Cathodic protection of a ship propeller shaftby impressed current anodes

Abstract

This work studies the application of cathodic protection by potentiostatic polarization method with impressed
current anodes for preventing corrosion phenomena on ship propeller shafts made of 17-4PH stainless steel,
in seawater. Tests were carried out on a full scale propeller system (more than 3 m long) by using one or two
activated titanium wires placed lengthwise in the interspace between the shaft and the stern tube. In order
to simulate ship navigation and ship berthed in harbour, flowing (40 L/min) and stagnant seawater were
respectively considered. Both technical solutions, consisting in the use of one or two titanium anodes, were
able to protect the shaft. The results are compared with the data reported in previous works with different
types and geometries of the anode.