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Old 13-07-2021, 08:54   #31
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Re: Near misses of lighting - use ferrite beads to reduce induced voltage spike?

Lightening is the bane of all water craft. Short of disconnecting everything and storing in a Faraday cage there isn't a lot to be done.
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Old 13-07-2021, 17:28   #32
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Re: Near misses of lighting - use ferrite beads to reduce induced voltage spike?

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Thank you for the additional details. I wonder if the Seatalk grounding is considered a "floating ground" in this configuration.

I also am curious if you know if the chassis of the Seatalk devices was grounded.

This real world experience is really interesting to me.

Forgot to add this:


Let's see: Chartplotter, Wind/Depth computer, depth transducer, depth transducer (both OK), wind at masthead, two i70 displays, autopilot display, autopilot, autopilot compass, AIS, AIS antenna, AIS GPS antenna. I think that's it.



I don't know about the chassis. Interestingly, the 3 displays appear to be fine. They were at the end of the run.
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Old 13-07-2021, 18:10   #33
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Re: Near misses of lighting - use ferrite beads to reduce induced voltage spike?

Have you ever heard of an insurance company offering a discount for installing a lightening protection system?

Me neither.
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Old 13-07-2021, 19:56   #34
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Re: Near misses of lighting - use ferrite beads to reduce induced voltage spike?

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Have you ever heard of an insurance company offering a discount for installing a lightening protection system?

Me neither.
A discount? I have heard of plenty insurance companies requiring lightning protection though.
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Old 14-07-2021, 06:30   #35
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Re: Near misses of lighting - use ferrite beads to reduce induced voltage spike?

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A discount? I have heard of plenty insurance companies requiring lightning protection though.
Really? I’ve never had an insurance company raise it. Including Chubb, Pantaenius and Markel.

I think it would be a good thing as it would pressure builders and surveyors to do something. And presumably the insurance companies have loss data about what works - and what doesn’t - such as the scam of those mast top bush things 20 years ago.

What lightening protection did they require?
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Old 14-07-2021, 06:44   #36
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Re: Near misses of lighting - use ferrite beads to reduce induced voltage spike?

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Really? I’ve never had an insurance company raise it. Including Chubb, Pantaenius and Markel.

I think it would be a good thing as it would pressure builders and surveyors to do something. And presumably the insurance companies have loss data about what works - and what doesn’t - such as the scam of those mast top bush things 20 years ago.

What lightening protection did they require?
I still have one of those brushes. It has managed to protect itself through three strikes, no damage to it at all.
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Old 14-07-2021, 06:55   #37
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Re: Near misses of lighting - use ferrite beads to reduce induced voltage spike?

There are two kinds of lightning protection systems.

Type ONE: A purpose installed set of grounding wires designed to help the current generated in a strike find its way out to the water without punching a hole in the hull or exploding a sea clock. Since this is a standard recommendation for how boats should be built, yes, some insurance companies will want to see it. Some surveyors will call out if it is missing.

All Other Types: Scams.

If you are struck by lightning with a properly installed grounding system, the current will travel down your mast, and out into the water. The EMP generated by the current flow will probably still destroy most/all of your electrical system, but at least your boat will be floating.

My insurance company reports about 20 claims a year from lightning strikes, with the average repair bill well over $20,000.
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Old 14-07-2021, 10:34   #38
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Re: Near misses of lighting - use ferrite beads to reduce induced voltage spike?

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Forgot to add this:


Let's see: Chartplotter, Wind/Depth computer, depth transducer, depth transducer (both OK), wind at masthead, two i70 displays, autopilot display, autopilot, autopilot compass, AIS, AIS antenna, AIS GPS antenna. I think that's it.



I don't know about the chassis. Interestingly, the 3 displays appear to be fine. They were at the end of the run.

One more comment: ONLY the network was damaged on these devices. They all power on just fine. But they fail the network connectivity.
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Old 14-07-2021, 14:39   #39
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Re: Near misses of lighting - use ferrite beads to reduce induced voltage spike?

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One more comment: ONLY the network was damaged on these devices. They all power on just fine. But they fail the network connectivity.
Yes, that was what sparked my curiosity. My guess is that the chassis ground did it's job but there is/was a flaw in the grounding of the interconnects.

As long as we are still talking about this... I have a burning question on the topology of the network and any grounding details you can relate.

My guess is that the path to ground was in between the discharge and the failed equipment. The working equipment was maybe on the other side of the ground path?

Yet another total guess but I'm curious.

Thanks,

Ben
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Old 14-07-2021, 15:56   #40
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Re: Near misses of lighting - use ferrite beads to reduce induced voltage spike?

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Really? I’ve never had an insurance company raise it. Including Chubb, Pantaenius and Markel.

I think it would be a good thing as it would pressure builders and surveyors to do something. And presumably the insurance companies have loss data about what works - and what doesn’t - such as the scam of those mast top bush things 20 years ago.

What lightening protection did they require?
No, not for boats. For historic buildings, antenna towers, bridges, lighthouses, power masts, airplanes etc.

