Testing hull anode

Paddydog`1

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When I lifted out this season my zinc anode was in very good nick -TOO GOOD? In plain english how do I test the integrity of the system?
 
What exactly happens if this kind of work doesn't get done..? :confused:

The metal parts it is fitted to protect could, as bebe suggests, corrode.

On the other hand it may only have been fitted as precautionary measure. If so nothing may happen.

It's a only few seconds work now that the boat is out of the water to check for a zero resistance connection between the anode and the stern gear or whatever it is supposed to protect.

If you find good connectivity then all should be well

If you find a high resistance or no connection at all then you have two choices.
Sort out the bonding;
or watch the under water bits and pieces for any signs of corrosion.
 
Not only underwater parts

The metal parts it is fitted to protect could, as bebe suggests, corrode.

On the other hand it may only have been fitted as precautionary measure. If so nothing may happen.

It's a only few seconds work now that the boat is out of the water to check for a zero resistance connection between the anode and the stern gear or whatever it is supposed to protect.

If you find good connectivity then all should be well

If you find a high resistance or no connection at all then you have two choices.
Sort out the bonding;
or watch the under water bits and pieces for any signs of corrosion.

Deterioration will occur on any metal part that is in "contact" with the water that the boat is floating in...especially salt water. So, if you have a pump inside the boat that pumps salt water such as A/C, Head, Bilge, etc...these will deteriorate from the corrosive action. Metal thru-hulls, props, anchor chain, rudder posts, and drive units and drive shafts are very sceptical as well.

This is a link to a fair explaination: http://boatsafe.com/nauticalknowhow/012000tip3.htm

Hope this helps.

Bill
 
QUOTE=[BeBe;3828193]Deterioration will occur on any metal part that is in "contact" with the water that the boat is floating in...especially salt water. So, if you have a pump inside the boat that pumps salt water such as A/C, Head, Bilge, etc...these will deteriorate from the corrosive action. Metal thru-hulls, props, anchor chain, rudder posts, and drive units and drive shafts are very sceptical as well.

This is a link to a fair explaination: http://boatsafe.com/nauticalknowhow/012000tip3.htm

Hope this helps.

Bill
[/QUOTE]

It rather depends on the metals and alloys involved and what combination of metals and alloys there may be that could lead to galvanic corrosion.

Some metals and alloys are to all intents and purposes resistant to sea water corrosion. 316 stainless steel in oxygenated water, tin bronzes, manganese bronze, nickel aluminium bronze, even dezincification resistant brass for example.

The trouble starts when two with more than about 0.1 volt difference in electrode potential are in contact or connected electrically. This means that things like folding props , made of Ni-Al-bronze and stainless steel need the protection of an anode despite them individually being corrosion resistant.

Wherever possible corrosion resistant alloys should be used. Bronze or DZR for through hulls for example.
 

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