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Old 30-10-2017, 11:04   #16
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Re: Lightning protection for you boat

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I have a trawler. I try to stay around sailboats when there's a chance of lightning!
Sadly, I wonder if this might be the best protection scheme available.
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Old 30-10-2017, 11:05   #17
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Re: Lightning protection for you boat

Good luck
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Old 30-10-2017, 11:15   #18
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Re: Lightning protection for you boat

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Originally Posted by CalmSeasQuest View Post
Sadly, I wonder if this might be the best protection scheme available.
Could be.

I have also read where boats with taller masts get hit more often than those with shorter mast

This I believe was on the same report that said boats without lightning protection get it less often than boats with lightning protection due to the path provided to ground, but that the protect boats suffer less damage
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Old 30-10-2017, 11:23   #19
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Re: Lightning protection for you boat

I was going to say that EMP Solutions appears to be snake oil. They say nothing beyond 'Tesla found a problem in 1916' and if you click the "know more" or product pages on their web site, they only say that same thing again, with no difference between the three products.

But it appears that they DO say more, they just say it in a pop-up window that requires active technology (why oh why?!) instead of a regular web page, so my browser was declining to show it. Note to EMI: Hire a real web site designer who is aware of these things.

Their magic saucer "balances" charges, but somehow needs no power source to do that. Hmmm. And it comes with a ten year warranty (against failing perhaps?) but despite a 100% performance history in all those thousands of non-US locations, there's no warranty against damages to the vessel it is installed on.

Kinda like when the bottle brushes first came out, and then magically the maker simply refused to make any warranty payments (they did warranty against damages) to the damaged vessels.

There's more objective research that was published last year, indicating that the "ground charge" actually flows in the moist air above the water surface, so that "grounding plates" several inches above the waterline combined with a conventional protection system will actually dissipate charges effectively, minimizing strikes. A work still in progress, but a scientific one.

EMP's masthead gizmo sure LOOKS pretty though.
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Old 30-10-2017, 11:39   #20
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Re: Lightning protection for you boat

I agree that there is no protection from being hit, except perhaps that EMP device of which I had no knowledge until a few minutes ago.

And yes, cat have a much larger ground plane formed by two engines and an anchor chain as opposed by an engine and a chain by monos.
That's why I am more scared by a thunderstorm than a gale....

However I do believe that one can minimize damage.
I have not been struck (yet), however a friend of mine on a 14mcat has, the lightning could not find an easy way from the mast to the water, so it traveled along a shroud, from the chainplate jumped a gap of 300mm into his electric wiring (we could see burn marks on his ceiling lining) and continued frying everything connected, including starter motors, alternators and electronics.
My friend and his family of four where on board and at part from a few seconds of vision loss, were unaffected.

I did a lot of reading and decided that providing an easy path from the top of the mast to the water was the best way for me to protect my equipment, so I connected a 4G insulated copper wire to the base of my mast,
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made a hole in my chain locker (catamaran) big enough to pass through this special piece of copper called a "dissipator"
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that I attached to the other end of the copper wire.
With the dissipator 1m below the bilges I felt more secure, still scared, but happier.

I still disconnected anything that could be unplugged but the idea proposed by Roxy is appealing to me and I will try to adapt it to my boat.

BTW, when I had my dissipator machined, I had to buy the solid copper rod, so I ended up with a few spares, if anyone is interested in one, just PM me.
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Old 30-10-2017, 12:36   #21
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Re: Lightning protection for you boat

We used a #4 wire connected to the top stay on deck at the turnbuckle with a length that reached the water secured to short length of pipe the size of our shaft with worn zinc all bounded together over the side when anchored or at dock. This also is a sacrificial zinc & gives the Boat a positive or negative charge to the atmosphere
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Old 30-10-2017, 13:02   #22
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Re: Lightning protection for you boat

My chartplotter, VHF and Tiller pilot all live in an aluminum case with foam inserts so act as a Faraday cage. I remove them when travelling and on a long passage could be put back in during a lightning storm while holding a compass course manually. All of my mast connectors are left unconnected when docked or anchored too except anchor light if needed. Not a total solution but reduces risk of equipment failure right?
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Old 30-10-2017, 13:07   #23
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Re: Lightning protection for you boat

In order to minimise any damage from a lightening strike I microwave my electronics.

Yeah I know sounds totally mad but it acts as a Faraday Cage and protects your electronics from the EM Pulse created by the million volt discharge of a lightening strike. Thing is you don't actually have to be physically struck to suffer from the EMP, a near miss can also fry your electronics. Just be sure to unplug the microwave from the mains/inverter during the storm.

You can also use your oven and even a metal biscuit tin will do the same job.

If I'm in a marina or harbour and hooked up to mains power I will often switch the breaker off and even disconnect my cable to reduce the chances of surges creating problems.
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Old 30-10-2017, 17:26   #24
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Re: Lightning protection for you boat

This subject has already been covered from all sorts of angles. I think I also contributed to it at some length, so it is probably all in the archives somewhere.

I used to work in telecommunications.

Without lightning strike protection, the costs of mainaining microwave and VHF towers would be so high as to make them impractical.

But not to worry--just go about sailing on a saline ocean providing a near-perfect earth electrode, with an unprotected alloy mast sitting as often as not on deck--or worse--on a keel only a few centimetres from that ocean--and keep your fingers crossed.

Oh--and in deference to Faraday, make yourself a quick hat out of alfoil. It won't save your arse--but it might preserve some of your brains long enough to wonder why you allowed this to happen.

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Old 30-10-2017, 18:53   #25
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Re: Lightning protection for you boat

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Someone once said "There are none so blind as those that will not see."

