Weird Effects of Lightning Strike

[GordMay]

Originally Posted by garyfdl

I think you're right and I'll go one step further... you can hear it! It sounds like a compressed air leak...

If your hair [arms, neck, head] begins to stand up, you [yourself] may be in danger of an immanent lightning strike.

[garyfdl]

Originally Posted by GordMay

If your hair [arms, neck, head] begins to stand up, you [yourself] may be in danger of an immanent lightning strike.

I've heard that as well and agree. Fortunately that (I'm happy to say) hasn't happened (yet).

[garyfdl]

Originally Posted by bdgWesternMass

I wonder if that hiss is steam.

No idea. But given the high humidity preceding T-storms it very well might be.

[GordMay]

Originally Posted by garyfdl

I think you're right and I'll go one step further... you can hear it! It sounds like a compressed air leak...

Originally Posted by bdgWesternMass

I wonder if that hiss is steam... I also wonder if the through-hull was opened by steam pressure build up.

Brontophonic sounds [Greek: thundersound], which are heard far less frequently than thunder, can give lightning a unique hiss, separate from the deep rumble of thunder.
Thunder travels at the speed of sound, and is usually heard several seconds [5 second for every 1 mile] after a lightning flash, but brontophonic sounds are perceived [more or less] at the same time as the flash.
One theory is that brontophonic sounds come from induced charge. The same potential difference that generates a lightning stroke, may create smaller pockets of electric charge, in the surrounding area. These may be strong enough, at the instant of the lightning, to make crackling electrical sounds, similar to static electricity discharge [or the hissing of a red-hot iron in water, or the tearing of fabric].

[Hartleyg]

Lightning fun!

I spent my working life building and maintaining mountaintop (and buildingtop) radio communications sites. In the desert Southwest, some of these sites get hit with lightning dozens of times a year, and the effects can be startling.

The "Hiss" you hear just prior to a local strike or simultaneous with a nearby strike is corona noise - the charge in the cloud is attracting an opposite charge on the ground below it, and when the difference is great enough, almost any vertically pointed object (trees, masts, flagpoles, upraised fingers) will begin to start a corona discharge, including the formation of "strike leaders", which extend from both the ground and cloud. This effect can also occur when lightning is not happening. At night or under dark clouds, the corona is visible - on sailboats, this is called "St. Elmo's Fire".

Once the strike leaders connect, the full strike occurs along the ionized path established by the leaders - sometimes with multiple arcs - high speed cameras have caught up to 43 sequential strikes along the same path!
The end result of the extremely high energy discharge can be astounding - and very non-intuitive, with odd burn patterns and damaged/undamaged equipment.

The best protection for your equipment (and boat) is two-fold: first, offer the lightning strike energy a low resistance (and preferably low cost!) path - a grounding electrode for your mast, for example, and by connecting your metallic shrouds to the same grounding electrode with appropriate wire/cable/strap. (or by directly connecting them to their own electrode) The thing with sharp corners is absolutely true - a sharp corner adds inductance, which is resistance for rapidly-changing current flow. Stranded wire is more inductive than solid, and the lowest inductance is solid flat strap or tape (which is why these are used for radio grounding).
Second, you can implement surge protection for your electrical systems. The sort of "surge protection" found in outlet strips and the like may help, but you can install what are called "whole house" protections, preferably where your shore power enter the boat, as most AC-related lightning damage comes from surges induced outside of your vessel. Wiring and RF cables from your masthead or other areas of your boat can be run through surge arrestors (of appropriate voltage) that are connected to your mast grounding electrode.

Hartley
S/V Atsa

[team karst]

Sounds like fun mr hartley

Did u experiment with horizontal grounding electrodes up in the mountains?

[Hartleyg]

Team karst,

Yes! At sites where the soil coverage was limited, it was common to use either surface or slightly buried copper cables as a grounding electrode. In much the same manner as boats, the capacitive ground definitely added to the performance.
The biggest factor in ANY site lightning protection scheme is bonding the site together - that is, to have a common grounding point, buss or ring (depending on the size of the site) that is connected to every piece of equipment, surge arrestor, etc. and of course the grounding system.
Every conductor entering the facility (antenna cable, power, telephone, etc.) should be equipped with a surge arrestor device.

Hartley
S/V Atsa

[tomtriad]

My hiatus gas been struck by lightning 3 times. Each strike was at the Metz masthead antenna and coursed through the wiring garness blowing all the fuses and frying all the instruments. Exited through the knotmeter and depth transducer. First strike exited through the hull from battery ground cable, leaving a football sized hole; the amas kept her afloat. Metz whip always knocked out but not vaporized - usually kanded in cockpit.

Suspect the can fell on the ballcock handle knocking it ajar.

Lightning us the boss. It goes where it wants to find ground.

[MicHughV]

I've sailed thru' countless lightning storms, but I've only been hit by lightning one time...and that was many years ago.

I still had a steel boat back then. There is no mistaking a lightning strike. The noise and light will be insane.

I had shut everything off....all the electronics.

I suffered no equipment damage, but for about 30 minutes or so, I was unable to touch any of my electronics (vhf, instruments, etc) due to immense static electricity build up.
Touching any of this equipment resulted in a rather heavy shock.

After about 30 minutes or so, everything was fine again.

I rather suspect that having a steel hull provided ample ground for the strike, thereby minimizing damage elsewhere.

[GordMay]

You’re more likely to survive a lightning strike if you’re doused in rainwater.

An experiment [1], that involved blasting fake human heads with electricity, found that water stopped around 33% of the lightning’s energy from entering the brain cavity, potentially lifting one's chances of surviving a lightning strike, by 70-90%.
But, of course, the best way to avoid being hit by lightning is to get indoors.
That's the conclusion [1] arrived at by a team of scientists who built fake human heads, zapped them with powerful bolts of electricity, and measured the results. The fake heads that had been soaked in water featured significantly less damage and lower internal exposure to electrical current.
Another study [2] found that wet victims survived lightning strikes more, frequently than dry ones because when a flashover occurs along the whole body, the probability of survival is higher than 50 per cent.

More about ➥ https://www.sciencealert.com/science...ightning-storm

[1] “Rain may improve survival from direct lightning strikes to the human head”~ by ens Haueisen, René Machts, et al
➥ https://www.nature.com/articles/s41598-023-50563-w

[2] “Lightning injury caused by discharges accompanying flashovers—a clinical and experimental study of death and survival” ~ by Masajiro Ohashi et al
➥ https://www.sciencedirect.com/scienc...768?via%3Dihub

[sealandsky]

With posts thus far being from sail boaters sporting a natural lightning rod, I'm a power boater and on our Chris Craft Catalina 480 am in the final stages of installing what i hope amounts to "lightning protection". 1) installed a new Sea View radar mast to accommodate my closed array radar, starlink flat panel antenna, sirius/xm antenna and a real-life aluminum and very pointed lightning rod. Attached to this rod is 4 gauge cable, which runs with only 4 bends to a lightning dissipation through-hull plate. 2) We have an aluminum welded pipe hard top on our fly bridge and we ran a second 4 gauge cable with only 3 bends to the same dissipation plate. The aluminum hard top almost resembles a Faraday cage. the one thing I need to remember is to lower the 2 very tall radio antenna's as they are about 6 feet taller than the lightning rod. Launching in 3 weeks and I hope it works!