Sailing in thunder & lightening...

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farmerdan79

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It seems it was probably too much to ask to have two long bank holiday weekends with glorious sunshine.

As such, I have seen the forcast for friday and it appears that there could be some heavy showers and possible thunder in the Solent area on Friday.

I have never been at sea in a thunder storm, and was hoping to be out on Friday, What special considerations should be made?:confused:
 
You can spend a small fortune on 'lightning protection' - particularly from American suppliers who will sell you an amazing range of gadgets - and still get struck. Or you can take a change of underwear, and never suffer lightning strike.

Gadgets are probably no more effective than hanging a rubber welly over the masthead. A TV programme researched some lightning gadgets and found some actually ATTRACTED lightning!

Thats about it. Basically, to use the old wartime analogy, if your name is on it, then that is that.

Some people believe that by hanging an earthing strap from the mast overboard it provides a path for the electrical charge if you have the misfortune to be hit, and this reduces the damage.

About the only thing you can do is to put your expensive electronics in the oven or a metal box. This stops them getting fried in the event of a strike, by the faraday cage effect. If the oven is big enough you can get in too, but it wont save the boat!

If lightning is nearby, avoid touching any metal objects: guardrails, fittings, winches etc, as you can get a nasty induction shock off them from nearby lightning.

For me, the thought of sitting at the base of a 30ft metal pole with lightning around is a big no - no. But after 50 years sailing, so far....
 
farmerdan79 said:
It seems it was probably too much to ask to have two long bank holiday weekends with glorious sunshine.

As such, I have seen the forcast for friday and it appears that there could be some heavy showers and possible thunder in the Solent area on Friday.

I have never been at sea in a thunder storm, and was hoping to be out on Friday, What special considerations should be made?:confused:
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Lightening scares me. Short of major modifications to the vessel I can't see anything you can do to protect yourself or the boat.

According to this Podcast earthing to the Keel is the last thing you want to do:
http://furledsails.com/article.php3?article=676
 
I've sailed a lot in lightning and been struck once. There really isn't anything you can do about the chance of getting struck but you can prepare by unplugging and placing in the oven any electronic devices - don't light the oven!
Being within the 'cone of protection' provided by the mast will protect crew from a direct strike, but warn them not to hang onto anything metal. Everyone not needed on deck should go below.
For me the bigger worry is whether or not the thunderstorm is packing any wind - some do, some don't - so reducing sail and preparing for a powerful but short lived blow is a good idea.
 
there is a load of techy info in Professional Boatbuilder.

http://pbb.proboat.com/index.php Search for "lightning".


The articles emphasise the pro-active approach to prevention, and conducting the charge to ground. Especially good is the article in #128, which discusses the effect of lightning on carbon masts.

FWIW, I know someone who has a steel plate connected to the base of her mast, with a tight shackle to a length of battery cable which goes overboard in thunderstorms. So far, it has worked well; she has not been struck :)
 
sarabande said:
FWIW, I know someone who has a steel plate connected to the base of her mast, with a tight shackle to a length of battery cable which goes overboard in thunderstorms.
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If Dr. Ewen Thomson in the Furled sails podcast is right, and if I understand him properly, then maybe that's not the right thing to do.
 
My surveyor pointed out that the lightning strap at the base of the mast, connecting the mast to the keel, needs to be re-attached, but to do so involves taking the mast out, so I haven't bothered. Shoudl I bother or is it entirely irrelevent to a billion volts?

A couple of videos on youtube show the masthead stuff taking a hit and splintering into sparks, but none of them say how the boat fared other than that:

http://www.youtube.com/watch?v=0JHUNgNb0Uo

http://www.youtube.com/watch?v=IP2jCcSR1qo&feature=related
 
We have sailed in some bad thunderstorms over the years (bad that is by UK standards) and it has to rate right up there in the rather not stakes. That said our worst one was when going south across the Channel when a line of really bad storms was headed north up from France. It passed over us as we crossed the lanes, the good news being that as it was headed north and we were headed south our exposure to it was less in time than had we been stationary or going the same way as the storm. We disconnected all aerials and moved the leads well away, put the Decca (it was pre GPS) in the cooker as I'd heard that was a good idea. We also hung a length of chain, normally used as a mooring strop, from a shroud into the water. The lightning was horrendous and hitting the water all around us yet despite having TWO metal sticks stuck up in the air the boat wasn't hit. The rain when it came was in stair rods and a far bigger problem then became seeing the ships in the lanes even with radar but at least the lightning had moved past. The same storm did lots of damage as it crossed the UK coast with lots of strikes.

