Freezing Spray

Freezing spray occurs when sea spray thrown up by wave action makes contact with exposed vessel surfaces at air temperatures below 0°C and freezes on impact. Ice accumulates rapidly on deck fittings, railings, masts, radar antennae, windows, and life-saving appliances. Because the ice forms high above the vessel's centre of gravity, even moderate accretion can dramatically reduce the intact stability margin and raise the centre of gravity to a point where the vessel becomes vulnerable to capsize — a hazard particularly pronounced on smaller fishing vessels and short-sea traders with limited freeboard. The Bering Sea, Norwegian Sea, North Atlantic, and Sea of Okhotsk are among the regions where freezing spray events are most frequent and severe. The IMO Polar Code (in force under SOLAS and MARPOL from 2017) identifies icing as a specific hazard for vessels operating in polar and sub-polar waters and requires that the stability booklet include icing allowances and that crew are trained to respond. The Polar Code requires an Ice Navigator to be carried on certain routes. Risk assessment includes monitoring the air-sea temperature differential, wave height, and wind speed: a large temperature differential with high sea state increases icing rates significantly. Officers should de-ice continuously once accretion begins, using chipping hammers, steam lances, or other approved methods, and should consider altering course or speed to reduce spray generation. Hatch covers, doors, and vents should be verified watertight before entering icing conditions.