Grounding Plate Issue

[markpj23]

During the last haulout we found that the screws attaching the grounding plates to the hull were completely gone. Picture shows it pretty well. I guess only the 5200 is holding them in place now.

So need I remove these entirely or just drill out the old screws and replace with new ones? What material screws should I use? FYI I have NO metal fittings outside the hull except the shafting & strut - all thru-hulls are Marelon.

[CSY Man]

Fiberglass hull?

Hmm, I got the same kind of grounding plate, same kind of 5200 bedding it in place.

If the screws are gone, ya would have leaks in the boat.
Perhaps only the heads are gone and ya can push the remainder of the bolt into the boat and replace..?

Or just drill out the old bolts and replace..?

[markpj23]

Originally Posted by CSY Man

Fiberglass hull?

Hmm, I got the same kind of grounding plate, same kind of 5200 bedding it in place.

If the screws are gone, ya would have leaks in the boat.
Perhaps only the heads are gone and ya can push the remainder of the bolt into the boat and replace..?

Or just drill out the old bolts and replace..?

Yes fiberglass. Hmmm.... will have to verify but I did not think these were thru-bolted.

[Maddog]

I'm curirous. Is that a copper plate? If so, why so much fouling? If there are no through bolts how do ground for SSB and Lighting protection?

Just trying to learn.

[hellosailor]

A grounding plate HAS TO BE through-bolted, otherwise how do you connect your ground wires to it?

The 5200 should do perfectly well keeping it attached, but I wouldn't rely on headless bolts to keep the ground system attached to it, I'd drill them out and replace them. Preferably with a more noble metal, sounds like they became sacrificial zincs.<G>

[Alan Wheeler]

Bolts/screw's, whatever, need to be the same material as the plate. It looks almost like they are slightly rusty, which leads men to think maybe they were SST. I may be wrong of course. But they need to be Silicon Bronze or if it is a copper plate, copper bolts would be even better. Otherwise you have two disimilar metals.
I am not sure if Monel or even Titanium would be better suited, I would be reluctant that the plate would then become the metal wanting to disapate.

[senormechanico]

It looks just like the plate on my boat. If so, it's a Dynaplate, made of bronze. The original thrubolts are bronze flathead machine screws with bronze washers and nuts on the inside of the hull.

Steve B.

[markpj23]

Originally Posted by hellosailor

A grounding plate HAS TO BE through-bolted, otherwise how do you connect your ground wires to it?

Somehow I had a mental picture that a single stud for the electrical connection protrudes from the center of the plate through the hull and the mounting screws on the end made the mechanical connection. Now makes much more sense to me that the mounting is actually a thru-bolt arrangement.

Guess I shouldn't be wankin' on those bolts from the inside while waterborne eh?



Thanks for all the replies!

[mike d.]

sure you can!? it will flush out any debris in the way of the new ones, and you won't have to pound the be-jesus out of them or your hands trying to get the old ones unstuck from the old ?5200??? or what ever is holding that thing in place!!!!!!!?

[CSY Man]

Yes fiberglass. Hmmm.... will have to verify but I did not think these were thru-bolted.

Uh-oh, not through bolted..?

I drilled 4 holes for my grounding plate...4 bolts and nuts, etc.

Using sheet-metal screws to hold the plate, ya have a thich hull or short screws.

If so, knock the whole thing off..Put epoxy in the holes and start over with new holes and bolts/washers/nuts.

I used SS bolts, no problems so far...6 years ago.

[btrayfors]

This thread illustrates exactly why you DON'T WANT and DON'T NEED an external SSB grounding plate. They are basically a very bad solution to the problem of providing your radio with an RF counterpoise for the sticky-uppy part of the antenna system. Lots of much better solutions, and tons of posts on this subject on this Board, SailNet, and the SSCA board.

Bill
WA6CCA

[CSY Man]

This thread illustrates exactly why you DON'T WANT and DON'T NEED an external SSB grounding plate. They are basically a very bad solution to the problem of providing your radio with an RF counterpoise for the sticky-uppy part of the antenna system. Lots of much better solutions, and tons of posts on this subject on this Board, SailNet, and the SSCA board.

Perhaps I should have consulted you before I installed the grounding plate?

In the meantime, it has worked great: Good reception and good transmissions: Talked to folks 4000 miles away and very happy with my system, including the $124.00 grounding plate.

That being said, I am open minded: What should I have done instead of installing a grounding plate?

[btrayfors]

Originally Posted by CSY Man

That being said, I am open minded: What should I have done instead of installing a grounding plate?

Read a little more widely. The subject of corroded and relatively worthless grounding plates has come up many times on the boards I cited.

Other options?

Simplest (a la Gordon West): a wide grounding strap from the tuner ground lug to a bronze thru-hull not otherwise connected to the DC grounding system. This will work, but isn't great IMHO.

Other possibilities: lots of copper strapping or plates INSIDE the hull (for a capacitive coupling to the seawater); tanks, etc. This will work, too, and is more effective over time than is an external ground plate.

Radials (insulated wires) under the deck or along the hull at or above the waterline work very well. So do aluminum toerails. So do pushpit/pulpit/lifeline complexes. These three are examples of pseudo-ground systems, and are very effective.

4,000 mile contacts don't impress me. I've been a ham for almost 40 years, and 4,000 mile contacts are a near daily routine for me. With 5-10 watt QRP rigs. I've worked a very good quality 10,000 mile voice contact from my boat in the BVI to New Zealand with a little portable 2.5 watt rig sitting on my lap. The secret to these and other contacts: a very good antenna, and some operating knowledge/experience.

Anyone can do it. Just don't be lulled into a catatonic state by all those folks who wanna sell you a $140 ground plate :-)

Bill

[Wahoo Sails]

Dag,
Got into it with the forum before as to what I should use instead of the Dynaplate (last boat) ... all I did was open a BIG can 'O worms. This is almost TOO funny, belonged in an old thread about things that PO's had done to boats. Night Wind has a Dynaplate as well (although no SSB) ........ it's mounted on the INSIDE of the keel!!!!!!!
Bob

[CSY Man]

Other possibilities: lots of copper strapping or plates INSIDE the hull (for a capacitive coupling to the seawater); tanks, etc. This will work, too, and is more effective over time than is an external ground plate.

Got that too.

4,000 mile contacts don't impress me.

Sorry, I tried to impress you..

Anyone can do it. Just don't be lulled into a catatonic state by all those folks who wanna sell you a $140 ground plate :-)

Guess I should not be happy about my SSB system that seems to work just fine, grounding plate and all..?

Dag,
Got into it with the forum before as to what I should use instead of the Dynaplate (last boat) ... all I did was open a BIG can 'O worms.

I had no idea, I thought a grounding plate was essential for good transmissions?

My bad..