Lighting protection

[Ixneigh]

For all the people who had close strikes: how many have the mast head ss whip radio antenna?

Ix

[Jherrell]

Hi, Everyone.

I'm Chip from here in Havre de Grace, MD. First time posting after lurking for a few years. Not sure how this post will work out, but here goes....

So, I have a 99 X that I've had for a few years, and I've decided to do a complete overhaul to include the electrical system - wiring, lights, batteries, so forth.

One of the things I'm terrified of is lightning on the water, and I've been reading everything I can on the subject. After a lot of thought and having a little bit more knowledge of the behavior of lightning, I've come up with the idea of bonding the mast with 4 gage wire, running it down the center board tubing along with the rope that lifts the centerboard, and then splitting the cable in the center board well and join (silver solder) each end to a 1 1/2" x 1/16" x 12' copper strap, running fore to aft, and fastened to the hull on each side of the center board. Essentially, I'd have two copper straps fastened to the hull on each side of the center board and running parallel with one another.

Considering lightning likes to travel in straight lines and following the least resistance, there would be a straight run from the top of the mast, down through the center board tubing and then to the copper straps along the hull of the boat. My mind's eye tells me lightning would like that arrangement, and I'd have reduced risk of side flashing off the rigging. ...Not eliminated, but reduced. The increased risk would be from being near the center board tube in the interior, but maybe I can further reduce risk by wrapping it in insulation.

Anyway, just wondering if anyone has an opinion on that?

[Neo]

Hi Chip,

Your contribution to this forum is greatly appreciated.

Lighting is not a theory but discussing it's behaviour is.... so in reality no one real knows exactly what will happen in any given (complex) situation.

Your project is well-thought-out ... except.....
1. It needs to be a heavy gauge copper wire (strap) to cope with the possible intense level of momentary current. If your wire is not thick enough it will vaporize in the 1st pico second of the strike.... and then the lightning will move on to vaporizing your mast in the 2nd pico second
2. Heavy gauge copper wire puts a lot of undesired weight high up on your mast .... This will definitely impair your Macs ability to sail upright
3. Yes lighting takes (and is attracted to) the "path of least resistance" but have you considered that you are raising that "point of attraction" 12 meters closer to the clouds? ... It's kind like "provoking a strike" (by 12 meters) which your whole boat will suffer if your conductor is not capable of coping with those nanoseconds of high current.

Personally I think our Mac's have the biggest advantage of all other yachts .... We can lower our Mast quite quickly even when we're on the water. Some might see this as a dangerous activity in a pending storm ... but honestly nobody really knows

[Jimmyt]

I agree with Neo. I wouldn't give it a good, grounded target. Also, if you get a direct hit, I'm not sure anything can protect you. Best to stay out of that sort of weather, and stay away from your standing rigging if you get caught in it.

What I have observed is; it doesn't always hit the tallest target; it will instantly vaporize small conductor - leaving the insulation hollow; even if it has a path to ground, it will still start a fire and wreak all sorts of havoc.

I have some experience with it...

[NiceAft]

Chip,

First off, welcome.

Did your research include doing a search on this site?

If not, go to the search area (upper right side of page), and type in lightning. You will get a wealth of information.

To put it in a nutshell, nothing works. Pray you never get hit. The best lightning plan is not to be near any lightning.

[Neo]

I have some experience with it...

Sounds like an electrifying experience Jimmy

[NiceAft]

Courtesy of BOATUS.
https://boatus.com/expert-advice/expert ... ning-facts

https://www.boatus.com/expert-advice/ex ... -lightning

[Starscream]

Hi, Everyone.

I'm Chip from here in Havre de Grace, MD. First time posting after lurking for a few years. Not sure how this post will work out, but here goes....

So, I have a 99 X that I've had for a few years, and I've decided to do a complete overhaul to include the electrical system - wiring, lights, batteries, so forth.

One of the things I'm terrified of is lightning on the water, and I've been reading everything I can on the subject. After a lot of thought and having a little bit more knowledge of the behavior of lightning, I've come up with the idea of bonding the mast with 4 gage wire, running it down the center board tubing along with the rope that lifts the centerboard, and then splitting the cable in the center board well and join (silver solder) each end to a 1 1/2" x 1/16" x 12' copper strap, running fore to aft, and fastened to the hull on each side of the center board. Essentially, I'd have two copper straps fastened to the hull on each side of the center board and running parallel with one another.

Considering lightning likes to travel in straight lines and following the least resistance, there would be a straight run from the top of the mast, down through the center board tubing and then to the copper straps along the hull of the boat. My mind's eye tells me lightning would like that arrangement, and I'd have reduced risk of side flashing off the rigging. ...Not eliminated, but reduced. The increased risk would be from being near the center board tube in the interior, but maybe I can further reduce risk by wrapping it in insulation.

Anyway, just wondering if anyone has an opinion on that?

Hi Chip, and welcome.

There are lots of thoughts about this. I decided to not do anything based on the numbers: with maybe 15,000 Macs out there, I've only ever heard of one being hit by lightning. And that one was out of the water at the time.

Plus, lightning protection on a Mac isn't the same as on a real keelboat. Doing things half-way may actually make a lightning strike MORE likely, and possibly the damage more likely too.

To make a yacht "safe" during a strike, it needs to have what amounts to a complete Faraday cage, with gauges and angles and material and locations all in sufficient size and quantity. Otherwise you are just changing the strike path, not creating a safe one. With a gigavolt coming down the mast and rigging the only way to make sure it goes into the water is to engineer a real Faraday cage for the yacht and its occupants. In my opinion, it's hard to properly protect a Mac, and if the design has any weak points...then side flashes are inevitable.

