14 weighted risk factors. Every vessel. Automatically.

AIS gap: the platform opens a dark event once a vessel's position gap reaches or exceeds 6 hours — one global cutoff, applied the same way everywhere, not a coastal-vs-open-ocean split. Once a gap is open, a separate step that classifies its likely cause also checks a shorter 2-hour bar, gated on whether the platform has any active transfer hotspot on record at all rather than this gap's actual distance to one, and it only runs after the 6-hour cutoff has already been met — so it never changes which gaps get flagged.

Ship-to-ship transfer (confirmed tier): two vessels within 500 meters of each other, both traveling under 0.5 knots, observed together across a span of 1 or more hours from the first sighting to the last, with no more than 4 hours between consecutive sightings. Verified when a paired draft change of at least 0.3 meters is also detected — one vessel's draft rising, the other's falling — within 1 hour before the encounter starts and 1 hour after it ends. A separate, stricter check aligned to Global Fishing Watch's published encounter definition (500 meters, under 2 knots, 2 or more hours, at least 10 kilometers from the nearest anchorage or port zone) is recorded as a pre-verification candidate, not a confirmed or verified event.

Draft-change anomaly: three independent checks against the port's own historical draft-change baseline. Magnitude: flagged when the draft change deviates more than 2 standard deviations from the baseline mean — not a fixed percentage. Directional: flagged when the change runs opposite the port's dominant loading or unloading pattern, regardless of magnitude. Zero-change: flagged when a vessel shows no meaningful draft change at a port with an established loading or unloading pattern.

Loitering: a vessel holding position or drifting slowly — under 2 knots — for 4 or more hours in open water, or 2 or more hours within 10 nautical miles of a known transfer hotspot. The episode is recorded as stationary when its footprint stays under 0.5 square nautical miles, or as a slow-roll drift when it covers that much area or more.

Identity history tracks flag, name, and MMSI changes for review

Coverage status checked against International Group P&I clubs

Entity-history mutations surface hidden-identity risk for analyst review