Struck by god with a bang!!- checklist

Jamesuk said:
Where can i find a pdf standard checklist in the event of a lightning strike?
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I find that hat, spectacles, testacies works for me.

Considering how rare a lighting strike happens I am pretty sure nobody has formally made a list.
 
JumbleDuck said:
http://www.kingjamesbibleonline.org/
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Behind the times - this is a more up-to-date translation: http://www.devotions.net/bible/00bible.htm

Job 36: 30 seems appropriate: "See, he scatters his lightning around him and covers the roots of the sea."

Jeremiah 10:13 is good, too: "When he utters his voice, there is a tumult of waters in the heavens, and he makes the mist rise from the ends of the earth. He makes lightnings for the rain, and he brings out the wind from his storehouses. "
 
Jamesuk: obviously your immediate concern is safety of the vessel. Then there will be another checklist of damage, particularly to electronics. It's well-known that some strike damage doesn't become apparent immediately, to which end some insurers give a standard claim revision window of 6 months. In other words, if lightning-induced damage emerges 180 days down the line, it's still part of the original claim. Worth checking whether this is the case with your insurer, once your heartbeat returns to somewhere near normal.
 
Flippancy about Biblical references apart, this is actually such a rare occurrence that you aren't likely to find a standard checklist. And in any case, what you need to check will depend entirely on the construction, fixings and fittings of a particular boat. The rule of thumb is that lighning will discharge to the sea from the point of impact by the most electrically direct path - so on a sailing boat, damage is most likely at the bases of the standing rigging. Metal hull fittings may well be damaged if in the path of the discharge, up to the point of them being blown out of the hull. Metal fastenings in wooden hulls may also be damaged. Of course, electronics are likely to have been (literlally!) fried; all such equipment needs to be checked in all modes of operation. Note that compasses can be severely affected by lightning - don't assume that your compass still points to North!

If you've BEEN struck by lightning, I'd suggest getting a surveyor to assess the damage for insurance purposes.

Sailing boats are MOSTLY protected from lighning strikes by the mast acting as a lightning conductor, which (counter-intuitively) makes it less likely that lightning will strike the mast or anything within a 45 degree cone from the top of the mast. You can enhance this effect by making sure that the mast is electrically connected to the sea - the text-book way of doing this is to wrap anchor chain round mast and shrouds and dangle the end in the sea. It doesn't mean you won't be struck by lightning, but it does make it less likely.
 
As said lightning will give huge currents from the mast to the sea. A heavy low resistance conductor to the sea from the mast base will reduce damage to other structure. I disagree about using the shrouds as part of the conductor because stainless steel is not a good conductor. It will get hot with relatively low current ie 100 amps for small rigging wire. This will soften the wire destroying heat treatment or simply fuse the wire. An ali mast is low resistance so should take a lot of current without damage except at entry and exit points.

So a check list might start with check bilges for water ingress. damage to through hulls prop shaft and rudder fittings.
Secondly check rigging for discolouration or signs of heat. Mast at the base and internal support structure.
Check safety wires pushpit pullpit etc for signs of overheating.
Check gas and fuel metal pipes they may have been part of a current path
Check compass for errors.
Check electronics to see what has survived.
I think those in order of likely hood of damage and critical to safety. good luck olewill
 
William_H said:
As said lightning will give huge currents from the mast to the sea. A heavy low resistance conductor to the sea from the mast base will reduce damage to other structure. I disagree about using the shrouds as part of the conductor because stainless steel is not a good conductor. It will get hot with relatively low current ie 100 amps for small rigging wire. This will soften the wire destroying heat treatment or simply fuse the wire. An ali mast is low resistance so should take a lot of current without damage except at entry and exit points.

So a check list might start with check bilges for water ingress. damage to through hulls prop shaft and rudder fittings.
Secondly check rigging for discolouration or signs of heat. Mast at the base and internal support structure.
Check safety wires pushpit pullpit etc for signs of overheating.
Check gas and fuel metal pipes they may have been part of a current path
Check compass for errors.
Check electronics to see what has survived.
I think those in order of likely hood of damage and critical to safety. good luck olewill
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All very good sense, but I think your point about the shrouds is open to debate. I don't doubt that the wire will behave as you say, but I don't think that damage can be avoided as you suggest in the event of a strike. I'm talking about minimizing the likelihood of a lightening strike, and in that case the currents aren't so large. In the event of a strike, the current will follow all the conductors regardless, and having a connection from the chain-plates to the sea might mitigate hull damage when the charge "jumps" from the chain-plate to the sea. Your shrouds will have taken the current anyway and the damage you suggest will take place whether or not there's a heavy conductor to the sea - but if there's an "easy" path from chain-plate to the sea, it may save your hull. Hull damage in photos of lightning-struck boats is very often below the chain-plates.

There's two situations here - one is the protective action of having the mast earthed to the sea, the other is the damage limitation effects in the unlikely event of being struck.
 
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