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Discussion Starter #1
Quick question: is there any special procedure for sailling in a thunderstorm?
 

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Depends entirely on the wind. Some have none, most have some, and many have squally winds that may overpower you if you don't shorten sail.

The wisest course is to reef early, and make sure you have enough searoom to leeward of the anticipated wind direction. Don't count on being able to make any distance to windward during the worst of it. Just reach, or close reach, and luff as needed. Put on lifejackets too (and a safety harness if you have one). Pay attention to your compass, as wind direction may change a lot during a squall, and you won't be able to see squat during the heavy rain. If the wind's just too much, I'd say drop all sail, anchor (assuming now you're not too deep to anchor), and wait it out. Usually in 20 minutes the weather's good again (not always, though).

The other concern is lightning. you can't do anything about it, but stay away from the mast and stays, they're electricity conductors. If you have a cabin, your crew is safest down there.

I can't be much more specific, as I don't know whether you're sailing a cruiser or an open boat, and not all t'storms are the same either.
 

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Having been caught out in a nasty RED/PURPLE cell from hell recently in a boat with no reefs I can give ya a tip that worked for me. After getting knocked down once and being pushed sideways before I could get her around, I left the jib set for a Starboard tack (backwinded) and set her on a Port tack about 15 degrees off the wind with the boom all the way to windward. This allowed me to sail at about three knots dead into a 40+ knot gale until I could reach a Windward shore and escape the wind, all while being POUNDED by 3/4" hail and having lightning like I haven't seen since Texas, scare the crap outta me. This little adwenture tought me much about what my boat and myself could handle. It also taught me that just because ya haven't seen storms like that in 11 yrs. of living someplace, doesn't mean they cannot happen.
 

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Ummm.. CharlieCobra, I believe that's normally called heaving to. :D
 

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Tell ya what a friend of mine did one time when we got caught in the middle of the lake by one of the "low odds" thunderstorms that were predicted: Down went the sails and on went the iron genny.

And I gotta tell ya: Being out in the middle of an area as flat as a billiards table with a 40' lightning rod sticking up in the air, with lightning crashing down all around you, is most definitely not amusing.

My friend: Don't worry, the mast on this boat is stepped thought to the hull. It's well-grounded.
Me: Here we are, sitting in the cockpit of a thoroughly soaking wet boat, ourselves soaking wet, that mast not 10' away, and you think that's going to help, eh?

Jim
 

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Discussion Starter #8
yeah motoring sounds like a plan but what about lighting?
 

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SEMIJim said:
Yeah, 'cept you don't normally end-up moving forward at 3 kts when you're hove to, IIUC ;).

Jim
It depends on the boat design. Some designs don't heave-to well, and will forereach at about that speed.
 

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saurav16 said:
yeah motoring sounds like a plan but what about lighting?
There's really not a lot you can do about it but pray. camaraderie's #1 and #2 suggestions are valid. (#3 is arguable--but let's not). Thing is: Lightning isn't going to strike your mast unless it was going to strike w/in a circle the radius of which is equal to the height of the mast, anyway. So, if you have, say, a 40' mast, you're only going to attract lightning for a 40' radius around you.

Jim
 

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Has anyone on this board ever heard of anyone being seriously hurt or killed by lightning while sailing? I haven't. People get killed by lightning in their homes and on Terra Firma all the time. Sailboats get hit by lightning every day (most of them unoccupied), doing tremendous damage to electronics and even blowing holes in hulls, but where are the statistics on sailors getting hurt by lightning?

If your rigging is properly grounded, you're in a "Faraday cage" protected by your shrouds, stays, mast, and boom. It's a far, far safer place to be than, say, jumping off your boat onto a metal pier while seeking safety. I suspect the major health risk to sailors from lightning is having a heart attack from worrying too much about what empirically appears to be just a small risk. So ground your rigging and if you're caught in a storm, do what needs to be done to ride it out and don't worry about the lightning. It will pass. If you're still worried about lightning, go with the statistics and give up golf!
 

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dan-

Unfortunately, most boats aren't sold properly bonded and grounded for lightning. And there are two schools of thought on this... a grounded boat is more likely to get hit than an ungrounded boat, so some people don't ground to reduce the chance of getting hit. Others, believe that a grounded boat will take significantly less damage, and weigh that against the risk of getting hit a bit more often.
 

