Thermal stress inside a disabled submarine.

Background: Submarine operations require strict adherence to standard operating and safety procedures and errors in judgement or accidents could lead to catastrophe and impair the submarine's ability to surface. In case of disablement of a submarine (DISSUB), the crew would have to survive inside the submarine for a variable period awaiting rescue. Microclimate and habitability of the submarine would have to be maintained and crew would have to consume emergency rations and water.

Methods: In order to validate these procedures, a simulation was carried out in which 80 crew members were closed up inside a submarine in harbour for 24 h simulating a DISSUB situation without power and ventilation.

Results: Average temperature of the submarine compartments rose from 29.33 °C at the beginning of the simulation to 33.5 °C at the end of 24 h. Relative humidity increased from 79% to 87.67%. Crew members consumed an average to 973 kcal worth of rations during the 24 h of the exercise with 500 ml water.

Conclusion: Submarine crew could survive successfully inside a disabled submarine awaiting rescue if thermal stress could be addressed. In the present simulation, the crew suffered from effects of thermal stress. Thermal stress would not only affect damage control capabilities, but could also lead the crew into earlier escape. Greater research and further studies are required to mitigate thermal stress and its effects in order to prolong survival.