Having heard about a mate getting hit recently by lightning at his anchorage, I've realised that indeed, lightning can strike twice, since it was the second time his yacht was hit.
As he tells it, the most recent lightning through his mast jumped to the railings and exited through the anchor chain into the water without cauisng any damage anywhere else. He has no specific precautions against a lighting strike. His mast is deck stepped and the rigging is steel, hull is full GRP with a bolt on led keel. Personlly, I have never had the experience nor I wish for it, but that does not eliminate the chance of getting a lightning strike. Reading up a bit about it never prepares you for when it happens either.
How do you protect your yacht against a lightning strike if at all, have you been hit and if so, were you onboard and what was the damage?

Always park beside a boat with a longer mast.

I've heard that multi-hull are more likely to be struck by lightning, so park beside a cat...

Trek said..
I think Jode is right.

Or park in the middle of a bunch of other masts. The theory of that one isnt that the lighting will hit someone else its that the static charge in the air will be lower because of the multiple paths to ground (masts) and lightning will be "defused" and not arc hopefully. Thats why power substations etc have poles with what look like upside down chairs all around. Its an attempt to de-static the local air.

Other than that a plastic mast would help, except in the rain.

Thats great if you have a chance to do that, but what happens if you are away and caught out solo?

Seebreasy73 said..

Trek said..
I think Jode is right.

Or park in the middle of a bunch of other masts. The theory of that one isnt that the lighting will hit someone else its that the static charge in the air will be lower because of the multiple paths to ground (masts) and lightning will be "defused" and not arc hopefully. Thats why power substations etc have poles with what look like upside down chairs all around. Its an attempt to de-static the local air.

Other than that a plastic mast would help, except in the rain.

Thats great if you have a chance to do that, but what happens if you are away and caught out solo?

Install one of these

Seebreasy73 said..

Trek said..
I think Jode is right.

Or park in the middle of a bunch of other masts. The theory of that one isnt that the lighting will hit someone else its that the static charge in the air will be lower because of the multiple paths to ground (masts) and lightning will be "defused" and not arc hopefully. Thats why power substations etc have poles with what look like upside down chairs all around. Its an attempt to de-static the local air.

Other than that a plastic mast would help, except in the rain.

Thats great if you have a chance to do that, but what happens if you are away and caught out solo?

Technically speaking the lightning is going to hit the mast and the current will flow or arc somewhere from the base of the mast to the water. That means if it really is a threat sit far away from the base of the mast to avoid getting caught in that lower arc/current flow. If possible where it's dry not wet. If you have an aft cabin sit in there. Then protect yourself and eyes from flying molten metal and shrapnel with lots of thick blankets. If sailing during a high risk electrical storm was mandatory then those not sheltering would need heavy clothing to protect from potential shrapnel and maybe a helmet with Uv welding goggles. Also ear plugs. Since some lightning strike victims were deafened. Completely extreme and silly but if one was serious that's what to do I think

Faraday effect helps protect the inside of a Faraday cage if the conductive outside is complete enough. ie. Aircraft with small windows, steel boats. I looked up carbon fibre masts and from what others say the lightning still strikes them no problem and worse, unless they are built for it, get blown apart at the high current points, spray shrapnel everywhere and are usually write offs!

Craig66 said..

Seebreasy73 said..

Trek said..
I think Jode is right.

Or park in the middle of a bunch of other masts. The theory of that one isnt that the lighting will hit someone else its that the static charge in the air will be lower because of the multiple paths to ground (masts) and lightning will be "defused" and not arc hopefully. Thats why power substations etc have poles with what look like upside down chairs all around. Its an attempt to de-static the local air.

Other than that a plastic mast would help, except in the rain.

Thats great if you have a chance to do that, but what happens if you are away and caught out solo?

Install one of these

the shear weight of it would sink the boat

Trek said..

Seebreasy73 said..
the current will only jump onto something that is conductive. naturally when it is wet everything is conductive.
I was thinking of getting a jumper cable and clip the mast to the safety line/railing to create a continuous earth link and another one that would be clipped to the same safety line/ rail with the other end dropped in the water with a bit of weight on it.
I am no electrician, but this is a basic earthing method that in THEORY should work, even if the cables would be toast at the end.
Again, because possibly the whole surface of the boat would be wet, I do not know how well this would work if at all.
One thing I have learnt is not to earth any electronic device through the battery unless you want your batteries blown.

Seabreezy though I couldn't guarantee it I think that is not the best plan. My guess is that if you electrically connected the mast to the water really well your mast would be much more likely to attract a strike. I f the mast was completely insulated from everything at its bottom end (ignoring the complication of shrouds) it wouldnt get hit. ie. it would be like a 10m length of aluminium in space. The potential difference (voltage) that could build up along the length of 10m of metal could never be high enough for an arc. Our problem is the static charge build up from air to sea and what you would be doing is making an elevated section of "sea" available for the lightning to strike. So the best plan would be a way to totally insulate the mast from all the other conductive stuff on the boat. Including a big connector to disconnect all the antenna and masthead light wiring etc.

if you are out alone cruising or mooring and get caught in a quick summer storm, wouldn't that still be a better option to create a direct line for the lighting to pass through rather than let it arc all over the boat's surface trying to find an exit point? I certainly would not want a hole in the hull below waterline.
The mast may be insulated, but if that is the only thing sticking in the air 11 m high aren't chances high being hit regardless?

