And this is?

[walt]

My .02

FYI, "grounding" the mast does not mean you need to have a chunk of bare metal in the water. It means you need to provide a method for the charge to get into the water that over competes with damaging side flash. Dr. Thomson Siedarc electrodes are not actually in the water, just above the water surface but these provide a good method to discharge the strike. Bonding to a metal keel that is painted so not actually conducting to water is also good grounding..

Regarding chain, when I was messing with the floating discharge surface conductor (post 30), I actually measured the inductance of a length of chain (I am a retired MSEE, did this sort of thing in my career), chain has a much higher inductance per length and weight than say a four gauge wire. Inductance delays response so something like four gauge wire makes a much better down conductor.

But... your idea to ground the mast to the anchor rode is not a bad one, everything about lightning is just doing what you can to improve your odds. Somethings are better than others.

My opinion especially for a trailer sailor with an ungrounded mast (you can never prove any of this) is that a four gauge wire with good bonding to the mast and adequate bend radius that just hangs over the side with the end of the wire near the water surface is about as good as you can do in fresh water and fairly simple. Put one on each side and have the wire run past the side stays so it forms a spark gap to the stay. If you want to get fancy, make a simple float at the end of the wire to always keep it just above the water surface.

Here is a picture again that I took when messing with all that stuff a bunch of years ago showing the surface discharge in fresh water (our lab had an ESD tester, snuck in this test while at work). FYI, a discussion involving electric fields will explain everything happening in the picture.

 

[stickinthemud57]

^^^
Maybe the most authoritative, evidence-based post on the subject I have seen in this thread. Especially love the little paper sail.

 

[JamesG161]

A typical page in many Hunter Manuals...

Lightning Protection System per a ABYC standard, that has merged with their Electrical Standard.

The Potection Zone is this known Science

https://en.wikipedia.org/wiki/Faraday_cage
_______
Sheltering

3) Anchored [ best for Safety, if possible, when storm clouds approach]

__________

A Lightning Ground Strike, near the Marina, can cause a Surging high voltage on your 120VAC Ground Wires

4) Plugged into Marina Power [ not a good thing]

You are counting on the Marina Power Supply to have Sufficient Grounding Rods for surge protection.
_______
If your boat or home is hit by the Main Lighting Bolt...

Measure the HOLE in them.

No HOLE, then a side strike or ground nearby.

Jim...

 

[walt]

Jim, correct about surge from being plugged into a marina AC. True for your boat or home. This article (Nigel Calder) has a section on surge protection. Sailing in lightning: how to keep your yacht safe - Yachting Monthly

Surge can come in through the AC (boat or home) but in the boat that takes a strike either direct or nearby, you have an additional problem of induced currents and voltages created by the EM fields generated. Even in conductors isolated from the strike or down conductors carrying the strike.

Our little subdivision in SW Colorado has a community well that pumps to a tank about 3/4 mile away on a hill. A few volunteers that live there (I got roped into this) just changed out the tank level control from a buried wire (which corroded and went bad causing the well pump to run continuously for 3 months and no one was monitoring this) to 433 Mhz wireless last fall and this spring Im going to harden everything for lightning. Here is what Im going to do.. (not going to unplug everything every time there is a thunder storm which happen often here during the monsoon season). This supplies our home water.. if it goes down the villagers will show up with torches and pitchforks!

First, we are going to install both type 2 and type 3 surge suppressors on the AC to protect the new RF control box we just installed. Type 2 is normally referred to as "whole house" and type 3 are typically the power strip surge suppressors. These have slightly different specs and reaction times.

Second, on the RF antenna, Im going to install gas discharge suppression. Our system has N connectors, this is what Im planning on using https://www.amazon.com/Coaxial-Lightning-Arrestor-Protector-DC-3GHz/dp/B08216DZ6H These need to be very well grounded. The article reference above has a quick discussion on these and questions how effective they are.. but regardless, Im adding them. Good RF specs, they should not cause any new problem.

