Key Points and Summary – The UK’s two Queen Elizabeth-class aircraft carriers, the nation’s most valuable naval assets, have been plagued by significant and persistent mechanical failures.
-Both HMS Prince of Wales and HMS Queen Elizabeth have suffered major breakdowns related to their propeller shaft couplings, leading to extended, costly repairs and alarmingly low operational availability. Investigations point to poor quality control and installation errors during construction.
HMS Prince of Wales Royal Navy (Queen Elizabeth-Class Aircraft Carrier). Image Credit: Royal Navy.
-These recurring issues have undermined the strategic value of the £9 billion program and raised serious questions about whether the Royal Navy can effectively maintain such complex warships.
Britain’s New £9 Billion Queen Elizabeth-Class Aircraft Carriers Keep Breaking Down
Currently, the UK operates two aircraft carriers, the HMS Queen Elizabeth and the HMS Prince of Wales. Both ships are Queen Elizabeth-class carriers, making them some of the most valuable assets in the British Royal Navy.
However, the Queen Elizabeth-class has not gone without its hardships. Both Queen Elizabeth and the Prince of Wales have experienced numerous technical difficulties, which have hindered their operational readiness on multiple occasions.
These challenges raise the question of whether investing in these carriers has been worth all the trouble.
A Brief History of the Queen Elizabeth-Class
The development and construction of the Queen Elizabeth-class was a massive undertaking, involving a consortium known as the Aircraft Carrier Alliance, which included BAE Systems, Thales Group, Babcock International, and the UK Ministry of Defence.
The total cost of the two carriers was approximately £9 billion, making them among the most expensive defense projects in British history.
These ships were built with a focus on flexibility and future-proofing, featuring an integrated electric propulsion system powered by Rolls-Royce gas turbines and Wärtsilä diesel engines.
This system was chosen over nuclear propulsion to reduce costs and leverage existing global refueling infrastructure.
Development on the Queen Elizabeth-class began in the 1990s, when the UK MoD began exploring options for a new generation of aircraft carriers.
The Strategic Defence Review of 1998 emphasized the need for increased offensive airpower and the ability to operate independently of foreign bases.
This led to the formal launch of the Future Aircraft Carrier (CVF) project in January 1999, to deliver two 40,000-ton carriers capable of deploying up to 50 aircraft each.
ATLANTIC OCEAN (Aug. 8, 2017) The Royal Navy aircraft carrier HMS Queen Elizabeth II sails in formation alongside the Nimitz-class aircraft carrier USS George H.W. Bush (CVN 77) during exercise Saxon Warrior 2017, Aug. 8. Saxon Warrior is a United States and United Kingdom co-hosted carrier strike group exercise that demonstrates interoperability and capability to respond to crises and deter potential threats. (U.S. Navy photo by Mass Communication Specialist 3rd Class Tristan B. Lotz/Released)
Design and Construction
Initial concept studies considered a range of possibilities, including extending the hulls of existing carriers, converting commercial vessels, and building entirely new ships.
The MoD briefly entertained the idea of conventional carriers operating aircraft like the Boeing F/A-18E Super Hornet or a navalized Eurofighter Typhoon, but ultimately leaned toward a design optimized for short take-off and vertical landing (STOVL) aircraft, particularly the F-35.
A joint team consisting of F-35 Patuxent River Integrated Test Force flight test members, U.S. Sailors and Marines, and the crew of the Japan Maritime Self-Defense Force Izumo-class multi-functional destroyer JS Kaga (DDH-184) are executing developmental sea trials in the eastern Pacific Ocean to gather the necessary data to certify F-35B Lightning II short takeoff and vertical landing aircraft operations. While aboard the MSDF’s largest ship, the Pax ITF flight test team has been gathering compatibility data for analysis in order to make recommendations for future F-35B operational envelopes, further enhancing the Japanese navy’s capabilities. The results of the testing will contribute to improved interoperability between Japan and the United States, strengthening the deterrence and response capabilities of the Japan-U.S. alliance and contributing to peace and stability in the Indo-Pacific region. Japan is an F-35 Joint Program Office foreign military sales customer planning to purchase 42 F-35Bs. The F-35 Joint Program Office continues to develop, produce, and sustain the F-35 Air System to fulfill its mandate to deliver a capable, available, and affordable air system with fifth-generation capabilities.
