How should we protect ourselves in a Electric storm.

[akopac]

I throw a portable gps and vhf in the oven when stuff like this looks imminent

[seabreez]

Originally Posted by Scorpius

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

Our rescue vessel got hit years ago. All aluminum plate boat with a radar arch. The antenna got hit and was burning like a candle on a cake, in pouring rain. Got to the boat and checked the bilge pump. All fuses were fried. Got the bilge going and returned to bed. Next morning, changed all the fuses and checked everything and only the fuses and the antenna had to be replaced. Vhf, radar, lights, pumps... no damage. I guess we were lucky...

[ilanortho]

Originally Posted by Oceanride007

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

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

My understanding is that on the boat all bets are off. Breakers won't matter; it will jump around where it wills across any gap anywhere, including normally non-conductive surfaces and air. Unfortunately this causes me great apprehension when I'm on the boat during a lightning storm.

[sailingchiro]

Lightning is the one thing I never want to encounter. I have seen a boat that was hit and it blew holes around the perimeter of the boat.
My plan, is to throw all electronics available into oven. Shut down battery switch. Hug the Epirb and handheld vhf. Then wrap chain around mast then drop the anchor in the water. Do I think this till work? Probably not but any chance to ward off lightning while on a boat, I will do it.

[Hardhead]

Does anyone have any experiences of lightning actually striking at sea?

When you're out there, it seems like the odds of being struck are high - being the tallest thing around for miles. They're obviously not that high in reality, but any good stories of what to expect if it happens?

[Seamentress]

Hello.
From what I can remember about Electricity and circuits, "it always takes the easiest path to go to ground".
So, why not make it as easy as possibly?
I am situated on a mooring in 20ft of water, we have some serious electrical storms in the summer months.
I have connected 10ft of "00" battery cable to both mainmast back stays, low down near the toe rail, at the end of the cable I have bolted the cable to a 1ft long 6" wide 1/4" thick brass plate, when Thunderstorms are present, I toss them overboard, and also lower my anchor and chain onto the seabed.
I have no idea if it will work, but I believe the principle is sound.
Thankfully, I have not been hit yet. God willing it will never happen!!

[Keithward]

Originally Posted by 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.

Exactly right. With the added caviot that all significant metal be bonded to the external
Ground. I Grew-up in st Pete Florida. (Tampa Bay) The only place with more lightening is in Africa. Light show most every night in summer. A professor at the University of Florida Gainesville is arguably the most renowned lightning expert. It’s his opinion that mast and shrouds and all significant metallic objects in the boat be grounded (bonded) to at least in one square foot surface area plate bolted to the underside of the boat. The plate can be made smaller by putting flutes in it to increase the surface area. Frequently you see them about five or 6 inches wide and 10 inches long they need to not be painted over. The purpose of bonding the lesser metallic items in the boat is to prevent very damaging side flashes additionally to establish within the electronics away to disconnect each piece of instrumentation completely for example unplugging it doing the work to create plugs behind the equipment

[Tudorsailor]

If sailing, and lightning is on its way towards you, is it sensible to start the main engine? I ask as one needs electricity to start a diesel but not to keep it running once started. Obviously I ask with regard to coastal rather than ocean sailing.

TS

[wingssail]

Not really wishing to bring bad Karma onto myself, but we have been lucky regarding lightning; never been struck or had damage even though we've spent many years in areas with high frequency of thunderstorms and lightning and seen many nearby strikes, including in our present location. During the summer we see lightning storms about 5 times a week and boats in our marina here have been hit. Once in Durban, South Africa, a boat in the next berth, one with a 100ft mast, was hit and lost all of their electronics and electrical equipment. In that same storm 5 boats in the marina were damaged by lightning. We were undamaged.

Do we have some very good or special lightning protection? Not really.

To protect our electronics against induced currents which result from the electromagnetic pulse, we have nothing. I believe that a nearby or direct strike can cause induced currents within the electronic or electrical device even when completely disconnected (like sitting in a locker). I don't think much can be done about this other than putting things in a metal box. We have placed a spare laptop, GPS, and VHF in the oven, once, during a particularly bad rash of lighting storms, which we then forgot about for several weeks. In fact, for a while I was absolutely convinced someone had come on our boat and stolen the laptop. Luckily we have to open the oven door to light the oven.

