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99.99999999 % of the time you will only be hit with a branch of that Lighting bolt and that may destroy all your electronics aboard or if your lucky maybe just your Depth Sounder like mine toasted. Unplug your electronics and turn battery selector switch off if the lighting and the boom happen same time or within 2 seconds from seeing the flash and hearing the boom.
You can put them in a lead lined box but thats a old myth and don't know if it will keep them safe.
Dave

corkscrew wrote:Ok....if I am anchored and its a lighting / thunder storm....see where I am going with this? What happens if the mast is hit by lighting? More important....what happens if I'm on the boat when it gets hit?

As the lead lined box melts with the heat of the lighting, with all ure toys inside. Making a nice metal rock you can use for an anchor.



Allan

tangentair wrote:I do not think any of the existing cables are heavy enough to carry the current/voltage of a lightning hit. They would burn through and the charge would seek alternate pathways. To properly ground a mast you would need at least a 00 (double ought) wire and a large disapation field - big metal plate, in my opinion. If you see it coming and can't get out of the way, lowering the mast - maybe, and getting to shore in a low dry enclosure are probably your best option(s) at least in my opinion.

Agreed.

That much power can't be controlled via a cable. If the electricity can't flow unrestricted, the cable will get HOT. Very Hot and melt or blow holes through the path it takes. Also, water isn't a great conductor of electricity. You need some kind of surface plate to disperse all that electricity.

Since I don't believe I am capable of grounding it sufficiently, I will opt for the stay away from the mast and stays and hope if it hits I'm not in the path to ground. I can replace my stuff that melts, not my family.

I think lightning is unpredictable. The high voltage can jump or arc, seemingly without reason. I see reports that say the lightning jumped from this to that, and so forth.

The best advice is of course to avoid being in the storm, next if caught in the storm to stay in the cabin, and as far away as possible from the metal support under the mast (in a 26x).

I really don't think there is much proactive that you can do -- all the reports I see have mixed results or inconclusive advice concerning grounding.

It's a fascinating subject. Around here there are thunderstorms just about every afternoon in the spring and summer.

Several years ago I was in the marina on my V222 with a thunderstorm overhead. I was laying on the settee reading when I saw an arc jump in from the chainplate and run it's way around to the keelwinch and then down and out the bottom via the keel cable I guess. It happened too fast to be scared. There was a scorch mark on some carpet I had tacked to the hull but that was about it. I can only conclude I was one lucky guy that day.

Good point above. Take some basic precautions and then just relax. If your numbers up, its just going to happen no matter what you do.

Lightening storms are not a problem over here,we get them but they are pretty tame compared with the ones you guys get.

i have never seen lightning hit anything,so if you are really worried,fill up you gas tanks and motor over to our side of the pond

Years ago I made up 4 heavy chains with a metal plate linked to one end and a quick link on the other. I sleeved the chain with bicycle tube and the plate with vinyl edge to protect the topsides. When I'm in the middle of a lighting storm I deploy them hanging overboard from each stay. The side, fore & aft stays create a cone of protection & hopefully if I ever have a strike....the path will be directed to the sea????

I've used this set up many times on my classic sloop and more recently on my X. I only bother to deploy it if its almost on me. I know all the controversy....and that there are those that say it won't help.....or it will attract lightning..... but its peace of mind to me & the wife.....and I don't have the mast grounded.

We just sit in the cockpit away from all the stays & mast, disconnect all electrics and sail out of it if were underway...or wait it out anchored in a cove.

I store the rig in a canvas bag in the bilge for added ballast.

So far so good....!

yesterday there was thunder in the distance and when mortoring back to the dock I reached up to grab the bimini and put it back to get ready for docking i got a jolt through the fabric, presumably I was grounding between the metal bimini frame and the metal steering wheel on the m model, no time to dump the jumper cables over the side, and not sure I wanted to be connected to the cables at that point, put on gloves quut messing with bimini and motored in uneventfully

it happened to a guy on catalina 22 a months ago when he touched the outboard

presumably the charges were building up on my boat, but there were no strikes nearby before or after

part of the reason for putting down the jumper cables earlier would presumably be to allow the buidup of ionization charge on the mast and other metal parts of the boat to dissapte into the water and reduce the chance of getting hit.

guess next time i will put one cable down from the mast and another from the lifelines or bimini, but I sure dont want the bimini with me under it to be the target. on our lake in colorado it seems to be the catalinas and macgegors with no grounding where the sailors get these kinds of shocks, the keel boats are better grounded and the owners dontseem to get the shocks

anyone have experience with those brush diffusers at the top of the mast?

and remember rather than telling everyone to look in archives, the search function works poorly better in google actually

Just be sure to remove the tin foil hat before all else

Actually the search function works quite well, if used properly. Unlike Google, it only searches for discrete words unless you use the wildcard function. Doing a search in the window at the top of the page using the terms "lightning prevent*" returns 16 results and will provide all of the answers that you want. Using the asterisk with the word "prevent" will return all words that begin with "prevent": prevent, preventing, or prevention.

To partially answer your question though, dropping the cables overboard will only increase the charge on the boat, not reduce it. The charge that you are experiencing is a positive charge that is coming from the water, in response the negative charge that is building in the lower levels of the clouds.

My experience with what you call diffusers (dissipators) is with terrestrial radio towers and not sailboats. It has been very positive (no pun intended) over the past 30 years. The theory is that they slowly dissipate the charge that is building up on the tower (sailboat rigging) into the near atmosphere, before it can reach the critical level needed to attract a lighting strike.

Grounding your boat and rigging will only work to channel the lighting strike to the water and then, only if all items on the boat are properly bonded.

~Rich

hhhmmm it could be difficult in any given strike to dispute what Rich says, however there is a real solution that will deflect virtually any electrical disturbance.

Of course you need not take my word on it, give it the ol college workout };~)

Cheers

For a lightning protection system for sailboats that you can purchase, take a look HERE.

This site describes a product called Strikeshield. Check out the tabs at the top of the page labled Products, Lightning Information, and Grounding Concepts for additional information.

Its not such a crazy question...Many old timber crayfish [ lobster] boats had a large metal plate fitted to the side of the hull under the pot tipper to prevent damage to the planking when the pot reached the surface. Either stainless or copper. And we were aware of possible lightning strike. We always ran a wire from the high point of the boat down to the plate. Any strike would run the wire and dissipate in the sea. I think that only if the voltage is interuppted would the wire heat up. On this I may be wrong. This could be compensated by use of heavy wire.
In the case of our 's, it would not be so hard to silcone a square foor of BARE copper plate to the hull and run a wire from the mast base to it...It could be placed under the hull out of sight. Growth on it would not be a problem due to it being copper. A silicone bead all along the length of the wire would bond it to the hull.
In the days of the old HF radios, these types of plate were essential to the radio working.
Puggsy...

This is going on my job list.

Why not just park next to a boat with a taller mast.