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Lightning Safety for MarinersSafety Tips for Boat Operations Near Thunderstorms
Lightning causes more injury and death than tornadoes in the United States and mariners have significant risk of being struck by lightning.
Boats operating near thunderstorms are at great risk of being struck by lightning. Lightning is attracted to tall objects and boats are normally the tallest thing out on the water. A strike to a boat can cause personal injury, death, hull damage and damage electronic equipment. During 2006, 47 people were killed by lightning and another 246 injuried. What Causes Lightning? - Lightning results from the discharge of static electrical energy that builds up between clouds and earth ground. A potential current of 100 million to 1 billion volts between a cloud and the ground can build as the friction of falling raindrops generates static electricity. Once this natural capacitor is fully charged and it overcomes the insulating atmosphere, a lightning strike discharges the pent up energy. Air within a lightning strike can reach 27,760°C (50,000°F), heating its path of travel to five times the surface temperature of the sun. How Far Away Is It? - An easy way to estimate the distance between you and a lightning strike is to count the number of second that pass after seeing the lightning flash and hearing the resulting thunder. Dividing the number of second that have passed by 5 gives the distance in miles. For example:
Boaters can use a hand bearing compass to determine if they are in a storm's path. If the bearings plotted for the average location of ground strikes to your boat remain unchanged, you are in the storm path and need to change course. At its Lightning Safety webpage, the National Oceanographic and Atmospheric Administration (NOAA) recommends following the 30-30 rule. If the time after seeing a lightning flash is less than 30 seconds from hearing the thunder, you are in danger of being hit and need to seek shelter. After seeing the last flash of lightning, wait 30 minutes before leaving safe shelter. Half of all lightning related deaths occur after the storm has passed. Pre-Trip Planning - Obtain current marine weather forecasts. They can be heard on Marine VHF Channels WX1, WX2 and WX3. The National Weather Service provides regular marine weather forecasts on these channels. Channel assignments vary by geographic region. Forecasts are available through NOAA Weather Radio (NWR) on portable weather radio. Other sources include the Internet and television. Stay off the water if thunderstorms threaten and plan for alternative routes in case a storm takes an unexpected turn. Lightning Safety on the Water - If storms are threatening, return to shore early. Open boats pose a high risk to passengers during a thunderstorm. A cabin will provide a safer environment for passengers and crew. While onboard during a lightning storm, stay away from electronic components and the radio except in an emergency. Avoid metal surfaces within the cabin and the shower. Wear a personal flotation device (PFD) during a storm and especially while on deck. A lightning strike can render a person unconscious and unable to protect themselves in a fall overboard.
The copyright of the article Lightning Safety for Mariners in Boating & Sailing is owned by Alan Sorum. Permission to republish Lightning Safety for Mariners in print or online must be granted by the author in writing.
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