That’s good advice on sacrificial anodes Josh. Thanks On Tue, Jul 9, 2019 at 1:07 PM Josh Muckley via CnC-List < [email protected]> wrote:
> Edd, > > What would you be using the fish for that you would be trying to help > with? By what metric would you know if they helped? Would you be able to > prove that it was or wasn't helping and determine why or why not? > > Most of the above questions *could* be answered if you had a galvanic > cell and meter and knew how to use them. For steel or aluminum boats this > is a critical tool for determining if sufficient anode protection exists or > remains. For fiberglass boats its probably not worth your time or money. > > Generally shaft and engine zincs are installed /recommended by the > manufacturer to prevent 2 DISSIMILAR metals from experiencing GALVANIC > corrosion. Notice that I didn't say "prevent a single metal from simply > corroding"? Attaching a zinc to a carbon steel plate in or out of the > water will accomplish nothing. The steel plate will still rust and at the > same rate regardless of the zinc. > > If the OEM zincs are being consumed too quickly then a problem *may* > exist. > First, if you are not connected to shore power then you can eliminate it > being a problem with other people's boats or the dock wiring. > Second, you may need to consider the duration of the service interval. > Talk to others regarding their service interval to get a feel for what they > experience. > Third, you may have a zinc that is too reactive for your waters OR for the > material that you are trying to protect. We call them zinc but in reality > they can be made from aluminum, magnesium, OR zinc. Boatzinc.com gives > good guidance in this regard. > Fourth, you may need or want to increase the size of the zinc to provide > more material. > > If you find that the service interval is long or that the zinc seems to > *not* be being "eaten" then it could be that the zinc isn't making good > electrical contact. IMO this is actually the worst case scenario since you > have a false sense of security that your metal is protected. > > So, IMO, the fish are at best a waste of money and at worst masking a > problem. For my 37+ and maybe for yours too Edd there just aren't many > underwater metals that need protecting. All my through-hulls are Marlon > (plastic). The engine didn't come with zincs (evidently the OEM doesn't > recognize a galvanic corrosion risk). Which leaves the shaft and the > prop. A cone on the prop and a clamp-on on the shaft. I've tried more > than one shaft zinc and oversized zincs just for kicks. At the end of the > year there is just more anode to throw away. Doubling up or oversized > would be my solution if a service interval longer than a year were desired. > > Josh Muckley > S/V Sea Hawk > 1989 C&C 37+ > Solomons, MD > > > > > On Tue, Jul 9, 2019, 9:58 AM Edd Schillay via CnC-List < > [email protected]> wrote: > >> Listers, >> >> Every once in a while, I come across a boat with a submerged zinc hanging >> from a wire off the stern of a boat. Some people swear by them and others >> think it’s a wasted effort. >> >> What does the group think? Is it worthwhile to add (especially when on >> shore power) and, if so, where do you connect it on the boat? >> >> All the best, >> >> Edd >> >> >> Edd M. Schillay >> Captain of the Starship Enterprise >> C&C 37+ | Sail No: NCC-1701-B >> Venice Yacht Club | Venice, FL >> >> Starship Enterprise's Captain's Log <http://enterpriseb.blogspot.com/> >> >> >> >> >> >> >> >> >> >> >> _______________________________________________ >> >> 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 > > -- Sent from Gmail Mobile
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