Volvo sterndrive anodes

[Battgirl 23]

Hi everyone some advice please on changing the large anode on the Volvo sterndrive ie the one behind the prop housing. Is this an easy diy or should it be left to so-called professionals?

It doesn't need doing right now I am just being proactive. Cheers

[Bogan 8]

If it's a 120 sail drive then the prop has to come off to change the anode.

 

Can be done pretty quickly, eg: on the floating dock when getting a scrub down.

 

The time is in taking off the prop and cleaning that up, and putting it all back together well.

 

Make sure you tighten the two screws that hold the anode on real tight - you don't want the anode coming loose.

 

The guys at the floating dock are pretty experienced and will likely give you a hand.

[Battgirl 23]

Awesome Bogan. Thanks. Have a great Christmas

[Island Time 1,234]

Yeah, easy enough, but the prop does have to come off. By the way, it's a saildrive, not a sterndrive - that is what some powerboats have

 

I sometimes change my anodes in the water - like tomorrow! The Kiwi Prop is pretty easy to remove - the volvo 3 blade folder was a PITA!

[Young Entertainer 59]

what is the issue with the anode coming loose?  I noticed mine was loose when I washed last time so planning on fixing it after xmas when I am out of the water mid Feb,  doe sit just mean that the other three on the saildrive after the housing might deteriorate faster?

[Island Time 1,234]

Unfortunately this type of anode never stays tight. The zinc erodes behind the screws, effectively making them loose. I've never found a solution for that. I think it does make the anode less effective, as I'd expect it reduces the electrical connection to the boat - but I've never measured it.

I have had the screws come out completely - once loose the anode can move a bit, and I guess over time they vibrated out. Did not seem to do any damage though...

 

A better anode has a galv bar thru it to bolt it to the boat, the bolt does not go thru the zinc, but with a saildrive anode of this type there is no option I know of.

[Battgirl 23]

Indeed IT it is a sail drive. Thank you for the correction and advice

[Farrari 4]

I watched Grant from Allvo marine replace my anode on my 120S the other day.  Some of the observations I made

• He was meticulous about cleaning the surfaces where the anode butts up to the saildrive and used a cleaner that didn't leave a residue
• He used a lead based grease on the mounting bolts
• He went through a process of tightening the bolts, tapping them with a mallet and re-tightening three times over
• He used a punch on the anode where it butted up against the bolts to reduce the chance of them coming undone

I have had a number of people mention to use the genuine parts because some of the third party products don't last as long.  There also seemed to be a couple of different anode part numbers that needed to be matched with the saildrive.  Using the model 120S wasn't enough to determine what anode to use in my case.

 

My observation was that it didn't take that long to do and while I could easily do it myself, it didn't cost that much to get a professional to do it for me and I had the confidence of a job well done.

 

EDIT:  Mine was a single piece anode that required removal of the prop.

[The big T 41]

Some Volvo saildrives have a three piece anode which is secured into a slot around the saildrive by three bolts which need an Allen Key. Real easy to do underwater.

You should have a quick snorkel to check before committing to a haul out.

[Island Time 1,234]

If it's a 120s, there are models 120s thru 120s D. There have been 3 part numbers for the anodes, now all superceeded by the final one. Yes, a good, clean flush surface and tight bolts is the best way on these one piece anodes. The idea is to try to get the electrical connection to the SD thru as much of the connection surface as possible, so that the current runs thru that surface, not just the bolts. The larger the good contact area, the longer the anode lasts before eventually coming loose as zinc is lost. If it's only the bolts, it does not take long at all!