Symptom diagnosis
Boat anodes disappearing fast — causes
An anode's job is to die slowly. When it dies fast — soft, fizzing, gone in weeks — it's reporting an electrical problem somewhere in the water around you.
1. Stray current at the berth
most likelyExternal voltage (a neighbour's wiring, a faulty pedestal, your own equipment) drives current through the water and strips metal at wholesale speed. A Victorian boat lost a $40k bow thruster this way.
Do thisMeasure hull potential with a reference electrode before replacing anything.
The stray-current guide →2. Wrong anode alloy for the water
commonZinc passivates in fresh and brackish water; aluminium suits both salt and brackish; magnesium is fresh-only. The wrong alloy under-protects or over-consumes.
Do thisMatch the alloy to your berth, not the chandlery shelf.
Swap alloys in seconds with IonGuard →3. New metal in the water nearby
worth checkingA new bow thruster, a stainless arch, a neighbour's new hull — the galvanic neighbourhood changed and your anodes picked up the bill.
Do thisA corrosion survey maps who's paying for whom.
Before you spend money
Don't just fit bigger anodes — that's treating the fuel gauge instead of the leak. The workshop's corrosion-testing service measures what's actually happening; monitoring beats guessing.
Want the numbers checked properly?
Tell the Builder about this symptom — it screens for it, and an engineer reviews every recommendation before anything is supplied.