Lightning protection question

[seafrontiersman]

I have a Watkins 23 centerboard boat; the centerboard is iron connected to a galvanized steel winch by stainless steel wire rope. My bright idea was to install a lightning rod at the top of the mast attached to a heavy copper wire running down the mast and attaching to the winch thereby creating grounding path through the wire. She has an encapsulated lead keel.

Is this a good idea?

[Cruisingdad]

That is completely your call. WIthout going into too much of a discussion on the rights or wrongs of whether to ground, I will simply say that an easy method is to ground out using the base of the mast and connecting a #4 wire to the keel bolts. No sharp turns.... make it as straight as possible. I am not saying that is the right way to do it as to really do it right is very indepth.

The problem using the keel that is painted and encapsulated is that it will not make a good ground (or so I have been told). That is why many people use a Dynoplate, a steel strip mounted outside the hull, and even some that use the running gear (which I would not suggest). My neighbor actually just clamps a set of jump cables on his shrouds and throws the other end into the water.

My personal opinion is that unless you plan to do it completely and totally correctly, do not do it at all. I believe that grounded boats are much more likely to get hit by lightning than non-grounded. I have a 63 foot mast. I am not grounded. I have never (knock on wood) been hit. My neighbor has a 50 foot mast. He's grounded. He has been hit twice.

Just food for thought, but every owner must make that decision.

[sailortjk1]

Just like Dad said, many believe by making the path less resistant you are actually inviting a strike.
However, usually the damage is far less than a non protected boat.

[seafrontiersman]

Thanks Dad!

I have no keel bolts but I believe that the Steel winch connected to the Iron centerboard by a stainless Steel wire rope will ground out the strike. I need to research this a little more I guess.

I've been on ships which have been struck by lightning three times and it scares me more than anything else on the sea, now I have something else to be worried about!

[ulferlingsson]

My advice: Try to create a Faraday's cage instead.

Get 4 battery crocodile clips, with about 4 feet of heavy gauge copper wire. When lightening comes, attach one to each stay (fore, aft, starboard, port) and let the wire hang in the water. Do NOT ground the mast in the center. With this arrangement you have some degree of protection if you stay away from the stays.

[oceanscapt]

I've never been struck by lightning (time to buy a wooden boat) but I doubt that running a wire down the mast to the winch, or keel, will do much to protect you from the strike. The amperage is beyond anything you can compensate for, the voltage and charge will go where it wants, not where you want it to go, and the EMP will kill almost every electronic item on board.

Are you inviting a strike by having a well grounded point high in the air? Don't know. Are you more protected by having your vessel at a voltage potential closer to the surrounding area? Don't know that for sure either.

I've seen lightning strike a boat in the middle of a marina, taller and shorter sticks all around. To me the best place to be is out of an area of lightning activity. If you can't do that, then the odds of getting hit, or not, are beyond your control.

[scottyt]

look at it this was what ever you do may stop 99 % of the lightning fro doing damage. the kicker is the 1% left is a couple thousand volts and several hundred amps and it will do plenty of damage on its own

[GaryHLucas]

Some years ago I did a grounding job on hi-frequency induction furnaces, because they were in a room next to the computer room. We used 2" wide copper braid run under the floor and connected to a 4' x 8' sheet of galvanized steel buried outside. The customer reported that they were amazed, all their interference problems went away! Hi voltage and Hi frequency are both skin effects, the current tavels on the surface of a conductor not in the middle. This is why all those round buss bars you see in sub-stations are actually thin wall hollow pipe.

So a mast makes a nearly perfect conductor for lightning, stays and wires from the mast to the keel not so much.

Some time ago I got hold of a roll of 6" wide copper strip. I thought that the way to really protect the boat is to carry it on board. If a lightning storm comes up, unroll it and attach it to the mast with hose clamp. Then drape it with no sharp bends right over the side into the water maybe 6 feet deep. Haven't tried it, wouldn't want to be on board to observe whether it works either!

Gary H. Lucas