How should we protect ourselves in a Electric storm.

[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.

[Chotu]

Just forget about it is the best approach. You are not going to stop or change lightning at all.

It doesn’t matter what you do with the circuits. The incredibly high current traveling through the air in itself can jump from one circuit to the other. On top of that, the high current in the air creates a magnetic field. This magnetic field will induce a current in any circuits nearby.

You can’t defend against lightning. The only Hope you have is a faraday cage. And getting one right as well as set up in time isn’t that easy.

Just accept that you have to take your chances.

[Mystic38]

It’s the most ridiculous thing I have ever heard.

turning off your electronics does nothing other than turn off your electronics

[Nicholson58]

We have experienced three strikes while in the Great Lakes. Not aboard for any of them. For reasons of convenience a couple of devices were hard wired To two pole mechanical switches. These all survived while massive damage happened elsewhere. All modern electronics when turned off still have power to the start Circuit board. The only way to kill the power completely is to break the source. You could do this by pulling the breaker but you leave many feet of wire, positive and negative leads, that could generate an induced spike if you are struck. For this reason I have added two pole switches as close as possible to all electronics so that the device is disconnected nearly like sitting on the galley table. I also disconnect all antenna cables. At the mast there is a 40-pin industrial connector to isolate every wire coming down the mast.

Nothing is certain with lightening but I know what I’ve observed.

[LittleWing77]

Originally Posted by Mystic38

It’s the most ridiculous thing I have ever heard.

It's the most ridiculous thing you've ever heard...?

I'm with Chotu. I once worked on a 55' custom yacht post-strike and everthing was fried, all the electrics including GPS and VHF, all the onboard entertainment, including all stateroom tvs and stereos. My friend, private captain and his wife, private chef, were onboard when it happened and were fine, luckily.

It made getting the rest of the way to the BVIs from just off Bermuda a bit tricky, however!

"You pays yer money and you takes yer chances..."

LittleWing77

[Nicholson58]

Note my post #4

The last time we were hit we lost

18 glass buss fuses
60 amp shore power breaker
One alternator
Stereo system
VHF radio
Bow cabin lights and all wiring
Several mast deck lights
Numerous other LED cabin lights
Main mast antennas
Main mast Windex, shattered bits and melted metal on deck
Autopilot computer
AIS Watchmate
Raymarine ST-60+ suite of instruments
All nav lightS
Transom paint checked around exhaust ports
Wet exhaust line compromised
Xantrex Charger inverter damaged

The Simrad chart plotter and it’s connected radar and sonar all survived. They were the only devices wired through two pole snap action air gap switches. Switches were off. This was no indirect or side spur hit. Witnesses on a nearby charter wer rigging for their daily fishing excursion and saw it. Top of my main mast, lit up the inside for a few seconds and jumped to two nearby boats, wrecking much of their electronics too. Five additional boats in the marina were also struck.

This convinced me to add the two pole switches everywhere and the main mast disconnect.

[Oceanride007]

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

[EmeraldCoastSailor]

unplug the microwave, insert handheld VHF, phone, and handheld GPS if you got it. And have the ditch bag ready.

[Mike Banks]

You can fit gaseous arresters in both battery or DC power legs, but you have to have a proper lightning protection system and its own earth plate to be more or less safe.

Lightning is NOT caused by storms, it is caused by the jet stream. Storms just provide it an ideal situation for the tremendously high voltages caused to reach earth. This charge build-up can discharge to earth when there are no visible storms, the so-called "Blue" lightning because it comes out of a blue sky.

Such discharges are usually quite severe when they do happen, but they are quite unusual.

There are degrees of severity in storm lightning discharges, because of local charge conditions and storm turbulence.

You can protect yourself and your vessel to a considerable degree by using a proper lightning protection system that will withstand a light discharge, but the main idea of lightning protection is to prevent the formation of an ionised pathway from your vessel to an area of high charge density in the atmosphere. That prevents, or reduces the likelihood, of a severe discharge. Those discharges one sees to the lightning rods on buildings are comparatively light strikes.

