switch to aluminium anodes

[Steve S]

I'm planning to switch Tigerfish to using aluminium anodes this year from zinc ones.

 

I've read they are a suitable for salt water with occasional fresh water use and they are now markedly lower cost than zinc ones.

 

Has anyone any experience of using aluminium anodes?

 

 

 

 

[Jim]

Confused by this Steve,

Your legs are Aluminium.

Are aluminium anodes a different composition so designed to take the crap and melt without harm to your equipment?

 

Jim

[Steve S]

Yes aluminium anodes are a different from the aluminium alloy used in the legs.

[sparky]

I looked into this as they apparently last longer than zincs..........but could not get a bennetau type prop anode in aluminium in this country !

I was told you should not mix aluminium and zincs together on same bonding system.

[Jim]

Proceed with caution.

[Steve S]

Thanks for your comments, seems I may be the first one to use Aluminium anodes.

 

I've ordered Aluminium anodes now to replace all the zinc ones (all knackered) on the boat. so time will tell. I'll let you know the result at next years haul out, if not before...

[Jim]

(all knackered)

Sounds like they're working then.

I just hope next years aluminium ones are not " still like new " after a year afloat.

Good luck Steve. I wish you well.

 

Jim

 

[great white]

Anodes are supposed to be a bit knackered after a season, that's why they are known as sacrificial anodes.

 

I thought [But have not researched to check] that its ally anodes for fresh water with occasional sea, and zinc for sea water.

 

Told that by a Member of the Yacht Club who kept his boat outside his house in Christchurch

[Maverick Martin]

Summary of benefits of each type of sacrificial anodes

 

Zincs are no good in fresh or brackish water but are good in saltwater.

Magnesium is good in freshwater not in saltwater

Aluminium is good in either and lasts longer than zinc 

 

I have just put Zinc anodes on my boat just because that's what I have always done but will look forward to your review Steve and may change over to aluminium next year

[niggle]

I wonder how they will work if the boats next to you have the zinc anodes?????

[Steve S]

Well I will probably find out!  It should not be an issue as they won't be bonded together unlike the anodes on one boat

 

Some clear info here on Zinc and Aluminium pros and cons.

https://www.anodeoutlet.co.uk/aluminium-versus-zinc-anodes/

 

 

[gaffa]

Steve ,

That noble metal chart shows that the aluminium alloys range covers performance that may only be slightly better than mild steel up to nearly as non noble as Zinc.

Basically you need a specific Anode alloy of Aluminium to be effective hence you need to be careful where and what you purchase.

 

I assume unbranded cheapies won't meet the required specs  and really expensive ones should hopefully exceed the specs however ,

there is a big difference in prices between suppliers/brands e.g Mcduff £23 solent anodes £7 for seemingly the same style

 

I was able to find a datasheet from another supplier  which gives a breakdown of constituent parts it might be useful to check against alternative suppliers before deciding on where and what to purchase

 

datasheet

 

Make sure whatever you purchase conforms to the correct MIL specs for sacrificial anodes  and if they can't supply the spec ratings or datasheets walk away .....teaching you to suck eggs I know but better to be safe than sorry.... There's a lot of cr*p on the market

Peteg

[shytalk]

procede with caution if you go to mg duffs website you can enter the info to tell you which to use im dealing with a boat at the moment which had aluminium anodes fitted last year the boat spent the whole time in the north sea the anodes were gone much faster than zinc that was fitted the previous year !!!! could cost more than the few quid saved on anodes 

[Steve S]

I'm using MGDuff and Tecnoseal Aluminium Anodes, boat goes back in the water on Monday 25th March.

 

The expectation is they will last a lot longer, we shall see. Happily I can check 6 of the 8 anodes and if necessary change them without taking the boat out.

 

There certainly is a lot of crap anodes out there, it's taking a risk using them, not something I'm prepared to do.

 

One thing I always do is check the bonding of the anodes to the boat by using a resistance meter (should be near 0 ohm) , doesn't take long and at least you know they are properly attached. If they are electrically isolated they can't do their job.

 

I buy the anodes from Anode Outlet, been doing that for a few years now, their website has got better and better.

[Steve S]

So a year on, how did the aluminium anodes do?

 

Well they worked fine, no evidence of electrolysis on the legs or props.

 

The anodes have all been eaten away a bit but here the REALLY GOOD NEWS, I don't need to buy any new anodes this year, yippee! quite a cost saving.

 

I'll post some photos of them next week after I've been down to the boat but I'd thought I'd let you know now in case anyone else want to reduce their anode costs by 50%!

[Wedger]

Always used Aluminium on Otter. She was on a tidal mooring almost on 'Two Rivers Meet' at the bottom of the Stour, Christchurch. Most seasons they were very knackered - reassuringly! No leg problems or most other parts but the beginnings of an issue with Volvo Ali props which surprised me. Sorted soon enough but had not expected that as they are supposed to be 'top banana' and not 'rot banana'

[niggle]

I used alloy while in Christchurch,tried them in Cobbs gone in 4 months so went to zinc

[jerry.shutter]

Steve,

Thats really interesting.

A how do you replace the anodes you can get at when in the water.

 

i have bought some scuba gear second hand as I used to dive. I was then told you cannot change them under water because of the water pressure behind the bolt will work loose and the anode drops off!

 

B is the resistance meter waterproof or have I got the whole thing wrong! 

[Steve S]

Here are the anodes after 10 months in salt water.

Basically to change in the water I can just lean over from the swim platform to get at them. You can't check the connectivity if replaced underwater.

Water pressure behind the anode causing them to drop off if replaced underwater sounds like a wind up to me!

[jerry.shutter]

So you do replace under the water Steve? 

It was a friend who is a mechanic and has a boat at Christchurch advised me.

If you have been replacing underwater for a period of time I will tell him and I will be very happy 👍👍👍

[Steve S]

No I haven't, all the ones in the photos I could reach from the swim platform if I needed to.

There is one under the outdrive, can't even see it unless I put down a camera on a stick.

[great white]

Nice pictures of the anodes looking as they should

 

Can I ask what your bronze props and stainless cones look like Steve

[Steve S]

perfect Charlie, no electrolysis at all.

 

[great white]

Great decision then Steve, well done Sir