Hanging anode question...

Black Valkyrie

Black Valkyrie

Active Member
Jul 19, 2014
688
Canada
Boat Info
1993 Sundancer 270 DA
Engines
Twin 4.3
So clearly something has changed in my marina. My anodes are dissolving at a far greater rate this season than last... possibly a new (bad) neighbor but who knows... after discovering I already have a galvanic isolator next step is purchasing a hanging 6 lb sacrificial anode (zinc).



Question is where to attach it to. I have twin 4.3s with alpha one gen 2 drives. Currently clamping the clamp to the fin / trim tab anode on one of the outdrives but that got me wondering: clamp is copper, cable is stainless and hanging anode is zinc. Is there an issue clamping copper to the zinc anode? Is there a better place to attach this to? Drawing blanks searching online.
 
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When you say "the bonding system" can you be more specific as to where on the vessel you perceive it to be connected?
 
your negative battery should be connected to both motors and both drives by bonding wires, so any place on the block will work. And if all the underwater metal is not bonded together, better fix it.
 
My boat is just fine and nothing is connected incorrectly. With regards to abode, only instruction specifically says not to connect it to the negative of the battery.
 
Did you test your galvanic isolator to make sure it's working properly? I had one go bad and I detected by testing it after I noticed my underwater zincs suddenly ate away rapidly.
 
Just came across this in my manual.

20180606_231427.jpg
 
importmonkey said:
Just came across this in my manual.

View attachment 56726
Click to expand...

Wow, got me thinking.

"Hanging anodes are a very popular accessory for dockside protection. Boat owners can readily extend the life of their shaft and propeller anodes by connecting a hanging anode to a vessel’s bonding system (e.g., a shroud line on sailboats) and lowering the anode overboard into the water. Hanging anodes are strongly recommended for corrosion protection of vessels with metal hulls; sailboats with limited anodes; and power boats with outdrives and outboards."

http://www.boatzincs.com/hanging_anode_zinc.html
 
Kinda makes sense though... wouldn't you want the stay current NOT going through your boats grounding system? Like a lightning rod has a seperate line to ground, not through the building ground?
 
From the Internet Info I can find when you connect an anode from a Shore Ground to the water you are in essence setting up your own protection area for stray Current. If you connect a hanging Anode to your Isolator then you are adding more/larger places for the stray Current to be dissipated. Though if "all of a sudden" you start losing your sacrificial Anodes faster than you used to, something has changed. Big time. I would start with my own system and make sure that sucker was working properly and that everything Ohmed out like it should. Then, if everything was copa, I would start adding stuff. Don't cover up an issue by adding components to a damaged or improperly connected system. It's a common mistake. I see really smart guys do it all the time.
 
Again... there's nothing wrong with the system on the boat - there are a lot of new neighbors with questionable boats so that's simply diverting from the question at hand
 
Okay... so I called boatzincs.com and had a great conversation with them. Basically need to create a bond to the engine block - they recommended using #8 green to bond a deck cleat to any bolt on the engine. They said the hanging anode would create a 100' radius of protection so anode could actually hang off dock and not the vessel, then just clip to the bonded cleat. (This all applies to boat in salt water fyi)

Also they said that if your anodes are zinc and you're in salt water, in this case the hanging anode is best to be aluminum as the voltage differential then greatly favors the aluminum anode. Either way both will greatly extend the life of your anodes, the aluminum being even more. Wish I had done this last season. Until I can get the bonded cleat installed they said clipping to the trim tab fin was acceptable.

Really good info from their engineer. Thumbs up for boatzincs.com
 
The guppy anode is made from a less noble metal than your other anodes, just like your regular anodes are a less noble metal than your outdrives and underwater gear you are trying to protect. In simple terms you just created a lower hanging fruit for stray current, it will be attracted to the least noble metal in the area. You should see the guppy start deteriorating hopefully at a faster rate than your regular anodes.
 
Black Valkyrie said:
Okay... so I called boatzincs.com and had a great conversation with them. Basically need to create a bond to the engine block - they recommended using #8 green to bond a deck cleat to any bolt on the engine. They said the hanging anode would create a 100' radius of protection so anode could actually hang off dock and not the vessel, then just clip to the bonded cleat. (This all applies to boat in salt water fyi)

Also they said that if your anodes are zinc and you're in salt water, in this case the hanging anode is best to be aluminum as the voltage differential then greatly favors the aluminum anode. Either way both will greatly extend the life of your anodes, the aluminum being even more. Wish I had done this last season. Until I can get the bonded cleat installed they said clipping to the trim tab fin was acceptable.

Really good info from their engineer. Thumbs up for boatzincs.com
Click to expand...
So you never connect it onboard? just leave it connected to the dock? photos? apparently with everyone on shore power in my marina running their air-conditioners its a problem.
 
The alligator clip is clipped to one of the bolts of the port exhaust elbow. Then I have it gorilla duct taped in the "groove" for the ER hatch so it doesn't pull out, then it goes overboard. I take the "fish" out of the water every few days and clean off the growth on the cable and the fish with a deck scrubber. It gets nasty otherwise. Things grow quick in our water.
 
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