Lightning

[Hippocampus]

We’re thinking of spending time on our next boat, a trawler, in the Florida keys and Bahamas. Areas we’ve not fully seen. When spec’ing our last boat read the Florida professor who is the guru on lightening protection. Given we can’t afford a LRC in Al and don’t have experience in Fe so it’s likely to be GRP. Have spent a scary week off the Bahamas when hove too to escape weather. Lightening all round us every day and night the whole time. Just waiting for a nearby strike and lights out on the electronics. Know FLA is a high risk area.
For sailboats multis are at much higher risk than monos. For power is there any general rule for which boats or type of boats are at higher risk?
Non electronic devices and engines with no electronics have better survivability. Do people let that direct their purchases if they cruise those areas?
Do people routinely carry portable gps/radios and place them in a faraday box like the oven only taking them out if there’s not any threat of strikes or build a small faraday box for storage and leave them there? Are any commercially available?
What if any mitigation systems do people employ? What the professor wants for money is huge and other devices apparently have little effect. What’s your read on this? Worth doing anything?

 

[rgano]

Bob Austen installed his electronic in such a fashion that all antenna and power leads could be disconnected as thunderstorms approached. I pull the plugs of all electronics in my house when gone or if thunderstorms approach when I am home. I used to place my handheld VHF in an ammo can. Never had a micro-processor controlled engine and would likely not buy a boat with one. Nowadays I switch off the breaker to the pier when storms approach to protect the lift motors and battery charger from spikes. Boat is under a metal roof; sooo? On my wooden trawler I ran a large diameter copper cable from the lightning rod at the top of the mast straight down with slow curve to a ground plate in the hull and bonded everything else I could to it, including iron fuel tanks. And then I prayed not to get hit.

 

[Chrisjs]

We did the simple things. We carried back-up radios (hand-held), back-up GPS (hand-held), and turned off as much as practical at the main breakers, especially navigation, radar, and radios. We also lowered the radio antennas. Then try to stay below decks. Obviously, your ability to control things depends on whether you are underway or anchored (preferably near a sail boat).

 

[Ski in NC]

Definitely avoid common rail or otherwise computer controlled engines. As part of my business I do failure investigations and if you have an electronic diesel and get a lightning strike, that engine is dead. And pretty expensive to fix. And the strike does not need to be on your boat. In a marina three or four boats away it still killed lots of computer stuff.

That was one reason on my boat I selected an old skool mechanical diesel. I might lose all my nav gear, but boat will still go. If I am still kickin, that is.

I carry a coil of #6 wire with both ends stripped and bushed out for like a foot. One end well above the radar in the air. Get in storm risk and throw the other end in the water, even dragging it if in motion. I have no idea if it will work if I get hit. Better than it hitting the radar, I think.

I think if you got twenty lightning experts in a room and queried their opinions on how to protect a non-conducting (al or fe) boat, you would get twenty different opinions.

 

[rgano]

On my trawler I had one of those stainless brush things on the top of my mast attached to the large diameter cable running to the ground plate. I think the brush is advertised as a "static dissipator," but I figured why not let it do double or whatever duty it would perform up there. Nowadays the Pilot stays under cover in poor weather or scoots home as it approaches.

 

[Hippocampus]

Heard mixed reviews on dissapators. Some even think it increases your risks.
Any thoughts on bonded v unbounded boats?
Any thoughts on Marelon v bronze thru hulls?
Cored v solid grp for pin hole leaks?
Any thoughts on which brands or types of trawlers make out best?

 

[Pete Meisinger]

Wait..What??

pete

 

[oscar]

Obviously, your ability to control things depends on whether you are underway or anchored (preferably near a sail boat).

You aren't controlling squat. And that sailboat theory is also urban legend. Your big masses of engine(s) are MUCH more interesting to the "path"......

 

[Hippocampus]

Does chain rode when your anchor is out have any impact? It’s a direct path to ground. The professor says lightening hits from above then spreads in the salt water in a zone from the surface to ~1-2’ below the surface not getting much deeper if I recall. We chatted and he wanted to build a “cone of protection “ with a host of small plates near the waterline fed by a lightening rod up high. Apparently for towers, bridges, skyscrapers, some farm equipment lightening is also a big deal. For small grp boats side flashes inside the air space contained by the boat are a problem even when there’s an outside path to ground. Dry air is a poor conductor. Does running the AC or a dehumidifier make a difference?
Here’s his site
http://marinelightning.com/

 

[kchace]

I have read every bit of information I could find about boats and lightning and have never seen any information about any proven technique to prevent a lightning strike.

https://www.boatus.com/seaworthy/magazine/2016/january/lightning-protection.asp

Here’s one article but there are many...

