On the evening of December 28, 1583, the merchant ship Ann Francis was caught in a storm and wrecked near Port Talbot, Wales. Among the gold and silver coins, compasses and weapons that went down with her was a brass padlock, one so well preserved that experts eventually wondered whether it could still be opened the way its maker intended. More than four centuries later, they got their answer.
Specialists from Amgueddfa Cymru, Museum Wales, and Cardiff University recently announced that the lock works. The combination spells A, N, C and E, and the researchers worked it out without damaging the artifact, using CT scans to read the mechanism inside.
A chest of valuables on the seabed
The padlock was recovered close to a collection of Spanish silver coins and two coin weights, which suggests it once secured a small chest holding items of real value. The lock dates from the Elizabethan era and is unusually complete. Many recovered locks have corroded into lumps; this one retains its moving parts, and the letters on its rings are still legible.
Museum curator Mark Lewis is among the specialists featured in the team’s video, which records how the rings still turn freely. “This lock still works, the rings still turn,” one of the museum’s specialists notes. “You can still work out what the code is, and you can potentially unlock it.” The same speaker admits the appeal was hard to resist: “I think it’s human nature; when you have a code to crack, that’s what you want to do.”
Why not simply force it
Grit had accumulated inside the mechanism over four centuries underwater. Turning the rings the wrong way, or too often, risked grinding the interior into ruin. Instead the team contacted David Williams, an expert in biomechanics at Cardiff University, to see whether medical imaging could reveal the lock’s internals before anyone touched the rings.
“There was a little skepticism of whether it was even possible,” Williams recalls in the team’s video. The worry was that a scan might show nothing but a featureless gray mass. In fact, the CT images resolved four moving rings, complete with notches and teeth, clearly enough for the researchers to deduce a candidate combination. Back at the museum, the rings were aligned to A, N, C and E, and the grit-caked key came loose for the first time in over 400 years.
Opening the lock turned out to be an act of conservation, not just curiosity. As the team’s conservator explained, grit left inside the mechanism would have continued to abrade the parts. Removing it through the safe opening helped stabilize the artifact for the long term.
Four hundred years of failures
Not everyone cracked it with scanners. The museum’s video features Peter Hughes, who spent years trying combinations on the lock by hand. “I could never find the combination,” he says. “I tried hundreds of times, unsuccessfully, and thankfully, technology and science has taken over.”
The result is more than a novelty. Non-destructive imaging is becoming a standard tool for studying archaeological metals, allowing researchers to document mechanisms, manufacturing details and even hidden inscriptions without taking artifacts apart. The Ann Francis padlock is a small object, but it demonstrates the method plainly: an object can be read, understood and preserved while staying whole.
The lock, along with the rest of the Ann Francis material, remains in the collections of Amgueddfa Cymru. Its code, at least, is no longer one of its secrets.
