NDT – Galvanic Corrosion Inspections

Galvanic Corrosion
Galvanic Corrosion Aluminium Saildrive Strut

Our surveyors perform galvanic corrosion potential surveys to assess, diagnose and troubleshoot galvanic and stray current problems on a boat, yacht or dock.

Please contact us today for a for a free quotation, or please ask for a sample report.

(See also our post about dezincification.)

With a electric potential inspection, we are able to assess the following:

  • Measuring a boat’s hull potential

The hull potential for a vessel is a function of its hull material and its underwater metals. Whether it is an aluminum, steel, fiberglass or a wooden vessel, the hull potential shows if the vessel’s underwater metals are protected against corrosion or not.

  • Verifying the boat’s bonding system

Sacrificial anodes such as zinc anodes attached to the hull of the vessel’s hull provide corrosion protection to underwater metals including but not limited to propeller shafts, metal struts, rudder posts, through-hull fittings, seacocks, stern tubes etc. via the bonding system. We are able to verify each component’s good connection to the vessel’s bonding system.

  • Checking the boat’s galvanic isolation

When a boat’s AC shore cable is connected to a dock’s power pedestal, it is possible for the vessel to galvanically couple to other boats and further underwater metals in the vicinity. We are able to determine the galvanic currents to and from the boat and comment on the possible measures.

  • Locating stray currents on the boat

The most insidious form of marine corrosion is electrical leakage that causes electrolytic corrosion, also known as stray current corrosion. It is able to quickly consume vessel’s sacrificial anodes and critical underwater metal appurtenaces. We are able to detect its existence and pinpoint its cause. It is good practice to have the stray current property of a boat inspected regularly – before the hull starts “to boil” or the submerged fittings start to get pitted or dezincified.