MacGregorSailors.com

Hello all,

I'm looking for your collective wisdom on the topic of lightning.

Last weekend we were in the HOA swimming pool, which is right beside our marina, when a nasty little storm rolled in really quickly. My first thought was...glad I'm not out there...which quickly turned to...What do I do if I am out there. About the time I had that thought, the pool closed because there were lightning strikes in the area. Which also led to the question....What do I do if I find myself in a lighting storm? Do I drop the mast? Am I grounded?

I have an 88 26D and I'm not sure what to do if a lightning storm blows in on me before I can get out of its way. If there is a grounding system, what part(s) do I check to make sure all is well?

Thank you for any advice, wisdom, or stories.

Curwen

The thing is, no one else is sure either.
If it were me and I was in Un sheltered water I would reef the boat way down and go below. Provided conditions weren't totally insane. If I could get in sheltered water and anchor in a timely manner I'd do that, and go below away from any metal that penetrated the hull like chainplates and swing keels. If condition were really bad and despite a double reefed main the boat was out of control I'd strike the sail and motor into the wind slowly even though you have to touch the wheel to do that. Or maybe let the boat lie ahull if it looked like it might be over quickly and I had room to drift.
If I saw the storm coming and it looked like a big one I'd take the sail down before it got to me and try to run away from it under power. I've done that before. You boats a better sail boat so only you can decide on that issue.
In terms of grounding there is no one way to do it. There is no consensus on lightning while boating except not to be near it. Light fiberglass watercraft don't afford much protection.
dropping the mast in a storm is probably not very safe either.
Ix

There are lots opinions around the net of whats best in lightening storm, the problem is none of them really agree with each other, some say put a ground from you shrouds to the water so say other things.

In reality the chances of being hit by lightening are very microscopic at best, it doesnt always strike the highest or most conductive object around, its just random.

Hunker down in the cabin and dont touch anything metal until it blows over seems to be the only point that most agree on, if thats an option

You can't do anything about it.

The MAC has a water ballast with a plastic keel - there is no suitable ground path for lighting on a MAC. You are pretty much in the same situation as a small open sailboat or a small ski boat power boat. All these types of small boats ply the coastal waters of Florida and California and the Gulf with the same dangers in mind. People in these areas know that lighting is more of a danger near the coast so they all tend to seek harbor and hide from lighting.

What if you can't?

People that sail across the oceans do not worry about this as much because for them everything is about survive ability - a lighting strike has a good chance of blowing holes in your boat - whatever down conductor you have that is a lousy transit for 200 amps will bow out. The mast being aluminum and rather large has the ability to transfer 200 amps without melting - is like a big aluminum 'bus bar' even bigger than the ones in switchboards I have designed to handle 3000 amps. But the small bolts and stays and fittings are not do sturdy with that kind of current. Chain-plates can blow holes in the hull. The positive charge of the water sometimes reaches up to the base of the mast and if your not in the way the charge can dissipate without destruction, but like a tornado - you never know what will happen. If you were to ground the base of the mast to the water you give the water a place to "connect" it's positive charge to the negative lighting, but what part of the water around you has the most positive charge at that very second that the lighting strikes? Your cable on the port side can be too far away from the more positively charges water on the starboard side, or the forward than the aft. So you would need grounding surfaces all around the boat cover all the odds of the water arcing up to meet the strike. Even if you did have a goop loop all around the boat in the water connected to the mast - in the event of a strike there is a good chance you will blow a hole in the hull where the loop is attached to the boat. It's not an easy thing to deal with.

The bottom line is that your really screwed - it's like storms or 100 foot waves or any of the other dozens of things out there in the ocean that can kill you.

My dad always said that he would get hit by lighting if he were on land or by sea if that's what the Good Lord wanted, so why fight it?

I,ve had sheet lightening come within 50ft of my boat twice , everyone on board wanted to get there pfd,s on ,I told them that's not gonna stop lightening from killing U !! , might help if the hull get blown out

sheet lightening comes across the the water like about 100ft high from the water up very spooky , like my T-Shirt say,s hull was Full So I,m back

J

Four articles you may wish to read.

