Boats and Hull Potential

A metal hull in water will inevitably have the potential to become corroded. Add a little stray direct current (DC) and this can become devastating.

Mooring your boat in a Marina can be a lottery. Whilst most are safe, reliable and offer a safe haven for your boat there are reasons to take care in checking where you are leaving your valuable craft.

Hull potential requires a Silver/Silver Chloride (Ag/AgCl) reference electrode. This is correct, the key thing here is not that it contains Silver but that is a reference electrode.

The addition of too many (or too large) Sacrificial Anodes will excessively lower the potential of the steel in the water.

The Hull potential measure in millivolts (mV) is simply the potential difference between the boats hull and a controlled Silver/Silver Chloride reference electrode.

From the minute your boat enters the water it starts to rot, corrode or rust.

The most difficult thing for boat owners is to understand what the Hull Potential value should be and what it means for their craft.