Gaseous arresters are devices designed to remove electrostatic charges from aerials and rigging etc. They are like gas fuses, they contain a gas at a reduced pressure, and they are placed between the positive and negative leads, with the centre electrode connected to a good sea or buried land earth.

The gas in the tube is at a reduced pressure and will become a conductor if the voltage reaches a set level, and it will continue to conduct current until the voltage drops, like the tube in a photographer's electronic flash unit, when it will then cease to conduct. When they go off they make a pop, and it is not unusual to hear them go off.

Since nothing is static during turbulent electrical storms, there is no simple way to describe it and its continual movement of charges except to say lightning is an electrostatic discharge phenomenon, and nothing will withstand a severe discharge undamaged.

However, if the immediate area around your vessel is devoid of any local areas of high charge, and the air is not thereby ionised (not easy with moisture in the air and dust) then the chances of you getting a BIG strike are considerably reduced. Other areas will have a better charge density and provide a better path, because there is no discharge to earth except from the lightning discharge itself.

There is plenty of information about providing lightning protection for vessels in the archives. For your own safety, ignore the people who tell you there is nothing that can be done. If you are aboard a steel vessel, with a proper sea-earth special discharge plate, (separate from the one for your radios and radar etc) you are far safer than aboard a glass vessel with no additional lightning protection.

You do not "Attract" lightning by fitting proper protection. The voltages are so high that your only chance is to decrease the likelihood of your vessel being the best pathway to earth, and the way to do that is to drain to earth any local charges likely to provide an ionised pathway to an area of high charge density.

You can put your expensive electronic stuff in a microwave oven not connected to any power source, which will give you both electromagnetic and electrostatic protection to delicate circuits during a storm. A safe built of Mu-Metal is even better.

[chris mac]

Our boat has not been struck(thankfully) I hope to keep it that way. But what preventative measures should we take? It has been explained to me like this, lightning just arced across the entire sky!! It is going wherever it wants, and taking out anything in its path.
So I dont take any precautions short of leaving a back up chartplotter(tablet) in a drawer away from all the other electronics .

[Scorpius]

Steel boat (hull, deck, and house). Aluminium mast. Disconnect the VHF antenna cable coming from the mast top. Been hit twice. No damage.

[SV Bacchus]

We were struck in the Bahamas in 2018. What survived? Everything we put in the oven, I.e. cell phones, laptops, Kindles & Garmin InReach. What, surprisingly, didn’t? Laptop power cord/brick that I forgot to unplug.

We were onboard when struck and for people it is a non-event. Heard ZZZZZ and saw blue/white flash outside and that was it. Top of mast was hit and we were inside the “cone of protection”. Prior to strike I was unsure about the cone but now a believer.

[joelhemington]

Great topic, and finally some positive solutions: double pole switching and disconnecting the VHF antennae sound like good precautions which could be achieved quickly when lightning approaches. I have also seen ads for mast top devices that are supposed to dissipate the lighting field. Just wondering if these things actually work or are just snake oil. I was once 500' from a lightining strike that blew up a big tree and killed a couple of people with the flying splinters. I was facing the other direction when it hit and was blinded by the light it gave off - those things scare the hell out of me!

[stormalong]

The first rule of lightning strikes is there are no rules. If you get a direct strike all of your electronics are toast. A nearby strike is another matter - damage is less predictable. The only thing you can do is disconnect your VHF and HF radios and hope for the best.

I keep a couple of handheld GPS receivers in a steel box and I have a bail out bag with a handheld VHF and an epirb. The bailout bag is far away from the electrical wiring - in a cockpit locker but even so anything can happen in a nearby strike.

[MultiCountryDon]

Looks like time to buy a large,old,2nd hand microwave at a garage sale.