Ken

 

[HiDHo]

Our only lightning strike was on our Cape Dory 28 sloop kept in the St. john’s river on a three point mooring out from our dock. The insurance surveyor classified it as damage from a “Lighting Side Streamer “. “ A direct hit to the 44’ aluminum spar would have sunk her according to the surveyor, with a large hole blown out directly below the spar”. The path was to a base loaded vhf antenna, down the spar thru the CD’s robust grounding system to all the Bronze Spartan sea cocks. The electricity etched beautiful fern shapes patterns into the bottom paint around each seacock going to river ground. It also jumped the air gap to a Danforth anchor stowed in our starboard cockpit seat locker and burned and crystalized a 6” diameter hole thru the locker side 1’ above the waterline and then to ground. Starboard midship at 1’ below the waterline a burned and crystalized 3” x 12” hole to ground. All the cockpit instruments fried including the disconnected coax and power cords for the vhf radio. The lightning shock wave had every hinged door ajar inside. Even though we had a hole below the water line the crystalized f/g gel coat and matting kept flooding water out till I hauled out the next day. The only part of my “static disapater” on top the spar that was left was 3”” stub of the rod and mounting screws !
I think the only protection is good insurance.

 

[rgano]

About the best you can do is to prevent EMF damage from nearby strikes. I don't think any but steel vessels stand much of a chance against one of those thigh-thick killers directly striking.

 

[HopCar]

Just anchor near a sailboat. God will strike the sailboat with lightening, as he should, and leave you alone. ��

 

[jleonard]

We had a strike in our marina several years ago and like Ski said 4 or 5 boats were affected. Some of the boats had all of their bronze they hulls get dezincified. The rest had some of them dezicified.
One boat lost 1 ac unite and both electronic brains for their crusaders. Also blew out most of the electronics.
One boat had arcing from 2 swim platform brackets and they had to be replaced.
I know of two tjer friends of friends boats that got hit and in both cases all of their thruhulls lost their zinc.
One if those boats had the wire brush thing that I now call a lightening attractor. Lol

 

[Hippocampus]

Unfortunately that’s not true. We were in Norfolk. Us (65’ mast), cigarette (maybe highest point 5’ ) fancy center console with 4 -300 or 350 hp outboards off his stern on next finger maybe 20’ away max. T top with antennas and radar on top but maybe 15-20’ at most. We were at dinner. Came back the finger was tilted and the 40’ center console below the water. Later told a pop up Tstorm came through. Nobody saw any direct strikes in the marina but there were strikes in the channel to come in. So as another poster said you don’t need a direct strike to destroy a boat. We went through our vessel carefully and no damage although we did no special prep.

 

[mvweebles]

I asked Steve D'Antonio about lightening protection. My understanding of his best thinking was to install a robust bonding system with oversized wire connecting the underwater bronze components.

https://www.proboat.com/2016/04/3530/

Peter

 

[guy with a boat]

Think about the current-carrying capacity of various wire sizes and then imagine the conductor size that would be required to send a lightning strike from the mast down into the water. Seems like trying to drain your swimming pool through a drinking straw, but less likely to work.

 

[Lou_tribal]

My take is that there is nothing different from a house if the lightning strike your boat. Current will follow the least resistant path to earth so the principal of lightning rod like for a house like Ski mentioned should provide some protection against direct strike.
Of course this is supposing that the lightning hit the rod, what is not he case for secondary strike or collateral damage.
And by some protection I mean against major damages not electronic which I don't care as I have barely any.

I have been caught once in a big storm in the middle of a lake and I swear I wished to have a lighting rode!!!

L

 

[dennismenace111]

We’re thinking of spending time on our next boat, a trawler, in the Florida keys and Bahamas. Areas we’ve not fully seen. When spec’ing our last boat read the Florida professor who is the guru on lightening protection. Given we can’t afford a LRC in Al and don’t have experience in Fe so it’s likely to be GRP. Have spent a scary week off the Bahamas when hove too to escape weather. Lightening all round us every day and night the whole time. Just waiting for a nearby strike and lights out on the electronics. Know FLA is a high risk area.
For sailboats multis are at much higher risk than monos. For power is there any general rule for which boats or type of boats are at higher risk?
Non electronic devices and engines with no electronics have better survivability. Do people let that direct their purchases if they cruise those areas?
Do people routinely carry portable gps/radios and place them in a faraday box like the oven only taking them out if there’s not any threat of strikes or build a small faraday box for storage and leave them there? Are any commercially available?
What if any mitigation systems do people employ? What the professor wants for money is huge and other devices apparently have little effect. What’s your read on this? Worth doing anything?