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In terms of grounding, how do you actually do this? I know I spoke with some people in my marina and they say they attach a piece of wire from one of the shroads and let it fall off into the water as the ground wire. Is this o.k. to do or are there better practices out there for grounding a boat.
 

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The people in your marina are deluding themselves into thinking they're protected... they're not. Shrouds and stays, made of 316 stainless steel, are very poor conductors of electricity, and the connection of the wire to the shroud is questionable at best, given the amperages we're talking about here. The wire's bare end trailing in the water also doesn't provide enough edge for it to act as a good boat-to-water grounding surface.

Ideally, you should have a heavy (4 AWG or heavier) wire running down from your mast, which acts as the primary lightning path on most boats since aluminum masts are fairly decent conductors of electricity, and down to a bolt or stud that attaches to a metal plate faired into the hull. The plate should have four linear feet of edge at a minimun—a 1' x 1' plate would do, but a 2" x 2" plate would be better—to dissapate the charge into the water.

The conductor connecting the mast and the stud should have as straight a path as is possible, since lightning doesn't like to turn corners. If you also bond the shrouds, stays, chainplates and stanchions to the same plate, it will create a "faraday" cage for the boat made of the standing rigging, and that should protect the passengers on-board from a direct strike.

YMMV... on some boats this works well, on others, not so good... If you have an external bolt on keel, the keel can often be used for the lightning ground surface—but only if it is external. Doing so with an encapsulated keel is a really bad idea.
 

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According to Chapman: " A measure of lightning protection can be obtained using the principle of the "Faraday Cage." A high pointed conductor, heavily wired to all points of the boat, seems to cast a cone-shaped umbrella in which lightning does not strike. Instead, the voltage is conducted safely to "ground" in the water via submerged metal parts such as the rudder, sailboat keel, or propeller."
 

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Quick question: is there any special procedure for sailling in a thunderstorm ?
Avoid it. If that's not possible, reef early and make sure the engine's ready. Make sure that you keep the bow (or the stern) facing the waves. Don't leave a lot of things loose in the cabin - especially in a small boat. If there are enough of them, and they are heavy enough, your boat may become unstable. Enjoy !
 

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Lightning is the one thing that you can do very little about.

The discussions of Grounded versus not Grounded are sound disscissions.
We can and have debated this at length.

But when you are out there on the water and you get caught in a lightning storm, what can you really do? Not a whole lot.

If the wind is overpowering, we know what to do, we have a plan of action that we persue. But when we get caught in the flash storm, in all seriousness, we are taking our chances and simply must ride it out.

Maybe the more important question is, do I have a plan in place if I do get struck? Do I have plugs on board? Where should the crew be placed? Etc..

During a lightning storm about three years ago, I look down below and my daughter is comfotably sleeping in the main saloon, RIGHT NEXT TO THE MAST SUPPORT. I quietly went below and suggested that she sleep in the aft berth untill this blew over.

If your going to be out cruising, its enevitable that its going to happen sooner or later. Try to carefully watch your weather window and use your best judgement.
 

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eherlihy said:
According to Chapman: " A measure of lightning protection can be obtained using the principle of the "Faraday Cage." A high pointed conductor, heavily wired to all points of the boat, seems to cast a cone-shaped umbrella in which lightning does not strike. Instead, the voltage is conducted safely to "ground" in the water via submerged metal parts such as the rudder, sailboat keel, or propeller."
Yes, but if the keel, rudder or prop aren't connected directly to the mast, via a relatively heavy conductor, chances are very likely that the lightning will sideflash through the boat to get from one to the other. This is more the case with a deck-stepped mast, than a keel stepped mast, especially if the keel is bolted to the mast step.

A Faraday cage requires that the pieces of it be connected electrically... if they are not, no Faraday cage is present. :rolleyes:
 

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We put the portable electronics in the oven ( a microwave is even better).

If you have radar, you can track the cells, and try manuevering to avoid them, but its hard to predict their patterns--sometimes you miss the cell you were worried about, and get slammed by a new one.
 
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