A shipwreck padlock code that had kept its secret for more than four centuries has finally been unlocked, thanks to modern scanning technology. The brass lock, recovered from the wreck of the Ann Francis off the Welsh coast, was opened after experts used CT scanning to peer inside its mechanism and identify the four-letter combination.
The lock dates to 1583 and was found by metal detectorist Peter Hughes in the sand near Margam in Port Talbot in 1999. It is part of a collection of artefacts from the Ann Francis, a ship caught in a storm on 28 December 1583 while returning from Spain. Its cargo lay buried beneath the sand for centuries.
From beach discovery to museum display
Hughes, from Maesteg, recalled stumbling on the first coin during a day off while walking Morfa beach with his detector. That find began a search that would span 21 years and yield hundreds of artefacts, including the padlock.
The lock was discovered close to a group of Spanish silver coins and two coin weights, suggesting it may have protected those items or secured a chest whose contents — perhaps documents or textiles — have not survived.
Hughes handed the hoard to Amgueddfa Cymru in 2017. In July 2026, the collection went on display at Swansea Waterfront Museum, with the lock as its centrepiece.
How the code was cracked
Dr David Williams, a research associate at Cardiff University’s School of Engineering, was initially sceptical when asked to try scanning the lock. The micro CT equipment, he noted, was not built for this kind of task. A first scan revealed letters inside the mechanism, surprising the team. A second attempt failed, but a third, using a different approach, produced the answer.
The code spells out ANCE. Senior curator Alastair Willis described the discovery as incredible, pointing out the scale of the challenge: four rings, each bearing six letters, give 1,296 possible combinations, all of which must line up with the loop at the top. Adding to the difficulty, other letters on the ends of the lock do not move and appear unrelated — perhaps, Willis suggested, to mislead any would-be burglar.
For Hughes, who had spent about 20 years trying combinations without success, the breakthrough was deeply personal. He compared the moment to opening the Ark of the Covenant and said he was truly thrilled.
A rare survivor in remarkable condition
Siân Iles, a senior curator at Amgueddfa Cymru, said the lock remains in excellent condition and still works as it would have done hundreds of years ago. Its proximity to the Ann Francis wreck and the rest of the collection allows it to be dated tightly, she added.
Iles noted that other examples she has seen are usually corroded or in pieces. The lock’s small size suggests it secured a chest or a small box, though what it protected remains unknown — one of the story’s enduring mysteries. What is clear is that the code mattered to whoever knew it.
