Dangers of Lightning Strikes

[Wind_Traveler]

I have often wondered what happens when a boat's mast is struck by lightning.

I would assume this is rather unavoidable, and more a matter of when then if.

Is this a serious risk or does it simply travel through the boat to the water safely?

Is equipment damaged?

Are masts equipped with some sort of lightning rod?

[Ex-Calif]

No problems starting another lightning thread but you may want to peruse some of the previous ones.

lightning - Google Search

What happens when lightning hits a boat contains a lot of depends.

[CaptainBW]

There are so many variables and opinions in the question of lightning but I'll try and offer a few things that I have seen/heard of.

Lightning protection: Most of what I have heard or read suggests there is not much you can do to protect your boat from a strike (i.e. lightning rod). Some boats have a heavy duty wire attached to the foot of the mast that goes to a keel bolt - grounding the boat as much as possible. I have seen some people use a static electricity diffuser at the top of the mast - the idea is that built up static electricity "invites" a strike. I have also seen elaborate wire configurations that attach to the standing rigging and drape into the water. One guy in our marina attaches a battery jumper cable to the forestay attachement and drops the other end into the water!

What can happen: We had a strike to our vhf antenna and it blew out the radio...no other damage. Our dock neighbors have been struck, blew out all the electronics, went out through his shore power cord and tripped our breaker at the boats panel. I saw a boat struck on a mooring - brand new Beneteau 38 (guy had it 1 week) - and it blew pin holes in the hull all along the waterline, totalling the boat. I have also heard of boats being hit with no damage at all.

Just my (not expert) opinion/experience. I will be interested to see what others post.

[fishwife]

The only thing I can say about lightning is that it is totally unpredictable in where it will strike and what damage it will do. Last year we were struck., not where I'd have thought likely, on the highest point, but on the bow roller. We have a stainless stem guard through which the power tracked to the sea. The stem guard was blown off the hull and the bow roller was partially melted and loosened on it's mountings, the bolts had been partially ripped out. I assume that some moisture under the steel was instantaneously converted to steam or even to oxygen and hydrogen. No electrics or other gear damaged, not even the windlass The two of us on watch were blinded by the flash for a few minutes with an after image that lasted over half an hour.
When we were on the hard getting repairs done, two boats in the water were struck and one sank after all her through hulls were blown out and the other lost all her electronics and had a fire on board. You never know.

P.

[Wind_Traveler]

Thanks mates. I will give those other threads a read as well.

[zeehag]

i am not recommending anyone go out with this intent but seems everytime we went on a pasage this past yr we ended up in middle of lightning storms---we werent near the bolts apparently---they were everywhere but we didnt get hit--i attribute it to bubbadaboatkat....feline protection system...

[boatman61]

Had a strike at anchor in Majorca in 97.. four of us were sat in the saloon chatting when there was a blueish flash down the middle of the boat... fried the bulk of the 'connected' electrics on the boat but luckily no other damage...
Fortunately was during a 'rich' period so was fully insured... 3 weeks later all was as sorted.. I love that company..

[sww914]

We got hit in a car in Florida a couple of years ago, not really relevant but here's my story anyway. It struck on the top of the driver's door and I was driving. SOOOOOOO loud! My left ear still isn't as good as it was before. I couldn't see much of what happened but my wife in the back seat saw the blue light flash all over the outside of the car like veins.
No damage to speak of, a tiny burn through the paint the size of a period (.) and a small burn through the clear coat of one wheel. Everything still worked fine, a Faraday cage works well in practice IMO.
A boat was struck near my mooring once, it was a piece of floating trash so if there was any damage it was indiscernable.

[zeehag]

the nasa engineer across from a friend got hit while at his dock behind his home 2 times in 4 yrs. we sailed thru storms frequently for a year and didnt get hit---go figger--must be the kat........

[boatman61]

Originally Posted by zeehag

the nasa engineer across from a friend got hit while at his dock behind his home 2 times in 4 yrs. we sailed thru storms frequently for a year and didnt get hit---go figger--must be the kat........

Remember to change the 'Cat' after the 9th Storm....