How should we protect ourselves in a Electric storm.

[japawil]

A question for those who have lost electronics due to lightning, where these covered by insurance or is that sort of thing considered “an act of god” and not reimbursable?

[sailorboy1]

Originally Posted by Oceanride007

At worst are we fooling ourselves that opening circuits protects us.

A lighting bolt may have 1 BILLION volts and has traveled 25 miles.

A little 1/4" circuit separation means nothing to it if it lands close.

[Crusty Joker]

Oceanride007,
First, I am one very lucky person, on multiple occasions. I have stood next to the strike several times, within a very few feet and not been hit. What you have to have is something better ground that will absorb all the energy... and keep you isolated. I had that. I was not on a boat or aircraft at the time, but I have experienced electrical storms that produced St. Elmo's fire on aircraft and have been solo during electrical storms, returning to base when in the US Navy in Florida.

For 007 on a steel 41 footer, I would not be out on deck in an electrical storm for any reason other than jumping overboard if that was required, heaven forbid.

You want to be inside, dry and not touching metal, but that is no guarantee.

A slight correction for Chotu... while it is the current that cooks, it is the voltage that jumps the great distances. Lightening may have a million volts. It also had the current to burn holes through the paint on my 240 Z... and damage the chrome rims. I was standing behind the metal screen door next to the electric panel and the screen door and electrical panel were both hit as was the power pole at the back of my lot...
I saw spots and tasted my fillings for a few days.

Lots of fun. If something happens to you it is very unlikely you will be telling us anything.

Stay low and inside the faraday cage of your great vessel Turn of the electrical and put your hearing aid and other devices in the oven...

Love reading what the seniors have to say.

My advice is try to keep up your payments in the dumb luck club!

I thank the creator and architect every day!

Uncle B

[Nicholson58]

You don’t need a microwave oven. Any metal box (the gas oven) provides the same Faraday cage. I really think that the cage is probably overkill. If you just toss everything on the galley table the results are probably not much different. Just get the wiring away from the things ( or double pole switch)

We have a spare Crappy plotter In a box and several alt devices with GPS, two hand healds.

The thingy at the top of our mast managed to save itself in every hit we’ve had. Not impressed. (See my previous post here)

[ilanortho]

Faraday cage

[rmlarson1098]

Originally Posted by Oceanride007

Ok just watching a video blogger mention he has shut off the Electronics & Electrical in a storm. Well, I do the same. Is that enough?.


My boat wired just like any other, now just imagine a lightning strike up the mast or nearbye, that induces amazing voltages in parallel paths and exits probably at different points and if it can't, it will build up a voltage, to the point where it can and will do incredible damage not just, direct hit is of course very bad but induced voltage, anything connected to that wire is at risk.


Now lets say we have turned off our electronics, that means a air gap of maybe a 1/4". But even worse, the return common wire is not switched and is connected to everything else including the battery, not good for your bank balance.


Now assuming the above is correct, would it not make sense to have double isolation, That means if I "open" the Isolating switch to the switch board supply and all the individual switches, that would make a bigger air gap to the battery.



Now the difficulty is the "Negative side" none of my feeds or distribution has any isolation at all. If we have had Double pole switching, would that reduce the risk at all. Not even sure if it has been attempted, can it be done, I do remember looking at a Ships DC circuit wondered why they had fuse protection on both + & - sides, thoughts?.



At worst are we fooling ourselves that opening circuits protects us.

We don't have an oven, and certainly don't have a microwave.
But we did buy a 2nd hand pressure-cooker at a thrift store, and we keep our (spare) handheld GPS unit and handheld VHF in the cooker, after wrapping them in tinfoil. Will this help? We don't know as we've never been struck by lightning. Makes us feel a little better though as we cringe in terror below deck, trying not to touch anything metal!
Good idea to unplug the VHF antenna. Haven't done that bit will from now on.
Best of luck, which is what one needs when dealing with bolts from above.

[billgewater]

Have seen lightening strike the same boat twice in the same marina. When we ventured towards the boat it had smoke coming out of the anchor winch!
It did not have the tallest mast among the nearby boats.
I had also read somewhere that catamarans with two widely spaced motors with drives in the water were more susceptible, but it all seems a bit of bad luck and being in the wrong place at the wrong time.
However, buildings, industrial smoke stacks and radio towers usually have lightening pathways from the highest position to the ground.
Does this make a good case for having a high "lightening attractor tower" close to marinas in high strike areas? In my current marina (unfortunate pun), on my jetty, two boats were hit. One, a large cat with a carbon mast and another monohull. The carbon mast was not salvageable and the internal electrical damage was total. The monohull lost most of the expensive electronics. The cost for these two boats would well exceed the cost of a nearby safety tower.
I also remember watching a video where some chaps fired a small rocket into the clouds. The rocket trailed a thin wire connected to the ground which provided an initial pathway for lightening. I think the exercise was looking at discharging potential strikes to protect buildings etc.
Of course insurance companies do their absolute best to prevent claims being made via lightening strikes.
Next time you are in Darwin, in the wet season, join the locals at the eateries on Stokes Hill jetty and watch the fantastic evening lightening displays. Humbling. Or promise the spouse a similar experience later on.

