Reduction in predicted survival times in cold water due to wind and waves

• Recent marine tragedies have called into question immersion suit standards.
• Our participants were immersed in harsh environments consisting of wind and waves.
• We compared heat loss in calm water to that in wind and waves.
• Wind and waves caused significantly greater heat loss.
• Predicted survival times were lower in wind and waves compared to calm water.

Recent marine accidents have called into question the level of protection provided by immersion suits in real (harsh) life situations. Two immersion suit studies, one dry and the other with 500 mL of water underneath the suit, were conducted in cold water with 10–12 males in each to test body heat loss under three environmental conditions: calm, as mandated for immersion suit certification, and two combinations of wind plus waves to simulate conditions typically found offshore. In both studies mean skin heat loss was higher in wind and waves vs. calm; deep body temperature and oxygen consumption were not different. Mean survival time predictions exceeded 36 h for all conditions in the first study but were markedly less in the second in both calm and wind and waves. Immersion suit protection and consequential predicted survival times under realistic environmental conditions and with leakage are reduced relative to calm conditions.