For boats they just eliminate coverage step by step until it’s worthless
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Old 14-07-2021, 16:03   #41
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Re: Near misses of lighting - use ferrite beads to reduce induced voltage spike?

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I still have one of those brushes. It has managed to protect itself through three strikes, no damage to it at all.
Static dissipaters require correct installation (electrical path to a grounding plate below the hull under the mast). Even then they don’t provide protection but something more comparable to camouflage. By bleeding charge you hope that the leader forms from something else than your mast.

If your masthead was hit but the dissipater survived it, then this is a strong hint that the installation was flawed.
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Old 14-07-2021, 17:58   #42
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Re: Near misses of lighting - use ferrite beads to reduce induced voltage spike?

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Yes, that was what sparked my curiosity. My guess is that the chassis ground did it's job but there is/was a flaw in the grounding of the interconnects.

As long as we are still talking about this... I have a burning question on the topology of the network and any grounding details you can relate.

My guess is that the path to ground was in between the discharge and the failed equipment. The working equipment was maybe on the other side of the ground path?

Yet another total guess but I'm curious.

Thanks,

Ben
Ben, let me see if I can put this in order:

Chartplotter: 12V supply from panel. It was not plugged in at the time, so nothing could have gone through there.

Wind/Depth computer: 12V supply from panel. Wind part of computer fried. Direct connection of computer to i70, depth displays correctly. Depth transducer connected to computer works fine.

Chartplotter & wind are connected to a 5 way.

ng cable runs to steering quadrant area, to a 5 way.

RM Autopilot and AIS reside here. Both connected to the 5 way, along with the autopilot compass and GPS for the AIS. I think there's a T connector in there too... GPS antenna, fried. Compass, OK. AIS and Autopilot, NG network fried, rest of both units appear to be operational. Both the autopilot and AIS have their own 12V source, as I recall.

From here, a Seatalkng cable runs to the binnacle. 3 displays there. All powered from the Seatalk cable. All OK. End of run.

Radar is WiFi. Own 12v source. Middle band is fried.

Important Edit: AIS was powered during strike. We leave it on to track our boat.
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Old 14-07-2021, 19:58   #43
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Re: Near misses of lighting - use ferrite beads to reduce induced voltage spike?

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Static dissipaters require correct installation (electrical path to a grounding plate below the hull under the mast). Even then they don’t provide protection but something more comparable to camouflage. By bleeding charge you hope that the leader forms from something else than your mast.

If your masthead was hit but the dissipater survived it, then this is a strong hint that the installation was flawed.
Mast bonded to the 4” wide x 1/16” thick copper strips against the hull. Strips arranged port to stud, fore to aft, bonded to chain plates, stanchions, and all standing rigging. All together approximating a Faraday cage and bonded to fore and aft to monster ground plates.

We happen to be the tallest mast in most marinas, harbors, at least where we were struck. You may thank us for taking the hit.

The best we have been able to verify by direct observation is that making your electronics not electrically part of your boat’s wires is possibly the best you can do. Totally isolated devices on Roxy survived all three hits we have taken. Connected stuff was fried. Note my detailed posts above.
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Old 15-07-2021, 03:58   #44
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Re: Near misses of lighting - use ferrite beads to reduce induced voltage spike?

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Ben, let me see if I can put this in order:
Thank you Bill,

I'm working on a topology fo a marine network and this first hand information gives me an idea of what to expect.

You have answered all my questions.

Enjoy your day,

Ben
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Old 15-07-2021, 05:49   #45
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Re: Near misses of lighting - use ferrite beads to reduce induced voltage spike?

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Mast bonded to the 4” wide x 1/16” thick copper strips against the hull. Strips arranged port to stud, fore to aft, bonded to chain plates, stanchions, and all standing rigging. All together approximating a Faraday cage and bonded to fore and aft to monster ground plates.

We happen to be the tallest mast in most marinas, harbors, at least where we were struck. You may thank us for taking the hit.

The best we have been able to verify by direct observation is that making your electronics not electrically part of your boat’s wires is possibly the best you can do. Totally isolated devices on Roxy survived all three hits we have taken. Connected stuff was fried. Note my detailed posts above.
If there is a good electrical connection between dissipator and a submerged grounding plate then the dissipater did all it could. Once lightning happens, and a static dissipater can’t (nor anything else) prevent that, it’s of no use anymore. This in contrast with a lightning rod which will attract the lightning bolt and can safely guide it to ground via the bonding cable.

Our boat has had two direct hits, the last one just before we bought it. Everything at the masthead was gone, vaporized. VHF antenna, wind instrument, Windex, navlights etc. Just some charred remains and a stub of antenna ending in where the stainless steel was molted. Unreal.

For lightning protection the copper strips against the hull are not enough. When lightning travels down the mast it is not going to travel via the copper bands to where you have a grounding plate… it will go straight down through the hull into the water. This is why the grounding plate must be right below the mast and the cable can not even make a sharp bend.

Lightning ionizes the air to make a conductor out of it; it doesn’t need copper bands to find it’s way, it will take the shortest path. In case of a wooden or fiberglass boat, this can sink it.
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