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Old 14-06-2012, 23:45   #1
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Lightning Strikes

My husband and I have been sailing for almost 30 years, most of them as liveaboard cruisers. While cruising extensively in S.E. Asia from Oz we sat through electrical storms almost every day and they scared the daylights out of us. Nobody could give us any ideas on how to protect the boat. Luckily, we were never hit. Over the years we've known quite a few boats that have had lightning strikes and despite many discussions, no-one seems to have come up with a foolproof, or even nearly foolproof, way of averting this disaster. Most of these boats have been repairable however, the latest one was a total write-off. Does anyone out there have any suggestions?
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Old 15-06-2012, 02:28   #2
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Re: Lightning strikes

We hate lightning storms...and we are on our way to SE Asia. I hope they are not really everyday!
There are so many strong opinions about how to avoid being hit, but we have friends who did research with a couple of USA marine insurance companies and there seemed to be no magic answer. Grounded and ungrounded boats were hit equally, mast top deflectors seemed to make no difference, etc, etc.
I guess we will just have to get used to "scared the daylights out of us!" days...but I hope that not often!
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Old 15-06-2012, 02:50   #3
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Re: Lightning strikes

Unfortunately, as you cross the convergence zone you will probably have to put up with the storms, known as Sumatras as they come out of that island. Visibility can be down to almost zero with torrential downpours and that horrible lightning. We travelled around Singapore and up the Johor Strait wearing dive masks as the rain was so heavy and stung our faces. But they only last for about an hour. We always unplugged our electronics until the storm had gone through. If you come through Cairns in North Queensland, look us up on our mooring opposite the Cairns Harbour Marina. If we're not there ask the cream cat behind us to give you our phone number. If we can give you any advice or help, we'd be only too pleased to do so. Otherwise, let us have your email address and we'll send you any hints that we think may be useful, as well as some contacts in Indo.
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Old 15-06-2012, 03:11   #4
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Re: Lightning strikes

There are a lot of threads on CF about lightning. Use the Google Custom search feature (in the Search pull down menu) and enter "lightning".

This will get you most posts on the subjet.

Don't bother using the Search Links or Search Gallery, it is a waste of time
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Old 15-06-2012, 03:42   #5
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Re: Lightning strikes

Grounding the boat does significantly reduce the level of damage when a boat is hit. It also possibly slightly reduces the chance of being hit, but the difference is very small.
There is really nothing you can do to the boat that will substantially reduce the chance of a strike, but grounding is worthwhile to minimise the damage.

Lightning strikes vary in intensity enormously so there is an overlap of damage between grounded and ungrounded boats. An ungrounded boat can be damaged less in a mild strike when compared to a grounded boat in a more severe strike, nevertheless grounding the boat is worthwhile.
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Old 15-06-2012, 04:00   #6
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Re: Lightning strikes

Thanks for those tips. It's a hard one, isn't it?
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Old 15-06-2012, 05:02   #7
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Re: Lightning strikes

Quote:
Originally Posted by Wotname View Post
There are a lot of threads on CF about lightning. Use the Google Custom search feature (in the Search pull down menu) and enter "lightning".

This will get you most posts on the subjet.

Don't bother using the Search Links or Search Gallery, it is a waste of time

What's wrong with having a new, fresh discussion about it?
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Old 15-06-2012, 06:10   #8
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Re: Lightning strikes

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Originally Posted by Rakuflames View Post
What's wrong with having a new, fresh discussion about it?
Nothing I can think of; what about you?
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Old 15-06-2012, 06:25   #9
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Re: Lightning strikes

When there is umpteen million volts heading for mother earth there not a lot you can do to stop it.
I know with aircraft (which get hit all the time) grounding every component to each other is very important.
This lets the electrons get to where they want to be with the least resistance.
Remember resistance equals heat and heat equals fried components especially electrical ones that really don't like it.
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Old 15-06-2012, 06:28   #10
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Re: Lightning strikes

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Originally Posted by noelex 77 View Post
Grounding the boat does significantly reduce the level of damage when a boat is hit. It also possibly slightly reduces the chance of being hit, but the difference is very small.
There is really nothing you can do to the boat that will substantially reduce the chance of a strike, but grounding is worthwhile to minimise the damage.
After getting a direct masthead strike while sailing I have come to the conclusion that nothing can be done to avoid being struck (other than not being in an electrical storm) and nothing can be done to minimize the damage caused by a strike. My keel stepped mast was grounded to the keel. Thru hulls were not grounded. When hauled the hull showed "treeing" (burn marks in the paint) at all thru hulls and even on the rudder at the gudgeon. In other words the lightning went throughout the boat. I've come to this conclusion after reading reams of stuff on lightning and small boats. I did this reading after being hit.

