Recommended safe speed in ice per POLARIS / IMO MSC.1/Circ.1519 - speed reduced from open-water speed as RIO score approaches zero.
Formula
$$ \text{RIO} = \sum C_i \cdot RIV_i $$
Symbol legend
| Symbol | Meaning | Unit | Source |
|---|---|---|---|
| $RIO$ | Risk Index Outcome | - | MSC.1/Circ.1519 |
| $C_i$ | Ice concentration of type i | tenths | ice chart |
| $RIV_i$ | Risk Index Value | - | MSC.1/Circ.1519 Table 1 |
Sources
- MSC.1/Circ.1519 - POLARIS.