lightning strikes on steel boats?

[fulkne12]

how does 1n overcome this? is it much worse on steel sailboats?

[Guillermo]

Have a look at:
http://www.cdc.gov/nasd/docs/d000001...7/d000007.html
From there:
"There is no such thing as lightning-proof boats, only lightning-protected boats. All-metal ships are rarely damaged, and injuries or deaths are uncommon. These ships are frequently struck, but the high conductivity of the large quantities of metal, with hundreds of square yards of hull in direct contact with the water, causes rapid dissipation of the electrical charge".

[fulkne12]

thank you for your intresting link .do you think lighting could cause damage to a steel boats finish if struck on the underside frome disapation ,it appears to me you might have a clue as to the depth of your knowdldge of this issue ,i would appreate any advice you could offer.

[Guillermo]

I have not a deep knowledge of this matter (I've never been struck by a llighthing! ), but I think we have to be cautious: Boats are not ships, so they do not have "large quantities of metal, with hundreds of square yards of hull in direct contact with the water". A typical small steel boat maybe is really small from the point of view of a direct hit, and also people aboard being quite close to it. And bottoms are painted, so more or less isolated from water, but probably not enough as to handle the tremendous voltage of a lightning. But all this is speculating on my side, as I do not know what the consequences on the bottoms could be, sorry.
More papers on the subject:
http://www.thomson.ece.ufl.edu/lightning/SGEB17.html
http://www.practical-sailor.com/news...5lightning.pdf
http://www.marinenet.net/Lightning.htm
http://www.sailingcatamarans.com/lightningarticle.htm
From this last:
"The best possible ground is a bare metal hull, but as the epoxy paint forms an insulating barrier, even a steel boat will need to fit a grounding plate"
Cheers

[solrac]

Don't know if this may help. but on flammable petroleum & LPG Plants, (earth based) all metal roofing must have a lightning installation (grounded) with a 35mm2 wire, that's what NFPA70 asks for protection.
Think some alike diameter wire attached to mast, (isolated) with enough dimensioned grounding plate on the outer bottom of the hull must be able to carry the load.

[Poida]

When yer times up yer times up.
Your more likely to get killed in a car accident travelling down to the boat marina.

[Bergalia]

Poida is correct. The chances of being struck by lightning while at sea (blue water at least) are virtually incalcuable. In many years at sea - and having weathered many a storm (gosh - look at the lamp swinging) I've not heard of a single strike on a ship/boat. St Elmo's Fire - yes - a regular occurance, and neighbouring thunderstorms scarey as hell, but - spectacular to watch.
But if you still have fears - try trailing a couple of thousand miles of thick copper-wire behind you - the landward end securely attached to a metal pole hammered into the earth.....

[solrac]

Originally Posted by Bergalia

Poida is correct. The chances of being struck by lightning while at sea (blue water at least) are virtually incalcuable. In many years at sea - and having weathered many a storm (gosh - look at the lamp swinging) I've not heard of a single strike on a ship/boat. St Elmo's Fire - yes - a regular occurance, and neighbouring thunderstorms scarey as hell, but - spectacular to watch.
But if you still have fears - try trailing a couple of thousand miles of thick copper-wire behind you - the landward end securely attached to a metal pole hammered into the earth.....

Maybe, simply using a copper anchor & chain....
Let's check a little: lightning is nothing but an electrical "arc" (similar as an electrode mig soldering machine) naturally produced as the higher atmosphere layers "statically charge" themselves (let's say POSITIVE + ) respect to earth (or water in this case, potential ZERO) to equalize atmospheric static charges.
As Bergalia said, on open sea (same thing happens at coastal waters), the surrounding water has a lower differential potential (micro-voltage) much lower than any thing floating on the hull, so, the lightning "trace-route" surely will go stright down there, instead of discharging energy through a semi-isolated thing and then to the grounded water.

[SamSam]

Originally Posted by Guillermo

http://www.sailingcatamarans.com/lightningarticle.htm
From this last:
"The best possible ground is a bare metal hull, but as the epoxy paint forms an insulating barrier, even a steel boat will need to fit a grounding plate"
Cheers

Also from the last...
"Don't use the sintered earth plate from your SSB. It is deliberately made porous and can explode if hit by lightning." Sam

[Poida]

Weat rubber shoes.

[longliner45]

Iv seen lightning damage to boats , on one shimper it blew the bow apart,,,,,but on a boat you are not grounded, your electrical system is delta,,,,self grounded ,,,lightinting is unmeasuable,,,,dont think that there is too much you can do to stop it ,but you can be ready for the damage it can cause,

[Jolly Roger]

All Classification Society rules have stringent recommendations for lightning protection in wood, FRP and metal boats.

A good technical article on the subject:

http://www.kastenmarine.com/Lightning.htm