An approach to design of sacrificial anode cathodic protection systems
for marine steel structures is proposed which is based upon the slope
associated with the linear relationship between potential and current density that arises as each of these parameters (potential and current density) decays with time. A comparison is made between cathodic protection design according to the proposed procedure and to the current recommended practice, an example of each approach is provided, and advantages of the former relative to the latter are discussed. It is demonstrated how the new procedure relates to past and present cathodic protection design practice; but, unlike these, the proposed technique is first principles based as opposed to being Emperical. The procedure inherently accommodates the rapid polarization approach which promotes formation of a particularly protective calcareous deposit and establishment of a low maintenance current density. It is shown also that calculation of the slope of the linear potential-current density relationship which characterizes polarization, in conjunction with
potential survey data, provides the basis of an improved protocol for defining the effectiveness of an existing cathodic protection system.
Key Words: cathodic protection, sacrificial anode, offshore structures, design.