Lightening on CN TowerThis past couple of weeks have brought us some absolutely spectacular lightning shows. Lightning with a thunder accompaniment always brings thoughts of safety (and fear) to mind. In a previous post about lightning safety, I managed to ease my mind by convincing myself that the higher masts around us would protect us from a strike. However, the truth of the matter is, if lightning would have struck our sailboat, there is no telling where it would have ended up. Our mast was deck stepped (the bottom of the mast sits on top of the deck, instead of going right through to the keel), which means that any lightning strike coming down the mast would have had to jump somewhere to continue its downward path. This is how holes get blown in the bottom of boats. Add the fact that the mast was practically sitting directly over our heads when we were laying in the v-berth and, well … you get the picture.

So now we are in a big metal boat; a big, highly conductive surface directly connected to ground (water), with a nice high metal canopy framework begging for a lightning strike. So am I really any safer?

I asked around the marina, and for the most part, people did not think that the metal boat would be safer – but then I came upon another boater who lives on a steel sailboat. He’s got the full deal going for him – a nice high metal mast and a highly conductive steel surface connected directly to ground. What he suggested is that we are actually safer in our steel shells because (in theory) the lightning strike should take the path of least resistance and flow easily and directly through the hull and into the lake. He likened it to a Faraday Cage.

Here is a quote from Wikipedia:

Cars and aircraft. When lightning strikes an aircraft or a car the electric currents induced on it are forced to travel on the outer skin of the vehicle’s body. If you were in a car, and the car were struck by lightning, it is not in fact the rubber tires that would save your life. If the lightning can jump from the ground to the sky, then it can jump from the ground to your car. What actually happens, is by being enclosed by the car’s cabin, the lightning travels around you, through the conductive frame of the car. This is because the car forms a Faraday Cage.

This is talking about cars and aircraft, but from what I can tell should also apply to boats. Anyone out there want to confirm this for me? Any modern day Franklin’s or Faraday’s want to experiment with this?  (Go fly a kite!)

Lightening to CN Tower2(Lightning Hitting CN Tower photo’s taken by Mathias Roussea on June 5th, 2008.)

"Lightning Strikes Again (and again)" by was published on June 15th, 2008 and is listed in Nature, Pictures, Questions, Weather.

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Comments on "Lightning Strikes Again (and again)": 18 Comments

  1. juliemadsen1 wrote,

    Why can’t I take pictures like that. this is one of the very best pictures I ever have seen. If you are safe or not, I really can’t tell, looking forward to see if anyone comment on this

  2. strathy wrote,

    Please note: I did not take those pictures – they were taken by Mathias Roussea. They are absolutely amazing though!

  3. 4T4RD wrote,

    Your grandfather, Walter Raleigh Workman, amongst his many avocations, sold lightning rods for prairie homes and barns. Perhaps you could find and install some for your peace of mind

  4. Constantino wrote,

    According to “Steel Away: A Guidebook to the World of Steel Sailboats”, “The concensus of opinion about lightning protection is to provide a direct path for grounding so that damage is held to a minimum. Therefore, steel is the safest hull material during a lightning strike, since the entire boat is grounded. The best protection comes when an aluminum mast is used since it acts as a giant lightning rod, but with a wood spar the stays will ground the current to the hull. A solid metal rod extending above all antennas and connected to the stays will assure that this is the path the lightning will take, although some masthead antennas can also serve as initial strike points.”
    (Steel Away: A Guidebook to the World of Steel Sailboats. Windrose Publications, 1986)

  5. Filippa wrote,

    Very very nice picture. I was amazed and I thought that you have taken these pictures until I saw you comment about Mathias Roussea..

  6. Daniel wrote,

    Hi

    I’m from Portugal, but living in UK since May, London near thames. I read your blog from the beginning. Very nice indeed. I came here because i though maybe to live on a boat. I like boats, i love beeing near sea or river, though im not a pretty good swimmer. Need to improve this. I think i will join a sailing club and see where it will take me, cause i have no boat experience.
    Keep your blog updated, its very nice to read it.

    Cheers
    Daniel

  7. Hilly Harrison wrote,

    Really interested to find your blog. Please take a look at ours, http://www.svgoldenmean.com. We are a family of four plus a dog living on board for 5 years so far.

  8. Ed Wise wrote,

    I have a 19 foot fishing boat. It is made of alluminum. What would happen to anyone in the boat if we were caught in a thunderstorm and the lightening hit the boat. This has been a subject that no one seems to know the answer

  9. strathy wrote,

    My guess is that it would not be a good situation for you. Aluminum conducts electricity just fine, but I assume this is an open boat – the lightning is going to hit you as much as the boat.

  10. Frank wrote,

    I haven’t stumbled upon too many stories about boats getting struck by lightning, but I guess all is possible, and when lightning is around you, its frightening either way. And whoever took that picture must’ve made a fortune off of it, simply amazing 🙂

  11. Jay wrote,

    I actually saw a fiberglass racing boat struck by lightning. Hard to tell exactly how the lightning traveled, but the aluminum mast is stepped directly to the steel keel, so most likely traveled down the mast through the keel to the water.

