I think there's some resistance test for the probe--not sure. THe meter head is just a dumb volt meter, so if that goes away you can use a digital VOM instead--it also works better.

If the probe is shot, then you'll need to buy a test probe that you toss over the side. One lead goes to a digital VOM, the other to ground. Not hard to make and use.

Jeff

PS : You'll make lots of friends at your marina if they findout you can test THEIR boat as well!

Peter,

Great write up on how to test the senor on the hard. Possibly Joel, could lock it in the How To thread so others would have a easy time finding it the subject just came recently & I gave out so bummer info telling the member I didn’t think it could be used unless it was in the water.

Norm,
Bigs Live On

If you look at Shane's first photo, it's the round disk on the bottom of the boat.
On my 1982 32' it's located close to the front of the port engine.
The center 2" disk is the reference electrode. The larger 6" disk is just a plastic insulator.

If your anodes are working properly, they will generate a slight electrical charge as they corrode and sacrifice themselves.
Ions from the zinc or magnesium anode will travel to the positive terminal, which is any metal that is more noble.
Aluminum is more noble than magnesium and zinc, so anodes made of those 2 metals will protect our aluminum hulls as long as the potential (voltage) is within a certain range. Below that range and the aluminum is not fully protected. The aluminum starts to act as a sacrificial anode "protecting" other more noble metals like stainless shafts, brass or bronze, by corroding and shedding aluminum ions. This is what happens if a brass cutlass bearing is installed by the boatyard instead of a phenolic or non-metalic bearing.

Look at the pictures of Jeff's bottom. Um, let me rephrase that. Look at the pictures of Jeff's hull.

If the potential is above the safe range you are creating a "battery" that is too big. You have too much anode surface area or you are using magnesium anodes in salt water. That causes the current to pull too many ions from the anode and push them to the aluminum hull. The hull and anodes are no longer polarized (electrically ballanced) and you have begun to electroplate the aluminum with magnesium or zinc.

Sandblasted, barnacled and painted-over Capac reference electrodes can be salvaged as long as the silver disk or screen is still there.
Once you remove the barnacles or paint and get down to the silver, you can use ordinary salt to deposite the chloride back on the silver.

I'll try to attach a diagram of the electrode.

THANKS, I feel so much better when I ama lernin...
Alot more things to see in Marinette Land...





"Figure it out'

John A told me the boat should be in the water about a month to get an accurate capac reading.

Joe

i bought a guppy from john A when i hooked it up there was no change is there a delay on it too?time for water to soak in the metal??sacrifical corrosion to start?


tim

... bought a guppy from john A when i hooked it up there was no change"

Could be you didn't wait long enough. If you're in fresh water, however, and that's a zinc guppy, then it's not going to contribute much anyhow. A magnesium guppy on mine adds about 0.1 volts--and immediately.

Jeff

jeff,i'll check when i get back forgot to this morning.it's suppose to be a magnesium guppy .as soon as the admiral gets home from work we are going back.

tim

jeff ,no change .72 with or without.

tim

Tim:
Have you tested and calibrated the capac meter?