Lightning Protection at www.japanese-home-gardens.com

For powerboats, a radio antenna may serve as a lightning or protective mast only if it is equipped with a transmitting-type lightning arrester or other means for grounding during electrical storms and if the antenna height is sufficient to provide an adequate cone of protection for the length of the craft. Antennas with loading coils are considered to end at a point immediately below the coil unless the coil has a suitable gap for bypassing lightning current. The size of the grounding conductor, interconnection, and grounding of metallic masses should be in accordance with principles noted earlier. Ordinary VHP whip antennas provide no lightning protection. Sailboats with metallic standing rigging will be adequately protected provided that all rigging is grounded and a proper cone of protection exists.

Lightning Protection

A grounded conductor or a lightning protective mast will generally attract direct lightning strokes that might otherwise fall within a cone-shaped space, the apex of which is the top of the conductor or mast and the base is a circle at the water's surface having a radius approximately equal to the conductor's height. Probability of protection is considered to be 99 percent within the 45-degree angle as shown in Figure 2-5.