So called preventative measures (like jumper cables on the shrouds) might make you feel better but that's about all. Foolishly I was never scared of electrical storms before being hit. Now, many years after the strike, I am just getting to the point where I can keep sailing through an electrical storm and not freak out.
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Old 15-06-2012, 06:43   #11
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Re: Lightning strikes

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Originally Posted by noelex 77 View Post
There is really nothing you can do to the boat that will substantially reduce the chance of a strike...
I can underscore this statement with an example:

Yesterday in our current anchorage here in Panama, a powerboat took a direct strike. The powerboat was anchored with large sailboats all around it and was the lowest point by a good 40'. None of the sailboats were hit. And the powerboat had an extensive lightning protection system that consisted of multiple down-conductors connected to multiple thruhull electrodes around the waterline.

So, not even a well-protected boat underneath much taller conductive structures is safe from a direct strike.

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Old 15-06-2012, 06:59   #12
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Re: Lightning strikes

Similar experiences. It seems to be random and most of what you do will be more for your own peace of mind that providing real protection.

Have been at seas, miles from land and any other boats with lightening strikes (and waterspouts) all around and not a problem.

A friend's sailboat was struck twice in less than a year at dock in the marina with dozens of larger and taller boats all around. He lost only his old flasher style fathometer but the VHF next to it and all the other electronics were fine. The main damage was a small hole in the hull. It looked like a clean through hole but no water came through. On closer examination there was a thin, clear window of fused glass sealing the hole.

Have read about boats where little or nothing was damaged and boats where everything was fried, even hand held devices, switched off, not connected to any antennae, wiring, etc. Look at this post from Maine Sail in a previous thread.

Death to PAPER ! More Nails in the Paper Chart Coffin . . . - Page 6 - Cruisers & Sailing Forums
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Old 15-06-2012, 07:13   #13
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Re: Lightning strikes

The founder of this company was a University of Florida professor and had done some research on lightning.

I don't know if there is a track record yet with his system, but the recommended installation will drive you to buy a new boat and have it installed during construction.
Lots of sciency articles on the website.

Marine Lightning Protection Inc.
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Old 15-06-2012, 07:19   #14
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Re: Lightning strikes

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Originally Posted by sokari View Post
...Most of these boats have been repairable however, the latest one was a total write-off....
So what damage occurred to the boat that it was a write-off?
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Old 15-06-2012, 07:19   #15
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Re: Lightning strikes

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Originally Posted by Vasco View Post
After getting a direct masthead strike while sailing I have come to the conclusion that nothing can be done to avoid being struck (other than not being in an electrical storm) and nothing can be done to minimize the damage caused by a strike. My keel stepped mast was grounded to the keel. Thru hulls were not grounded. When hauled the hull showed "treeing" (burn marks in the paint) at all thru hulls and even on the rudder at the gudgeon. In other words the lightning went throughout the boat. I've come to this conclusion after reading reams of stuff on lightning and small boats. I did this reading after being hit.

So called preventative measures (like jumper cables on the shrouds) might make you feel better but that's about all. Foolishly I was never scared of electrical storms before being hit. Now, many years after the strike, I am just getting to the point where I can keep sailing through an electrical storm and not freak out.
Sounds like you unlucky, but lucky!. One of the biggest dangers to fibreglass and wood boats, in particular, is if the lightning exits via one of the thru hulls. The hull disintegrates around the fitting and the boat sinks. I think you must have been close to that point.
Your grounding system is designed to exit the lightning via the safest point the keel. Lightening does not always follow this grounded path so it by no means foolproof.
It is certainly possible the ground system on your boat took some of the energy and prevented more serious damage, but in some cases the ground system is of little help.
The ground system is not designed to reduce the chance of a strike, although there is some evidence it may be a slight benefit in some circumstances.
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