[FloridaBoy]

Hello All! Took boat out in the river, put on scuba gear and dove to scrub hull and put new shaft zinc on. Found a thick copper plate on stbd side. 3/4 inches thich, 14 inches long, 4 inches wide, pointed on forward end, flat on the aft end. So, I reckon it's a grounding plate for SSB or to ground against lightning?? Can anyone tell me how it is connected? I'm thinking to the lead in the keel and then via the stainless keel bolts? Very interesting... Have never seen any copper strap or braid anywhere in bilge, but wasn't really looking. Thanks for any help/advice. You guys are the most knowledgable! Kevin

 

[FloridaBoy]

Happy ST Patrick's Day to all! k

 

[Jaramaz]

One never know how others are thinking, maybe some PO has thought it was good to make grounding the way you describe - doesn't sound great, though.

Sure there is no connection to inside?

Most use of large Cu plates are either grounding or cooling. Both cases there should be a connection on the inside of the boat.

There are of course more exotic possible uses och a Cu plate: blocking a hole, hope to work as antifouling, ....


/J

 

[Frogwatch]

Probably a ground for VHF, USB or other instruments. It is NOT a real lightning ground and should not be considered as such. Oh, don't paint it but do scrub it.

 

[aa3jy]

Looks like something like this?
GUEST Dynaplate Sintered Bronze Ground Plates | West Marine

 

[FloridaBoy]

Yes, it looks like that but, it is pointed on the end facing the bow. The PO bought everything from West Marine. I didn't note any writing on the plate. Will check next time. So what? They screw it into the lead? I don't get it. kevin

 

[FloridaBoy]

I mean, it can't ground anything unless it's connected to something, right? For the record, I'm am a fledgling electrician. kevin

 

[FloridaBoy]

Ok, I looked up mounting instructions for the guest dynaplate. So, I need to do some investigating for a backing plate somewheres on that side of the boat. Alright, a mystery and a learning process. Very cool. How much ya wanna bet it isn't hooked to anything? lol kevin

 

[hellosailor]

Solid copper? Or perhaps sintered bronze?

Solid copper could be a DIY grounding plate, but the Dynaplate is sintered (foamed metal, lots of air in it) bronze. A dynaplate is a radio ground, and can actually be dangerous if you use it as a lightning ground. If a zillion volts goes through it, all the water in all the spaces in the sintered metal superheats and turns to steam, with explosive results that can blow the plate and a big hole in your hull.

So take a look inside the boat. A Dynaplate is a good thing for radios, but if the PO was foolish enough to use it for the lightning ground as well, you'd want to relocate that connection ASAP. If you have an external metal keel, usually the lightning ground would be factory connected to that, directly.

 

[Mechsmith]

I have a somewhat larger plate electrically bonded with #9 copper wire to the standing rigging. It's obviously intended for lightning protection.

 

[deniseO30]

is the inside viewable? could it be a keel cooler?

 

[FloridaBoy]

I'm gonna run down to the boat and look, after work. See if I can find it, inside the hull. I know just where to look. I'll let you folks know. Kevin

 

[aa3jy]

Do you or did you have an HF radio and or LORAN aboard?

 

[FloridaBoy]

I didn't. But boat is 41 yrs old. Mighta coulda had one. It's problably just that. I just have no experience with it. I'll problably find out tonight what it is and if its connected to anything. Kevin

 

[FloridaBoy]

Ok, went to boat. Looked around. Found 3 1/4 inch bolts sticking through the hull. Spaced about right for the plate. Middle bolt had 2 nuts on it like it was used to fasten a wire to it. No backing plate, just washers, small ones on each bolt. Nothing wired to it..... Now what? LOL! Guess I better get started reading and learning...Kevin

 

[aa3jy]

If it was a Dyna Plate they only have two bolts. Bolt length would have been longer to accommodate hull thickness, backing plate and several locking nuts.