Researchers crack 400-year-old shipwreck padlock code using CT scanning

Researchers from Amgueddfa Cymru – Museum Wales and Cardiff University have successfully identified the four-letter combination of a 16th-century brass padlock recovered from the Ann Francis shipwreck. Using micro-computed tomography (CT) scanning technology, the team identified the code 'ANCE' for a device that had remained sealed since the ship wrecked in 1583.

The Discovery and Technology

The padlock was recovered from the wreckage of the Ann Francis, which ran aground on Margam Beach, near Port Talbot, on 28 December 1583, after being driven off course by a storm. The artifact was discovered by metal detectorist Peter Hughes, who found it alongside a stash of Spanish silver coins and two brass coin-checking weights.

To crack the code, museum conservators worked with engineers at Cardiff University's School of Engineering to utilize micro-CT scanning, a technique typically used to examine biological structures like bones.

Dr. David Williams, a research associate at Cardiff University's Musculoskeletal Biomechanics Research Facility, explained: “By creating a detailed 3D image of the internal mechanism, I could see how the notches lined up with the letters and identify the exact combination.”

The Complexity of the Lock

Alastair Willis, Senior Curator for Numismatics and the Welsh Economy at Amgueddfa Cymru, noted the complexity of the device. He stated there are four different rings with six different letters on each, resulting in 1,296 different combinations. Willis added that the lock includes non-moving letters on the ends that are unrelated to the code, which may have been intended to "mislead any potential burglar."

While the exact contents of the container the lock secured remain unknown, researchers believe it may have guarded a captain's chest containing Spanish silver, high-value textiles, or sensitive maritime correspondence.

Historical Significance

Experts described the find as uniquely significant because it can be tied directly to a securely dated shipwreck. Siân Iles, a senior curator at Amgueddfa Cymru, said the lock is in "excellent condition" and provides a "really good context" for the period.

The padlock is currently on public display at the National Waterfront Museum in Swansea as part of the Ann Francis treasure hoard, which was recovered over a 21-year period between 1996 and 2017.

---

Sources

• independent.co.uk: Scientists crack code to 400-year-old padlock from shipwreck | The Independent
• bbc.com: Code cracked for Margam shipwreck padlock solving 400-year-old mystery

This article was drafted with AI assistance and checked against the sources above. Company claims are reported as claims. Cover image is AI-generated.