Re: New to group, and Static Fireworks on P19

james nolan (
Wed, 2 Jun 1999 11:46:50 -0600

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West Wight Potter Website at URL
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The electrical discharge you see is either due to a high electric field in
your vicinity or a wind generating charge on your boat.
A car antenna and car builds up charge when it the car moving. The ball on
top of the aerial prevents corona discharges from the aerial. These
discharges would appear as static noise on your AM radio while driving. A
wind can generate the same charge on your boat and sails. The order of the
voltage of this type is about 10kV. Sharp edges tend to bleed off these
A high natural electric field would occur due to the low humidity of
Colorado and the presence of charges in clouds above you. This is what makes
your hair stand on end or your ice axe "squeal" in the mountains. This field
can be very high and is even an precursor to lightning discharge. You'll
notice the discharges at sharp edges.
Also there is a natural voltage induced in the mast of the boat due to the
earth rotating through its own magnetic field. You can measure this voltage
with a voltmeter between the keel (in the water) and the mast. It's usually
on the order of tens to hundreds of millivolts. This electric field varies
with latitude, here in Colorado it is about 15mV/meter.
You might try the lightning preventor available at West Marine. It's a
stainless steel array of points that bleed off static build up on boats. It
would go on top of the mast.

Jim Nolan