Lightning Strikes

[Greg_Colleen]

Hi all,
Has anyone here had any experience with lightning strikes? If you're out in the open ocean and you get hit by lightning, what actually happens? Should I "earth" my mast or does that just attract lightning? Any advise would be appreciated (preferably from people who have had experience with lightning strikes).

Thanks

Greg & Colleen

[Paul L]

No, bonding the mast does not attract lightning. The most typical issues with strikes are loss of all electronics. There's a fair amount of reading on the subject if you search a little. Start here
https://www.boatus.com/magazine/2017...ng-strikes.asp

[a64pilot]

Originally Posted by Paul L

No, bonding the mast does not attract lightning. The most typical issues with strikes are loss of all electronics. There's a fair amount of reading on the subject if you search a little. Start here
https://www.boatus.com/magazine/2017...ng-strikes.asp

I believe that it in fact could, a lightning rod on a building doesn’t “work” if it’s not grounded.
Lightning’s streamers of course come from grounded objects and when one connects the circuit is made and Bam.
I don’t believe streamers come from non grounded objects.
Of course it’s likely your mast is grounded whether you bond or or not with rigging, chain plates and salt laden wet decks etc.

The point of bonding to a ground is to protect of course, not to keep from being struck, but it’s possible it may increase the chances of being struck.
How much if any? I don’t believe anyone can even give that an educated guess.

My personal belief is not much at all, I believe that for all intents and purposes of streamer formation our masts are grounded.
But that’s my opinion, worth absolutely nothing.

[billknny]

Although I have not been ht by lightening (Yet!) I know of many boats that have been. As stated, the loss of all electronics on board, is typical. Plugged in, or not. Turned on, or not. And a direct hit is not needed. Not just electronics, but batteries, alternators, engine electronics...

This is something I think is greatly under-appreciated by a lot of today's cruisers. Every boat out on the ocean is one lightening bolt away from sailing in the 19th century. If you suddenly lost all of your electronics a week away from shore, could you find your way to a safe harbor? Are you sure? No communications, no weather info, no gps, no electronic charts...

[Frankly]

There is no reliable evidence that a grounded (earthen or seawater) mast, tower, whatever is more likely to attract a strike than an isolated mast. There is plenty of evidence that if the mast is isolated bad things can/ do happen. I have seen a couple of badly damaged boats where the lightning made its own path to the ocean (no ground).

Over the years I have experienced loss of electronics from nearby strikes, and the back stay ground conductor got hot enough to discolor the crimped lug on Cbreeze when lightning struck an OAK tree about 50 ft away.

Keeping a battery powered GPS stored in the oven is probably a good idea (take it out before cooking the turkey).


Frankly

[S/V Illusion]

About the only certainty here is that you might not want to take advice from anyone who can’t spell lightning correctly.

[Paul L]

Originally Posted by billknny

Although I have not been ht by lightening (Yet!) I know of many boats that have been. As stated, the loss of all electronics on board, is typical. Plugged in, or not. Turned on, or not. And a direct hit is not needed. Not just electronics, but batteries, alternators, engine electronics...

This is something I think is greatly under-appreciated by a lot of today's cruisers. Every boat out on the ocean is one lightening bolt away from sailing in the 19th century. If you suddenly lost all of your electronics a week away from shore, could you find your way to a safe harbor? Are you sure? No communications, no weather info, no gps, no electronic charts...

You missed the really unfair part of the lightning strike. Your steering compass can get remagnetized and is generally no longer reliable.

[Emmalina]

Hit 3 times on 2 boats Insurance doesn't like me any more LOL

[daletournier]

Originally Posted by Paul L

You missed the really unfair part of the lightning strike. Your steering compass can get remagnetized and is generally no longer reliable.

People forget this or dont know this.

[Emmalina]

Originally Posted by daletournier

People forget this or dont know this.

Always keep a notebook with opencpn and a puck gps in the oven !
Think the most important instrument for me is depth !

[Frankly]

[QUOTE Think the most important instrument for me is depth ! [/QUOTE]


Amen. "As long as you have water under the keel you have options."


Frankly

[a64pilot]

Actually any ferrous metal can become pretty highly magnetized, had a helicopter get hit in Germany, every piece of steel was magnetic, engines, transmissions, everything.

One of these will tell you
https://www.ndtsupplies.com/2480.htm...AaAuDXEALw_wcB

[acem]

I have been in vehicles struck by lightning but not a boat. I won't go into details. It was scary butI am ok.

A sailboat mast is a much more likely path for lightning than air so if you are on open water grounding your mast will not increase your chances of getting struck. If you are in a marina with alot of other sailboats I am not sure.

I ground my mast.

Put your backup electronics in a metal box such as an ammo box. It is a better Faraday cage than your oven and you won't cook them when preheating your oven!

Thx-Ace

Thx-Ace

[Neptune's Gear]

There are two basic reasons to ground your mast. The first is that if you are hit, you provide a good patch to ground, and are less likely to have side flashes etc that will complicate the damage, can cause large hull penetrations, and even kill. So, this is a good idea.

The 2nd idea is that the addition of a good ground gives the rig the same PD as the sea, making it "invisible" to lightning, and therefore less likely to be struck.

However, nothing is 100% reliable, and boats with and without "protection" are hit every year. The oven trick does not always work.

Its also interesting that more Cats are hit than monos. Perhaps this is a function of surface area, or maybe that it is harder to properly ground a cat rig than a mono's. Good grounds have nice, straight paths, no serious bends...

[daletournier]

Originally Posted by Neptune's Gear

There are two basic reasons to ground your mast. The first is that if you are hit, you provide a good patch to ground, and are less likely to have side flashes etc that will complicate the damage, can cause large hull penetrations, and even kill. So, this is a good idea.

The 2nd idea is that the addition of a good ground gives the rig the same PD as the sea, making it "invisible" to lightning, and therefore less likely to be struck.

However, nothing is 100% reliable, and boats with and without "protection" are hit every year. The oven trick does not always work.

Its also interesting that more Cats are hit than monos. Perhaps this is a function of surface area, or maybe that it is harder to properly ground a cat rig than a mono's. Good grounds have nice, straight paths, no serious bends...

The cat think is interesting. When I was in Bali 3 cats got zapped by lightning.

I'm currently in Shelter bay marina Panama, last week just before I got here there was a big electrical storm , a cat got a direct hit, all other boats were fine.