Zinc on a line?
- Thread starter Ed H
- Start date
- Status
By line you mean a zinc fish on a stainless steel cable with jumper cable type clips. Connected to mast rigging chain plates or stern railing. Works only if boat is fully bonded. I have two one at stern and one on side chain plate.
Keeps me covered just in case zinc's on prop shaft fall off without telling me.
Below is a link to a thread that I started in April in the Ask-All-Sailors forum on the topic -- but with a twist on the theme for the fish. Instead of a zinc fish, I am using Aluminum Alloy as the anode material. Read the details of the Ask-All thread for the rational.
Subsequent to the thread in April:
- The chandlery staff at one of the major boat yards in my area say that they are gradually phasing out zinc in favor of Al Alloy. Does the same job and lasts longer. And they say Al Alloy is more environmentally friendly than zinc.
- I am having very good results with the Al-Alloy for the fish anode. It does seem to be noticeably retarding the shaft collar zinc's depletion rate. (Yes that one is still zinc.) About 20 days ago, a diver was doing a bottom clean of my neighbor's boat. I asked the diver to check the condition of my shaft zinc. I put on the dock another of the exact same shaft zinc model that I had been using as a fish anode for about 30 days prior to my switching to the Al alloy fish anode. This zinc anode was still looking pretty good, maybe about 10% depleted, so I figured that if the current collar zinc that that had been on my shaft for 5-6 months was looking a bit long-in-the-tooth, the diver could replace it with the 90% still good zinc. The diver came up and reported that the 5-6 month zinc on the shaft looked about the same as the 90% zinc I had put on the dock. So being used as a fish, one shaft zinc depleted in about one month about the same as the other shaft zinc did in 4-5 months with the Al alloy anode also hanging in the water. I will have another collar zinc check in a few more months. But since my collar zinc's typically last 4-6 months, it seems I am way ahead already.
The attached pic's are:
- The 90% collar zinc. The diver said that my current same model five months on the shaft in the water zinc looked the same.
- The Al Alloy anodes that I am using as the "fish". The shiny one is new. The pitted one has been five months in the water protecting my boat. The anodes are actually used by fisherman to protect crab/lobster pots. I've got a many year's supply for less than the cost of one of West Marine's fish zincs.
http://forums.hunter.sailboatowners.com/showthread.php?p=910425&highlight=aluminum alloy
Subsequent to the thread in April:
- The chandlery staff at one of the major boat yards in my area say that they are gradually phasing out zinc in favor of Al Alloy. Does the same job and lasts longer. And they say Al Alloy is more environmentally friendly than zinc.
- I am having very good results with the Al-Alloy for the fish anode. It does seem to be noticeably retarding the shaft collar zinc's depletion rate. (Yes that one is still zinc.) About 20 days ago, a diver was doing a bottom clean of my neighbor's boat. I asked the diver to check the condition of my shaft zinc. I put on the dock another of the exact same shaft zinc model that I had been using as a fish anode for about 30 days prior to my switching to the Al alloy fish anode. This zinc anode was still looking pretty good, maybe about 10% depleted, so I figured that if the current collar zinc that that had been on my shaft for 5-6 months was looking a bit long-in-the-tooth, the diver could replace it with the 90% still good zinc. The diver came up and reported that the 5-6 month zinc on the shaft looked about the same as the 90% zinc I had put on the dock. So being used as a fish, one shaft zinc depleted in about one month about the same as the other shaft zinc did in 4-5 months with the Al alloy anode also hanging in the water. I will have another collar zinc check in a few more months. But since my collar zinc's typically last 4-6 months, it seems I am way ahead already.
The attached pic's are:
- The 90% collar zinc. The diver said that my current same model five months on the shaft in the water zinc looked the same.
- The Al Alloy anodes that I am using as the "fish". The shiny one is new. The pitted one has been five months in the water protecting my boat. The anodes are actually used by fisherman to protect crab/lobster pots. I've got a many year's supply for less than the cost of one of West Marine's fish zincs.
http://forums.hunter.sailboatowners.com/showthread.php?p=910425&highlight=aluminum alloy
Attachments
Rardi....Thanks for the info....I had a friend who inform me not to long ago that I could just reuse the cables and bolt on some cheaper zinc disc or plain zinc bars instead of the fish to save money. The aluminum idea sounds pretty good will have try it out.
Thanks Mon...
Thanks Mon...
OneCoolAir:
Here's the URL to the crab/lobster pot page for the company (a specialist foundry) that I bought my Al Anodes from. Note that they have the same thing in zinc. From recollection, no matter what the shape or size, the $/lb of anode material turns out to be very consistent. They don't make collar or prop zinc shapes.
Price is great ... but shipping does add. However, if you have marina buddies that would agree to share an order --- ?
http://www.rotometals.com/Crab-Lobster-Pot-Anodes-Zinc-or-Aluminum-s/41.htm
Here's the URL to the crab/lobster pot page for the company (a specialist foundry) that I bought my Al Anodes from. Note that they have the same thing in zinc. From recollection, no matter what the shape or size, the $/lb of anode material turns out to be very consistent. They don't make collar or prop zinc shapes.
Price is great ... but shipping does add. However, if you have marina buddies that would agree to share an order --- ?
http://www.rotometals.com/Crab-Lobster-Pot-Anodes-Zinc-or-Aluminum-s/41.htm
My boat is fully bonded from stern rail to bow pulpit. Even the stainless steel rub rail strip down sides of boat is bonded as well as the swim ladder.
My main concern is the prop and all other under water mechanical running rigging. Then there are the metal thru hulls farther forward just behind and next to keel. Thus two zinc's hanging in water....
To make things easier I Hang the cables on the dock cleats in these areas, then connect cable clips to stern rail and mast side chain plates. So when I go to pull out of slip I just unclip and go. Works great when I forget to unclip. The clips just snap off and fall onto the floating dock. Just don't forget the shorepower cord!! Or that forgotten spring line...:naughty:
The hanging zinc must be electrically connected by wire to the whatever it is on the boat that you want protected. Hanging only from a dacron, or nylon, or poly line dock-line won't do it. Generally, the hanging zinc should be electrically wired to the engine block, which in turn is connected to the shaft and the prop, and also to which every other bonded thing on the boat ultimately has electrical connectivity to (i.e. that's the motor block). This is why people clip the fish wire to the standing rigging or the pulpits because usually these have electrical contact with the engine block. That said, the electrical connection for a fish even to the engine may not be as good for prop protection as is a shaft collar zinc or a prop nut zinc. This is because I have read that the thin coating of gear oil can disrupt full flow of electrons between the shaft and the engine. Also the mating flange interface between the propeller shaft and the shaft exiting the transmission can rust, further limiting the electron flow to the prop. The work-around is a shaft brush which maintains constant electrical contact on the shaft inside the boat. The shaft brush is bonded to the engine and then the fish wire is connected to the same spot. So now you have an electrical connection of the fish to the prop/shaft by both the shaft brush and through the transmission gears. A pic of a shaft brush is below. I've done this to my boat.
Attachments
Thanks Rardi- That was my line of thought also but I see several of these in our marina... I was wondering if they knew something that I did not. Ed H
- Status