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Lightning "protection"

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exf4gib
1st Mate

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42 Posts

Initially Posted - 05/13/2017 : 04:52:11

Our C-25 purchased earlier this year is kept on a Texas freshwater lake in a location frequented by thunderstorms. While inspecting the keelbolt area after reading Don Casey's book, "Sailboat Electric Simplified", I didn't notice any grounding from the mast to the keel area, as Casey references in his book. Are any of you familiar with this issue and/or are aware if Catalina "builds in" this type of bonding during manufacture, or is this something owners are responsible for fabricating on their own? Our sailboat will soon be pulled from the water for a hull cleaning and painting, a good time to look into performing this "mod" if needed. Thanks!

Arnie W.
85 C-25 TR/FK #4747 "Lifted"

Steve Milby
Past Commodore

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Response Posted - 05/13/2017 : 06:46:18

This is a very complicated question, and the last time we discussed it here, there was no clear answer. Generally it is thought that lightning protection does in fact protect if there is a strike, but it is also thought that lightning grounding attracts lightning strikes to some extent, thus increasing the likelihood of a strike. Some people hook a jumper cable to a stay and drop the end in the water, thinking it provides protection, but it probably doesn't provide much protection, and it might increase the likelihood of a strike. So, it is generally thought that, if you install lightning protection, you should either be thorough about it, or don't do it at all. Being thorough generally means using very heavy gauge electrical wire to tie together all the shrouds and stays and the mast and connecting them all to a very good ground. It would be easier to ground to the older cast iron keels, but not so easy with an encapsulated keel.

None of my boats have had lightning protection, and none have ever had a strike. I live aboard my C&C every summer, and have sailed many boats through severe thunderstorms on the Chesapeake Bay. A friend's C25 was struck in it's slip in Indiana while unoccupied, and it was damaged and repaired. Another friend's 24' Seafarer was struck on it's mooring in Indiana while unoccupied, and a transducer was blown out of the hull and it sank, was re-floated and repaired. I have never known anyone who was injured or killed by lightning on a boat, but I'm sure it has happened.

Personally, I think the actual risk is slight, and I choose to go without lightning protection. I try not to sail when a thunderstorm is likely, but sometimes it can't be avoided. If you sail on a smallish inland lake, an easy solution is to return the boat to it's slip if a thunderstorm threatens, and get off the boat. If you sail on big waters, you often just have to sail through it, telling everyone to avoid touching any metal deck hardware.

For about 15 years I have slept on the boat every night during the summer, often during severe thunderstorms, and now that I'm accustomed to it, it's no more scary than sleeping in my house during a thunderstorm. Whether you live in a house or on a boat, a strike is possible, but not likely. If I sailed and lived in an area where lightning strikes are more prevalent, I might have to re-think it.

Steve Milby J/24 "Captiva Wind"
previously C&C 35, Cal 25, C25 TR/FK, C22
Past Commodore

Edited by - Steve Milby on 05/13/2017 07:04:07

islander
Master Marine Consultant

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Response Posted - 05/13/2017 : 07:07:20

I agree with Steve that installing lightning protection could attract a strike but honestly I feel your chances of being struck is small. If it bothers you park your boat next to a larger sailboat with a taller mast.

ask yourself this, Your boat is an 85. In 32yrs has it ever been struck?

Scott-"IMPULSE"87'C25/SR/WK/Din.#5688
Sailing out of Glen Cove,L.I Sound

Edited by - islander on 05/13/2017 07:10:51

Stinkpotter
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Djibouti
9017 Posts

Response Posted - 05/13/2017 : 10:19:16

Use the Search function above looking for "lightning" in the subject in all forums, and check "Archived posts"... You'll see some long threads.

I know of no manufacturers who build in lightning protection--I presume due to liability risks. Lightning is an extremely fickle and powerful phenomenon that can overwhelm "systems" meant to mitigate it. If that happens to a boat built with protection, is the builder therefore responsible for either "attracting" the strike or providing "poorly designed" protection?

In several events I've known about, friends' boats have apparently been very close to strikes directly to the water, frying their electronics--apparently due to the magnetic pulse surrounding the strike. There was no evidence of the boats or rigs being hit.

"Experts" are all over the map on the best course of action. But as Steve suggests, sailors all over the world sail through thunderstorms without being struck, while boats sitting in marinas, even surrounded by taller masts, are occasionally struck. Some say a person standing in a small runabout is in more danger than someone in a sailboat with a huge aluminum stick pointing into the sky.

So read those threads... You probably won't know what to think when you're done--I'd say nobody does.