Ray

http://www.boatus.com/seaworthy/magazin ... raft_1.asp

http://www.boatus.com/pressroom/release ... 0WHgV_3bv4

http://www.boatus.com/seaworthy/magazin ... g-odds.asp

http://www.boatus.com/seaworthy/magazin ... htning.asp

Highlander wrote:I,ve had sheet lightening come within 50ft of my boat twice , everyone on board wanted to get there pfd,s on ,I told them that's not gonna stop lightening from killing U !! , might help if the hull get blown out

sheet lightening comes across the the water like about 100ft high from the water up very spooky , like my T-Shirt say,s hull was Full So I,m back

J

Yeah, I pretty much already know what will happen on 'boat' if lighting hits it - there will probably be a huge arc from the mast plate through the cabin deck down to the bow vent where the plug is thus blowing a hole right through the bottom of the boat and probably sinking it in a matter of minutes. That's why I will be hiding in the aft berth if i get caught in lighting because the motor has a ground path to the water - but still, that's just for MY "survive-ability", not for 'boat'. I have no delusions - 'boat' will be blown through and through if hit by lighting. I seriously doubt the resulting holes will be survivable for 'boat'.

That's not really my question, my question is this:

If I DO survive a strike and I am (most likely) treading water - what happens to me when the lighting strikes the water again? Am I 'grounded' because I am in the water? Or do I get fried by the next bolt that hits the water in my vicinity?

I'm not sure how to survive lighting when swimming. Anyone Know?

I would love to hear from someone who has been struck or their boat has been struck in marina or something. I asked one of the lake park rangers here in Utah and he had never seen any boat ever get struck in 10-15 years. These are mostly power boats with no mast. I'm deathly afraid of lightning but would be curious to know how often it actually happens. (I guess it only takes once).

Thank you, as always you guys are a fount of knowledge. I'm just trying to avoid the really, really stupid things that get people hurt.

I wanted to see if there was a consensus on a best practice.

I will check the links out.

Thanks again,

Curwen

Curwen wrote:Thank you, as always you guys are a fount of knowledge. I'm just trying to avoid the really, really stupid things that get people hurt.

I wanted to see if there was a consensus on a best practice.

I will check the links out.

Thanks again,

Curwen

Ha! Hey guys! he called us a "fount" of information! (sounds like we fooled him).


fount1
fount/
noun

a spring or fountain.

Oh, wait a minute, I just looked up "FOUNT" - he means we are a leaky fountain in the bilge - okay - that's true, and that's what happens when the lighting strikes the boat too - you get a fountain in your hull.

Well ok then

My V22.2 was hit by lightning but I was not on board. It hit the free standing aluminum mast I had retrofitted the boat with. This mast was the shortest mast in the anchorage. There were 15 other boats there.
They were all spaced about 300 feet apart.
It traveled down the mast and exploded the carbon fiber sheath on the wood butt inserted into the aluminum. (To make the mast a bit longer.) it left the aluminum at the juncture between the two materials and went into the metal swing keel, going through the fiber glass of the trunk and out of the sheathing on the keel. It also put a 1/4 in hole in the hull at the forward bulkhead right below the waterline.
All the electronics were at first inoperable but curiously, started working again a few days later.
None of the admittedly basic wiring was harmed. The carbon fiber was everywhere. I beached the boat and repaired the damage. I redid the sheathing at the butt of the mast and put a sharpened piece of stainless on top. The previous factory mast had a sharpened SS whip antenna installed by me. My current boat has one also even though I have no radio on board.
Note this boat had a very large piece of iron for a keel that took up most of the cabin. It did not have stays. It did not have any cable dangling in the water. Possibly a heavy wire from the keel pivot bolt to the aluminum mast might be a good idea but the boat never had any issues with that again.
I entertained a design whereby the mast went right through the boat like a daggerboard and coujd be used as a spudding pole in shallow waters. This would also allow a direct route to the water. However I nixed the idea as too much work.
On the M model, a metal tube inserted into the dagger board and connected to the mast base might also work well.
Trying to ground a strike is all well and good but really, it has to be in a straight line to be effective. There are a lot of side discharges that jump off angles in conductors. I think some keel stepped masts used to be connected to a keel boat. But for best results is has to be a straight path.
On boats with conventional back stays, that's where I would choose to hang a cable or some such. Maybe a dyna plate grounding plate. I had that on the v22.2 before I re rigged it.
So far I have not heard about boats sinking suddenly from lighting. Explosions, fire, loss of life, yes, but not sudden sinkings. If BOAT survived the strike he would have time to locate the leak, my bet being either near a chainplate, or somewhere around the bottom of the dagger board trunk. A difficult area to get to.
Ix

I guess the boat could float with a tiny 1/4 inch hole but the M boat, (unlike yours) does not have a metal swing keel in the water to dissipate most of that charge - all that amperage that is coming out of the bottom of the mast is going to go looking for a path to the water and there is no path with a plastic dagger board - the electricity is going to blow right through the bottom of the boat. The reason why I think it will blow out the bow vent is because the dagger board trunk on the M boat is so heavily insulated with sand and resin that I doubt the charge would find many positive ions there to attract it. You would literally have an open arc of electricity blasting thought the top of the cabin straight for the nearest water source it could smell - namely - the forward part of the ballast tank - ka-BOOM! By the way, sitting in the cabin under the mast would probably kill you and anywhere withing 10 feet of the mast would probably injure you real serious.

