Grounding Plates, How Attached?

[Traveler 45C]

How are grounding plates attached to the hull? Are they through bolted or secured only with 5200?

 

[doc g]

The ones I've seen are thru bolted and then you use the thru bolts to electrically connect the ground wires to ,sealed from the outside with a caulk. .....................Pat

 

[MikeP]

What Pat says...

 

[REBrueckner]

What do you mean "grounding plate'..... for what?

Do you mean zincanode, or SSB or lightning? All would use a thru hull bolt as already noted, but external type/location/design might vary..

 

[Fanfare]

I have the original port and stbd ground plates which are thru bolted so they can be connected to the ground strapping system. This puts all my bonding system at ground (water) potential. A decade or two later I replaced the old AM radiotelephone with a single-sideband unit. Unlike newer Hatterases, I do not have a built-in ground plane for the SSB antenna counterpoise. So I added two more very large ground plates. All four of mine are made of sintered bronze, thousands of tiny bronze balls compressed into rectangles. The theory is that the very large surface area of the porous balls would equate to a very large water surface and handle the radios as well as lightning strikes. It really has not worked very well for the SSB, and I have always been dubious about the lightning, but so far, so good.

I have noticed the similarity in appearance between my sintered ball ground plates and a Claymore mine. Lightning + water = instant steam, expansion of 250X volume in limited space filled with metal balls. Yikes!! Fortunately I seldom dive below the boat in thunderstorms. Anybody seen one of these after a hit?

 

[MikeP]

"I have noticed the similarity in appearance between my sintered ball ground plates and a Claymore mine"

But unlike the Claymore, you can't remove the material and use it to heat C-rations.

 

[REBrueckner]

"It really has not worked very well for the SSB, and I have always been dubious about the lightning, but so far, so good...

Reports indicate that as the crevices become filled with marine organisms they effective area exposed to the water is greatly diminished...
I have only heard of large cooper sheeting working well for SSB, but I'm not really familiar with them.

For separate lightning protection an isolated copper plate with serrated edges works best...minimum of a square foot...nothing connected from inside the boat except the lightning ground....

 

[DCMY #92]

The through bolts used for grounding plates are not just ordinary bronze bolts. They are gold plated. If you are removing and rebedding the plates take care not to damage the bolts. It's worth the effort.

 

[shark 1007]

I agree with the Claymore comparison and as I inspect my ground plates I can almost make out "front toward enemy" in mine.

Otherwise I agree and simply reinstall mine with bronze over length bolts and 5200 the holes. The little bumpy surfaces give the plate more surface area for ground plane.

 

[Trojan]

The plate is not much good for the ssb radio by its self. It will not work for a counter poise for the antenna. Its a ground only. You need a antenna tuner for ssb antennas on a boat.


BILL

 

[oldboat]

perhaps you should drop a pm to Scrod. he seems to have some truly beautiful bolts.

http://www.samsmarine.com/forums/showthread.php?t=10574&highlight=bronze+bolt