Dave Bristle
Association "Port Captain" for Mystic/Stonington CT
PO of 1985 C-25 SR/FK #5032 Passage, USCG "sixpack" (expired),
Now on Eastern 27 $+!nkp*+ Sarge

GaryB
Master Marine Consultant

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Response Posted - 05/13/2017 : 10:50:09

I agree with the others. My boat has been sitting just off Galveston Bay in a marina since it was new and it's never been hit and I know of no one that has.

If you're really worried about it I'd install one of these lightning dissipaters. I've seen them on a lot of boats with taller masts than mine. These allow any static charge that builds up on the boat to dissipate into the air.

https://www.westmarine.com/buy/forespar--lightning-master-static-dissipater--185225?recordNum=1

Also, you might want to look at this site. I just found it after a quick search so know nothing about them.

http://marinelightning.com/systems_build.html

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GaryB
Andiamo
'89 SR/WK #5862
Kemah,TX

Edited by - GaryB on 05/13/2017 10:53:07

Voyager
Master Marine Consultant

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5238 Posts

Response Posted - 05/13/2017 : 22:05:10

The story I've heard time and again is, if lightning hits the mast and has no clear route to ground, it will make its own route and blow a hole in your hull. This will sink your boat.
I've connected the tabernacle bolts to the keel bolts using a piece of #4 AWG solid ground wire inside the head area by the compression post. This is industry standard lightning ground protection for your home electrical power and cable wires. Should be good enough for a boat.

Bruce Ross
Passage ~ SR-FK ~ C25 #5032

Port Captain � Milford, CT

Steve Milby
Past Commodore

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Response Posted - 05/14/2017 : 05:03:51

The reason why lightning protection is a complicated subject is because lightning doesn't behave the same way every time. A bolt of lightning doesn't usually take a straight line to ground. It zigs and zags and sometimes it splits into many separate charges, each of which finds it's own path. The unprotected C25 that was hit at my Indiana marina didn't sink. The strike broke up and smaller elements of it penetrated the hull above the waterline, burning many little pinholes in it.

Many authorities recommend grounding not just the mast, but all the stays, and all the major metal deck hardware, including the genoa tracks, pulpits, lifelines and stanchions, etc. I don't know whether that's necessary or not.

Grounding the system to a lead keel encased in fiberglass doesn't provide a good path to ground. Some authorities recommend installing a grounding plate or similar device to serve that purpose, but, on another boating forum, "The Hull Truth," a member said "Just remember, lightning is very powerful. If it strikes your lightning rod and travels to your ground plate, it may blow that ground plate right off your boat." http://www.thehulltruth.com/boating-forum/24101-grounding-plates.html (See post #7.) I don't know if that statement is true, or if it's hyperbole, but you need to learn more about grounding plates to help you devise a system.

Before you decide to do it, consult the most reliable authorities you can find, to help you devise a plan. Don Casey would be a good place to start, but I would recommend that you supplement his ideas with information from other sources. This looks like another good source. http://www.sailnet.com/forums/gear-maintenance-articles/20124-understanding-lightning-part-two.html If you decide to do it, we would love to hear a summary of your research, and a description of your system.

Steve Milby J/24 "Captiva Wind"
previously C&C 35, Cal 25, C25 TR/FK, C22
Past Commodore

Edited by - Steve Milby on 05/14/2017 05:11:45

Stinkpotter
Master Marine Consultant

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Djibouti
9017 Posts

Response Posted - 05/14/2017 : 09:09:13

quote:
Originally posted by Voyager

...I've connected the tabernacle bolts to the keel bolts using a piece of #4 AWG solid ground wire inside the head area by the compression post...

Bruce's keel, BTW, is the encapsulated lead Steve refers to (as is yours). It would seem a strike to his mast would have to blow some of the rather thick encapsulation off to get to the water from the keel bolts. It might prefer a path from the bottom of his wire, through the hull next to the keel, or who knows where... As I said, there are lots of opinions, but nobody knows for sure.

But in this area, where Bruce and I live, real lightning storms are relatively rare compared to Florida, Texas, or even the Midwest where I grew up. In fact, I often think people around here don't know what a real summer boomer is like--greenish-black sky under an anvil cloud, where you can practically read the newspaper by the almost steady light it creates!

Dave Bristle
Association "Port Captain" for Mystic/Stonington CT
PO of 1985 C-25 SR/FK #5032 Passage, USCG "sixpack" (expired),
Now on Eastern 27 $+!nkp*+ Sarge

islander
Master Marine Consultant

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Response Posted - 05/14/2017 : 11:21:45

So I googled the average tornado's for Texas in a year. They get an astounding to me 127. Maybe your barking up the wrong tree here?