Storms in the USA are much much worse and the stuff of tornadoes too. We are moving there to live aboard so it tends to give pause for thought! I've been there on land in some really wild ones, with hail the size of tennis balls that wrecked roofs and damaged cars and the lightning is something else.

Is there a 100% safe solution? I doubt it but the use of the oven as a Faraday cage in which to put electronics to avoid them being decimated in a strike is well documented so worth a go. Otherwise stay within the cone of protection from the mast and keep hands away from metalwork and rigging seems to be the best idea.
 
youtube is excellent. Just shows how many boats are hit each year.

Rethink on lightning protection coming up !
 
sighmoon said:
So far, it sounds like he's saying no, because you don't want the charge forming inside the boat.
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I think he's saying that. I was hoping a few YBWs would have a listen and explain it all in simple terms and offer an opinion. As you say, it's long listen!

sighmoon said:
I wonder if a seawater soaked spinnaker halyard, led from mast head to sea would help?
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If Thomson's correct, and if I've understood him then not at all.
 
Lightning scares the willies out of me !

Once I was approaching Plymouth from Binic, a thunderstorm appeared on the horizon and it looked violent enough that we altered course several times in a vain attempt to avoid it, not ideal as we were navigating entirely by DR in poor vis, but that was the least of our worries.

We eventually got overtaken by it, saw a ship nearby get hit, then there was lightning hitting the water around us.

My crew of the time was a macho 'nothing fazes me' type, but when this was going on he just turned to me and said " it's just a matter of time isn't it ? Let's blow up the dinghy ! "

So we did, towing the inflatable mid-Channel; we weren't hit but it was definitely scary.

One point is that when lightning is close, the vis' is usually poor too.

On another occasion I was with my then wife in Poole, approaching the entrance to the River Frome when a violent electrical storm descended on us.

My wife, an ardent feminist who reckoned women are far superior, scurried down below out of fear and left me to it !

At the river entrance a chap in a Mirror dinghy was having a lot of trouble getting back to the river, so we gave him a tow, not without misgivings as I was rather keen to get among the taller masts in the river, but I reckoned if we'd left him to it we deserved to get hit.

This Karma obviously worked, we didn't get struck, and he later tracked us down and bought us drinks all evening !

Added to the worries of electrocution & fire, I have read that a lightning strike can blow all the seacocks clean out of the bottom, which sounds like the recipe for a Bad Day.

At my moorings, a wooden 21' yawl with wooden masts, among the shortest rigs in the club, was hit and had a plank blown out of the side...

I have a length of chain with a snapshackle to clip onto the shrouds and trail in the water in lightning conditions, shrink-sleeved to avoid knocking the topsides.

Some schools of thought say this may actually attract lightning I know, but at least it would avoid the dangerous 'spark plug' effect between mast foot and keel supports on my boat.

I suspect Old Harry hit the nail on the head, take reasonable precautions but if your time is up, it's Goodnight Vienna !
 
certainly agree with putting any portables eletronics in the ovan and not touching anything metal I am not usally scared about sheet lighting when I am sailing as that is cloud to cloud but fork lighting scares me silly on a boat patically when you are the tallest thing as the eye can see. Though havent been struck yet though it is one experiance I would be very happy to live my life without.
 
farmerdan79 said:
It seems it was probably too much to ask to have two long bank holiday weekends with glorious sunshine.

As such, I have seen the forcast for friday and it appears that there could be some heavy showers and possible thunder in the Solent area on Friday.

I have never been at sea in a thunder storm, and was hoping to be out on Friday, What special considerations should be made?:confused:
Click to expand...

Amongst all this talk of ovens, earthing straps, and etc. I'm surprised no-one has said the obvious.... "just don't go out" :o
 
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