Third, you need to make sure the system has a good single point ground - which we do have.

The Nigel Calder article also shows a 12 volt surge suppressor which might be something to consider. Not a problem I have with the well house.

 

[walt]

Some pictures of our community well in SW Colorado- oddly enough sort of related to the wire brush in this post LOL.

This is the well pump house showing the new 433 Mhz Yagi antenna

About 3/4 mile away on a hill is a tank that holds the water and creates the water pressure for the homes. When we installed the wireless sytem, we were wondering how we would know it was working and one of our team had the idea to put a white light at the tank that came on when the float in the tank told the well house pump to run. So.. I installed a white light up on the hill at the tank. When the white light comes on, the well should be running. It turned out to be a great tool and its still running (but with significantly lower intensity and color temp than shown in the picture). The light has been named "The Eye of Sauron" It was said that few could endure its terrible gaze

Now the sort of related part.. The HOA runs this well and I snuck in a little experiment that no one knows about except anyone reading this post. This is NOT about trying to discharge the earth which is completely futile. It is about messing with the electric field at the top of the mast. The details of why are in the two technical papers I posted back in post #7. The idea is to make this as crappy of a lighting rod as possible. Does it work.. dont know and hope to not find out. Im hoping no one in the HOA notices and starts asking question LOL. Im pretty sure it doesn't cause any new problem.

 

[walt]

I find a couple articles posted in this thread interesting so will share.

From this Nigel Calder article in Yachting monthly dated July 22, 2022

Sailing in lightning: how to keep your yacht safe - Yachting Monthly

How much of a concern is sailing in lightning? Nigel Calder looks at what makes a full ‘belt and braces’ lightning protection system

www.yachtingmonthly.com

Grounding terminal

Metal hulled boats can use the hull as the grounding terminal. All other boats need an adequate mass of underwater metal.

In salt water this needs a minimum area of 0.1m². In fresh water, European standards call for the grounding terminal to be up to 0.25m². (my note.. .25 square meter = 2.69 square ft = 1.64 ft per side)

A grounding terminal must be submerged under all operating conditions.

An external lead or iron keel on monohull sailing boats can serve as a grounding terminal.

---------------------------------------------------

I believe what Nigel Calder describes in the article is what ABYC uses and it ignores or excludes Dr Ewen Thomsons Siedarc electrodes. Siedarc electrodes are always placed just ABOVE water line and of course dont meet the area requirement.

Now go read the Loose Cannon article (Jan 3 2023?) on insurance posted earlier Lightning Is Huge Factor in Rising Insurance Costs. Why Won't AB)YC Help?

I think this is a great article and would recommend reading the whole thing. Ill just post some snips on the interesting part regarding Dr. Thomson and Siedarc.

Thomson’s biggest contribution came 20 years ago when he developed a new type of grounding electrode, essentially a copper rod potted with resin inside a through-hull fitting. Air terminals and external metal structures such as stanchions and rails were connected to mutiple patented “Siedarcs.

Significantly, Siedarcs were designed to be mounted a few inches above a boat’s waterline. Decades of foresic study of lightning damage had led Thomson to conclude that this was the optimal placement. That’s where he had often found a great deal of hull damage due to lightning.

”

What (lightning) wants to do is to go to the ideal ground as soon as it can, and it so happens that the surface of the water is the best path. It will actually find that water surface much faster than finding the keel or down deeper in the boat.

As noted in the earlier story about the system, Thomson lightning protection has enjoyed a good track record over the past two decades. There is reason to believe that if all boats were so equipped, boaters would be safer and insurance claims for lightning damage would plummet.

Why this hasn’t happened is simple. News headlines and statisticians do not record when lightning hits a boat and no damage occurs. In some cases, if the owners are away, and the system works as designed, even they may not be aware that lightning had struck

.