Scott-"IMPULSE"87'C25/SR/WK/Din.#5688
Sailing out of Glen Cove,L.I Sound

Stinkpotter
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Djibouti
9017 Posts

Response Posted - 05/14/2017 : 12:27:30

I see an annual average of 147 for Texas, but per square mile, Florida beats them with 55 in a quarter of the size. Indeed several of our Texas compatriots here have had some wind damage...

Dave Bristle
Association "Port Captain" for Mystic/Stonington CT
PO of 1985 C-25 SR/FK #5032 Passage, USCG "sixpack" (expired),
Now on Eastern 27 $+!nkp*+ Sarge

Edited by - Stinkpotter on 05/14/2017 12:28:17

exf4gib
1st Mate

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42 Posts

Response Posted - 05/16/2017 : 08:53:48

Thanks 'Skipper's' for the excellent feedback! What got me started looking into this was Don Casey's book, "Sailboat Electrics Simplified". Looks like this has opened a beehive, considering the varied responses. Since my C-25 is 30+ years old, has "lived" in central TX her entire life (freshwater only) and doesn't appear to have been struck by lightning, Will keep her in the slip with lots of other taller "sticks" (and hopefully better conductors) nearby when thunderstorms threaten.

Arnie W.
85 C-25 TR/FK #4747 "Lifted"

GaryB
Master Marine Consultant

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4275 Posts

Response Posted - 05/17/2017 : 19:10:42

quote:
Originally posted by exf4gib

Thanks 'Skipper's' for the excellent feedback! What got me started looking into this was Don Casey's book, "Sailboat Electrics Simplified". Looks like this has opened a beehive, considering the varied responses. Since my C-25 is 30+ years old, has "lived" in central TX her entire life (freshwater only) and doesn't appear to have been struck by lightning, Will keep her in the slip with lots of other taller "sticks" (and hopefully better conductors) nearby when thunderstorms threaten.

By chance do you know Fred Lindsey?

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GaryB
Andiamo
'89 SR/WK #5862
Kemah,TX

Voyager
Master Marine Consultant

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5238 Posts

Response Posted - 05/17/2017 : 20:02:23

They say that Tampa Bay is the Lightning capital of the USA. Here in CT we have about 6-10 severe thunderstorms per year. NWS defines a severe tstorm as producing heavy rain and/or hail, damaging winds and frequent cloud to ground lighting.

Bruce Ross
Passage ~ SR-FK ~ C25 #5032

Port Captain � Milford, CT

exf4gib
1st Mate

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Response Posted - 05/18/2017 : 12:24:05

By chance do you know Fred Lindsey?
[/quote]
I do! He introduced me to the seller of the C-25 I purchased earlier this year. Coincidence!

Arnie W.
85 C-25 TR/FK #4747 "Lifted"

GaryB
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Response Posted - 05/18/2017 : 16:34:43

He and I used to be friends back in the late 70's when I had my Hobie 16. I used to go to Canyon every other weekend during summer and he and I got to know each other.

Don't know if he remembers one particular evening sail we had on his dad's Cal 29. We watched a big thunderstorm west of the lake for an hour or more and it didn't seem to be moving so we decided to sail the Cal. There wasn't much wind so it took us a while to get down to the area near LCYC. All of sudden lightning bolts were hitting all around us on the shore and the rain came down in buckets. Knowing the Cal had the tallest mast on the lake at the time and we were in the middle of the lake by ourselves I was pretty scared.

We dropped sail, started the Atomic 4, and headed back to the marina as fast as we could. About halfway back it seemed like we weren't going as fast as I had remembered going in the past so I asked him what was up. That's when he advised the carb was leaking and he was afraid to go any faster! Needless to say I moved a little more forward in the cockpit.

Obviously we made it back OK but that night has stuck with me all these years.

BTW... if you need any help when you pull your boat let me know and I'll bring my mast lowering rig.

Association Member

GaryB
Andiamo
'89 SR/WK #5862
Kemah,TX

Edited by - GaryB on 05/18/2017 16:39:09

exf4gib
1st Mate

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Response Posted - 05/19/2017 : 16:01:30

Quite a story Gary! Next time I run into Fred, I'll mention you to him. Appreciate your offer of help. The folks who're doing the bottom job also included pulling the boat out of the water and removing the mast in their estimate. The marina also has a mast stepper pole and they pulled the mast for me. Now collecting the last of the parts to refit the mast with new lighting, wiring and masthead equipment. Fortunately, wire halyards are in good condition so may not have to replace them at this time.

