Anyone who’s ever left a car at the shop for “a couple of days” knows how this usually goes. The mechanic calls; they’ve found something else while they were in there, and your couple of days turns into a couple of weeks.<\/p>\n
The Royal Navy got its own version of that call. It just dragged on for more than seven years<\/em>.<\/p>\n HMS Vanguard, the oldest of the four submarines that carry Britain’s nuclear missiles, went into Devonport’s shipyard in December 2015 for an overhaul and a refuel. Devonport is part of Plymouth, England (yes, that Plymouth, the one the Mayflower sailed from). She didn’t sail back out until May 9, 2023, and Navy Lookout, an independent site that follows the Royal Navy closely, puts that at about 89 months. Building her at Barrow in the first place took about 83.<\/p>\n Those numbers have been making the rounds on defense sites again over the last few days, so I went back through what’s actually been published. The overhaul wrapped up a while ago, but its ripple effects are still very much a thing.<\/p>\n If you’ve never seen one of these boats up close, they’re big. The Royal Navy lists a Vanguard-class submarine<\/a> at about 492 feet long and 15,900 metric tons submerged. Before anyone heads to the comments, that works out to roughly 17,500 short tons, as we use in the States. Either way, they’re the biggest submarines Britain has built so far.<\/p>\n The Royal Navy calls this kind of job a Long Overhaul Period and Refuel. If you’re picturing something like an oil change, it’s a little more involved than that. Basically, they open the boat up, overhaul her major systems, and refuel her reactor.<\/p>\n The fuel in a submarine reactor comes as a core. That’s essentially the whole load of uranium the reactor burns, built to sit in there for years, so swapping one out is, as you’d expect, not a quick job.<\/p>\n There’s a catch, though. Vanguard had already been through one of these overhauls, and that first time around, she’d been given a newer core, called Core H, that was supposed to last the rest of her working life. Nobody planned on refueling a Core H when the boats were designed, according to Navy Lookout, and Vanguard ended up being the first submarine to have one refueled anyway.<\/p>\n So why refuel her at all?<\/p>\n A land-based test reactor in Scotland, which is pushed far harder on purpose than any submarine reactor ever is, turned up signs of what’s believed to be tiny leaks in the fuel’s cladding, the thin metal skin wrapped around it. None of the submarines had shown anything like it. The Ministry of Defense decided to give Vanguard a fresh core anyway, as a precaution, since she’d be coming in for her overhaul regardless.<\/p>\n That’s arguably the most forgivable bit of the whole story. Navy Lookout lists refueling problems among the reasons for the overrun, which isn’t too surprising for a job nobody had done before.<\/p>\n The rest of it’s harder to defend. Navy Lookout also blames poor management and COVID, and it quoted one senior officer calling Vanguard “a textbook example of how not to set up a major project.” The plan, by the same site’s account, was a maximum of four years and \u00a3200 million. The contract wasn’t fixed-price, and the final bill reportedly ended up north of \u00a3500 million. I couldn’t find a final figure from the Ministry of Defense itself.<\/p>\n Vanguard has three younger sisters, Victorious, Vigilant, and Vengeance, and all three had already been through their own overhaul-and-refuel jobs at Devonport by the time she showed up. Navy Lookout puts their average at about 42 months, and the Royal Navy’s own page for Vengeance says hers took 40. Vanguard’s 89 months is more than double her sister’s 42, and it tops the 83 months Barrow needed to build her.<\/p>\n Figures: Royal Navy, Navy Lookout.<\/p>\n Honestly, it’s a pretty rough look when a refit outlasts the build, and I’d guess the Royal Navy knows it. Vanguard’s job did include a refuel nobody had tried before, so some extra time was probably fair. More than seven years is a whole lot of extra time, though.<\/p>\n Britain has kept at least one nuclear-armed submarine hidden at sea every day for more than half a century. The idea’s pretty simple: if nobody can find the boat, nobody can take out Britain’s missiles with a surprise attack, which is kind of the whole point of having them.<\/p>\n Doing that with four boats leaves little slack. While one’s out on patrol, the others are getting ready, heading home, or sitting in maintenance, so taking one out of the rotation for most of a decade means the rest have to stay out longer.<\/p>\n They’ve been doing exactly that. Navy Lookout says each of the last nine deterrent patrols has topped five months. On April 18, a Vanguard-class boat came home to Faslane, Scotland, after a reported 205 days at sea, one day more than the 204-day record set by a boat that came back early last year. Navy Lookout counted it as the longest continuous patrol on record for a Royal Navy submarine.<\/p>\n If you’ve seen 204 days quoted as the record over the last week or so, that number’s a little out of date.<\/p>\n So was the record-setter Vanguard herself? I can’t tell you that. The Ministry of Defense keeps the name of the boat on patrol secret, and in April it told reporters it doesn’t comment on patrol lengths, either. Even the Royal Navy’s own write-up of the homecoming<\/a> leaves out the number.<\/p>\n The Royal Navy did say Prime Minister Keir Starmer went out to meet the boat at sea and that 140 submariners were aboard. Their families got a weekly allowance of 120 words to send them one way, with every message vetted for security, according to the Royal Navy. That’s about 17 words a day.<\/p>\n Navy Lookout says the boats were designed to carry food for three to four months at most, so on patrols like this one, canned food ends up packed into every spare space, including passageway decks. I’d call six-plus months in a steel tube with a can-lined hallway a pretty big ask, even for people who volunteered for it.<\/p>\n For comparison, the US Navy’s 14 Ohio-class missile submarines spend 77 days at sea per patrol on average, according to the US Navy’s fact file<\/a>, a little over a third of that British boat’s 205. Having that many boats also gives the US room to shuffle them around, like when two 18,750-ton Ohio-class boats swapped coasts<\/a>.<\/p>\n The line for the dry dock hasn’t gotten any shorter, either. HMS Victorious arrived in Plymouth in 2023 for what the Royal Navy calls a Deep Maintenance Period, under a contract with Babcock that the UK’s Submarine Delivery Agency put at an estimated \u00a3560 million. In May 2025, she moved into the dry dock<\/a>, and according to Navy Lookout, it’s 9 Dock, where Vanguard spent most of her refit.<\/p>\n She was still at Devonport as of Navy Lookout’s April report, which also said a third boat had spent more than 19 months at Faslane without joining the patrol rotation. From the looks of things, that’s left two boats trading off the patrols, and it goes a long way toward explaining those 200-day trips.<\/p>\n Britain’s next missile boats, the Dreadnought class, are being built at Barrow-in-Furness, and the Royal Navy expects them to start replacing the Vanguards in the early 2030s. Navy Lookout doesn’t expect the first one on patrol before 2032, even though her first steel was cut a decade ago.<\/p>\n Barrow hasn’t exactly been speedy lately. The newest British attack submarine, HMS Agamemnon, needed about 13 years at the yard before four tugboats eased her out<\/a> last month. So it’s safe to say the Vanguards will be doing this job for a while yet.<\/p>\n Until the Dreadnoughts show up, Britain’s deterrent stays on these four boats, and the oldest of them, HMS Vanguard, passed 33 years in commission this August.<\/p>\n","protected":false},"excerpt":{"rendered":" Anyone who’s ever left a car at the shop for “a couple of days” knows how this usually goes. The … <\/p>\nSo how does a refit take longer than a build?<\/h2>\n
Her sisters got through theirs in about half the time<\/h2>\n
So what happens when one boat is stuck in the yard?<\/h2>\n
Victorious has been at Devonport since 2023<\/h2>\n