A Flagship Failure Traced Back To Construction

Britain’s newest aircraft carrier left the shipyard with both propeller shafts crooked, and nobody caught it until the $3 billion warship broke down at sea.

Story Snapshot

An investigation found both propeller shafts on HMS Prince of Wales were misaligned during construction.
The error was measured in fractions of a millimeter but still crippled the 65,000-ton carrier.
The ship spent 328 days in dry dock after a breakdown just two days into a major voyage.
Taxpayers footed a repair bill reported at roughly $31 million, later cited near £25 million.
The Royal Navy insists the problem is not a design flaw shared across its whole carrier class.

Builders Missed A Crooked Shaft From Day One

HMS Prince of Wales passed its sea trials before entering service, and vibration from the starboard shaft was judged within acceptable limits at the time. But a later investigation, launched after the shaft broke down, found the shaft had actually been misaligned since construction. The port shaft showed the same defect.

The Ministry of Defence confirmed this in a letter sent to the House of Commons Defence Committee. The investigation’s official conclusion named one clear causal factor: the starboard shaft was misaligned from the build stage, and key components were installed incorrectly. That is not a vague excuse. It is a direct admission that workers got it wrong when the ship was built.

Two Days At Sea, Nearly A Year In Dock

The problem became impossible to ignore in August 2022. The carrier left Portsmouth for a major voyage to the United States and broke down just two days later. Divers found a failed coupling connecting sections of the starboard shaft, forcing sister ship HMS Queen Elizabeth to step in and finish the mission. The carrier limped back to Rosyth, the same shipyard that built it.

What followed was not a quick fix. The ship spent 328 days in dry dock, an enormous stretch of time for a vessel meant to project British naval power. Engineers eventually floated it out of dry dock after nine months of repair work, with the Royal Navy crediting civilian partners from Babcock and BAE Systems for the fix. A warship built to deter adversaries instead sat parked at home.

Millimeters That Cost Millions In Taxpayer Money

Officials later said the shaft was misaligned by as little as 0.8 to 1 millimeter, an almost invisible gap that still managed to knock a flagship carrier out of action. The repair bill reportedly ran to $31 million, with other reporting citing a figure near £25 million paid from the Royal Navy’s own budget. For a program already costing British taxpayers roughly £3 billion, that is real money thrown at a mistake that should have been caught at the factory.

Navy Downplays Scope While Reviewing Old Contractors

Royal Navy officials have consistently framed the failure as an isolated “emergent defect” rather than a systemic build problem, telling the public the rest of the ship suffered no damage and that repairs would let the carrier return to its planned schedule. Officials have also said they are “confident” the issue is not a class-wide design flaw affecting the carrier’s sister ship. Still, the Royal Navy ordered an urgent review involving former members of the original shipbuilding alliance and current industry partners specifically to make sure the same failure does not happen again, a step that only makes sense if serious doubts remained.

That gap between public reassurance and internal review is the real story here. A government can tell taxpayers a problem is contained while quietly demanding accountability behind closed doors. Voters who watched years of bureaucratic excuse-making on this side of the Atlantic will recognize the pattern instantly.

“When HMS Prince of Wales ran sea trials before entering service, vibration from the starboard propeller shaft was assessed as being within acceptable limits. It was not. After the shaft failed off the Isle of Wight in 2022, an investigation found it had been misaligned during…

— Alan Taylor-Shearer (@Altaylorshearer) September 5, 2026

A Warning For American Shipbuilding, Too

This saga matters beyond Britain. NATO allies lean on ships like this carrier for joint exercises and deterrence missions, and a broken-down flagship weakens the whole alliance’s credibility. President Trump has pushed to rebuild American shipbuilding and demand real accountability from defense contractors rather than accept cost overruns as routine. The Prince of Wales fiasco shows exactly why that pressure matters: a millimeter of sloppy workmanship, hidden for years, can sideline a warship and burn through millions in public money before anyone admits the truth.