Lightning

Lightning strike on yacht

This summer a strong storm with heavy rain in Altea (Spain)...
http://www.youtube.com/watch?v=zPZpnUZoWNI

That's why I love sailboats (not to be in, but to have around in a storm).

I have been hit by lightning twice on a delivery of a 44' Lagoon from France to Annapolis. I was at the Flying Bridge about 4 meter from the mast foot (shouldn't have been there in hindsight) and one of my crew was lying on the couch in the saloon looking outside trough a roof hatch.

We knew we were going to be hit becouse the lightning had surrounded us and was closing in on us. When it finally hit I fended my eyes of and heard a loud bang with white light. The crew member lying on the couch remembers seeing the lightning hitting the mast. This happend twice that night and our only damage was the VHF antenna.

no one can figure out lighting....maybe 50% fact,50% guesswork....we where hit in MD.one summer and i spent the next 9 years researching and talking to other victims...found out nothing that could be put in stone,except be lucky........examples...2 same type small boats,on different occasions,where hit in palm beach inlet...#1,all safe,but burnt a little...#2,all dead...............a small sportfish,w/very short riggers,docked between two large sailboats at elbow key..he gets hit in his searchlight,wipes out his electronics,and no one else has any sign of a hit..........riding back from west end in the worst lighting storm..antennas and long outriggers..we can see lighting hitting the water many times very close, but it never hit us ????? be lucky

The aviation industry has been dealing with this issue for some time. If an aircraft with a FADEC (full authority digital electronic control) on the engines were to be hit by lightning, things would go quite, and in an airplane that's a "very bad thing".

Do a search on HIRF and HIRF/L protection and you will see how this is done with aircraft.

Basically what is done is each piece of electronics is "hardened" by putting it into a box that is grounded and has no holes in it. All of the cabling is shielded and the shielding is grounded and the cabling connectors are metal and are grounded to the shielding and the case. Lengths of cabing that are not shielded and grounded act like antennas and pick up the lightning, so you don't want unshielded runs of cable anywhere in the boat.

It can be done, the radios and electronics in aircraft are hardended, but it is expensive and since it happens infrequently and the effects aren't usually life threatening, electronics in boats aren't hardended. There is testing that can be done, and the FAA and the military have standards for the protection of hardware, but as I've said it costs a lot to make the hardware hardended, and the engineering and testing aren't cheap either.

My concern would be with electronic engine controls. A lightning strike would leave you dead in the water and when you are offshore, that's just a bad place to be.

There was an excellent article in PassageMaker magazine recently about lightning. It describes a new system being installed on a 40 ft boat which routes the charge down to a series of discharge ports along the water line of the boat. {Very similar to static wicks on an aircraft}
I don't have the info with me but a check of PassageMaker online might bring up the article.

Cheers

It was the July/August 2010 issue on pages 44 to 53. The company mentioned is Marine Lightning Protection - http://www.marinelightning.com.

to my knowlegde it is like a lightning strike on a tree. the sap vaporizes and expands instantainously causing the tree to explode.

As the concrete holds moisture it has same effect - vaporises, expands, explodes (when structure fails to withstand the pressure).

My question would be "what is the effect on a steel hull boat with a alloy mast"

I know the mast would melt but
the discharge to the lowest potiental and
what path it would take,
along with how well earthed you are inside all would affect whether you get fried or not?

I dont know....
I would be interested if any1 had a answer to
will you get fried in a steel hull boat or will the water act as a strong enough insulator to allow survival?

Sorry people.
I just read the post here by Captin Tom
I wish to agree with every thing he has stated BUT
lightning must be thought of as potiential difference not pos and neg...
A HIGH POTIENTIAL DIFFERENCE will discharge to a LOW POTIENTIAL DIFFERENCE. a high charge will go to a low charge potiential.

Lightning can BOTH-
discharge from the sky/clouds to a ground or
discharge from the GROUND TO THE SKY/clouds.

lightning from clouds to earth- can be caused by smoke particals, dust/dirt, polution, the lists are endless, these bolts are caused by a static build up from friction between these particals, think of this as a "positive ion generator" or high potiential.

Lightning earth to sky- can also be caused by water molecules rubbing against each other as a "ion generator" (like a waterfall) or low potiental.
or
a high potiental has discharged too much and has become a low potiental.

the reason positive and negitive is not used in the description is the charge in a circuit does not flow from pos to neg as most think... it flows from neg to pos. lol
it wasnt descovered untill the age of necular study and it was too expensive & too much hassel to change the text books and teachings untill receint times.

why it hits some boats and not others could be the depth of its keel compared to the others around it, if this isnt right then resistance or some other factor may be at play... i would have to think about it further and know more about the conditions surrounding it all.

hope this helps your understanding.

