Sheltered flat water with minimal currents, easy entry and exits and no more than 500m from safe landing sites.
Unsheltered inland open waters, estuaries and lakes, or sheltered coastline. Small waves or surf less than 0.5m, currents less than 2km/h, crossings no more than 1km from safe landing sites.
Sheltered coastal waters with possible wind against wave or tide effects and moderate breaking seas. Possible surf entry and exits less than 1m, currents less than 4km/h, up to 5km crossings or from safe landing sites.
Unsheltered coastal waters which may encounter steepening swell and breaking seas, wind against wave or tide effects. Entry and exits may be difficult and involve negotiation of surf up to 2m. May involve fast currents up to 7km/h and up to 10km crossings or from safe landing sites
Unsheltered coastal waters, isolated remote areas and ocean with crossings or distance from safe landing sites of up to 30km. May encounter large, steep swell, breaking waves and complex fast currents. Possible dangerous surf entries and exits with waves more than 2m.