Industrial Inspection & Consulting was given the opportunity to CT scan a collection of pocket watches recovered from a historic shipwreck. After spending years underwater, the watches were heavily corroded and encrusted, making conventional examination difficult without risking further damage to the artifacts.
Industrial computed tomography (CT) provided a way to look through the corrosion, glass, case, and accumulated material without opening or altering the watches. The resulting 3D datasets revealed internal components that were no longer visible from the exterior, including gears, shafts, plates, springs, hands, and portions of the original winding mechanisms.
One of the challenges with shipwreck artifacts is that the object visible from the outside may bear little resemblance to what remains internally. Corrosion products and marine deposits can obscure features while fragile components underneath may still retain their original geometry.
CT scanning uses X-rays collected from hundreds or thousands of angles to reconstruct the object volumetrically. By digitally slicing through the reconstruction, we were able to examine the pocket watches layer by layer and separate many of the internal features from the surrounding corrosion and debris—all without physically disturbing the artifacts.
WATCH 1 - Hands of Time
With the original dial no longer clearly visible, one objective was determining the original orientation of the movement. CT slices revealed the internal gear train and features associated with the winding mechanism. By following these components through the volume and comparing them with external case geometry, we could establish the winding side of the watch and identify the original 12 o’clock orientation.
This is an important advantage of CT compared with a conventional 2D X-ray. Rather than interpreting overlapping components from a single projection, the CT dataset can be rotated, sectioned, and viewed from virtually any direction to understand how individual features relate spatially.
One of the most interesting discoveries was that portions of the watch hands could still be identified within the damaged assembly. Although the exterior glass had been severely affected, CT allowed us to trace the remaining hand geometry relative to the center arbor and reconstructed orientation of the watch. Our client postulated that because the ship sunk due to a fire, the glass melted and preserved the hands at the time of the wreck.
This creates the possibility of estimating the position of the hands when the watch was damaged or immobilized. Importantly, the CT evidence can show the physical position in which the hands were preserved, but that does not necessarily prove the exact time the watch stopped running or the exact moment the ship sank. Movement during impact, heat exposure, glass deformation, corrosion, or subsequent deterioration could potentially alter their positions.
watch 2 - ludgate hill
The second pocket watch demonstrates another advantage of computed tomography: the ability to recover identifying information from an artifact whose exterior has been severely damaged by corrosion and prolonged exposure to the marine environment. By digitally sectioning through the watch and adjusting the CT visualization, previously concealed lettering and markings became visible within the surviving structure.
Among the markings revealed in the scan are “Ludgate Hill,” “SLOW,” “FAITH,” and the Serial Number “2899.” Ludgate Hill is particularly significant because it was home to the prominent London watchmaker J.W. Benson, which manufactured and sold watches from its Ludgate Hill premises during the nineteenth century. Period advertising specifically identifies the company’s watchmaking operation at Ludgate Hill in London.
