I have a shaft coupler from PYI (R&D marine?)... Anyway, they provide a "solution" of installing a jumper between coupling bolts to provide a ground path. They state the purpose as being "if needed". I have had a hard time getting straight scientific answer as to when "if needed" applies. Some people do it by default. Others claim that it is for bonding and electrical protection, others for lighting protection.
I have never installed the jumper. Without better guidance it is my belief that without the jumper now my anodes protect my boat and my boat alone - the shaft and prop exclusively. I have no other underwater metals besides the keel and I don't have the keel tied to battery ground. For limited lighting protection I do have the mast bonded to the keel. I could be convinced that I'm doing it wrong, but for now I know that the prop and shaft are protected. Mike, as a possible solution for your stray currents you could try a shaft coupler... If you have one try removing the ground wire. As for anodes, boatzincs.com has a chart to explain the different metals and salt/fresh/brackish waters. I too like camp for the copper button but to the best of my knowledge they are only available in zinc - No magnesium or aluminum. To ensure electrical continuity I have been using NoOx electrical grease under my aluminum anodes. I also wack them pretty hard while repeatedly tightening the fasteners. Let us know how your search turns out. Josh Muckley S/V Sea Hawk 1989 C&C 37+ Solomons, MD On Sat, Aug 11, 2018, 1:42 PM Persuasion37 via CnC-List < cnc-list@cnc-list.com> wrote: > Thanks Joe > > I think I’m suffering from stray current corrosion. I’m on a ball at the > yacht club and as said earlier, the only time I’m connected to AC is when > Persuasion is on the hard. I’ve started eliminating different devices > looking for the leak. A very slow process. > > Mike > PERSUASION > C&C 37 K/CB > Long Sault > > On Aug 10, 2018, at 3:16 PM, Della Barba, Joe via CnC-List < > cnc-list@cnc-list.com> wrote: > > I am a bit late to this, but FYI: > > Galvanic corrosion is caused by two different types of metal in water that > are electrically connected. The “less noble” metal is the one that > corrodes, which is why we use zincs (or magnesium or aluminum). > > There has to be a path between the metals for this to happen. This can get > much much worse when on shorepower because all the boats in the marina end > up wired together via the green ground wire connection. If no one buys new > zincs but you, guess who supplies the entire marina with anode material? > YOU DO! Galvanic isolators are 100% needed for any boat on shore power for > this reason. > > > > The other form of corrosion is stray current corrosion. This does not need > different metals to work, just electricity flowing through the water. The > current moves metal from one place to the other, this is how electroplating > works. This can be very complicated to track down and can do a vast amount > of damage very quickly. There are a lot of different ways this can happen, > but imagine a boat with the keel connected to the ground bus, a negative > ground engine, and a SSB ground plate with DC connection through to the > radio. We now have 3 different underwater metals connected to the negative > side of the DC system. If the onboard ground bus and wiring are not > perfect, some current will flow through the water too. > > > > Joe > > Coquina > > _______________________________________________ > > Thanks everyone for supporting this list with your contributions. Each > and every one is greatly appreciated. If you want to support the list - > use PayPal to send contribution -- https://www.paypal.me/stumurray > > _______________________________________________ > > Thanks everyone for supporting this list with your contributions. Each > and every one is greatly appreciated. If you want to support the list - > use PayPal to send contribution -- https://www.paypal.me/stumurray > >
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