Paint on Lightning Protector

[coopec43]

These people seem to know what they are talking about. But I wonder if anyone really understands lightning?

"The grounding plates or strips must not be painted. If the grounding plate or strip is copper or bronze, the natural antifouling qualities of the copper will keep it from fouling".

Lightning Attenuation Onboard

[Jim Cate]

Originally Posted by coopec43

These people seem to know what they are talking about. But I wonder if anyone really understands lightning?

"The grounding plates or strips must not be painted. If the grounding plate or strip is copper or bronze, the natural antifouling qualities of the copper will keep it from fouling".

Lightning Attenuation Onboard

I hope that their understanding of lightning is better than their understanding of marine fouling, which for centuries has flourished on coppered bottoms. Jimmy Cook could have explained this to them...

Jim

[coopec43]

Originally Posted by Jim Cate

I hope that their understanding of lightning is better than their understanding of marine fouling, which for centuries has flourished on coppered bottoms. Jimmy Cook could have explained this to them...

Jim

I don't follow your post. My understanding was that copper sheathing was an excellent anti-fouling (maybe it would be banned these days?)



I did a bit if reading and found James Cook preferred wooden sheathing apparently but copper was in use as an antifouling on a lot of other ships around that time.


HMS Alarm was chosen because, in 1761, a letter had been sent regarding the ship's condition, saying that the worms from the waters had taken a significant toll on the ship’s wooden hull.[5] Before the copper plates were applied, the hull was covered with Soft stuff, which was simply hair, yarn and brown paper. The copper performed very well, both in protecting the hull from worm invasion and in preventing weed growth for, when in contact with water, the copper produced a poisonous film, composed mainly of copper oxychloride, that deterred these marine organisms. Furthermore, as this film was slightly soluble, it gradually washed away, leaving no way in which marine life could attach itself to the ship. However, it was soon discovered by the Admiralty that the copper bolts used to hold the plates to the hull had reacted with the iron bolts used in the construction of the ship, rendering many bolts nearly useless. In 1766, because of the poor condition of the iron bolts, Alarm's copper was removed.[6]



AND

With the American war in full swing, the Royal Navy set about coppering the bottoms of the entire fleet in 1778. This would not have happened but for war. This also came about because in 1778 a Mr. Fisher, a Liverpool shipbuilder (who did a brisk trade with West Africa) sent a letter to the Navy Board.[10] In it he recommended "copper sheathing" as a solution to the problems of ship worm in warm tropical waters, and the effect on speed of tendrils of seaweed latching onto hulls


Now where am I going wrong

[Jim Cate]

Now where am I going wrong

Coppering is quite effective against shipworm, but not so much against other forms of fouling. Do you not remember Cook having to careen Endeavor for scraping now and then? Vessels of the Royal Navy, whilst blockading the French in the interminable wars were gradually rendered incapable of maneuvering properly by the growth on their coppered bottoms.

Most anyone with a bronze prop can tell you that despite the claim made in the post I originally quoted, growth readily attaches to props, and I've seen modern coppered bottoms with huge amounts of growth. Folks who use Dynaplates find that they foul quickly, and they are bronze. And so on...

Thus I questioned the statement "If the grounding plate or strip is copper or bronze, the natural antifouling qualities of the copper will keep it from fouling".

You are free to believe what you wish, my reading of history and my personal observations say that the statement is not true.

Jim

[coopec43]

Originally Posted by Jim Cate

Coppering is quite effective against shipworm, but not so much against other forms of fouling. Do you not remember Cook having to careen Endeavor for scraping now and then? Vessels of the Royal Navy, whilst blockading the French in the interminable wars were gradually rendered incapable of maneuvering properly by the growth on their coppered bottoms.

Jim

Yes I've read somewhere James Cook had to careen Endeavor but he chose not to use copper sheathing for his first voyage. (Maybe he later cursed his decision)

". Cook choses not to add a new and experimental copper plating because he felt that it was too easily damaged".

James Cook - His First Voyage

Copper of course is an ingredient of antifouling paint because of its' toxicity to marine life.

I can't find any reference to where the RN was defeated because of marine growth.(I'd be interested in that)

They did have problems securing copper plates initially because they didn't understand electrolysis.

[coopec43]

Maybe this post is off-topic? (Apologies if it is)

https://www.fox61.com/article/news/l...a-ccf35330dd1f

[Frankly]

Having owned two sailboats for lots of years with solid copper ground plates and one with a large Dynaplate (now residing with A64), the fouling clan love both the copper and sintered bronze.

