Lightning Damage

[rbishop]

Yeah..., for some reason my GPS and autopilot were the most susceptable. Radio needless to say gets wiped out. I know the mast is the structure taking the hit, I guess some very large induced currents are being generated and picked up by these pieces of gear and/or the cabling that runs between the devices.

 

[AndrewB]

A suggestion from CWBB ...

Fit a condom over the top of your mast.

No better or worse than any other method I've heard, ranging from wire bottle-brushes to lucky rabbit's feet.

You moor in South Florida, the lightning capital of the world? I gues you have to live with it. (I took a hit there, too, on a brief visit). Seriously though, this topic comes up over and over on the US , so its well worth searching through the <A target="_blank" HREF=http://old.cruisingworld.com/forums/arch_067/index.pl>archives for some very erudite debate and strongly held opinions among Florida denizens, though without any satisfactory consensus.

 

[oldharry]

Its like I said Vyv - it makes me FEEL better to provide an easy path for lightning to go over the side rather than through the hull - or me!

Rationally, as you rightly say, a spark several Ks long is unlikely to be deflected from its chosen course whatever we do - and I dont believe that a deck mounted mast is any less likely to attract ligthning than a keel mounted one - the gaps between the base of mast and rigging and the sea are so tiny compared with the overall length of the ligthning stroke that it will make no difference.

Ligthning dislikes going round corners and will happily jump several feet further (i.e. through the cabin from mast mount to keel bolts) rather than deflect round the outside of the hull. My (forlorn) hope is that it MIGHT just follow the direct path down the forestay and into the sea if I make it easier that way.... But I have no real scientific basis for this - like I said, it just makes me FEEL a bit better having done SOMETHING!

The only way to prevent lightning strike is to find some way of stopping the ground streamers developing, or of dissipating them before they reach the downward leader - and solving that one will one day make somebodys fortune!

 

[oldharry]

Just goes to show that even 'Coast Guard Approved grounding systems' are not effective in preventing lightning strike and damage. Its pure speculation to wonder whether the damage would have been worse without it?

 

[oldharry]

Re: A suggestion from CWBB ...

Sorry Andrew - condoms arent really strong enough... but is this a a good use for old 'yellow wellies'!

Probably as effective as a witches brush - and a lot cheaper!

 

[rbishop]

Re: A suggestion from CWBB ...

OK. Thanks for the reply and suggestion. I'll definitley check out the BB.

Rog

 

[rbishop]

Re: A suggestion from CWBB ...

Well, you know, a problem I run into (being a little lazy I guess) is that it's real inconvient and arguably dangerous, having to run around and collect equipment to store in an oven or what not. With the sudden approach of some of these storms you just don't have the time and in addition, the damn sensors are still susceptible.

 

[rbishop]

Yeah I've heard and tried that one too. Generally when I'm moored. However on one ocassion, I was nailed by lightning while moored, all gear in a steel Coleman cooler. The displays and stuff placed in the cooler faired OK, but the hard mounted sensors like the GPS head and sounder were not removed and were destroyed.

Rog

 

[rbishop]

Thanks for the reply. This is my first venture into the world of boating forums. Is there something wrong with the power boat forum? Or, is it not a good idea to get into too many of these forums?

Rog

 

[rbishop]

Thanks for the reply. Gave me some insight into some things I had not heard before concerning the primary grounding system.
Yeah, I've tried the "fuzzy brush", but I don't get it. I can't understand the theory behind it and apparently, it does not work.

 

[rbishop]

That idea I have not heard before! Thanks for the reply.

 

[BrendanS]

Nothing wrong with the powerboat forum, we're a friendly bunch with a wicked sense of humour.

Most of the regulars read and post on all the forums, so seeing the same message several times is not usually necessary

Generally speaking, anything of a technical nature is posted here. The scuttlebutt (sailing) and motorboat forums are for everything about voyages, advice on harbours, techniques and general chit chat and (usually) good natured abuse.

 

[Guest]

I don't have a sharp point at the masthead. However, I do have a quite pointy antenna for the radio at the
stern. Is lightning likely to by-pass the mast and hit the antenna, or perhaps hit both?

Seems to me that on my little 18ft trailer sailer there is not much that I can do, other than avoid thunder storms,
or pray.


Ray

Ray

 

[oldharry]

Frankly I dont think it makes a lot of difference which part of the boat is hit - the end result is going to be much the same!

Its usually the highest point that is hit so the mast is arguably more vulnerable. But its capricious stuff, and there do not seem to be any hard and fast rules other than the old saw of 'not standing under a tree.

Now whenever the thunder starts rumbling, I remember that, look up at 30 foot or so of metal mast being clearly the highest point for quite a long way around...... and wonder if there IS anything I can do about it

Except pray.....!

 

[Zach]

I moved to Florida from San Fracisco, CA about 6 months ago. Sailing during the summer moths down here is a hair rising experince. I installed a grounding system to my 24' boat with a help from an electrician. It cost about $80 in hardware, and we were able to buy most of them from Home Depot and BoatUS. I hope it will save my skin if a ligthning decides to hit my mast. I do not have any valuable electronics on my boat, so the device protection was not a concern. However, I saw a product feature at www.boatingnews.com that may help you. The company's web address is www.seacom.us. Happy sailing.

Zach

 

[rbishop]

Thanks Zack.
I checked out the website. Looks like this company does have product to designed to protect electronic gear from lightning damage. Their website is pretty informative. Guess I'll give them a call and ask some questions.

Rog

 

[rbishop]

My understanding (limited albeit), is that may be considered a primary protection. Which may save the boat and lives. From what I am learning, is that their are two levels of protection. One designed to save lives (i.e primary) and secondary protection to save electrical systems. It appears that for the most part, electrical systems are taken out as a result of induced currents. Not from direct strikes!

Rog