The final design incorporated a large flight deck optimized for aircraft traffic flow, a spacious hangar capable of housing up to 20 F-35Bs, and a gallery deck for aviation support facilities.
The ships were built with integrated electric propulsion, utilizing gas turbines and diesel generators to power electric motors that drive twin shafts.
Automation was extensively employed to reduce crew size and through-life costs, and modern waste disposal systems were implemented to enhance environmental performance.
Construction of HMS Queen Elizabeth began in July 2009, and she was named in July 2014 in honor of Queen Elizabeth I. She was commissioned into the Royal Navy on December 7, 2017. Her sister ship, HMS Prince of Wales, followed with steel cut in May 2011, launching in December 2017, and commissioning on December 10, 2019.
Mechanical Issues for Queen Elizabeth-Class
Both HMS Queen Elizabeth and HMS Prince of Wales have experienced significant mechanical failures, particularly related to their propulsion systems. One of the most persistent issues has been with the propeller shaft couplings.
These couplings are critical components that connect the segmented shafts driving the propellers. In August 2022, HMS Prince of Wales suffered a major breakdown off the Isle of Wight due to a failure in the starboard shaft coupling. Divers discovered that the 33-tonne propeller had malfunctioned, and the ship had to be towed back to port.
The repairs took nine months, during which the vessel was unavailable for operations.
A similar issue occurred in February 2024 when HMS Queen Elizabeth was forced to withdraw from NATO’s Exercise Steadfast Defender due to a problem with her starboard shaft coupling. Although the Ministry of Defence claimed these were unrelated incidents, the similarity of the failures raised concerns about systemic issues in the design and construction of the carriers.
Investigations into the Prince of Wales failure revealed that the shaft had been misaligned during the build stage and that key components had been incorrectly installed. These findings suggested deeper problems with quality control and oversight during construction.
Operational availability has been another area of concern. Parliamentary data revealed that HMS Prince of Wales had spent only about 21 percent of its time at sea since commissioning, with roughly 33 percent of its time dedicated to repairs.
This low sea time undermines the strategic value of the carriers, particularly given their intended role in NATO operations and global deployments.
The frequent need for one carrier to substitute for the other due to breakdowns has further complicated planning and reduced the Royal Navy’s flexibility.
What Happens Now?
To address these issues, the Royal Navy has initiated a series of upgrades and overhauls. HMS Queen Elizabeth underwent a major refit in 2025, which included significant work on the propulsion system, navigation controls, and damage control systems.
During a seven-month dry dock period in Rosyth, both propeller shafts were replaced to prevent future failures. Additional work included replacing 284 hull valves, cleaning rudder blades, inspecting sea inlet pipes, and renewing anti-fouling paint. These upgrades were aimed at improving reliability and extending the ship’s service life.
Queen Elizabeth-Class In 4 Words: Just Not Worth It?
In my opinion, aircraft carriers are valuable assets, but they are only as good as the navies that maintain them.
The constant malfunctions on both the Queen Elizabeth and the Prince of Wales says more about the Royal Navy than it does the carriers themselves.
Ideally, the British Navy should field more carriers; however, the reality is that the UK no longer has the budget or personnel to maintain a large, globe-spanning navy like it once did.
About the Author: Isaac Seitz
Isaac Seitz, a Defense Columnist, graduated from Patrick Henry College’s Strategic Intelligence and National Security program. He has also studied Russian at Middlebury Language Schools and has worked as an intelligence Analyst in the private sector.
More Military
Russia’s T-14 Armata Super Tank Mistake Still Stings
SR-72 Darkstar: The Mach 6 Mothership for the F-35 and F-47
China’s J-20 Mighty Dragon Fighter Can Be Summed Up In Just 4 Simple Words
The MBT-70 Tank Still Haunts the U.S. Army
Russia’s ‘New’ MiG-35 Fighter Is Officially ‘Circling the Drain’