    No one on the sailboat was injured.

    A person on the powerboat towing them was thrown into the water, either from the force of the strike or the surprise of the helmsman of the power boat. (My money is on the later.) The man overboard was brought back on board quickly, wet with a great story and luckily no injuries at all.

    While an interesting story – our club is much more careful about racing in potential thunderstorms.

  12. pete koehorst wrote,

    A few years ago, alongside the marina at Wrightsville Beach N.C. our 45ft. fibre glass sailing boat was struck by lightning. She has a deck stepped aluminium mast and a six ft, carbon antennae.My wife and I were on board and standing below amidships admiring the storm, when there was a terrific jolt. I rushed up on deck and saw a brown cloud hanging over the mast-top. The antennae was split down the middle as was the mast headlight lens and the bits were lying on deck. All the electrics, including the self steering computer were fried, except for the mast headlight, (strange?) and the radar, mounted on the mast. My guess is that there is no hard and fast rule as to the effects of a strike, and we were by no means the tallest mast in the marina.

  13. Justin wrote,

    I lived aboard a 38′ Moody sailboat as a child for about 4 years, age 8-12.

    We once saw, in a very crowded harbor, the shortest mast in the harbor was struck by lightning. There were easily a hundred boats in the harbor. I don’t know how that one turned out though, but it didn’t sink. I think it may have been a small day sailor or race boat, probably not a lot of electronics to worry about.

    There was another time in the Bahamas that we were anchored next to another boat of roughly the same size and mast height (approx 40ft length, and about 55ft mast heights.) They were anchored about 20 yards away, and they were hit at the top of the mast. The blast blew the vhf antenna clear off the mast, and it hit the water in flames. All the fluorescent lights below had their covers blown off and most of the electronics were fried. The anchor light, which was at the mast head and INCHES away from the point of the lightning strike, was the only thing still working.

    Ours was a fiberglass boat with an aluminum deck-stepped mast. Whenever the weather got bad and lightning surrounded us, we always started the engine. The thought was that if we were ever struck and it blew out all of our electronics or engine starter, we could still beach the boat if the lightning happened to blow out a metal through-hull fitting.

    Love the blog, by the way!!! Keep up the great work!

    Fair winds,
    Justin

    There are various opinions on the efficacy of lightning rods on boats. Some feel that while they may work in transporting the electricity to the water, it can also increase the risk of a strike by attracting one to the lightning rod. We never had a lightning spike or anything like it on our boat.

    We do have other friends, however, who have been struck 3 different times on the same boat, at different times. Three times they had to replace all of the electronics on board.

  14. Chuck Dinkel wrote,

    I remember reading in  a sailing magazine years ago a story of the results of a lightning strike on a sail boat where everyone on board had severe effects of the concusion and high intensity electric field without actually being struck directly. Sorry, can't remember the source. It was an eyeopener.  Still looking forward to boat life, though. 

  15. Micki wrote,

    In the US, both the Lightning Protection Institute and UL (Underwriters Laboratories) have written codes and standards for lightning protection systems for boats. Having a lightning protection system installed will not change the probability of a strike occuring, but the system will provide a safe path to ground should a strike occur. A steel or aluminum craft does have the advantage of forming a Faraday cage (if it is electrically continuous.) Water is about as good of a ground as there is, so getting the lightning bolt safely directed from the mast to the water is the trick here.
    There is a secondary phenomenon associated with voltage the size of a bolt of lightning. An energized electrical field usually travels in a variable diameter around the charge. This can arc and cause surges of transient voltage to occur in other conductive material that fall within it's proximity (radio wires, battery cables, appliances, etc.) It's not uncommon for it to take a few days for some of this peripheral damage to begin to show up after the strike occurs.
    Installing this type of basic faraday lighting protection system is not a 100% guarantee that some damage will not occur, but it has a pretty solid history of minimizing the amount of damage that occurs should a strike happen. WIth that being said, it's good to avoid touching any metal (or conductive) surfaces when you are in a lightning storm. The safest place to be in a lightning storm is within a well-grounded faraday cage. A good LPI certified designer/installer should be able to offer some helpful specific advice on the best way to achive that in individual situations. It's not rocket science, but does require some special considerations in light of the materials required to safely divert those larger voltages associated with lightining.

  16. Rob Toronto wrote,

    If you were concerned about a lightning strike, wouldn't it be prudent just to attach a good diameter copper ground wire to the mast, and dangle about 6 feet or so over the side and into the water?

  17. warrier wrote,

    There is a secondary phenomenon associated with voltage the size of a bolt of lightning. An energized electrical field usually travels in a variable diameter around the charge. This can arc and cause surges of transient voltage to occur in other conductive material that fall within it's proximity (radio wires, battery cables, appliances, etc.) It's not uncommon for it to take a few days for some of this peripheral damage to begin to show up after the strike occurs.<a href="http://www.tec-idiomes.com/">Cursos de ingles en el extranjero</a>

  18. john wrote,

    Well we're hoping to live aboard a steel boat for part of the year soon and this lightening thingy was playing on my mind . Now I feel alot better about it …but I think some heavy duty copper will come in handy on the event ….

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