POLARIS Rating

POLARIS, the Polar Operational Limit Assessment Risk Indexing System, is the IMO methodology for judging whether a ship may enter a given ice regime under the Polar Code. It computes a Risk Index Outcome as RIO = C1xRV1 + C2xRV2 + C3xRV3 + C4xRV4, summing the concentration in tenths of each ice type times the Risk Value for that ice type and the ship’s ice class. A positive RIO means normal operation; values between zero and a negative threshold mean elevated risk with speed limits; below that the regime is to be avoided. POLARIS reads the same concentration, stage, and ice-type fields that the egg-code ice chart encodes.