Stern Drive Anodes

[calamitys38]

Hi

Am new to this forum, so aplogies if this has already been answered. I bought a Sealine S38 in Apr this year (2008). The Stern Drive anodes were all new. I lifted the boat end Jul 08 as the stbd collar anode had almost entirely worn away, yet the port one was still OK (although it had worn). I took the boat out of the water for the second time last week for her winter layup and again, the stbd collar anode had worn to about 25% whilst the port one still appeared to have a lot of life left in it.

Is this normal. Engines are Volvlo Kad 300 with SS duoprops.

 

[[2068]]

Having SS props doesn't help.

Physically disconnecting shore power when not in use does help.

If still dissolving, start to suspect other boats, or are there any steel walls nearby?

dv.

 

[wbartram]

This is what you need:

http://www.ybw.com/forums/showflat.php/Cat/0/Number/1630309/an/0/page/0

Plus ALU anodes

http://www.performancemetals.com/default.asp

Regards

William

 

[Piers]

I'd be concerned that one was not being eaten (your port anode) and would want to check all the bonding connections were still correct and well made. If the anode isn't being eaten, something may well be.

Had a similar time on a previous boat (Princess V39) when I found a bonding wire had sheared but had hardly moved from where it should have connected. It was only when I went to move it that it fell free. Re-made it, and the anode began to be eaten again. Never did find what was being eaten in its place!

 

[calamitys38]

Thanks all your replies. Vessel has a Galvanic Isolator and was berthed with only other boats ahead or astern - nothing either side. There was a metal piling post nearby, but only one of these. Disconnected shore-power from Aug to end Oct, then re-connected for Engine Room tube heater to be run. Port anode is being eaten, just not as much (or as apparently as fast) as the Stbd one.

 

[RIN]

I have something similar going on. I used the Sealift at Cowes for a scrub and to change the anodes on my P286 and the port anode was a little bit worn

But the stbd one was considerably more worn

I put this down to the fact that we have a finger berth on the stbd side which contains a lot of metal, but after reading Piers' post above, I will try to find and check the bonding cable

 

[CHI]

I also have an S38 with volvo D4 260hp engines. I also noticed that the zinc anodes were being eaten fairly quickly, but evenly on both drive legs. I also have a galvanic isolator fitted.
Decided to fit the Volvo Active Corrosion Protection system which helped. Anodes still being eaten( which is what you want to see) but at a slower rate. The reference and active anodes do need to be cleaned each lift out to keep the system functioning. Quick easy job though.
Certainly worth checkling all bonding wires on legs whilst out of the water.
Any more info i can help with please feel free to PM me. /forums/images/graemlins/ooo.gif

 

[macnorton]

Took mine out and all anodes/ legs /props /skin fittings etc were all fine. But the stainless ladder that is isolated had been eaten away, /forums/images/graemlins/confused.gif i have now fitted an anode to that! but what the heck is going on there???
Any ideas anyone?

 

[VicS]

To those who find the anode on one drive is not being consumed I would say make doubly sure that it is making good electrical contact with the drive.

As to an isolated stainless steel ladder being eaten away ........ Indeed what the heck is going on. Check that is is isolated I suppose but even then ????? Not made of what you think perhaps. /forums/images/graemlins/confused.gif /forums/images/graemlins/confused.gif

 

[[2068]]

Both those look like variations on "healthy" to me.

dv.

 

[macnorton]

The ladder is stainless and not magnetic, it was factory fitted when she was built!