Lightning Protection: The Truth About Dissipators. This is the title of an email I received yesterday from Practical Sailor written by Darrell Nicholson, a local South Florida sailor who writes about lightning protection and electrical systems on boats. Check their bookstore at Practical Sailor.com

 

[Joe Pica]

Does chain rode when your anchor is out have any impact? It’s a direct path to ground. The professor says lightening hits from above then spreads in the salt water in a zone from the surface to ~1-2’ below the surface not getting much deeper if I recall. We chatted and he wanted to build a “cone of protection “ with a host of small plates near the waterline fed by a lightening rod up high. Apparently for towers, bridges, skyscrapers, some farm equipment lightening is also a big deal. For small grp boats side flashes inside the air space contained by the boat are a problem even when there’s an outside path to ground. Dry air is a poor conductor. Does running the AC or a dehumidifier make a difference?
Here’s his site
Marine Lightning Protection Inc.

Dr Thompson marine lightning system researcher and designer installed protection on two boats that I've have cruised with. One was witnessed to be struck off the Dry Tortuga's and there was no damage. Inspection of the dissipation cones ringing the hull just above the water revealed tracing indicative of a strike dissipation in a special coating on the cones. He is the real deal having conducted extensive research and testing to validate the protection. Note he is the first to admit that there is no absolute prevention of a strike. His system is simply a Faraday cage protection for the occupants. I've attend two of his lectures ... that were way above my head.

 

[Captain James]

Ha ha funny.

 

[Wayne]

'Lo All, I have had two lightning strikes. My old sailboat had a 65' mast with two antennas on the top. I had a 2" wide copper strip running from the bottom of the mast to a large thru-bolted ground plate. It was never hit by lightning in the years I owned her in Virginia and Florida. However, lightning did strike a piling located about 20' behind her. It was split vertically into three sections. The Celestial had twin VHF antennas, a GPS and radar antenna mounted on a radar arch. Lightning struck one VHF antenna and it looked like a peeled banana - three strips of fiberglass (the covering) splayed out at the base. The center fiberglass rod had a burn mark where the metal antenna center conductor was wrapped around it. All DC electronics where destroyed, but the AC electrical stuff was OK. The electronics technician said that from the base of the antenna, the electrical energy traveled through the ground/shields and (probably) through the engines and props. All fixed underwater gear had #10 ground/bonding wires, which were not damaged.

 

[angus99]

We had a 24-ft Columbia Contender sunk at our sailing club with dozens of pepper-shot holes in the hull. There were several boats with much higher masts on the same dock, but it appears the CC, for some reason, was the most attractive.

BOAT US has some interesting, if dated, stats on boat-related fatalities associated with lightning strikes: https://www.boatus.com/magazine/2013/october/reports-fishing-tops-lightning-deaths.asp. If I'm reading correctly, 14 “general boating” (non-fishing) fatalities over the seven-year study period.

 

[Hippocampus]

Interesting post and link Angus. Always think about attributable risk. From the link the risk would seem quite low. Wonder if deaths are weighted to small boats similar to risk of drowning. Once you get over 35’ or so that risk falls significantly. People are surprised when I tell them I continue to believe my risk of drowning on passages is much lower than when I’m on a continental shelf or in sight of land.

 

[angus99]

Interesting post and link Angus. Always think about attributable risk. From the link the risk would seem quite low. Wonder if deaths are weighted to small boats similar to risk of drowning. Once you get over 35’ or so that risk falls significantly. People are surprised when I tell them I continue to believe my risk of drowning on passages is much lower than when I’m on a continental shelf or in sight of land.

I agree—statistically, it shouldn’t bother me to be in a lightning storm. However, no one has told that to my amygdala.

I’ve toyed with the idea of rigging some kind of standoff to a stout, dedicated 15-ft tall antenna, preferably non-conductive and with no electronics connected. The standoff would have a clip to hold a length of robust conductor with enough weight to hold the end below water. This would theoretically create a viable, low-resistance path to ground outside of the boat. The entire apparatus would stow like any other antenna when not in use, but could be rigged in a few minutes when outrunning a storm isn’t possible. Not sure, however, what would happen to all that energy once it’s in the water and whether it would back feed into the boat via the bonding system.

 

[Transaxial]

Does chain rode when your anchor is out have any impact? It’s a direct path to ground. The professor says lightening hits from above then spreads in the salt water in a zone from the surface to ~1-2’ below the surface not getting much deeper if I recall. We chatted and he wanted to build a “cone of protection “ with a host of small plates near the waterline fed by a lightening rod up high. Apparently for towers, bridges, skyscrapers, some farm equipment lightening is also a big deal. For small grp boats side flashes inside the air space contained by the boat are a problem even when there’s an outside path to ground. Dry air is a poor conductor. Does running the AC or a dehumidifier make a difference?
Here’s his site
Marine Lightning Protection Inc.

