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Old style dual bronze grounding tube questions

Discussion in 'Technical Discussion' started by cleanslate, Jan 3, 2020.

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  1. cleanslate

    cleanslate Senior Member

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    On my 1981 Ocean Yachts I have a dual grounding tube about 12 feet long running outside at the turn of the keel which has been painted over the many years. Is the many layers of paint causing me a bad ground ? Should it not be painted? Also the inside of the tubes is filled with sea growth . Perhaps clean that out with a long piece of all-thread-rod?
    If not, can I just sand it clean in various spots to get a good ground?

    I have one grounding stud coming up through the hull in the engine room from it for sure.
    Since it's so long , I would assume there are other studs coming through the hull ? I haven't found any, but really haven't looked that hard either.
  2. cleanslate

    cleanslate Senior Member

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    I'm still waiting Captn Ralph...:)
  3. Capt Ralph

    Capt Ralph Senior Member

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    Damm, I missed your first post.

    Your looking at good old fashioned SSB Di Pole ground field contact planer (AKA DynaPlate) or a real crude lightning / static dissipater.

    Somewhere should be a heavy cable or strap towards the SSB tuner or the tallest metal part of your boat (mast, arch, radar array, bridge hand rails or window frame.

    With later technology, it is today; just drag under your boat.
  4. cleanslate

    cleanslate Senior Member

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    I don't know where all the wires go, will have to trace them . Sure it's not grounding things that are still needed on the boat ? I don't have a SSB or anything like that in my electronics stuff... Would this be hooked up to the bonding wires for all the thu hulls and sea cocks ? There is a bronze thin wide window screan size strap going from the thru hull grounding stud to somewhere unknown to me...I'll trace that to at some point.
    Anyway there are multiple wires and such going to the stud.
    Thanks for the info and I'll keep you posted.
  5. cleanslate

    cleanslate Senior Member

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    Oh, last dumb question . Where does my boats 12V DC grounding go to from the electrical panel then? To that underwater tube or the engine block ?
  6. Capt Ralph

    Capt Ralph Senior Member

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    Any bonding wire or strap should NOT be used for ships DCv negative return (ground) ever.
    Not to be confused with ships 115/230 Vac leads, your bonding wires may be green or white.
    DCv cables should be black, red or yellow. These are guides, subject to what the ships mfg had on hand may have well been used AND, any cluck since.

    If a bonding strap does terminate on these tubes, then it is just a part of the ships bonding and dissipater.

    A newer DaynaPlate can replace those old tubes-o-drag.

    From your DCv panel, both connects should go directly (or best path) to the batteries.
    Avoiding the block.
    You certainly do not want to share any engine wires with the rest of the boat.
  7. Oscarvan

    Oscarvan Senior Member

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    That does smell like SSB.....
  8. Capt Ralph

    Capt Ralph Senior Member

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    There must be miles of that strapping in my Bertram. The factory SSB copper straps were considerably wider and took corners and bends with a fold. Near artwork.
    The later Icom tuner just had a #6 green wire.
    We have two very large DaynaPlates Under us strapped as static dissipaters.
    Out bridge top is made of alloy near a half tower.
  9. cleanslate

    cleanslate Senior Member

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    Ok, thanks I will look into it at some point. Yes my 12 volt DC does go to the batteries...duh, I knew that already but I do confuse easily. I've got so many projects on that old tub of mine while it's out of the water for the winter. I never winter out of the water, but had to this year to tackle many things I've been putting off. That old tube thing is one of them.
    I should have named my boat '' Transducer'' , I just removed two last week. Leaving the holes open till they turn the water back on so I came do a good scrubbing and clean the bilge, makes for two nice drain holes got em' port and starboard of the keel for now! Lol.
    Another one is old but going to stay in cause its flush with the hull and still works an old depth unit. I put in a shoot through the hull unit for my Simrad GPS unit. Still have the old Slumlog spinny thing sticking out of the bottom too. That's staying for now .
  10. Capt Ralph

    Capt Ralph Senior Member

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    Shoot thru the hull is good but nothing beats a real transducer in the water. Now you have 2 holes to fill, put a real mans ducer in one of those holes.
  11. cleanslate

    cleanslate Senior Member

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    Lol! I'm good at that! ..But my Airmar transducer does a great job so far for two years. I'm going to fill in both holes WITH...west system. Lol.

