Hanging Anode install advice

[farmer.leo]

Just got a hanging zinc to drop in the water while moored between outings. Looking for some advice on bonding the anode to the engine / saildrive.

It's and SD20 saildrive and I there are a few likely candidate bolts on it for a terminal and wire. But how do I get the connection to the outside?

1. connect the wire to an existing stanchion, then clip the anode wire to the stanchion
2. look for a different fitting
3. drill a hole, embed a bolt in epoxy, connect the inside wire with a terminal secured by a nut, same for the external wire to the hanging anode

I've read that stainless steel is not as good a conductor as other metals. So I'm not sure that option 1 (or 2) is ruled out. Also, my first instinct would
be to use a small stainless bolt for option 3. How critical is the voltage drop? How big should the wire be? How big should the bolt be, and what metal?

Interested in both theory, and actual experiences.

 

[pvb]

I've read that stainless steel is not as good a conductor as other metals. So I'm not sure that option 1 (or 2) is ruled out. Also, my first instinct would
be to use a small stainless bolt for option 3. How critical is the voltage drop?

For your purpose, stainless steel is fine. It won't introduce a significant voltage drop.

 

[Tranona]

You could put a bolt up through the deck with a nut on top and enough spare thread to use a dome nut to clamp your hanging wire terminal. The wire would then be removable and the bolt covered when not in use. Make sure the other end is attached to a saildrive housing fastener, not to the engine.

 

[VicS]

For your purpose, stainless steel is fine. It won't introduce a significant voltage drop.

MGDuff supply hanging anodes on a stainless steel wire.

 

[pvb]

MGDuff supply hanging anodes on a stainless steel wire.

Exactly. I think it was Calder who started the ridiculous rumour that stainless steel washers introduced a big resistance.

 

[maby]

I hate drilling unnecessary holes through decks. On our previous boat I installed a terminal in the cockpit locker and ran the wire out under the lip of the lid - never came across a locker that shuts so tightly that it will not let a single core insulated wire past.

 

[Quandary]

On ours I ran a heavy insulated copper wire from the top of the leg back under the cockpit to a bolt in the bulkhead inside one of the cockpit lockers ( the bolt also serves to hold a timber batten with hooks from which warps are hung to be easily reached in the locker) there it is connected to the eye on the end of the bare stainless steel wire of the hanging anode. I used a pinch bolt to form another loop eye about 1/3 of the way along the stainless wire to suspend the zinc from the toe rail so that the anode is in sight and about the same depth as the exposed leg, this serves to take the weight rather than at the wire to wire joint. When not in use the anode sits in the bottom of the locker, when it is deployed the wire emerges from underthe lid via gap at the hand grip recess. (Just like Maby's?) I did consider taking the wire from the leg all the way to the toe rail but then it would not have been as easy to tidy everything out of sight when under way.

 

[David2452]

I do a bit of this in reverse (mag hanging anodes v zinc permanent) as the marinas I do most work in are fresh to slightly brackish and salt as soon as vessels leave the lock for a cruise. Resistivity of copper is 1.68×10−8 whereas stainless is 6.9×10−7 for this reason I use good quality 4mm2 tinned copper well sealed. Enough length should be allowed to allow line of sight between the anode and the component it is intended to protect. I have to replace the anodes for customers on a fairly regular basis but the cable is all still good. I do use stainless fixing bolts but as the tinned eye on the end of each cable contacts either the hanging anode or the vessel bonding they could just as well be plastic as no current flows through them.

 

[farmer.leo]

I hate drilling unnecessary holes through decks.

Yes, my original feeling as well. But if stainless is not a problem, there should be an opportunity to use an existing fitting which are stainless. I'm going to look over the boat again and see about another solution. Thanks for all of the ideas.

Coming out of a locker makes more sense when using it to store the anode. My original thought was to have it hang in a nylon mesh, but the more I think about it the more I realize an anode isn't really a status symbol. ;-)

 

[maby]

Also, think carefully before buying one of the purpose built hanging anodes - they are horribly expensive! I bought a standard peardrop anode at a fraction of the price and soldered a decent thickness copper wire to one end of the steel support bar. The solder took easily with a bit of plumbers flux and a small blowtorch and the result worked fine for a year with plenty of zinc left at the end. Probably not the greatest idea in the world to try the same with a magnesium anode - wouldn't want a blow torch near that!

 

[nigelmercier]

I made my own by soldering a wire to a bolt-on anode, and also attached a hanging cord.

I drilled a hole inside the spare gas locker and fitted a stainless eye bolt, with a wire going off to the saildrive. The eye bolt is used to connect the hanging cord, and the wire via a crocodile clip.

 

[Robin]

Ours (called a 'fish anode over here 'cos it is moulded to look like one) is crocodile clipped to the backstay chainplate and a wire is taken from one of the through bolt nuts on that to the engine which in turn is connected to the gearbox in turn connected to the shaft.... I have cable tied the hanging wire to be just the right length to get the 'fish at prop depth with a clear 'view' of it. For when we leave our berth the 'fish gets lifted and put into a kid's plastic bucket on the stern deck that with a longish line attached doubles as a pee bucket for me at the wheel so I don't rapidly fill the holding tank with a mix of pee and flush water rather than something more substantial that I would rather reserve the space for.

 

[DaveS]

I use a hanging anode made up of all the old half eaten sail drive anodes plus the 10mm rings machined off them to make room for the rope cutter. I have an insulated wire connected to -ve (and the engine etc.) with a crimped spade terminal which emerges from the vent hole above a cockpit cave locker, which the hanging anode plugs into. The hard bit is to remember to remove it before setting off. I do have a large red tape attached to the anode lying across the cockpit seat to remind me, but it doesn't always work...

 

[schrimpy]

Hi , can someone help , had a D2-75 volvo with a sail drive and folding prop which had an anode on prop and anode on saildrive ,

changed boat which is a 2009 bavaria cruiser 50 and had same engine and saildrive but a fixed 3 blade standard prop , on the bavaria i have an anode on sail drive a mushroom anode stuck to hull and no anode on prop. Am I safe to say that fixed props dont have anodes? Can anyone help , maybe owns similar drive/prop ?