Royal Navy Will Retrofit Type 45 Destroyers To Keep Them From Breaking Down
The UK Defense Ministry hopes contractors will be able to upgrade the gas turbines and generators on all six ships in the next five to seven years.
Defense contractor BAE Systems has secured a contract worth approximately $226 million to upgrade the diesel generators on board the U.K. Royal Navy’s six Type 45 destroyers. This is the second part of a two-phase program, called Project Napier, which aims to finally fix a long-standing reliability issue with the ships that could leave them stranded without any power and render them combat ineffective in the middle of a crisis.
Under its part of Project Napier, also called the Power Improvement Project (PIP), BAE, together with subcontractors BMT Defense Services and Cammell Laird, will replace the two existing diesel generators on each Type 45, add a third one, and modify the high voltage systems on the ships to handle the additional power. This is on top of the Equipment Improvement Plan (EIP), in which Rolls-Royce is working to upgrade certain components of the destroyers' gas turbines. The U.K. Ministry of Defense expects the first destroyer with all the new modifications will be ready by the end of 2021 and the entire the fleet will have received the upgrades by sometime in the early 2020s.
“The PIP will ensure the fleet of highly sophisticated Type 45s can continue to be deployed successfully on operations around the globe, protecting the U.K.’s interests worldwide,” the country’s Ministry of Defense said in a statement.
“Our aim is to rapidly restore command confidence in the power and propulsion system of the Type 45 fleet, demonstrate value for money, and safeguard vital skills for future generations of warship support,” David Mitchard, the Managing Director of BAE Systems Maritime Services, said in a separate press release.
When Mitchard talks about restoring confidence in the system, he’s referring to power generation problems that have plagued the Type 45s since the Royal Navy commission the lead ship, HMS Daring, in 2009. At the core of the issue is the design of the destroyer’s advanced integrated electric propulsion system.
At present, the system uses a pair of Rolls-Royce WR-21 gas turbines and two Wärtsilä diesel generators to produce high voltage electric power, which then runs a pair of General Electric induction motors that propel the ship. Transformers also siphon off some of that power to run the ship’s various on board systems.
One of the main benefits of this arrangement is that it can be relatively compact compared to traditional ship power plants, allowing for the electric motors to sit closer to the propellers, reducing the overall length necessary for the driveshaft. It also gives ship designers more freedom to arrange components with a hullform and situate them in ways that are better suited to routine maintenance and replacing entire components.
The gas turbines on the Type 45s were also supposed to be significantly more efficient that previous designs, allowing for one turbine-and-generator pairing to power the ship during regular, non-combat activities. This in turn would reduce wear and tear and fuel requirements, and leading to lower operating costs overall.
Unfortunately, the Type 45’s complete engine arrangement has proven to be inherently unreliable. The biggest issue doesn’t actually have to do with the generators or the electric motors, or even the design of the gas turbines, at all.
The problem lies primarily with one additional component, called an intercooler-recuperator, on the gas turbines. This feature takes the heat the engine produces and uses it to improve the efficiency of the overall system. In redirecting that thermal energy, the setup actually helps keep other parts cool.
The Northrop Grumman-designed device has been a weak link from the very beginning, breaking down on a regular basis. This in turn can cause the turbine to fail entirely. When that happens, the electrical load builds up in the attached generator, which at a certain point trips a failsafe mechanism, causing it to shut down, too.
If this happens, the entire arrangement is no longer generating power. If both sets of turbines and generators fail, the ship no longer has any power at all for propulsion or to run vital systems, leaving it effectively dead in the water until engineers can fix the problem. This is bad enough during regular sailing, but it could be deadly in a combat situation or any other crisis.
It is known that HMS Daring’s engines broke down in 2010 and again in 2012. HMS Daultless lost power during a training exercise in 2014. Then in 2016, ships had to tow HMS Duncan back to port just two days after she left.
These issues are not necessarily unique to the Type 45s. As a general rule, modern guided missile destroyers typically have significant power requirements on account of the need to run powerful air defense radars, sensor and combat management suites, and other missions systems.
