Looking for opinions from this forum

[NiceAft]

Our mast’s are huge lightning rods. Is there an advantage to lowering a mast during lightning storms?

[Russ]

It's quite a hassle to lower the mast.

There are a zillion opinions of lightning. I'm so confused.
What I have come to understand is that if you don't do it right, you could make it worse.

Salt water/fresh water and grounding. It's mind-boggling.
Dissipators on top of the mast.

So much info out there.

For me, I think I'll just pray.

[Be Free]

Ignoring the old saw about opinions, I'll wade in with mine.

No.

I've followed every thread and read every paper I've come across regarding lightning and sail boats. They all fall into three categories: Do nothing, some type of grounding/lightning rod arrangement, and Faraday cages to limit damage. I've not seen any type of consensus but I have seen a lot of anecdotal evidence supporting each position. I don't consider anecdotal evidence to be evidence in the strict, scientific sense and since it supports all three in a fairly even manner it's really not conclusive in any case. Most of the arguments supporting the lightning rod and Faraday cage mitigation do not understand how a lightning rod works or why a "Faraday cage" that can block RF frequencies will not necessarily be effective against lightning.

So, in the absence of any compelling evidence supporting any position, I choose to go sailing and not worry about it.

[Russ]

If it were easy to lower/secure the mast, it would be a benefit to lower windage in a T-Storm. The winds worry me more than lightning. I try to stay close to shore where there are taller things than me.

[Jimmyt]

1. Lowering the mast on the water with a lightning storm approaching is a bad idea. If you can see it and hear it, you can get struck.

2. You trade a tall mast for a much lower target, but now have wire rope all over the deck and cockpit, possibly drooping into the water. We can debate whether grounding plays a part or not, but I would rather not have wire rope in the water in a lightning storm.

3. Lightning does whatever it wants. I have some experience with it. We have a fair amount of it here. For once, it's good not to be number one.



I'm with Bill. I'm not going to increase my risk of injury by dropping the mast. I'm going to go sailing - but watch the weather. If I get caught where I can't get near easier targets, I'll go below, try to get away from chainplates and the mast base, and say a quick prayer...

[NiceAft]

Thanks, but I’m not speaking about sailing.

I will be at a transient slip at a marina. There is a thunder storm expected, so I will stay at the marina an extra day.

I am inquiring about lowering the mast while there. Does it make sense to do this for the time I am there while a storm blows over?

[Jimmyt]

No

[svscott]

In my opinion, if you're in a marina and there are taller and bigger boats around you, you're not as likely to get struck. I wouldn't work on the boat with the storm present but if you've got time before the it rolls in, it makes sense to me to lower the mast and secure the rigging tight to the mast. I've always heard the highest metal is most at risk.
With that in mind, lowering the rig seems wise to me.

I was out sailing and fishing on Presque Isle Bay, Lake Erie after getting done working 2nd shift at about midnight one night last summer, we could see a lightning storm about 20 or 30 miles out over the lake. My friend and I checked the radar and the storm looked to be passing well North of us so we decided to go fishing for an hour anyways. After a half hour on the water, our fishing lines or the boats rig began audibly buzzing. I immediately reeled in the fishing line, pulled the genoa down, and started the engine to make a beeline back into the marina. With the engine running, we couldn't hear the buzz anymore and nothing bad happened but it was SCARY! We never did see any part of that storm come close to us.

[NiceAft]

We have no choice but to be on the boat, no hotel around to check into. If there is, we will. I will lower the mast as a precaution. Middle of the week. I am told there are many open slips, so no taller boats around. I’ll let you know the results, or where to send flowers to.

[DaveC426913]

Curious. Does anyone have any statistics on sailboat lightning strikes?

How often does it happen?
What damage occurs (obvs electronics)
Any injuries/deaths?

[Jimmyt]

A few YouTube videos for discussion's sake... The first two go to the question of what typical damage is. The third is likely snake oil.

[OverEasy]

Hi NiceAft,

So no one wants to be called “Sparky” right?

I think JimmyT (and the others) has the right idea in not working around anything metal and tall within a couple miles of a lightning storm.
By the time you see-it/hear-it “it’s” too close (IMO).
Time to stay away!

In the Marina lowering the mast from the mast pivot plate would have the top of the mast in the slipway and pose a possible hazard to others safe operation.

Statistical Odds are pretty darn low that any one individual boat gets hit by lightning.
So there is that to have some comfort in.

The challenge from my perspective is not the lighting hitting a particular boat but the subsequent Electro Magnetic Pulse (EMP) that will affect every boat’s electronics particularly if there is a length of conductor connected to it ( which is just about everything connected to power or antenna or unplugged wire length connected to a device (think of the wire between a switch to the device).
What? Yup, just about all of it is susceptible to an EMP.
What determines IF there is damage is a whole bunch of seemingly random aspects such as distance from strike (the EMP effect decays at roughly the square of the distance (meaning it decays quickly the further away from the strike), the length of the conductor connected (the longer the conductor the more it picks up), the frequency of the pulse ( lightning is actually a rapid series of pulses at no set frequency per-se), and earth ground potential.

