Source: Mariners Learning System, by Captain Bob Figular

Operating in a cold climate presents the challenge of keeping warm while operating a boat. As the temperature drops or clothing becomes wet, more insulation is required to keep the body from losing its heat. Wind affects body temperature. Those parts of the body exposed directly to the wind will lose heat quickly, a condition commonly referred to as “wind chill.” On bare skin, wind will significantly reduce skin temperature, through evaporation, to below the actual air temperature.

The combination of rough seas, cold temperatures, and wet conditions can quickly cause the crew to become less effective. Crew fatigue will occur more quickly when these conditions are present. Many accidents occur when cold induced fatigue sets in because the mind loses attentiveness and physical coordination diminishes. Even a person that is moderately cold and damp will exhibit a decrease in reaction time that is also a symptom of the onset of hypothermia.

Hypothermia is the loss of internal body temperature. Normal internal body temperature is 98.6°F and is automatically regulated by our bodies to remain very close to this temperature at all times. A minor deviation either up or down interferes with the bodily processes. Being too cold will adversely affect the body. Even a minor loss of internal body temperature may cause incapacitation.

Signs that a person may be suffering from hypothermia include:

• Pale appearance
• Skin cold to the touch
• Pupils are dilated and will not adjust properly when exposed to light
• Poor coordination
• Slurred speech / appears to be intoxicated
• Incoherent thinking
• Unconsciousness
• Muscle rigidity
• Weak pulse
• Very slow and difficult breathing
• Irregular heart beat

A person suffering from the effects of hypothermia will tremble and shiver; however, these symptoms may not always be present. When a person stops shivering, their hypothermia may have advanced beyond the initial stages. Do not give a person suffering from hypothermia alcohol!