Hamble anodes

[Aldous]

Aldous you might consider amending your survey to include a question about galvanic isolators (not that I'm an expert!) as these have the potential to slow anode wear afaik....

Thanks I have added a question about this in. The link in the above post for the survey now works. Having a galvanic isolator does appear to slow anode decay.

 

[Aldous]

Doubt you will find anything that looks like a pattern. Think about why you have anodes and you will realise that location is only one of many variables that have an effect on the rate of erosion. Dont think either that the Hamble in general will be much different from any other river with marinas and a high concentration of boats.

I agree finding a pattern is unlikely. As anode decay will vary on a boat by boat basis and there are many variables which can have a effect on this. This will hopefully show some of the general theories however. It is unlikely the Hamble will be much different but anecdotal evidence suggests it could be.

 

[Aldous]

Your link does not work on my Mac, however I moor midstream at Foulkes (between the rail and motorway bridges).

I was suffering heavy anode wear for the first two seasons with OB, but this was due to issues with the boat itself now resolved, rather than the river. I also use a dangling anode at the mooring, and I am now getting at least two seasons from a 4kg anode above each shaft. I did think it might have been the brackish water especially after heavy rainfall, and definitely think this contributes to the barnacles, but not the anode wear.

I recall Volvopaul suggesting horrendous anode wear at the Cabin yard, just a couple of hundred yards away, so possibility variations due to localised stray current issues. AC faults are worse than DC ones for anode erosion due to stray current.

Now if you can come up with an anode that also prevents barnacles - well ...

Sorry that the link did not work, it hopefully should again. Your theories are really helpful and interesting, it is amazing such a short distance seems to make a difference. It is possible that the brackish water makes a difference as zinc anodes do not work so well in brackish water, with aluminium sometimes being used. But with the variations in salinity in the area you mention zinc are probably still best. The salinity at Bursledon bridge can vary from 32 ppt down to around 12, so this is a big difference.

 

[davedpc]

Yes your right Trevor it was bad at cabin but worse further up river with the same boat and very slow in Swanwick where I was nearly at the end so more mid river. I wonder how I'll get along now with you at Foulkes.

Im also at Riverside boatyard. I do know that the Hamble was used for the D day landings and the area around my mooring is strewn with 303 cartridges etc etc.

 

[burgundyben]

Might be worth reading this thread I started.

http://www.ybw.com/forums/showthread.php?403541-Current-leakage-radius-affected&highlight=

 

[superheat6k]

B
My Azi was moored at The Cabin, between the A27 bridge and the railway bridge, and suffered very rapid anode wear. She is now at Portishead, and ok so far, but I have added a Galvanic Isolator. I think the current surge where the river narrows at the A27 has an impact, and VolvoPaul had a suspicion about the metal railway bridge.

I thought that was the tide - what's anode wear like off Fawley !!!

(I'll get my coat)