Fleet Utilization History

Method & caveats

• Source. Every series is one segment’s daily rows from the daily AIS-utilization snapshot (one row per snapshot date and segment). The history accumulates forward from the day it started; it is not back-filled, so early windows may be short.
• Utilization (robust). 100 × employed_tonnage ÷ total_tonnage, where employed = total minus idle. Idle (anchored, moored or stopped offshore) is read straight from AIS speed and navigational status, so utilization is the idle-complement on a deadweight basis and is independent of the registered-draught problem. A rising line = idle capacity absorbed = effective supply withdrawn.
• Adjusted utilization (experimental). Utilization multiplied by the slow-steaming speed index, to credit only fully-laden steaming rather than every not-idle ship. It deliberately reads lower than the headline and the direction is what matters; treat the level as indicative only.
• AIS coverage. Observed deadweight (vessels with a fresh fix) over the segment’s registered deadweight — a quality gauge for how representative each day’s read is, shown separately because it tracks feed health, not the market. A segment with neither a fresh AIS day nor a recent fallback snapshot is left blank rather than fabricated.
• Segments are split into gas, tanker, container, bulker and other. This is the trend companion to the latest-snapshot Supply & Demand utilization read, and a sibling of the Fleet Deployment History.