    Works fine on that thin almost 1/2'' or so old Ocean hull of mine. At least the bottoms and sides up to the rub rail are solid glass , no wood in my hull till you get to the hull to deck joint...ugh.
    Last edited: Jan 6, 2020
  12. cleanslate

    cleanslate Senior Member

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    Going to the boat tomorrow , going to put on new zincs and do other stuff, anyway like a lot of boats, I have one big zinc mounted to a thru stud on the transom . Wouldn't that be my grounding / bonding plate for all things bonded in the bilge ?
  13. Capt Ralph

    Capt Ralph Senior Member

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    No, as you said, that is a big zinc. A sacrificial anode.
    It may be connected directly, indirectly or not at all to the copper tubes but it has a different roll in life.
    The zinc is to protect all it is connected to by letting its softer material get eaten away by galvanic erosion.
    The tubes are there to offer better electrical connection to the sea water. Hopes this helps.

    I may be able to expand on this late tonight when I get back in and crack a new bottles seal. Still may not make any more sense so lets go with this.

    So much for retirement. I'm off to install fresh 7030 injectors in a 12V71TA.
  14. cleanslate

    cleanslate Senior Member

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    Ok got it. Think my tubes are staying for now. Not sure what the do yet, on my boat. But they do not leak or move or nothing. They are way low now on my list of things to do while I'm out for the winter. I'll live with the light drag they create. I'm a 12 knot guy on a 12 knot boat .

    But not in my CC Dory! Lol that's my Aqua-Harley! Fast and fun and a bit safer than a Motorcycle. Which is something I would like , but my need for speed at times that would not be a good thing on the bike.
  15. cleanslate

    cleanslate Senior Member

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    Ok I did some simple observations yesterday on my bronze tubes.

    From the thru stud in the engine room there are the following connections ;

    1 - A wide bronze wire mesh strap kind of inbedded in the fiberglass / gelcoat going to who knows where?

    2 - My single strand uncoated bronze or copper wire which goes to all sea cocks.
    Which I need to replace in the forward bilge near my #1 bilge pump. It's eaten away by some old wires hanging in the bilge which I removed by previous owners .

    Where do I get that wire, just use the stuff used for houses etc. lots of copper wire on line ? Grainger ? Can I use green stranded ground wire which I have already ?

    3 - A larger wire coated wire like a small battery cable running to an un known place , maybe bridge / helm top?
  16. Capt Ralph

    Capt Ralph Senior Member

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    I use #8 Green Ancor wire in the bilge. This has tinned copper leads.
    Better shrink crimp lugs. Fresh bronze (not brass or stainless) nuts or screws when attaching to the thru hull.
    Galvanic current/voltage is not much so you want to keep the connects clean and resistance low to avoid bilge side voltage drops over a bad connect.
    When a vertical strap is needed, maybe a #4 or larger cable as it may be used for dissipating charge (static or lightning).

    The original factory bonding wires were probably the cheapest material that would just-do the job when built. If their connects are still dry and clean (no patina), them leave them alone.
    But when in doubt, swap them out.

    Now would be a good time to get closer to your thru hulls while checking out the electrical connects, to further inspect the backing plates, hose clamps and cock operation.

    Speaking of hose clamps, I have found many attempts of using a hose clamp to attach a bonding strap to a thru hull. Sometimes even factory.
    I am not a fan of this and when approved by the owner, I can usually find a better way to make a strap connection.
    If you find this on your boat, look around, there is always something to bolt or crew to.
    I remember drilling and tapping into a plug bolt on an old Chinese cock once.
    Last edited: Jan 26, 2020 at 12:28 PM
  17. Capt Ralph

    Capt Ralph Senior Member

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    I found On/Off gel cleaner to really clean up bronze. Just brush a lil on the area that needs to be cleaned. You will need a large fan with good air source. The reaction gives off one wallop of a gas.
    Rinse with water and let dry.
    I use a bronze/brass mini wire brush (tooth brush sized) to further clean up the contact area and then apply a dab of NO-OX-ID as a contact grease then make my connect.

    Be careful down in tem dar bilges, dar be monsters dun thar..


    https://www.sanchem.com/electrical-contact-lubricant.html
    Last edited: Jan 26, 2020 at 12:43 PM
  18. cleanslate

    cleanslate Senior Member

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    Lol! I see Bigfoot in my bilge at times! No water it's winter up here in Yankee land. It's all shut off . I'll use bronze wool and sand paper. Good to know , all of it. It's just not my bag anything electrical , but I can work on it out of necessity.
    Good to know about the bronze washers and nuts . I would have used S/S which I have in my Yacht stock room.

    All my Cocks are in fine working order! Just worked one today!
    No scary stuff going on with them. Many of my bonds are good. But I know of one bond wire that is bad, gets wet a lot with bilge water at lowest point in my boat while at the dock. Ocean used uncoated wire. At least on my old boat.

    Thanks a million on your years of knowledgeable information you give here on YFs. It saves people like me a whole lot of time and certainly makes me look/sound nautically smarter than I really am....but I'm still learning. This goes for many others on here to, lots of know how info.
    This shared info helps keep a lot of us keep on enjoying and keeping our vessels, which other wise might go up for sale in disgust.