Lightning Facts: An Analysis of Lightning Strikes
Published on February 19th, 2015
The odds of getting struck by lightning are about one in a million. But if you own a boat, the odds of it being struck by lightning are significantly higher – about one in a thousand. However, not all boats are created equal when it comes to lightning.
A just-released analysis of 10 years of insurance claims by Boat Owners Association of The United States (BoatUS) shows that certain boats are significantly more at risk than others. But which ones? And, what can you do if you’re caught on open water? BoatUS has some answers:
Let’s first state the obvious: It’s a no brainer why monohull sailboats with their tall masts pointing to the sky have significantly more lightning claims than powerboats – 3.8 chances per 1,000 versus a 0.1 chance in 1,000 for bass boats-runabouts-pontoons. The national average for the probability of a boat lightning strike claim for all types of boats and sizes is 0.9 chance per 1,000.
Size matters: It’s also not a stretch to understand why larger boats of all types – which present a larger target to the skies – are struck more often than smaller ones. A boat 40-65 feet in length has 6 chances per 1,000 while boats 16-25 feet have just a 0.2 chance per 1,000. Increasing the height of a sailboat mast from 35 to 45 feet nearly triples the odds of being hit.
Location matters, too: Where boating populations are dense and lightning is common, strike insurance claims are high. Six of the top 10 states in terms of frequency of lightning claims – Florida, Mississippi, Louisiana, Alabama, South Carolina and North Carolina – all lay within the thunderstorm hotspot in the Southeast and midsection of the country. Heading west, the frequency of lightning claims falls to about 1 chance in 10,000 along the Pacific Coast, or about 1/10th the national average.
The effect of two hulls: A multihull sailboat is almost twice as likely to have a lightning claim as a monohull. Why sailing cats get hit more is unclear, although theories include lack of a keel, more wetted surface, larger footprint, the dockage of cats at the outside edges of a marina, and higher average mast height.
What can you do to lessen the chance of a strike on open water? According to the University of Florida’s “Boating Lightning Protection” by William Becker, it’s better to run for protection than remain in the open, so long as you can make it all the way back to shore and take shelter in your car or an enclosed building and are not caught at the shoreline.
If that’s not possible, do what is. Lower antennas. In an open boat, stay low, keep arms and legs inside. If there’s an enclosed cabin go below to the center. If your boat has a lightning protection system, avoid touching anything connected to it such as a mast. Turn off any electronics and don’t touch them. That includes avoiding the VHF if possible. If you can, remove it and store down below.
To view the full analysis online, “Striking Lightning Facts”, in the January 2015 issue of BoatUS Seaworthy Magazine, go to BoatUS.com/lightningfacts.