This is an interesting topic, but I could not find a consensus on what to use for lightning
protection – except prayer. Because this approach risks the development of TMJ during a severe storm, I plan to try something simple and inexpensive. The direct, low resistance path includes no connections or bends which would add resistance and heat up. The hope is to keep most lightning out of the boat, not just give it a safer route
through the boat via the mast
. This would also keep it further away from the electrical/electronic systems and reduce field effects.
There is a great deal that we do not know about lightning and lightning protection.
The “non-conventional” systems, based on “lightning elimination”, or “early streamer emission” have not demonstrated clear superiority to the conventional system; at least not enough to create a consensus. Whether the rod tip is a sphere, pointed, rounded, a brush, or any combination of these, may not make a huge difference, since the definitive study has not yet been done. Controlled studies are difficult, and the favorable reports are something like; “it works for my customers”, from groups with a financial bias.
There is also a great deal we do know.
A “conventional” system consists of a rod (or air terminal) with a conductor to ground. This system has been quite effective on land for centuries.
The “rolling sphere” theory seems to have a reasonable consensus, as does the speed of sound, whereby your can calculate the distance from the lightning at 5 seconds per mile when hearing the thunder. We also know that you can’t predict where or when lightning will strike, so any lightning protection should be set up at the onset of the storm, or sooner. That is - long before the first close hit. You don’t want to be handling a hoisted copper wire then, even if it is insulated.
Hoist half inch PVC pipe, 8-10 ft long, with a halyard
(attached near the bottom of the pipe, and a rolling hitch 3-5 ft above the attachment), so that the top of the pipe is near the top of the antenna
. 8 G (or larger) stranded, insulated copper cable (about $0.62 per foot at Home Depot, or $150 for 100 ft of tinned marine
grade, from Boater’s World) runs through it, ending at least 12 inches above the antennae. The top 12 inches of insulation
are removed, and the bare copper wire strands are possibly splayed open (or pointed or rounded). For a catamaran
, stretch the wire almost straight to the bow netting, away from metal, through a small piece PVC pipe and into the water
. Remove insulation
near the water level and splay open at least three feet of the wire in the water. The wire is held in place in the upper PVC tube by a wad of electrical
tape on the wire. For a monohull
, lead the wire through a short piece of PVC pipe, over the lifelines
. Choose the side that has the least electronics
to minimize any field effect.
The PVC will add rigidity to allow the wire to be hoisted above the antennae, and extra insulation where the wire contacts other surfaces.
If the wire is left in the water for long periods of time, it should be cleaned periodically. If left in the water for prolonged periods, consider the tinned copper wire. Also, rinse any salt
off the wire and PVC pipe so it doesn’t become a conductor.
If your mast
height can navigate the ICW
, this whole system should cost you less than $50. (Of course you could pay more if you feel that will help it work better.) If your mast is much taller, consider 6 G wire (or larger). Once you have determined where to attach the halyard
, and have put the tape on the wire, it should only take a few minutes to set up. This process will be more difficult when sailing.
Of course, I would keep this completely separate from the bonding system.
I am not trying to sell anything, and I would appreciate suggestions about this simple, inexpensive approach. I am not a lightning expert, but have put considerable thought into the problem after reviewing some of the literature.