GROUNDING PLATES

Craig Mac · Post by **Craig Mac** » Mar 11th, '11, 08:28

My friends boat has grounding plates mounted on the bottom towards the bow--I have no grounding plates---and I see many with one mounted at the stern---what ths concesus on these?

bob lico · Post by **bob lico** » Mar 11th, '11, 08:46

the grounding plates should be up forward as far as possible (and still be in water at all times) the have maximum distance from the main bonding zinc mounted on transum. without main zinc there are rudder,shaft,tab zinc toward stern. you want maximum distance to minimize differants in potential (battery effect).

Bruce · Post by **Bruce** » Mar 11th, '11, 10:15

Unless your running a side band radio, forget it.

In Memory of Vicroy · Post by **In Memory of Vicroy** » Mar 11th, '11, 11:06

Roger what Bruce says. Most of our B31s were made before VHF marine radios were in common use and our boats were factory equipped with ground plates (some, like mine, with two) for AM marine radios that operated on the same lower frequencies that SSBs do today.

Not needed for bonding, VHF radios, or GPS. They were helpful for LORAN - which operated on low frequency - but that's moot now that loran is gone.

UV

bob lico · Post by **bob lico** » Mar 12th, '11, 00:12

well i know craig is much smarter then the average bear . this being said i assume craig was well aware of uhf and loran so my post stands inside the boat in the v-berth bilge the two grounding plates are connected together with at least # 6 gauge wire they are now in parrallel . from each stud you go to one off the thru bolts of the bottom plate on the outriggers you do the same on both use # 6 gauge also the key here is do not make 90 degree turns run the wire as the crow flys from point to point. yes craig a lightning strike is a bitch especially 90 miles offshore.a little effort and isolating the power to the electronic are well worth the effort!

Bruce · Post by **Bruce** » Mar 12th, '11, 08:04

I really hope no one believes that a #6 wire is gonna dissapate a strike energy or for that matter carry it even far enough to make it to the plate.

If someone is going to do this to "feel better" use flat copper ribbon at least 3 to 4 inches wide for the surface area from all connecting points to the plate.

The issue then becomes forcing all that energy thru a 1/4, 5/16 or 3/8 bolt in to the dimpled surface area of the plate. Good luck.

Thats like accelerating Rosie ODonnell to the speed of light and then trying to pass her thru a door way. Ain't gonna happen without taking half the ajoining wall with her.

bob lico · Post by **bob lico** » Mar 12th, '11, 08:19

bruce that wire going to the base of the outriggers is about 4' long . and the strike will take the path of least electrical resistane , incidently make sure the rigger are totaly insolated from the rest of boat including extension bar from bridge. i have four 1/4" bolts on the two plates conected together with a copper strip.
look at the post " lico seating" the picture of jp`s bridge has a white w/p electrical panel and switches. this is the way it is done. feed to panel comes from main distribution thru isolation transformer and lighting protection electronics then to panel to protect all bridge electronics and engine gauges, etc. this lightning protection i better then nothing at all .the feds and ny state paid a huge amount of money to make sure the FAA and the state court house would have certified lightning protection,

bob lico · Post by **bob lico** » Mar 12th, '11, 08:49

bruce i should mention here the main concern is not to take a strike at all! by making this protection you have made the (air terminals) in this case tip of the outriggers the exact same potential as the salt water you are floating in. hopefully the lighting strikes some distance place then you on the bridge. chances are a full strike would destroy the gunnel where outrigger are attach to plate before even getting to the down lead. the nfpa (the gorverning body for those who install l/p) uses # 6 or 4 bond the main down lead on a regular basic to connect "points" like plumbing vent ,ant,a/c to main 2/0 braided cable.
phoenix is going to do the l/p on hospital at west point milatary school next month.

Bruce · Post by **Bruce** » Mar 12th, '11, 09:25

Bob,
Buildings are a totaly different scenario as a ground halo installed around the perimeter with an internal ground halo and use a suppression demarcation point for all outside wiring and coax entries.

You can't do this with a boat.

Rf becomes a hugh problem as even a nearby strike can inductively and or capacitively couple thousands of volts into your cable and coax system.

Unless you build a faraday cage around the boat, rf is gonna penetrate and with the lousy surge protection on electronics, your cooked.

While you can try and dissapate this thru short cable runs thru the ground plate, I've yet to see a 3"x10" ground plate prevent damage.

bob lico · Post by **bob lico** » Mar 12th, '11, 22:33

phoenix is state/federal certified , rather senseless to go into positive ions when nobody else is interested.like i indicated a niche in the electrical contruction field that nobody wants to go into.however you may be lone bidder and the price per hour is more then attorney.maybe one or two come up a year.

In Memory of Vicroy · Post by **In Memory of Vicroy** » Mar 13th, '11, 18:18

The path that an electrical current takes on, in, or thru a wire or other conductor is dependent on the frequency. Zero frequency, such as DC current, goes nice and peaceful doen the insude of the wire....as the frequency increases, the current wants to get outside the conductor...static electricity is ulta high frequency and does NOT PASS THRU THE WIRE...it travels on the outside, so that's why flats are better than rounds....lightning is static for frequency purposes. The use of grounding wires vs. grounding strips is simply a matter of cost and ease of running.....Bruce is correct of course, a #6 wire is worthless to conduct any sort of lightning strike, and all you are asking for using that is a hole in the bottom of the boat.