Even more likely if you have a real stout for-stay that is not insulated with a furler there is a good chance the charge would jump across and down the fore-stay looking for the metal chain and anchor thus blowing right through the chain locker down to the waterline. It would pretty much blow off the front of the boat. That's why I will stay away from the bow and hide in the aft berth if the lighting comes looking for me. The motor is a good conductor and would take the brunt of any charge that hits the aft section and the motor is big enough to take the hit without blowing up.

I will remove the battery terminal wires so the strike does not travel into the aft battery compartment and blast me with acid and just sit back there an suck my thumb until catigale or seahouse come to rescue me.

It has been said to dangle some chain into the water from a shroud, that would give it the lowest possible resistance path to the water, end of the day lightening strikes whatever it will, I mean plenty of trees get struck and wood is a rubbish conductor and the huge majority of strikes go straight to the ground and I cant see the iron content in the general earth being overly high.

For the life of me I cant remember hearing a news story when a boat has been struck by lightening and sunk, we all go and jump in our cars daily and we dont worry about the chances of being seriously hurt or killed and I would think the chances of being a serious car accident is about a million times higher than the chance one little boat being struck by lightening.

In fact just about everything we do every day have a much much higher chance of doing us damage than the chance of being struck by lightening.

You have a much better chance of winning first prize in lotto than being killed by lightening, someone wins lotto every week, someone doesn't get killed by lightening every week and when was the last time you won lotto?

This is what one calls a totally irrational fear

NiceAft wrote:Four articles you may wish to read.

Ray

http://www.boatus.com/seaworthy/magazin ... raft_1.asp

http://www.boatus.com/pressroom/release ... 0WHgV_3bv4

http://www.boatus.com/seaworthy/magazin ... g-odds.asp

http://www.boatus.com/seaworthy/magazin ... htning.asp

Post by sailboatmike » Wed May 25, 2016 3:24 pm

For the life of me I cant remember hearing a news story when a boat has been struck by lightening and sunk, we all go and jump in our cars daily and we dont worry about the chances of being seriously hurt or killed and I would think the chances of being a serious car accident is about a million times higher than the chance one little boat being struck by lightening.

This is what one calls a totally irrational fear

If only that were true, - it depends on where you live. Folks in Florida have a chance of 1 in 1000 of getting hit if they are on the water in a sailboat. You need to read the posts that Niceaft put up - all the statistics are right there for people in the US. It's MUCH more likely you will get hit by a bolt in your sailboat than winning the lottery if your in Florida. Read his post links. For people in the gulf it is a serious matter - I'm not real keen on the dangers in Australia. Do you guys have lighting?

Also. right there in his post links is a story of a sailboat getting hit by lighting - it blew som pretty good chunks right out of the bottom, and that's where they were headed if they did not start bailing - to the bottom.

My dad sold insurance for a living so he had all the actuarial tables on lighting injuries and he told me that anyone outdoors is in a good place to get bitten by lighting and that if your in a sailboat it's even worse. He never said it was an irrational fear - and it's not. It's just something you can't do anything about if your too far from shore to get off the water, so therefore he said there was no point in worrying.

Similar experience to Ixneigh. Our boat was struck by lightning on the hard (on trailer). It jumped from the boat to the house. Blew out all the LEDs in the boat and zapped an old knotmeter. Zapped a couple tvs and dvd players in the house, the smoke detectors, and scared the pants off the admiral. But boat wiring was okay. It did burn a small hole in the hull where it (apparently) jumped from the boat to the ground - on the side below the waterline. It was right at the fender, so i assume it jumped to the fender from the hull. However it happened, it blew the fibers from inside out, delaminated in the area of the hole slightly, and was visible once you knew what to look for. It was so non-descript that I originally thought the lawn guy had kicked a rock or something up into the hull. When i ground the fiberglass down to repair, i found about an inch or two around the hole that looked burnt (blackened), but overall it didn't appear heavily damaged. The hole itself was actually tiny.
Just remember, the bolt of lightning is still only one electron across...