In Greece, Lost anode - how long before saildrive damage?

jonrarit

jonrarit

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Bavaria 36 with a Volvo MD2030 and a 130S sail drive

I'm on holiday in greece with 14 days to go. We lost our saildrive anode yesterday (big clonk but no damage)

Currently in Kephalonia and I can get a new anode in a few days if need be.

The question is how much damage would be done if I continued my holiday without the anode or do I lose the three days and await the arrival of a replacement?

thanks in advance

jonathan

S/Y "Mr Fox"
 
Electrolytic corrosion will start as soon as protection is lost. The site and extent of the "damage" will depend on how much motoring you do and how long the anode is missing. I don't have a sail drive, and my hull anode seems to last about 4 years, however, the season I lost the connecting strap across my flexible couplings was enough to start my prop's problem with loss of zinc from the brass. the strap broke about mid season and the zinc loss was quite worrying until I got a professional opinion on it. I'm monitoring it every year and will have to replace it eventually; far sooner than expected. The best advice is to pop off for a few days and come back when the new anode is likely to have arrived and change it then. That way you don't lose any sailing and minimise the corrosion. My understanding is that sail drives have quite an "interesting" mix of dissimilar metals.
 
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Mine is a Yanmar Saildrive. My prop anode gets quite badly eaten by electrolysis during my 6 month season afloat. The Saildrive leg anode can last 2 or 3 seasons without change.

Personally and based upon no science, I'd prefer to replace a missing anode as soon as possible, equally importantly, I'd establish why I lost it in the first place and do something to ensure that the replacement doesn't come off, too.
 
14 days largely on the hook or on town quays with no mains electricity = minimal risk for a Volvo Saildrive, providing the coating is reasonable nick and the Saildrive is properly isolated from the engine.
When you haul out, check the mounting lugs for the anode. I recently helped out a friend by diving on a 130 with a loose anode to sort it out. The original problem had been a nut and bolt working loose, allowing the anode to move about a bit: tightening the nut and bolt wouldn't stop the anode moving about. When I removed it, the mounting holes through the lugs on the Saildrive had worn into ovals, hence it wouldn't tighten up properly. As a temporary fix, I put a washer between the anode and the lug and tightened up the nut and bolt on to that, stopping the movement. I think the original problem was that the fitter didn't use Loctite or similar when he replaced the anode before relaunch.
 
jonrarit said:
Bavaria 36 with a Volvo MD2030 and a 130S sail drive

I'm on holiday in greece with 14 days to go. We lost our saildrive anode yesterday (big clonk but no damage)

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How long had the anode been on the saildrive to start with. Mine( sail drive) lasts a season & my prop anode lasts half a season so really the anodes must be doing something. That will give you an idea if you are in an area of high electrolytic activity.

It is has little to do with how well the bolts re tightened ( provided they are not actually loose to start with) as the anode corrodes around the bolts in the same way that the rest of the anode corrodes so it stands to reason that the bolt will soon have nothing to grip. After a while the best they can do is prevent rotation of the anode
 
Hi Jonathan
Bad luck. To give you a bit more time could you drop another anode over the side in line of sight to the prop?
Donald
 
Aja said:
Hi Jonathan
Bad luck. To give you a bit more time could you drop another anode over the side in line of sight to the prop?
Donald
Click to expand...

Sensible suggestion

But its cable has to be clipped to a suitable point on the saildrive upper gearbox to ensure a good electrical pathway between the lower leg and the hanging anode.
 
Many thanks for the help guys,

Have ordered a new one which will be here tomorrow. There's worst places to be stuck in the world for a day.

Off to practice holding my now ...this is going to be a snorkel job :)

jonathan

PS - It was last years's anode and "looked" ok but obviously not ...... will of course have a spare on board in future too guarantee we will never lose one again :)
 
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