As such, the U.S. Navy encountered similar issues with its attempts to retrofit its Arleigh Burke-class destroyers with a similar hybrid electric drive that also featured three generators, with one being on standby in case of a failure. The two active generators could barely handle the strain of running the ship's Aegis radar and powering the electric motors turning the drive shafts at the same time.
“At that point you are a light switch flipping on away from winking out the whole ship,” a Navy official told Defense News's David Larter. That American service has now scrapped plans to install the drives on 34 ships, leaving only USS Truxtun with the new propulsion system.
But the design flaw in the intercoolers on the Type 45s was apparently a known issue even before the ships entered service. It was only supposed to occur primarily in operations in extremely warm climates and even then only produce problems gradually, giving the crew ample time to remediate the problems before a major break down occurred.
“The WR-21 gas turbines were designed in extreme hot weather conditions to what we call ‘gracefully degrade’ in their performance, until you get to the point where it goes beyond the temperature at which they would operate,” Royal Navy Admiral Sir Philip Jones, who is First Sea Lord, the United Kingdom’s top naval officer, told members of the country’s parliament in 2016. “We found that the resilience of the diesel generators and the WR-21 in the ship at the moment was not degrading gracefully; it was degrading catastrophically.”
Jones defended the design decision by saying that it would have been “poor value-for-money” to buy ships designed to weather any temperature. But at the same time he added that the ships had trouble especially during the summer months in the Red Sea and Persian Gulf, two areas where the Royal Navy routinely conducted operations when the ships first entered service and continues to do so today.
The new generators and electrical systems will help prevent a total breakdown in the event of a turbine failure. Rolls-Royce is in the process of building an intercooler-recuperator that will be more reliable and successfully tested the first prototype system in 2017. The Royal Navy expects the full cost of both phases of the Project Napier upgrades to be more than $350 million.
Improving the reliability of the Type 45s is a critical issue for the service, especially as it prepares to begin operations with its new super carrier HMS Queen Elizabeth, which could occur as early as 2021. The aircraft carrier will already require significant escorts if the United Kingdom intend to operate in anything approaching a contested environment and even more so given that it is woefully lacking in defenses itself.
Workers can reportedly perform the intercooler-recuperator modifications in four weeks, which is within the time frame of normal in-port maintenance availabilities, according to a report by Defense News. The generator work will be significantly more intensive, reportedly requiring technicians to physically cut holes into the ships’ hulls to get at the necessary components.
The project already costs money the U.K. Ministry of Defense can barely afford to spend. In 2017, it emerged that it was considering a number of plans, including severe cuts to the Royal Navy’s amphibious capabilities, to try and help free up funds and sailors primarily for Queen Elizabeth. Any delays or other issues might lead to cost overruns with Project Napier that could further eat into resources that are already stretched thin.
There might be more defense spending trimming still to come as the United Kingdom's economy struggles as the country moves ahead with plans to leave the European Union, also known as the British Exit, or Brexit. In January 2018, the U.K. government put existing budget cuts on hold pending an independent review, in no small part because of outrage from members of Prime Minister Theresa May's own Conservative Party over the proposals, but its unclear if they'll be able to completely avoid these demands for more austerity in the end.
“The program is dependent on the availability of ships to undertake the conversion, balanced against the Royal Navy’s standing and future operational commitments,” the U.K. Ministry of Defense said somewhat ominously in its official notice about the PIP contract. The issue, of course, is that without the upgrades, the Type 45s may not be able to meet those operational demands anyways.
In December 2017, the Royal Navy admitted that all six of the destroyers were pierside for one reason or another. There are rumors that HMS Diamond, which returned to port in 2017 after suffering a propeller shaft failure, has effectively become a test ship for the turbine and generator upgrades, which could keep here out of action for months.
And unlike the services Type 23 frigates, which it plans to replace with a mixture of new Type 26 and 31e frigates, the Type 45s are expected to continue serving on for the foreseeable future. If they keep ending up in port for heavy maintenance, though, the ships may end up being available for the modifications whether the Royal Navy likes it or not.
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