I am with the camp that the copper sheathing on wooden hulls was for worm prevention.

So I paint my copper plate and scrape the edges.


Over the years I have found fouling is very location dependent. We drug an unpainted dinghy around the Exumas for a month. When we put her in the davits for the return trip home her bottom was clean. In St Andrews Bay the dink will have small barnacles in a week.


Frankly

[GordMay]

Originally Posted by Mike Banks

If you look in the archives you will find quite a bit of argument and useful information on the lighning phenomenon and the many interesting aspects of it ...

Indeed.
Here’s a few (± 571) ➥ https://cse.google.com/cse?siteurl=w...+gordmay&sa=Go

[RaymondR]

I vaguely recall a story about Lord Nelson taking of across the Atlantic to the West Indies in his copper bottomed fleet after a French fleet and on finding them not there returned to European waters. Apparently he got there and back whilst they were still underway getting there in their non copper sheathed vessels.

With all the masts sticking up it begs the question as to whether they used lightning conductors and whether they were connected to the copper sheathing?

[GordMay]

The Last Remnant of Napoleon's Ship - Lightning Rod
https://www.military.com/video/opera.../3236820654001

[Gerrycooper56]

If the grounding ‘plate’ is made of sintered bronze then painting over it will defeat the purpose. A sintered bronze plate, being effectively open relies on the fact that water can get into it, significantly increasing the surface area available to dissipate.

[paul2884]

Are you sure it for lightning and not the grounding plate for the SSB radio? considering the amount of energy it will have to disapate i would be supprised if it were effective.

[hernandobeach]

There are a number of methods that are very effective when trying to protect power or sailing boats. The first consideration/task is the design and installation of a very robust, proper bonding system. The second consideration should be to disconnect all electronics not needed at the time. That will include the power as well and connected antenna, sensors, etc. The focus is to isolate where possible, remove the path that lightning could possible follow to systems and equipment in its attempt to dissipate to a lower potential. The third consideration is to give lightning one or more paths it can follow that make it easy for it to get from point "A" (where it is-- a charge in the sky) to point "B" where it want to go (earth "0") to dissipate that charge. Remember lightning is mother nature's best example of difference in potential.

A side note, for you in the Tampa area or anyone that likes to win a bet (perhaps for adult beverages), It is said that "Tampa" or the Calusa Indian spelling of it, is believed to mean "sticks of fire". One historian claims the name was a result of poor communications between the Spanish and the Calusa tribe. He version is the Calusa word was "itimpi"........ I go with the "sticks of fire" as I was told by a Calusa tribe member that is what it means.

The path(s) lightning will follow is random. It will depend on the amplitude of the strike, the bulk of the energy is DC, so the resistance vs. impedance of the path(s) it will follow is critical. A very well bonded and grounded vessel will survive the strike, but induction alone may do damage, so the goal is to reduce the paths (disconnect stuff).

The majority of lightning energy will follow the lowest resistance and impedance path to the lower potential (the water, earth). No one has ever beat Ohm's law. I=E/R Do the math, take any voltage you desire, compute the amount of current that will follow a 1-Ohm (the R) path. Then increase the "R" and see what the current does. Depending on a number of atmospheric factors, lightning is about 70,000 volts to the inch at sea level. Compute the voltage level it requires to travel miles through the air!

I found that the installation of a large stranded conductor properly connected to the tower legs of a diesel power sport fish and a significant length of the conductor put in the ocean while at dock provided a very effective path to channel and dissipate the energy of a strike. This and disconnection of everything possible proved very effective for several years my partners and I kept a boat at Walker's Cay.

Another boater witnessed our Bertram suffering a direct strike on the tower. When we got the call from the dock master, two of us flew to check on "Overtime" as the boat was called. We had some minor damage (mostly induced) and several AC connected devices. We did not disconnect the dehumidifier systems and fans to circulate the air we had installed. They were toast and had to be replaced the next trip over (typical plug and play units).

Had we not taken the extra steps, I am sure the outcome would have been much worse. I have a few "war stories" from my years of involvement, but save those for another day. As stated by another, lightning do not always strike the highest point.

I hope this helps...........

[hernandobeach]

I should have stated I used a large conductor make up of over 100 fine stainless conductors. I purchased it from a salvage place called Sky Craft in Winter Park, FL. The cables were over 50' each and not inexpensive.

The conductor was connected to the tower legs using multiple large clamps that held stainless pipe we had cut in half lengthwise. We also added conductive grease to the connection, that was wrapped with a rubber tape. to prevent the grease from dissipating.

[BobbyHR]

https://nemasail.org/news/7279551