Lightning mitigation exists for sailboats, including cats, but it isn't toilet brushes or weird masthead woo devices. Educate yourself.

The alloy mast is the main game, so earth it via adequate conductor(s) to the sea SURFACE so the voltage equalisation has a chance, which happens in microseconds, if not nanoseconds.

Shrouds won't do it, neither will anchor chains. The lightning that hits your boat WILL get to the sea surface, so help it do that as much as you can. Then you can deal with sideflash and induced currents with peripheral bonding as well for both personal safety and best chance of saving equipment.

Either that, or develop a friendly relationship with your insurance company.




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Old 30-10-2017, 23:29   #26
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Re: Lightning protection for you boat

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Originally Posted by BigBeakie View Post
Mike Banks

👍👍👍

Someone once said "There are none so blind as those that will not see."

Lightning mitigation exists for sailboats, including cats, but it isn't toilet brushes or weird masthead woo devices. Educate yourself.

The alloy mast is the main game, so earth it via adequate conductor(s) to the sea SURFACE so the voltage equalisation has a chance, which happens in microseconds, if not nanoseconds.

Shrouds won't do it, neither will anchor chains. The lightning that hits your boat WILL get to the sea surface, so help it do that as much as you can. Then you can deal with sideflash and induced currents with peripheral bonding as well for both personal safety and best chance of saving equipment.

Either that, or develop a friendly relationship with your insurance company.




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So many comments and views. Big beakie I would be interested in more information from you on your thoughts.
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Old 31-10-2017, 01:52   #27
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Re: Lightning protection for you boat

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Observations following our three hits are that electronic items that survived were all installed with a main breaker on the + "off". They also had a two pole manual mechanical air gap switch also "off". The two pole switch is as close to the device as possible, inches, and interrupts both plus and negative leads. Note that all modern stuff has a software power switch and continuous connection to the boat common ground. This means off is not disconnected from boat wiring. I also disconnect all antenna cables. My mast wiring passes through an industrial monster 64 pin connector. I use this to disconnect the mast entirely.
As engineer I can comment that this is ONLY way to go - disconnect all equipment that you want to save completely from positive, ground, from each other and from mast, creating big gaps and physical insulation between disconnected wires. Master disconnect connectors - perfect solution. This will save at least some if not all equipment. Remember - very sensitive devices like phones often survive, because they're not connected to anything. And think (of course, in advance) how and where electricity will discharge if lightning occurs.
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Old 31-10-2017, 02:48   #28
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Re: Lightning protection for you boat

Still Looking,

Honestly, the best resource I could find anywhere was Dr. Ewen Thomson at www.marinelightning.com Go through that site carefully.

He has done the hard yards in designing equipment and layouts for the best results. He's done agreat job designing our system for the new Freeflow aft mast cat.

I also found locally an electrical engineer specialising in high voltage systems and he agreed 100% with Dr. Thomson's research. That's good enough for me. If you have any specific questions, I'd be happy to expand further , such as mast grounding direct to water for catamarans.

And fully agree with Ranchero on disconnecting as much as possible if you have enough warning time. But thunderstorms can creep up on you while you're asleep at anchor, when you're most vulnerable, i.e. near land.



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Old 31-10-2017, 04:17   #29
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Re: Lightning protection for you boat

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If you get struck by lightening, nothing will protect your electrical and electronic systems. They are almost certainly total toast. A current flux of millions of amps per second generates a powerful, and rapidly changing, magnetic field which induces large voltages and currents in every conductor around. Including on all the circuit boards in every piece of electronic gear--enough to fry all those IC chips. No matter if they are turned on or not, no matter if they are plugged in or not.

When somebody tells you that paper charts are obsolete, you might want to remind them that every boat is just one lightening strike away from the 19th century.
You can protect a spare VHF-kit, GPS, etc from the EMP by putting them in a dedicated Faraday cage or in the oven. Your boat will be then two lightning strikes away from the 19th century

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Originally Posted by Alberg30Shill View Post
My chartplotter, VHF and Tiller pilot all live in an aluminum case with foam inserts so act as a Faraday cage. I remove them when travelling and on a long passage could be put back in during a lightning storm while holding a compass course manually. All of my mast connectors are left unconnected when docked or anchored too except anchor light if needed. Not a total solution but reduces risk of equipment failure right?
Good procedure, should be standard on all sailboats!
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Old 31-10-2017, 06:45   #30
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Re: Lightning protection for you boat

Spare portable electronics stored in a mild steel box are likely to survive a lightning strike. Leave the batteries out of the devices if you can. And have a VHf radio that works with regular alkaline batteries. Keep several batteries in the box too. This need not take up a lot of room. There are VHf radios that have GPS and run with regular batteries. A small solar panel can recharge mobile phones.

I also agree that disconnecting electronics will reduce the probability of damage. But that isn't always possible.

When a purveyor of lightning "protection" includes a warranty against damage while using their kit I'll get excited. But the reality is that you can DIY install surge arresters on RF and transient protectors on DC power cables and they will help. You can provide a low resistance/inductance path from the mast and shrouds to the ocean and that will help. But nothing can guarantee no damage from lightning. At least I am aware of no product or system that includes such a guarantee.

Web sites talking about "surface charge" on a highly conductive salt water ocean sound like gibberish to an engineer. The idea of providing multiple exit points for current is not a bad idea on a boat without a big lead keel. But you have to weigh the risk in drilling multiple through hulls. I suspect many more boats sink due to faulty through hulls than from lightning strikes. Some advocate holes just above the water line but still there is some risk. And there is no way to precisely position an electrode above the water line when the waves are anything above a ripple.
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