Arnie W.
85 C-25 TR/FK #4747 "Lifted"

JB0101
Deckhand

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Response Posted - 05/22/2017 : 21:55:20

Really enjoyed reading this thread. Reminded me of a rescue mission I was on somewhere around 1998. We were on a 25ft Safe Boat (aluminum hull with flotation sponsons) at night. Racing to a disabled vessel NW of Key West well into the Gulf of Mexico, we were surrounded by the typical Summer Florida thunderstorms with lightning strikes every 25 to 30 Seconds. Thankfully, the winds were less than 10 kts and we were able to make maximum speed of around 35 kts. As we went under a Thunderhead it became very active with lightning striking all around us. Amazingly it had little or no rain and excellent visibility. Several strikes were within a few hundred yards of our boat. I was contemplating what our safest course of action would be on an aluminum boat, with an aluminum deck in salt water and drenched rain gear (don't think sterns guarantees personal safety against lightning strikes). Possibly not the best answer, I figured I just wanted to get out from under that cell and went with Scotty's famous reply, "I'm giving her all she has Captain". I know that I had nothing to do with my crews safely making it through, I believe that is in the Lord's hands. But, as we punched through, there were three strikes that struck the water within 100 feet of the boat. The strikes made the water glow for about a 50 foot radius around the strike. Very similar to Phosphorus glowing but at a boiling intensity, (I suspect phosphorus was the glowing part). That was a sight which I am extremely thankful to have witnessed all the while thinking this could be the last thing I see.

GaryB
Master Marine Consultant

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4275 Posts

Response Posted - 05/23/2017 : 19:09:51

quote:
Originally posted by exf4gib

Quite a story Gary! Next time I run into Fred, I'll mention you to him. Appreciate your offer of help. The folks who're doing the bottom job also included pulling the boat out of the water and removing the mast in their estimate. The marina also has a mast stepper pole and they pulled the mast for me. Now collecting the last of the parts to refit the mast with new lighting, wiring and masthead equipment. Fortunately, wire halyards are in good condition so may not have to replace them at this time.

If he doesn't remember me tell him I was the guy with the blue and white Hobie 16 and lived/live in Houston. It was probably in the '73 - '75 time frame.

Oh yeah, we were drinking warm Texas Pride beer. LOL
That is the nastiest stuff I ever drank even when it was cold.

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GaryB
Andiamo
'89 SR/WK #5862
Kemah,TX

Edited by - GaryB on 05/23/2017 19:11:40

Stinkpotter
Master Marine Consultant

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Djibouti
9017 Posts

Response Posted - 05/23/2017 : 19:44:19

quote:
Originally posted by JB0101

Really enjoyed reading this thread. Reminded me of a rescue mission I was on somewhere around 1998. We were on a 25ft Safe Boat (aluminum hull with flotation sponsons) at night. Racing to a disabled vessel...

Great story! Was this a USCG rescue? It's hard to describe the power of lightning, or the feeling of being so exposed to it out on the water. The good news is that in salt water, it apparently tends to go directly to the water even in the presence of a metal mast or boat in the vicinity. In fresh water, that changes. I'm pretty sure I've read that while Florida has the greatest density of strikes in the country, the most deaths, injuries, and damage there have been on lakes--not in the Atlantic or the Gulf. (The same thing is true about stray voltage in water around docks and marinas--it kills people in fresh water, but is mostly "uncomfortable" in salt water, where the greatly increased conductivity makes the human body less attractive. (We are, after all, mostly salt water.)

Dave Bristle
Association "Port Captain" for Mystic/Stonington CT
PO of 1985 C-25 SR/FK #5032 Passage, USCG "sixpack" (expired),
Now on Eastern 27 $+!nkp*+ Sarge

Voyager
Master Marine Consultant

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5238 Posts

Response Posted - 05/23/2017 : 20:08:37

I had a very close call with lightning in my 13' Zuma on a Connecticut lake. The wind all but died, the dark clouds overcame us and I was out in the middle as the storm hit. I broke out my paddle and headed towards the nearest shore. I beached the boat in some guy's yard who was out in his barn enjoying a brandy and cigar. He asked me to get out of the rain and join him. Very nice barn - mostly a hangout for rich guy toys.
A bolt came crashing down no more than 50 yards from the beach and the boat, and I figured it would have had my name on it. I later noticed some burn marks on the aluminum spars. Too close for comfort for me.
Of course, 20 minutes later, the sun came out and wind piped up - back on the boat sailing...

Bruce Ross
Passage ~ SR-FK ~ C25 #5032

Port Captain � Milford, CT

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