Another school of thought talks about bleeding off the charge that initiates a strike, by using diffusers at the top of the mast. That is not a proven science and there is lots of discussion and controversy around sharp points and multiple sharp points, and grounding plate area, and plate gauges. So much controversy that I'm almost sure that whatever I do won't be perfect and may make things worse.

Maybe an alternative is to save up for that 90HP and get outta dodge when it's time to go?

[Jimmyt]

I have some experience with it...

Sounds like an electrifying experience Jimmy

Somewhat

Hit the top of my chimney cap, caught the framing on fire, vaporized the wire for the deck lights.





We got a vent-free gas fireplace and eliminated the chimney, eliminating a 2 ft x 6 ft metal target from the roof. Since the Admiral is an EE and designs lightning protection (among other building systems), she had lightning protection installed during the rebuild. The system terminals only extends about 12" above the roof, so, I figure we were going to get hit anyway if it was that close. The grounding grid system uses an open-braid copper conductor. She also added sugar suppression to our electrical and electronics entrances.

The house next door is at least 15 feet taller than ours, and there were numerous taller trees it had to dodge to hit the chimney.





I like Starscream's approach. "Maybe an alternative is to save up for that 90HP and get outta dodge when it's time to go? ". Right there with you, man!

[Jherrell]

I'm definitely not hung up on the idea, and I have done enough reading and research on the subject here and elsewhere to know that there is no solution to lightning strikes. It's a fickled, seemingly random, natural event that can't be prevented. My thoughts on it were - If it can't be prevented, then why not give it the easiest path to follow? No sharp corners. Just a nearly straight run from the top of the mast down to the straps to discharge, and hopefully it won't seek a more desirable path through the hull. From what I've read, you really can't tease it out of the sky regardless of the grounding system you have in place. It's going to strike using it's own criteria.

One of the reasons I got the Mac was the ability to run if you had to, but my fears come from the thought of being sound asleep on the hook at 2am when a 10% thunderstorm forecast materializes into one of those unexpected "holy crap" micro storms. I like the idea of the Faraday cage, and I will either build one or just use the microwave to store cellphones or hand held radios in case everything else gets zapped. I just keep having these thoughts of a hole blown in the hull, all the electronics burnt up, and the motor inop. I don't want to pose for a picture like Roger did with everyone standing on top of that Mac demonstrating its floating capabilities. Maybe the best solution for me is a dinghy, a bag of Cheetos, and a 12pk in case of a holing.

Awesome comments and insights. Thanks. I think I'm going with the "Do nothing" COA.

Can't wait to get her in the water this year after nearly 10 years on the trailer, but wow, almost everything needed to be replaced or refitted, and I still have a ways to go. This Mac was already Gucci'd-out for its time when I bought it - thru hull marine A/C system, on demand hot water with water pressure system, about 500Ah of AGM batteries, an in-mast Facnor furling main, built-in Honda generator, and a coveted Vetus bow thruster to name a few. Unfortunately. much of that had to go or be replaced, but she'll be in the water no matter what. Hopefully, we'll meet some of you out on the Bay this year.

Cheers!!

[Inquisitor]

Someone else in another thread mentioned (Emily and Clark's Adventure) YouTube videos. I saw the following video and it helped explain the issue and the goal. I'm not qualified to say if he is right. https://www.youtube.com/watch?v=PurMG7KHdW4&t=1200s

The CliffsNotes
The lightning protection devices, brushes at the mast top, grounding to the water are not about transmitting the actual lightning strike. They are to dissipate any charge build up in the boat so that it is no more a desirable target than the surrounding air. As such, they don't need to be the very thick copper gauge above... they are simply transferring milli-Amps at high voltage over a LOT of time.

[Inquisitor]

We could do a group buy and cut cost down to $4.


https://www.amazon.com/YXQ-Stainless-Lo ... B07CGM3X1B

[Jimmyt]

I'm definitely not hung up on the idea, and I have done enough reading and research on the subject here and elsewhere to know that there is no solution to lightning strikes. It's a fickled, seemingly random, natural event that can't be prevented. My thoughts on it were - If it can't be prevented, then why not give it the easiest path to follow? No sharp corners. Just a nearly straight run from the top of the mast down to the straps to discharge, and hopefully it won't seek a more desirable path through the hull. From what I've read, you really can't tease it out of the sky regardless of the grounding system you have in place. It's going to strike using it's own criteria.

One of the reasons I got the Mac was the ability to run if you had to, but my fears come from the thought of being sound asleep on the hook at 2am when a 10% thunderstorm forecast materializes into one of those unexpected "holy crap" micro storms. I like the idea of the Faraday cage....

Chip,
Your boat, your rules. Lot of varied experience (and knowledge) here. In the end though, you're the Captain. If you want to build a grounding system, Faraday cage, or even a flux capacitor; as long as you post about it, we'll be cheering you on!

Lightning is a fickle beast. A guy down here got picked off running in a center console boat with his family, miles away from a thunderstorm... The old adage that says, "if you can hear it or see it, it's close enough to strike you", seems to be true. And you are correct; the weather forecast is, at best, an educated guess.

Do what you think is the best thing for you and your crew.

Jim

[Jimmyt]

We could do a group buy and cut cost down to $4.


https://www.amazon.com/YXQ-Stainless-Lo ... B07CGM3X1B

Looks like something I'd use to clean my guns...

[Inquisitor]

We could do a group buy and cut cost down to $4.


https://www.amazon.com/YXQ-Stainless-Lo ... B07CGM3X1B

Looks like something I'd use to clean my guns...

Good lord have mercy... 30mm - You using that cannon for varmint?