Mast Head dialed in

[Rosco]

Such an easy realignment of the mast head which provided info on key elements. Namely the crazy looking spread wire issue is actually a lightning deflector. Not sure but apparently it distributes electrons so as to not attract lightning. Wow really? I doubt it. So a luckily we have a mast tower so it was free. New all around light. New VHF Whip antenna and a better sense of the stuff up there. Good process. I hope this helps us newer sailers who were inspired by Christian Williams as I was.

 

[gareth harris]

Lightning dissipators have come up before. I did a fair bit of research when I had my boat in Pensacola, and a lot of conflicting information was out there. My take was that it was vital to ground the mast so that a strike would most likely go down the electrical cable (the thickest available) available rather than take a random path.

Whether to build a Faraday cage around the hull was more in question, since it could lead to lightning taking a path through the hull leaving a hole below the waterline, although it would offer better protection to people inside the cabin.

Dissipators are designed to allow a steady flow of electrons into the atmosphere so that there is not a high voltage difference between a tower and the atmosphere. On a boat with a grounded mast in salt water, the grounding plate will attract electrons which will go quickly up the mast to replace those dissipated, so the dissipator will not achieve much.

Years ago I posted a link to a study on the subject which you may find with a search.

Gareth
Freyja E35 #241 1972

 

[Rosco]

Thank you so much. We get almost zero lightning here and a few vessel have them. I thought they were to scare birds when I first saw them.

 

[Christian Williams]

Bird does seem more like it …

 

[Drewm3i]

The device is called a "lightning dissipator," made by Forespar; as far as I have learned, they work "in theory," but not "in practice"--as the amount of electricity (i.e. billions of volts) is far too great to be dissipated by a device with so few points. To work (even in theory), the device has to be grounded to the water with large cable and metal that is in direct contact with the water's surface.

The latest in the (dubious) field of "lightning protection" are these so-called "CMCE" devices:

Lightning Protection Company, CMCE Lightning Protection, Lightning Suppression Florida - Encore Land and Sea FL

Encore Land and Sea delivers expert lightning protection solutions, including CMCE systems, lightning rods, and arresters across Florida, ensuring reliable safety for residential and commercial properties.

www.encorelandandsea.com

But the real authority on the subject can be found here:

Marine Lightning Protection Inc.

marinelightning.com

My Ericson 38-200, Walden, had one such dissipator device installed after a strike ~four years prior--and while under contract, it was (side) struck again with some electronics damage and negligible hull damage; the mast was not grounded so the device was completely useless. During my 2018-19 refit, I removed the device and bonded the mast step to a keel bolt with a brass ground strap and 2/0 AWG cable with minimal bends. I also installed a "gas-block surge protector" in the VHF coaxial to divert a strike-charge to ground (connected to mast step). This whole setup was never tested thankfully.

My Hunter has all of its shrouds and mast connected with ~4-6 AWG cable to a fabricated stainless steel bonding plate at the forward keel bolt, which is what Sabre also does. Thankfully, this boat's system has also not been tested.

 

[Rosco]

Bird does seem more like it …

True, I doubt that it lives up to the billing...to use a saying I once heard.