Clarity would have helped Michael Krieger who keeps his big Hatteras sportfishing yacht in South Florida. Worried about lightning strikes on his outriggers and technically savvy, Krieger hired Thomson to design a lightning protection system. But then he could not find any marine electronics companies willing to install the Sidearcs, citing legal liability.

Amazingly, some boatowners suspend their critical thinking when it comes to the marine insurance industry. Insurance companies make policy based on claims. When Thomson’s lightning protection system succeeds, as was the case in St. Augustine recently, there is no claim. Boatowner Brian Bosely did not phone his insurance company with the good news. No note was taken.

If you have been around this forum for a while, you might remember boat babe. Wasnt her husband Brian Bosely.. could be wrong.

 

[walt]

FYI, Loose Cannon has what I think are good articles on both the wire brush things and Dr Ewen Thomsons Siedarc above water electrodes. If you want to limit reading, just skip the first link and go to the second on Siedarc electrodes.

First one discusses the wire brush things.

NASA's Go-To Lightning Guy Disses Fuzzy Dissipators

After Fires, Manufacturer Settles Energy-Sector Case in Texas

loosecannon.substack.com

A snip

Mata was asked whether Forespar’s “static dissipator” works as advertised. “The short answer is no,” he said, elaborating:

Most of these devices tend to smooth the electric field, prevent the electrical field from becoming too large. What they do, in fact, is to delay the formation of an upward streamer, which is a component of a strike. If you have a probe, if you have an electrode, if you have a brush, that is going to smooth the electrical field, and it's going to take a much larger electrical field gradient to have an upward streamer developing from those electrodes. It means it takes a greater electrical field to do that.
So, because it’s going to take (a steamer) longer to develop, something next to it can get struck. What these devices do in fact is somehow protect themselves, they don’t provide protection to anything next to them.
Let’s say I have a sailboat that has only one mast, and I want to put one of these brushes at the very top. What is going to happen, if I have lightning in the area, is that an upward streamer coming from that brush device is going to get delayed slightly, but, instead, (you'll have) an upward streamer from a rope—it doesn’t have to be metallic, by the way. Anything you have up there, like a weather sensor, that is what will launch an upward streamer, and that is what's going to get struck.
That device doesn’t shield the boat.

Second article is more interesting regarding the Siedarc electrodes. FYI, I am a big fan (bias) of Dr Ewen Thomson and his Siedarc electrodes

Proven Lightning Protection That Gets Little Respect (Except From Adopters)

How Ben Franklin's Ideas Were Refined for the Age of Fiberglass and Aluminum

loosecannon.substack.com

Recommend anyone interested in lightning protection read the whole article. Some snips..

Thomson’s eureka moment was the realization that the best path to ground for was not a metal keel or an underwater plate. The spark was powerfully drawn to surface of the water, which becomes a proton-engorged capacitor during thunderstorm conditions. Hence, the idea of Siedarc electrodes, mounted just above the waterline to channel the lightning out of the boat—hopefully without causing harm.

In fact, Thomson has come to believe that keel grounding and below-water grounding plates and even the grounding strips he incorporates are redundant and could actually be counterproductive.

Since 2003, 109 boats have incorporated Thomson’s system using at least one Siedarc terminal. Of that number, four owners have reported having electronics damaged by lightning strikes. All were catamarans, none had installed surge protection. Otherwise there were no injuries or hull damage

 

[walt]

I posted a picture previously of a floating discharge electrode prototype that utilized Dr. Ewen Thomson's idea of placing the discharge electrode at the water surface where the charge naturally wants to go and by far the best place to discharge in fresh water. This was a setup intended for a trailer sailboat with an ungrounded mast which guarantees a spark from the bottom of the mast to the nearest water surface if you dont do anything. I was happy to see Dr. Thomson's Siedarc electrodes discussed by Loose Cannon. Anyhow.. a summary of pictures from a few years ago.

Does it work.. dont know as I have never been struck by lightning. Been shocked on shrouds, heard buzzing and popping noises etc but never a direct strike.

below... sailing

motoring at hull speed