Researchers use medical scanning technology to crack 400 year old padlock

Researchers from Amgueddfa Cymru. Museum Wales and Cardiff University used medical imaging technology to unlock a brass combination padlock from a 1583 shipwreck.

The padlock belonged to the Ann Francis, a ship that wrecked off the South Wales coast in the Bristol Channel during a storm. The vessel was returning from a trading voyage to Spain when it grounded and broke apart on Margam Beach near Port Talbot.

The lock remained sealed for more than four centuries until it was recovered as part of a treasure hoard found by a metal detectorist between 1996 and 2017. Engineers at Cardiff University's School of Engineering used micro-computed tomography to examine the device. This scanning technique usually helps doctors study bones and biological tissues, but the team adapted it to create 3D images of the lock's internal mechanisms.

By looking at how the notches lined up with the letters, David Williams identified the four-letter combination as ANCE. Experts believe the lock originally secured a captain's chest containing high-value textiles, sensitive maritime correspondence, or Spanish silver. The padlock is now on public display at the National Waterfront Museum in Swansea. While the team successfully revealed the code, Alastair Willis of Amgueddfa Cymru. Museum Wales noted that the specific meaning of the code to its original owner remains unknown.