UV

bob lico · Post by **bob lico** » Mar 13th, '11, 20:03

wow ------one more time a good defense beats a good offense . we want to A) make sure there is a taller ant.,sailboat mast or bigger boat next to you however if your by your by yourself you would want to netralize those ions floating around your tip of outriggers the best you can by eliminating the differance of potential from those positive charged clouds looking to find negative source.by connecting with a positive and isolated path from the tip of outrigger to the salt water around us in a attemp to nolify a strike. you could write thousands of pages of theorys after looking up internet. theorys by scientist are great however some of us have to be both responsible and liable for results.we have never had damage from a strike in 40 years from north patchouge firehouse to the FAA building at islip airport. a strike there would be devastating because they control every aircraft coming in from overseas between boston to washington dc.the boat takes a strike you will have damage one way or another this system on a boat will reduce risk a great deal.it will NOT absorbed 25,000 amps dc. no matter what i do because i cannot disperse strike with a field of driven ground rods .

Brewster Minton · Post by **Brewster Minton** » Mar 13th, '11, 20:15

I have an LPS. It produces a negative ion dome around the boat. So far so good. I have had strikes all around the boat and so far so good. I don't know how it workes or if it does but I feel better. I'm not very smart soo.

bob lico · Post by **bob lico** » Mar 13th, '11, 20:20

smart man brewster that does the same thing a tryed to explain only much better however the same holds true if you do get hit there is nothing you can do to prevent the damage except what i mention about with isolation transformer and surge protection for electronics. with alot of luck on the damage at least you may get home.

Brewster Minton · Post by **Brewster Minton** » Mar 13th, '11, 20:30

I dont care about big waves or wind. Lightning scares me the most. The only time I asked myself "What the f%#k am I doing tuna fishing was with lightning raining down all around the boat. Boy did I feel stupid. More than normal.

bob lico · Post by **bob lico** » Mar 13th, '11, 22:22

yes brother it scares me also .given the choice hit the riggers, damage the gunnel and other damage just be happy it does not hit the captain! or the raft! i examine your L/P on your boat with you if you remember. i would keep what you have.

In Memory of Vicroy · Post by **In Memory of Vicroy** » Mar 14th, '11, 10:17

I keep about 8' of heavy chain on board and drape it around an outrigger base and into the water when the lightning gets close. One year during a UVI several of us were trolling around a deep water oil rig when a big bolt hit the rig....zapped my Icom 125 radio and some other stuff....I was about a half mile from the rig....another time had a strike on a power line running down the dock in Venice, La. and it took out all the electronics on AJ, every doggone device. Ins. paid for most of it. Computer chips and especially FET semiconductors (Field Effect Transistors) do not like stray static currents. We had a strike on a tall pine tree in the yard of our law firm building years ago that did about $50K of damage to compters, printers, likker machine, etc.

UV

Rawleigh · Post by **Rawleigh** » Mar 14th, '11, 11:24

I thought that the theory was that the ground helped bleed off the static charge that attracted the lightning strike. I have seen high speed video that shows an arc rising from the thing being struck to meet the bolt coming down from above. Whether this is correct or not I cannot guarantee.

Capt. DQ · Post by **Capt. DQ** » Mar 14th, '11, 13:09

Rawleigh,

Cloud to ground or either ground to cloud lightning. I can tell you this, all bets are off when it comes to lightning, as it is very unpredictable no matter what protection is in place. There is really no way to accurately measure how many amps are being delivered. Just HOPE your not the one being struck.

DQ

In Memory Walter K · Post by **In Memory Walter K** » Mar 14th, '11, 14:15

With all the technologies, scientists, and brainiacs around, what these past few years have taught me is we don't know diddle about Mother Nature. She rules our roost as she wishes and all we can do is live in it the best we can.

AndreF · Post by **AndreF** » Mar 14th, '11, 19:58

One night we were some 50 miles offshore in a hell of a storm about 2 AM, lightning all around us. My nephew and I were on the bridge just motoring at 5 knots into the waves as a supply boat knocked us off the stand-by bouy. Was it rough?, well the outriggers were dipping into the Gulf every now then. One of the kid's friends climbed up the ladder and asked me "what do you do about lightning?". I said, why, are you scared?, he said no, I said , well, you should be. He climbed right down.
Lightning can be your friend too, sheding light on a situation when needed. Happened to me going into South Pass of Mississippi River in a storm. Lit the pass right up to thread the rocks.

Rawleigh · Post by **Rawleigh** » Mar 15th, '11, 09:41

It always amazes me that the "underwater" jetty at Southpass isn't marked and lit better!

bob lico · Post by **bob lico** » Mar 15th, '11, 10:51

rawleigh as you explain object about to be hit by lightning " bleeding off" to cloud above is correct. part of certification is a gorvernment mandated seminar to attend every year. all kinds of high speed photo`s now you realize why old man zeke had his silo hit by lightning and burn down the barn because it was the highest point in a 25' area. by grounding the highest point and keeping it seperate from the bonding system we bleed off the static charge 24/7 instead of the 8' chain method which requires vic to put out this chain when lightning is in the area ,of course lightning may hit when the boat is moored or off hours. although i have had lightning all around me in 50 years of boat ownership i have never have had my boat or house hit ---thank God here is a sample of a air terminal phoenix installs ,i have L/P on my sayville home but never installed on florida digs because it was no higher the the houses around port saint lucie.

bertram31.com

GROUNDING PLATES

GROUNDING PLATES

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