[Oceanride007]

Think we are talking mitigation, not avoidance, think any action of having redundant equipment thrown into Oven Pressure cooker whatever. But I do like Nicholson58 idea of industrial Connection at mast and Aerial, not sure how to make it accessible and pretty. Double isolation for select equipment, that could work on a existing installation. As would a separate common isolation between Negative busbar and Battery Negative. Not a high priority thou. For a new build wonder if we have the room for individual micro arresters, or fuses. Like I said, have seen this on ships, but would like specialist recommendation on this.
Something else is having nice "quick connect" like spade connectors to NMEA Backbone & select equipment (I like the air gap). And a procedure.

[LittleWing77]

Originally Posted by Oceanride007

Hey Littlewing, did that vessel, switch off anything. If so did they have Double pole switching.? Bet they didn't.

Good question. I expect they had all their nav stuff on, since they were underway and delivering the boat to Tortola.

Charlie ducked into Bermuda so he could at least get a VHF and handheld GPS to get them the rest of the way Tortola, then it was a matter of hauling the boat, stripping everything out and ordering a lot of electonics from the mainland.

The owners were totally pissed that the boat wasn't going to be ready for their traditional post-Christmas cruise starting on Boxing Day. As I recall, it took until Dec 19th for all the electronics just to *arrive* on Tortola! Never mind getting everything installed and re-wired.

Owners - sheesh!
LittleWing77

[David B]

A chain from the base of the mast over the side has a good chance of the lightening going that way, and not through the bottom of the boat. Deck-stepped masts in particular, need a decent path to ground (sea).

Disconnect antennae, put portable devices in the oven or microwave, turn off all breakers (most boats have breakers on the +ve and -ve buses). Make sure gas is off at the bottle, and if there is a copper or braided line leading to it, disconnect that too.

[David Pakes]

We were hit in Titusville on the ICW in Aug09. I was in the cockpit at the time watching the approaching storm, not holding onto anything metal. I had put all that I could (small nav gear, hh radio) in our microwave, turned off all the electrics that I could and waited. A loug bang, hiss, sparks falling down around the cockpit as bits and pieces of our masthead VHF antenna, wind instruments (electric and windex) sailed downwards into the water and onto the deck. Strictly speaking I should have been below with the galley slave but, you know, I wanted to see if anything happened. Next time I will go below. I have previously seen, while in a brief storm on Sydney Harbour waiting for a race to start, a lightning flash nearby followed by arcing between my cockpit winches.
Damages included repairs to the anemometer gauge as well as a new masthead fitting, new VHF antenna and radio (which had fried), repairs to my Simrad autopilot black box (free compliments of Simrad NZ), and a week or so later my oldish Xantrex inverter/charger died and had to be replaced.
A day or so previous to the strike I had replaced a battery cable that led from the bottom of the mast support (stainless metal tube) to the nearest keel bolt so it was new and well secured. I believe, rightly or wrongly, that this may have saved me from a lot more damage. I don’t know really as, like most of us perhaps, I’m just a handyman boat owner.
A few weeks later while up on the hard at a boatyard in Deltaville, Virginia I had their electrician inspect the boat. He found one small elec item that connects the wind, depth and log instruments located behind the switchboard that needed replacing. I might add that there was a 60’ sailboat in the same yard with holes in its hull from a lightning strike, among other damages. The techie also said that whenever they have work to do on a boat that has been hit by lightning they automatically right off all the electronics and some electrics and replace them all with new. He justified this approach by saying that, even if electronic equipment is still working now that may not be the case in a week’s, month or a year’s time as they anticipated electronic kit could keep failing and it would be due to the lightning strike. In my case, other than the inverter charger that, fortunately, hasn’t applied to us as we continued cruising. I think all the electrics on that almost new 60’ sailboat would have cost more than I paid for my boat.
I didn’t claim on my insurance as the total cost of repairs did not quite reach the excess limit but, in future, I would look closely at a full claim.

[Oceanride007]

Just checked my Autopilot CB, it only single pole. 2 would be better.



The breakdown voltage for air is roughly 3 million volts per meter according to wikipedia.



Someone mentioned a lightening strike that has already travelled 25 miles is not going to let a 1/4" bother it. Well don't think its quite like that, that flash is jumping from ionised particle to ionised particle, Anyway yes lightening strike is extremely high voltage, induced voltage less so. But lets say I open my future 2 pole CB to protect my AP, I have also opened a switch a couple of meters away, not sure but that lightening strike may see something more than that quoted air gap, pause and maybe dissipate without doing damage to my Autopilot.


Of course I cannot know, but I would be more comfortable with a 2 pole breaker.

[Talos]

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Safety isn't an option ..!!

[Hardhead]

Many years ago, I was driving, and about 200 feet from a radio tower that was struck by lightening. Ear-splitting KA-BOOM, and a total blinding white-out from the flash. It was the most massive bang I've ever heard in my life. All I can say about it is - it's not really up to you what happens at that moment...

[smac999]

I have not seen a lighting stike boat, but I have seen one that hit a 10,000v powerline across the channel.

lots of ground lines were melted up. including inside electronics so unless you have all double pole breakers. turning off the pos only likly isn't going to do much.