Scapa Flow

Method. Each signal is normalised to 0–10 against an empirical cap, then blended weighting safety (detentions 0.40, casualties 0.35) above operational congestion (0.25). A port is scored only on the signals it has data for, and the weights renormalise — a missing signal is never credited as a safe 0.

Coverage. PSC and casualty data here is regional (US, UK, Canada), so most ports show only congestion and carry a low-confidence flag. Detention/casualty counts come from a country-scoped name match (≈60% of US detentions resolve); unmatched records are dropped, not force-fit.

Detention and casualty signals are screened against open port-state-control and marine-casualty records, combined with our own AIS-derived congestion. Updated Aug 27, 2026.