete their PIP more quickly.
Ahead of the demanding integration challenge, the main work was the removal of the two legacy Wartsila W200 (2MW) Diesel Generators and replacing them with three MTU (3MW) V-20 Series 4000 DGs. Two of the three units were swapped directly but the additional engine was placed in the forward machinery room (FMR), an operation that involved cutting open the hull. A small part of the officer accommodation has been converted to house a new high-voltage switchboard room to help manage approximately 5MW of additional power now available. Other substantial tasks were to reconfigure the Platform Management System (PMS) and refurbish the two (21MW) WR21 Gas Turbine engines. The troublesome GT intercooler-recuperators have been replaced with a more reliable design.
The MTU Series 4000 diesels take advantage of 20 years of refinements in diesel engine design and are more fuel efficient, produce lower emissions are quieter, smoother and easier to maintain than the W200. Like the engines they replaced, the new DGs are housed in acoustic enclosures which makes for a better engine room working environment and reduces radiated noise. Being optimised for anti-air warfare, reduction of the T45s underwater signature was not top priority and they are reputedly relatively noisy. The Gas Turbine Alternators and some machinery sit on resilient mounts or ‘rafts’ to reduce energy from vibration transmitted into the water but full-ship acoustic hygiene is not the same standard as the Type 23 or 26 frigates.Type-45-Propulsion-Layout-3
The 4000 series engines use common rail direct injection (CRDI) where the fuel is stored at variable pressure in a cylinder or ‘rail’ connected to the engine’s fuel injectors via individual pipes. Increased injection pressure produces finer fuel atomisation that burns more fully and more cleanly. An electronic control unit determines the timing of the fuel injection and the amount of fuel injected – making for very efficient engines. The MTU series are also common to the re-engined Type 23 frigates and the future Type 26 frigates, streamlining logistic support and training requirements.
One of the many causes of problems was that in service the engines were run harder than expected, GTAs were run at almost double and the DGs four times that assumed at the design stage. The T45 propulsion system did not have the inherent redundancy that MEs were accustomed to having. Due to the overall reliability issues, often both DGs were run instead of one at a time, as a backup to avoid dreaded Loss of Power to Command (LPC) incidents. The PIP will fundamentally change the way a T45 operates its engines, moving from a two prime-mover ship designed to run mainly on its two GTAs, using the two DGs only occasionally, to a fully Combined-Diesel-Electric-and-Gas (CODLAG) arrangement. Post-PIP, the five prime movers can be mixed and matched in a flexible combination of nine standard operating modes that will be efficient and resilient.
The PIP is part of the wider Equipment Improvement Plan (EIP) for the T45s initiated under Project Napier in 2014. The decision to select Full Integrated Electric Propulsion (FIEP) for T45 was made relatively late in the design process and was not tested ashore as thoroughly as it could have been prior to installing the system in the lead ship, HMS Daring. (The T45’s similarly innovative PAAMS air defence system was developed over a longer 18-year period and has proved much more reliable). The RN had previous experience with diesel-electric propulsion in submarines and the Type 23 frigates but at much lower power. The more recent Albion class LPDs and Wave class RFAs also feature High Voltage DE drive but not to the same level of integration as T45.
The electrical system is complex, besides the prime movers and their alternators, there are the two 20MW Advanced Induction Motors (AIM) that propel the ship driven from Pulse Width Modulator (PWM) converters and Harmonic Filters that deliver current in the appropriate form to the AIMs. There is also a transformer for the ship services power supply, multiple switchboards and Dynamic Breaking Resistors that absorb energy from the motors when slowing down before being reversed to go hard astern.
Although the Gas Turbines were the main source of breakdowns, there are other points of failure of varying severity within the complex system and the EIP includes 47 individual modifications or additions to propulsion-related equipment. The EIP initially went for quick wins, dealing with the obvious weaknesses resulting in a dramatic increase in the mean time between failures. About 55% of the EIP had been completed across the T45 fleet by 2019 with work ongoing during refits and maintenance periods. Examples of modification include a new fuel centrifuge to improve fuel quality and a de-humidifier for the electric drive channels.
To further compound the T45 reliability issues, a new through-life support model was adopted for the class at the outset. Contracted Logistics Support (CLS) meant the RN only carried out operator-maintainer tasks and BAES was responsible for fault diagnosis and repair. This reduced crewing requirements but when there were problems the MEs on board lacked the spares, technical manuals and understanding to analyse or rectify faults at sea or without help from civilian contractors. This inevitably resulted in T45 spending more time alongside and made it harder to grip the problems as they emerged.
This is being addressed by Project Vesta which has two aspects. The first is to improve T45 availability through the replacement of obsolete equipment, particularly software and electrical components, some of which date back to the late 1990s. The more important second strand is to modify the support solution to give ships’ staff the right spares, tools, maintenance routines, documentation and training to deal with the full spectrum of diagnostics and repair tasks.
A high price has been paid by taking a risk on an innovative propulsion system. The effects of a decision taken at government level 22 years ago continue to impact warship availability and the RN’s reputation today. EIP and PIP have finally begun to grip the issue, although like so many other aspects of naval support and procurement, taking far too long. FIEP has at least delivered the fuel efficiency benefits it promised and many of the lessons learned have contributed to the robust propulsion design of the QEC carriers and the Type 26 frigates. (The highly unusual muff coupling failure experienced by HMS Prince of Wales is a one-off mechanical issue and the QEC propulsion has otherwise proved to be both efficient and reliable). At the time of writing, HMS Daring is well into her PIP at Cammell Laird and HMS Dragon is having the work done in Portsmouth, concurrent with her major refit.
The T45s are due to be replaced in the late 2030s. Delivering their replacement (the Type 83 destroyer programme and its Anti-Air Warfare system of systems) is likely to be expensive and complex. It would not be surprising if T45s have to soldier on well past their planned out-of-service dates. Having spent more time alongside in their early careers than would have been anticipated, this will at least extend their hull life. With the addition of Sea Ceptor, upgrades to Sea Viper and PIP, the class should be well prepared for the demands of operations in the 2030s.