Hunter 29.5 Marina can't seem to give us the correct placement for our zincs. On the 29.5 the prop shaft length out of the boat is only 2 1/2 inches. They have put a round zinc on that very short shaft area each of the last 2 years, but everytime it is pulled, the zinc, the hardware is always gone. We aren't sure if it lasts a day a week or a year. Is there any other place to put the zinc? Is there a bottom, or wing area? Thanks
- Status
Right on the shaft
If I follow you, you do want a round zinc put on the short shaft area. And yes, at the end of the season it will probably be gone. I went with two zincs and have a small piece of one left at the end of the season. There is some debate that installing two zincs simply doubles the available area for electrolysis but does nothing to double the amount of time you get. Jury's still out but I use two. Finally, I learned something important about installing zincs last year - don't just hand tighten them with a screwdiver, even if you have the right tip. Instead, be sure to use an allen wrench and tighten it as tight as possible. (half of a zinc was left, causing incredible vibration, not because it wore off but because it wasn't tightened down enough and literally came unscrewed). Hope that helps. Paul
If I follow you, you do want a round zinc put on the short shaft area. And yes, at the end of the season it will probably be gone. I went with two zincs and have a small piece of one left at the end of the season. There is some debate that installing two zincs simply doubles the available area for electrolysis but does nothing to double the amount of time you get. Jury's still out but I use two. Finally, I learned something important about installing zincs last year - don't just hand tighten them with a screwdiver, even if you have the right tip. Instead, be sure to use an allen wrench and tighten it as tight as possible. (half of a zinc was left, causing incredible vibration, not because it wore off but because it wasn't tightened down enough and literally came unscrewed). Hope that helps. Paul
Zinc on Shaft
I had a zinc come loose a few years back but now I use a zinc that uses allen screws that screw into other half of zinc,use allen wrech to tighten each one a little at a time back and forth and hit each side of zinc with hammer as you tighten each allen screw,don't over do it hitting them with hammer. I have not had a zinc come loose since. nick
I had a zinc come loose a few years back but now I use a zinc that uses allen screws that screw into other half of zinc,use allen wrech to tighten each one a little at a time back and forth and hit each side of zinc with hammer as you tighten each allen screw,don't over do it hitting them with hammer. I have not had a zinc come loose since. nick
The Secrets of Zincs
I had posted a question not long ago about zincs disappearing in 90 days or less. I have checked the boat and boats around me. The marina is supposedly checking the dock wiring. I'm not holding my breath. Went under the boat the other day, water 60 degrees in Florida, Brrrrr, and installed two zincs. I was told that if you use two zincs they should be in contact with each other or they can be at different electrical potentials, increasing the galvanic action. Don't know if that is a necessity or not but the other way did not work so I'm trying it. Instead of hanging another sacrificial zinc over the side, (those guppies that West Marine sells for just a little below a mortgage payment), I have chosen to hang a piece of aluminium, a more noble metal, until I get this issue resolved. Will let you know how this works
I had posted a question not long ago about zincs disappearing in 90 days or less. I have checked the boat and boats around me. The marina is supposedly checking the dock wiring. I'm not holding my breath. Went under the boat the other day, water 60 degrees in Florida, Brrrrr, and installed two zincs. I was told that if you use two zincs they should be in contact with each other or they can be at different electrical potentials, increasing the galvanic action. Don't know if that is a necessity or not but the other way did not work so I'm trying it. Instead of hanging another sacrificial zinc over the side, (those guppies that West Marine sells for just a little below a mortgage payment), I have chosen to hang a piece of aluminium, a more noble metal, until I get this issue resolved. Will let you know how this works
There are zincs and there are zincs
Someone (ABYC?) rates zincs and some are a lot better than others. The zinc needs an electrical connection to the metal needing protection and it needs to be as direct as possible. Therefore, the keel or wing will probably not work. If your zincs are disappearing in such a short time, you have an issue which can be very expensive. You may want to add a galvanic isolator or check it if you have one. They are a very simple device which introduces a known voltage drop to the incoming ground circuit. They are simply a pair of diodes back to back in series with the ground line as I understand them. Assuming your own boat is ok electrically, the problem might be (and usualy is) caused by your neighbors boat or the marina wiring. The "Guppy" is a good plan or just wire up a bunch of old zincs and use them the same way. I would not ever count on aluminum for corrosion protection. If you have access to a reference electrode, you can measure voltages with a meter and figure out the problem. The marina may and should have one.
Someone (ABYC?) rates zincs and some are a lot better than others. The zinc needs an electrical connection to the metal needing protection and it needs to be as direct as possible. Therefore, the keel or wing will probably not work. If your zincs are disappearing in such a short time, you have an issue which can be very expensive. You may want to add a galvanic isolator or check it if you have one. They are a very simple device which introduces a known voltage drop to the incoming ground circuit. They are simply a pair of diodes back to back in series with the ground line as I understand them. Assuming your own boat is ok electrically, the problem might be (and usualy is) caused by your neighbors boat or the marina wiring. The "Guppy" is a good plan or just wire up a bunch of old zincs and use them the same way. I would not ever count on aluminum for corrosion protection. If you have access to a reference electrode, you can measure voltages with a meter and figure out the problem. The marina may and should have one.
Nick, Alan is giving up a 'go fast secret'
We all should be grateful. Thanks Alan. The only drawback with that zinc location is that it is useless as a shaft retaining device, should the coupling fail to hold the shaft pulling-down in reverse. For back-up, add a pair of opposing hose clamps to the shaft just in front of the log. Now I'm doing it. Thanks again Alan.
We all should be grateful. Thanks Alan. The only drawback with that zinc location is that it is useless as a shaft retaining device, should the coupling fail to hold the shaft pulling-down in reverse. For back-up, add a pair of opposing hose clamps to the shaft just in front of the log. Now I'm doing it. Thanks again Alan.
Actually,...Fred
...a pair of large plastic wire ties work better. The plastic ties will be less likely to change the balance on the shaft and they will not have a galvanic responce to the zinc. Also for removal, a sharp knife will do the trick whereas a rusted clamp can be a pain to remove.
...a pair of large plastic wire ties work better. The plastic ties will be less likely to change the balance on the shaft and they will not have a galvanic responce to the zinc. Also for removal, a sharp knife will do the trick whereas a rusted clamp can be a pain to remove.
Alan, the clamps go inside the boat.
where they can be maintained and inspected. And the worm gears are installed opposite of each other so as to neutralize balance. An old hot rodding trick is to use clamps on a car drive shaft and move them about to find better balance. And to rely on nylon cable ties to keep a shaft in the hull is basically a useless gesture. They slip too easy.
where they can be maintained and inspected. And the worm gears are installed opposite of each other so as to neutralize balance. An old hot rodding trick is to use clamps on a car drive shaft and move them about to find better balance. And to rely on nylon cable ties to keep a shaft in the hull is basically a useless gesture. They slip too easy.
- Status