Protection from a lightning strike from above is one subject to consider for sure. A different way lightning can enter your house, boat or whatever is by way of the power supply lines. I recently had yet another power surge that fried thousands of dollars worth of electronics like microwave, electric range clock, thermostats, battery chargers, and two expensive printed boards for my heating and hot water boiler in my house. Everything has delicate circuit boards in it now. It was hard to find anyone that really knows this field so I tried to figure it out myself. I was referred to one specialist that works in large industrial complexes and he clarified a lot of things in a general way. A "cascading system" with three levels is the best protection and longest lasting. The small Type 2 suppressors, like the Square D SDSA1175 for under $100 is ok but will burn out from one large hit and/or many small hits. Installing a large Type 1 permanent suppressor will "grab" the large spikes without failure, leaving the downline Type 2 and Type 3 suppressors to do the fine voltage regulation. Type 3 are like the power bar type suppressors found in hardware and electronics stores. Don't confuse these suppressors with cheap "protectors" which are just a fuse.

There are hundreds of brands and variations of these suppressors but one I might suggest for a 30 or 50 Amp 120 or 240 volt supply is a Type 1 Square D SDSA1175 (Schnieder Electric) which is rated at 20kA capacity and comes with a green LED to show everything is well (these little ones are not permanent) and which can be mounted directly to the one or two Line wires, one to neutral and one to ground.I am no marine electrician but that is how it worked at my yard. One of these 1175 is about $50 and is a 3x3x3" cube. I think a large Type 1 like a SurgePure 1 or 2 or 3 depending on the level of protection you and your electrician feel you need is a good primary protection. One very knowledgeable electrician that I was referred to suggested to use as big a suppressor as you can afford as your Type 1 at the power source or splitter box ahead of the breaker panels. I had access to a SurgePure Mach 4 1600.It is 347/600 volts and 3 phase but doesn't matter. Just use phase A and C for the two lines. The clamping voltage, which is 1800 volts on this $3,000 unit, can knock off the big power surges coming in that could destroy a smaller unit and the 1800 volts getting through can be handled by the next two suppressors in the series. This Mach 4 has a Voltage Protection Rating of 1200 volts Line to Line and 1800 volts Line to Neutral. Total surge capacity of all 5 10 gauge leads is 560,000 amps. On land these suppressors all need a direct route to a good ground. So on a boat with a large steel keel is this adequate for a ground? He says NOTHING will save you from a direct hit but something like this should "grab" most damaging surges without failure.

I have not heard much regarding surge suppression on boats other than it was mentioned in the above link. This is really a different thing involving shore power probably. I hope this sparks some discussion on protecting boat systems. Another angle to this surge suppression is that every day, all the times your lights dim or surge brighter you are getting voltage spikes that are slowly but surely killing all the electronics on board. Cleaning up these spikes is a very good reason in itself to look into one or more levels of protection. I believe I have my yard protected on land. Maybe it is time to start on the boat.

 

[timb]

I agree—statistically, it shouldn’t bother me to be in a lightning storm. However, no one has told that to my amygdala.

I’ve toyed with the idea of rigging some kind of standoff to a stout, dedicated 15-ft tall antenna, preferably non-conductive and with no electronics connected. The standoff would have a clip to hold a length of robust conductor with enough weight to hold the end below water. This would theoretically create a viable, low-resistance path to ground outside of the boat. The entire apparatus would stow like any other antenna when not in use, but could be rigged in a few minutes when outrunning a storm isn’t possible. Not sure, however, what would happen to all that energy once it’s in the water and whether it would back feed into the boat via the bonding system.

is it the idea that when the apparatus is vaporized the current will follow the plasma trail?

 

[Group9]

Lightning is funny. In the marina where we kept our sailboat, we were hit once by lightning, and all we lost was our anchor light and mast head VHF antennae (which was vaporized!). But another sailboat, with a shorter mast, a couple of slips over, got hit four times in the same period.

 

[Wayne]

Transaxial - We have a lightning/surge protector installed between our house's meter base and the incoming supply line. Knock on wood, we have never had a surge come into the house. Power company installed it at a cost of $5.00/mo. Seems to work, even when lightning destroyed a transformer just down the street.

 

[Transaxial]

Transaxial - We have a lightning/surge protector installed between our house's meter base and the incoming supply line. Knock on wood, we have never had a surge come into the house. Power company installed it at a cost of $5.00/mo. Seems to work, even when lightning destroyed a transformer just down the street.

Thanks Wayne. I haven’t had my system long enough to know if it works but others in my area have good reports. Do you know a brand or specs on what the power company installed for you? There is a lot of different sizes and specs to consider when you go shopping personally! What you have sounds like a Type 1 since it is installed on the main line before the panel. They must have some experience in this field.