The field can exceed 1,000 volts per meter on a dry day. The normal electric (E) field averages about 150 volts per meter.
This gradient can be measured and is usually expressed in volts per meter. Imbalance in electrical charge causes a potential gradient to develop. Simply put, the imbalance can occur due to the movement of the air, which like the movement of a person across a carpet, can cause electrical charges to be moved from one place to another. Lightning is a final result of the natural creation of an electrical charge imbalance in the Earths atmosphere. Are these claims reasonable in light of what is known about lightning? Is the cost of protecting a vessel with one of these devices a good investment? Can you really placate Thor, the god of lightning? How Lightning Occursįirst, let’s examine what we know about lightning. Although the devices appear to be little different from the forms that have been used on both aircraft and stationary constructions, some of the marketing claims have been rather innovative. The terminal may take the form of a vertical spike with a sharp point or some more exotic shape and construction.įor years, a number of companies have started to aggressively market on-purpose lightning protection devices for use on boats. There may be a lightning protection air terminal mounted at the masthead. The highest mast will be well grounded to the sea through a copper wire of suitable size, which connects to a metal plate mounted on the hulls exterior surface. Most boats are built in compliance with the safety grounding and lightning protection recommendations of the American Boat and Yacht Council (ABYC). In many ways, our ability to deal intelligently with lightning is little advanced from Benjamin Franklins approach.
Lightning awareness generally takes one of two forms: (1) aware, concerned, resigned, do nothing or (2) aware, concerned, do something, and hope what was done will be more beneficial than harmful.
Sailors also will be interested in reading about our discussion of conventional lightning protection systems in Getting a Charge Out of Lightning.Īll sailors-except those who sail exclusively in the most northern but still liquid reaches of the Arctic Ocean, or most southern parts of the Antarctic Ocean-are well aware of lightning and its inherent risks. The following Special Report first appeared in the Jissue of Practical Sailor. When these devices first appeared on the market, we did a fair amount of research to find out whether they realistically could be expected to spare a sailboat’s mast from a lightning strike. These are the downside-up, wire-brush-like devices you see sprouting from antennas and rooftops in cities and towns, and more frequently, on sailboat masts. About this time of year, when lightning strikes become frequent occurrences, we receive a good deal of mail asking about static dissipators such as the Lightning Master.
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