Survival at Sea - Attack of the Gumby Suit
Of all the dangers of working at sea, shipwreck is probably the most vivid in people’s imaginations. When a ship goes down the crew is left stranded in what are often rough conditions and cold water. At best they may have the basic emergency equipment found in a life boat and at worst they may be left floating with only a life vest on.
Part of going to sea as a scientist is learning how to stay safe in case of an emergency. Weekly safety meetings teach us safety procedures, such as being able to recognize different alarms (fire, abandon ship, man overboard). Members of the science team practice reporting to muster stations carrying life vests, long pants, shoes and hats, all of which will reduce sun exposure if stranded at sea.
An important but also amusing part of safety training is putting on an immersion suit, also known as a Gumby suit (due to its resemblance to the American claymation character). An immersion suit is a large waterproof neoprene wetsuit designed to be put on over clothes. It provides floatation and covers everything but the eyes, forming an insulating layer of air next to the skin. When a boat sinks there may be only a few minutes to put on an immersion suit. During the first week of the cruise we timed ourselves while putting on a Gumby suit. Initial times among the science crew ranged from 20 seconds to 35 minutes, but everyone was eventually able to do it in less than 2 minutes.
Scripps vessels require all crew and scientists to have immersion suits in their state rooms when working at latitudes of greater than 32° in the Atlantic and greater than 35° in all other oceans. In warmer climates the suits are handed out on deck if needed. Wearing an immersion suit reduces your cooling rate by six times compared to regular clothing. In cold water an immersion suit is essential. At our current water temperature of 30°C (86°F) it would take more than 12 hours for hypothermia to set in, but in freezing water at 0°C (32°F), a person would become hypothermic after less than two hours.
Surprisingly detailed research has gone into understanding how the human body reacts to cold water immersion. Researchers subjected hapless volunteers to a wide range of trials to understand how factors such as sea roughness, type of floatation device and floating position affected survival. Are you better off staying in the water or sitting on top of an overturned boat? Are you better off with your head in the water, or above the water? Should you keep moving to stay warm or just keep still in the water?
The key point to remember is that water is a good conductor of heat and air is a good insulator. So you are better off if you can get out of the water because water will quickly remove your body heat. You also need to reduce the body surface area exposed to cold water. Therefore it is better to keep your head out of the water than to lie flat. Most importantly, it is better to float calmly in the water with your knees by your chin. If you paddle to stay warm you will actually lose heat more quickly because heat will be transferred to your extremities.
The R/V Roger Revelle is a large global-class research vessel, capable of braving even the roughest of waters. The ship is very unlikely to sink, and in that event the many well-equipped life rafts will ensure the survival of everyone on board. Nevertheless, we all rest safer knowing that we can don a Gumby suit in less than two minutes!
by Susan Schnur
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