I seem to think that lightning rod theory may be at play with regards to yachts mast. Grounding the mast via shrouds, chain plates and keel may help to prevent a strike rather than attract one.

Eastcoasters said..
My lightning strike strategy is quite simple.

Find a much bigger boat with a much bigger mast and go and anchor near it. Not TOO near though.

again, won't work when you are caught by the storm underway, but generally that is my current marina strategy. Question is, is it good enough?

We got a direct strike on our 15m GRP sloop Solitaire whilst anchored in Port Clinton, north of Rosslyn Bay in 2012. Night time event and a major league lightning display immediately overhead. Unfortunately, it would appear, we had the highest mast amongst the anchored boats.
One unbelievable flash of light and milliseconds later ....kaboom! Auditory overload, lights out and bewilderment. WTF! Checked on the step-mother who has a pacemaker and was sitting next to the alloy keel-stepped mast...no worries as she's indestructible. Takes more than a few million volts to cook her. My father slept through it all due to good quality Scotch whisky and dodgy hearing aids.
We lost all our electrics other than electric toilet :-))) and main engine alternator. Small fire in the inverter which I think acted as a pretty good, if somewhat expensive, fuse! Everything else kaput. including fridge, freezer, microwave,GPS x 2, radar, depth sounders x 2, all stereo,TV,...you name it..apparently all LED and modern electronic stuff is very sensitive to voltage overload so all instrument panels, switch panel, inverter, Fortunately everything was well documented with receipts so eventually $30k worth of electronic replacement via a (not very) cheerful Club Marine. Fortunately we had no hull damage via the chain plates or earthing plate. No water coming into vessel. We were very kindly "buddied" back to Rosslyn Bay by a neighbouring yacht and immediately contacted Club Marine who informed us that they couldn't do anything without a quote from a marine electrician. Not many of them ( or anything else) in Rosslyn Bay so I told them that I would need an assessor which they reluctantly agreed to finance. We paid a diver to check the hull which appeared OK. The assessor was very helpful and agreed that the yacht would need slipping on our return to Gold Coast to assess hull/keel and more detailed chainplate inspection. He arranged for all the other necessary people to check out and assess the repairs needed. Getting full and accurate details of the damage from a limited supply of tradesmen was very difficult and time-consuming. My biggest help was having every single receipt available so that date of purchase and the price were not an issue for Club Marine.

What did we learn from the experience and what would we do next time?
All our mobile phone batteries, which were fully charged but not connected to charger at the time, were immediately discharged to zero so, In event of electric storm, lob everything important, including phones, into the oven or microwave....Faraday Cage, as mentioned by 2bish. Especially important to put your back-up handheld VHF/UHF units and laptop computer in there if you have a back up navigation system. Consider having a back-up VHF aerial and cable extension. Unplug, don't just switch off, whatever you can from the internal 240V and 12V sockets.... most nav systems can easily have the input lead removed from the back of the unit...just DO IT!! Turn off any mast head electronics such as anchor light, wind instruments and TV antenna and don't use the VHF. Power at the mast head might well attract a hit...we had the masthead antenna "on" as I had the stereo system "on"...they were connected together so I'd suggest turning it off. My guess is that this might have been our downfall....power at the masthead.
Turn the mast head anchor light "off'. Many yachties have a cheap solar garden light on board as a back-up light and this will temporarily replace the masthead light as a 360 degree light during the storm. Our hit was directly onto the VHF antenna (which we later found on the aft deck curled into a question mark shape)....our neighbouring boat thought we had let off a "masthead distress flare" during the storm but we know now it was the VHF aerial glowing red hot. During lightning, keep away from the mast in the saloon if it is keel-stepped. As slammin has just posted, wrapping some chain around the mast base and then over the side might give an easy earthing path rather than damaging the hull.
I've read up on lightning strikes heaps (after we got hit unfortunately! ) and it appears that the US Navy and Royal Navy have spent billions trying to find a preventive approach but have not found anything predictable. The upside-down witches broom seems to be as good as anything else!
On a final note, I have met 2 yachties who have been hit twice and have heard of many more than that....that's a worry!

Agree Seabreasy73. I should have stressed that we were at anchor so we only had an anchor light on.. If we were under way in a storm at night we would still keep the nav lights on.....collision might be even more of a danger than lightning.

So, two guys are on the golf course when lightning starts striking all around them.
"Hang on, I know what to do" says one as he pulls out his No 1 iron and holds it above his head.
"Bloody Hell!" yells his mate "are you crazy, you'll get us both killed!"
"Nah" he says, "only God can hit a No 1 iron"

Its definitely a problem. Lightning destroyed this boat.
www.bbc.com/news/av/uk-scotland-46099803/yacht-fire-rescue-after-thailand-lightning-strike

There is no surefire way to protect a yacht from lightning strike as far as l know.
We just gotta live with it hence the necessity of a good insurance.