WHERE IN THE WORLD ARE THOSE PESKY CABLESHIPS? BY KIERAN CLARK
A GLOBAL ANALYSIS OF CABLE SHIP PATTERNS, INFRASTRUCTURE PROXIMITY, AND PROJECTED ACTIVITY USING AIS DATA
T
he global subsea cable network—the invisible backbone of the internet—relies on a small fleet of specialized vessels for cable installation, inspection, and maintenance. These cable ships play a vital role in ensuring connectivity between continents, yet their operational patterns remain difficult to interpret. Most tracking is based on AIS (Automatic Identification System) data, which shows where ships are and how fast they’re moving, but offers little direct information about what the vessels are actually doing. This article presents the results of a geospatial analysis of over 7,500 AISbased data points, focused on identifying where cable ships gather, how their behavior varies by region, and what their proximity to infrastructure might reveal about their operational roles. The goal is not just to observe where ships are located, but to interpret the likely purpose of that presence—whether conducting cable repairs, deploying new systems, or awaiting assignment. AIS data was collected at six-hour intervals, creating a consistent global dataset of vessel locations, speeds, and identities. Points where ships moved slowly for extended periods were flagged as potential operations or staging events. To understand what may have been happening during those periods, each data point was compared against a global list of known cable depots and cable factories. If a ship remained within 50 kilometers of a depot or factory for more than 24 hours, it was assigned a projected classification:
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• Installation if near a factory • Maintenance if near a depot • Unclassified if no infrastructure was nearby or conditions were inconclusive • Installation was prioritized if both a factory and depot were in range, based on two factors: the understanding that some factories can supply spare cable for repairs, and the assumption that when a ship is located near a factory-adjacent area—such as Calais—it is more likely preparing for a new installation than conducting a repair The 50 km proximity threshold was chosen to account for uncertainty in infrastructure coordinates and minor inaccuracies in AIS-reported vessel positions. Some facility