To protect ourselves from light discharges and high current flows we have large battery cables from the mast and the chain plates to the closest keel bolt. These cables are direct and nearly straight. Our keel is lead and not encapsulated.

We do not have insurance for lightning damage, so we really have our fingers crossed that we don't get hit. So far, in 34 years, that has worked.

[Richard Harper]

I added connectors to physically isolate the power to the VHF and autopilot and disconnect switches for the power and ground to my outboard engines and fuses on each wire going up the mast which can be removed to create an air gap after a lightning strike while anchored off Key Largo. I always disconnect everything when lightning gets close or when I leave the boat.
I have not had a direct hit since but a boat next to me was hit and it still burned out the CDI module on one of my outboards. The engines were isolated from the electrical system but still connected to the start switches by 20' of cable. I am thinking of disconnecting this cable at the engines for additional protection.

[vpbarkley]

In a building, lightning protection takes the form of a lightning rod above the structure, a dedicated ground sunk into the earth and a conductor between the two. Very simple.

Do you think it would it be a good idea to wire delicate electronics and the building's electrical system to the top of the lightning rod?

In a sailboat you have a mast and a keel. This is analogous to a lightning rod and a dedicated ground. Hopefully you have a good conductor between the two.

Typically, you mount lights, antenna and wind instruments atop the mast. And, radar is mounted on the mast. These are wired to the boat's electrical system and electronics.

With this arrangement, during a lightning event, the boat's electrical system and instruments are wired directly to it. The results are understandably calamitous.

If you think of the mast as a lightning rod, you would do well not to connect the boat's electrical system and delicate electronics to it.

[sailorladd]

make sure your rigging is earthed into the water.

[Scorpius]

Originally Posted by Seamentress

Hello.
From what I can remember about Electricity and circuits, "it always takes the easiest path to go to ground".
So, why not make it as easy as possibly?
I am situated on a mooring in 20ft of water, we have some serious electrical storms in the summer months.
I have connected 10ft of "00" battery cable to both mainmast back stays, low down near the toe rail, at the end of the cable I have bolted the cable to a 1ft long 6" wide 1/4" thick brass plate, when Thunderstorms are present, I toss them overboard, and also lower my anchor and chain onto the seabed.
I have no idea if it will work, but I believe the principle is sound.
Thankfully, I have not been hit yet. God willing it will never happen!!

The voltage and current of a BIG lightning strike will overwhelm just about any conductor and/or insulator. Unless all electronics and electrical devices are inside a good Faraday cage (like an all metal oven or microwave) they will probably be fried. Yes, the lightning will take the easiest path to ground - but a big strike will melt an awful lot on the way. Lesser strikes won't be nearly as damaging. Most of us have aluminum masts. Make sure the foot of the mast is well connected, with a HEAVY cable to a foot square unpainted metal plate as close as possible to the mast OUTSIDE the hull and in continuous contact with the ocean. It doesn't hurt to have the shrouds and stays similarly connected.

[DumnMad]

Originally Posted by Seamentress

Hello.
From what I can remember about Electricity and circuits, "it always takes the easiest path to go to ground".
So, why not make it as easy as possibly?
I am situated on a mooring in 20ft of water, we have some serious electrical storms in the summer months.
I have connected 10ft of "00" battery cable to both mainmast back stays, low down near the toe rail, at the end of the cable I have bolted the cable to a 1ft long 6" wide 1/4" thick brass plate, when Thunderstorms are present, I toss them overboard, and also lower my anchor and chain onto the seabed.
I have no idea if it will work, but I believe the principle is sound.
Thankfully, I have not been hit yet. God willing it will never happen!!

Stainless is some 25 times more resistant than aluminium.
Better to attach your copper cable to the mast.

[houseofcharm]

I always had the wack idea that if stuck in a FL spontaneous storm in my then powerboat, I'd drop a jumper cable into the drink with the other end clamped to a railing of mast light.


And we were hit twice at home, once in FL, moved to NY and a month later hit again. The bolt came through a lawn of huge oaks and maples into a lowly crabapple tree which actually survived.


The EM field as well as direct current in the home's electrics did about $7 in damage including 3500 to a Nissan Z car, fried CPU, exhaust sensor etc.



We were in practice back then and patients vividly all told their lightning tales when I mentioned ours-some wild stories.