From an Engineering perspective when confronted with an impending lightning event and valuable or difficult to replace electronics is to do is to:
1) Turn off and physically disconnect all devices from power and antennas
2) Where possible (like with our Garmin GPS chartplotter and VHF Radio) we remove it from the boat and bring it (home) with us.
3) Install fuses or circuit breakers at or below the rated amperage for the device (yes there may be nuisance trips but the lower the fuse or breaker trips the better)

While there are lighting surge protection devices such as one would put in your home AC electrical panel but those require a hard ground connection to work and would only apply is you had an AC power connection to shore power but that would only protect you from a EMP surge coming from the shore power source, not from an EMP sensed onboard.

There are some lightning suppression systems that attempt to actively balance out the electrical charge potential between the vessel and atmosphere. (Lighting is static electricity and can be earth positive-sky negative or vice versa.) How a system would actively sense a local build up of charge potential fast enough to activate and then be able to locally reverse or dissipate it is beyond me.

There are great passionate theoretical arguments for and against “grounding” ones mast to the water via chains from the stay cables.
From a Design Engineering perspective lightning is a lot of voltage and a lot of amperage at the same time pretty much all at once.
The cables are SST (not a stellar conductor and there are at least four connections with about 6 cables) and the mast is aluminum (great conductor almost as good as copper). “IF” one were to ground I would be inclined to ground directly at the mast with a ‘O’ gauge copper cable several yards deep in the water. BUT DOING THIS WOULD MAKE YOUR MAST “THE PREFERRED LOCAL TARGET”.
So that means yours is the target and your stuff is closest to the EMP source.

So, clear as mud huh?
Which is why we prefer to disconnect and remove.

Stay safe or if you prefer should we start calling you “Sparky”? or “Sparks”? or “Sparkles?” or “Tingle Toes”? or “Twinkle”? or “Zap”? or …….

[Jimmyt]

We have no choice but to be on the boat, no hotel around to check into. If there is, we will. I will lower the mast as a precaution. Middle of the week. I am told there are many open slips, so no taller boats around. I’ll let you know the results, or where to send flowers to.

I see your problem more clearly. Maybe you could go to a restaurant, mall, movie, etc during the storm. Statistically, you're fine. But, if you know it's tornado weather, you don't shelter in a trailer park (pardon the dramatic analogy).

Take care. Be safe. Have fun. Make your decision. Your boat, your rules.

[OverEasy]

Here's the good news and the bad. According to reports from our BoatUS Marine Insurance claim files, the odds of your boat being struck by lightning in any year are about one in 1,000.

[Highlander]

Ray many yrs ago I was coming into Owen Sound Marina in Geogain Bay ON, during a pending thunder storm thunder & lightening all around us I was heading down the channel to the nearest unloading spot which was the boat launch ramp so as we could all deboard 8 people from the boat just as we were approatching the ramp a 40ft sail boat with about a 75ft or larger mast coming in behind us we heard a big crack of lightening right above us just as we were looking up then bang a big exsplosion on top of his mast that then arched over to the light post beside the boat ramp then another bang the light on the post exploded then arched over to the marina building about a 1000ft away the arch of lightening then hit the end wall of the building where the hydro entered the building another exsplosion & the building caught fire , when the lighening hit the sail boat we were smack in the middle between the sail boat & the light post which was approx 30ft above the water line their were approx 25ft on either side of me my fishing boat was a 22ft Alum cubby cabin with two 16ft outriggers up in the air so i,d say that light post became my sacrifcial lamp so to speak talk about having horse shoe,s up my butt lol
people on the sail boat were all ok but all his electronics & diesel engine were fried as well as a electrical fire which they were able to extinguish , they threw us some lines & we helped them tie up to the wall awaiting the fire dept.
so i guess u really don,t know how u r gonna luck out in that kinda situation kinda like drawing straws !
I,ve had a few close calls with lightening maybe I,m anti-static or lighten neutral
I,ve had events where the hair on my arms would b standing straight up & kinda dancing or run my hand thru my hair while I,d hear a crackling sound on top of my head & get a static shock , had a few times when my shrouds were making a humming crackling sound like a radio loosing it,s station it was like my shrouds were radio speakers

Now that,s when u should go out & buy a lotto tckt
Anyway I,ve come to the conclusion it,s best to slip , dock or moore next to boats with taller mast than ur,s so far it,s worked for me
BTW my boat got hit during a lightening storm in my drive way with the mast down after the storm I went out to check on the boat as we had a big bang really close to the house anyway found that the main breaker on the boat had trip tried resetting to no avail then check my house main panel found the circuit breaker had tripped also so after further investigating found my 8ft fiberglass VHF antenna was fried & my 110vlt 30amp plug on the boat was fried also so got lucky their also !, so mast down did not help me their not sure if the lightening hit the trees around my boat first ? .
I,d say ur best bet Ray is to invite someone over to ur slip u don,t like & say can u help me hear for a little while give that person two alum poles wet one with water & tell them to hold it up in the air while holding the other one in the water then say I,ll b back shortly just going to get us a bottle of wine to celebrate ur up coming demise !
Cheers J