A protective suit that reduces the body heat-loss of a person wearing it in cold water, e.g. when rescuing someone from the sea. A dressed person in seawater at 0°C can get exhausted in minutes and die in a quarter to threequarters of an hour. Immersion suits are designed to prevent crewmembers from death due to exposure and hypothermia. To do this, a suit must cover all the body and its extremities, except the face, with highly insulating waterproof material.
Immersion suits are intended primarily to ensure thermal protection in the cases where it is impossible to embark a fully enclosed lifeboat. Immersion suits should not be worn when boarding fully enclosed lifeboat. The experience gained after the January 2007 abandonment of the containership MSC NAPOLI shown the potential risks resulting from wearing immersion suits in fully enclosed lifeboat. Although outside temperatures were frigid, the members of the crew who wore immersion suits suffered from overheating and dehydration.