IF you wonder about my question in the other post about this subject...
I think I know the answer but having a second oppinion will never hurt and can save a life or two.

Sharkbait, thanks for sharing your comments.
Well, pos to neg, neg to pos, from or to the clouds, all I know is that lightning is probably the scariest thing a mariner has to deal with.
But it makes for nice pictures.

too true capt.
I hope it helps, it not a easy subject.

A huge deal is the way a whole grounding assembly is installed.

When lightning strikes even a working "protection" (e.g. anthena - cable - grounding), the whole assembly is subject to some serious electricity. And that in turn generates all kinds of secondary effects (powered cable generates some electromagnetic field. When the "power" is those of a lightning, that field is no joke either.) Hence it could still fry stuff around even without "body of lightning", pardon layman's terms, hitting anything but designated route. That's why EM shielding is useful, and distance is a good start at that (e.g. if your lightning-catcher antenna is too close to your radio antenna, EM will cause "secondary spike" in radio circuit, which while weaker then original could still well be enough. Same's gonna happen if grounding cable is laid in unshielded proximity of other wiring.).

By the same virtue it is critical that all components used are on the excessive side - if cable's too "thin", it will work the same way heating spiral in your toaster does when subjected to lightning strike, with the body of yacht playing toast.

sorry people'
spoke to my dad (electrical engineer) who said to strike out the positive and negitive ion terms i used in my post... apart from that it is right...

I do agree with Arcanisx there is enough high voltage and amperage to cause a mini EMP (electro magnetic pulse).
dad is not sure if there is any way to protect any modern electronics.
to his and my knowledge all military electronics which could be exposed to a EMP are protected by using the old tube technology (tubes are same as those found in very old radios and tvs), these tubes are impervious to EMP's unlike all IC's versions etc... (the reason tubes are still manifuctured).

I suppose if you use a faradays cage over the electronic device it may protect it. but this has many factors as well.

here's a link to faraday's cages on wika for those who are interested

Faraday cage - Wikipedia, the free encyclopedia

it's pretty cool LOL

I know this is an older thread, but I live in the Tampa Bay Area so it is relevant. This time of year there are weeks where I am confronted with the possibility of a lighting strike almost daily. Lightning is the one thing that scares the heck out of me. Over the years I have been on several boats that have endured a direct hit. Almost all had significant electronic damage. The most scary however was a few summers ago as I was coming into Venice inlet through a squall there was a loud CRACK BANG and an "arc" of electricity (?) from my Morse throttle lever to my hand inches away. Scary but I was not hurt. But it has left an impression on me, and has not helped my image of lightning.

But it is not the damage to electronics that is my biggest concern, it is the safety of the crew, passengers and myself. For those who operate from a flying bridge as I do (enclosed with or without tower), what do you do when it is inevitable you will be in a squall? Do you stop the boat and go down below until the threat passes? Or do you continue on and hope for the best?

I ask because most of the charter fishing boat capts in the area seem to run right through these squalls from their FBs with apparently little regard to the risk of a strike. I cannot count the times I have been confronted with this decision. Could it be that tubular metal (stainless, aluminum) serves as a Faraday Cage?

I would really be interested to know what other capts do in this situation.

Thanks!

John

Run like hell and hope for the best. I certainly won't leave a boat floating with nobody at the helm. One good thing about Florida weather is that it's often small cells that you can run between or around. Even though lightening can travel a long distance, it at least lowers your risk. As for the charter fishing captains, they're a breed onto themselves. They understand fish and the paycheck at the end of the run. Not much else in life matters (At least when they're out).

No, I wouldn't leave a boat essentially "NUC" not under command either. But...what about anchoring? Especially in a slow boat like mine...

Is anchoring something some would do in lieu of running an electrical gauntlet?

I helped manage and maintain a fleet of GBs in Sarasota for 15 years and none of them were ever hit by lightening. So the odds at least are in your favor. Then again, maybe not based on your history.

But seriously, about all you can do is set up a lightening rod at the highest point on your boat, attach a very heavy cable to it and run it to a large bonding plate located on the underside of your hull. To be truly effective the rod has to be high enough to create a "cone of protection" over and around your boat.

I would only recommend anchoring as a strategy if you saw on radar that the storm was moving away from you or you were moving in to a storm that was passing by. If you don't have radar on your boat look into one of the real time radar apps for your smart phone if you have one.