Implementation- immersed structures

In the case of cathodic protection by impressed current for fixed structures, the anodes are generally immersed at a rather important distance from the work that need to be protected while trying to minimize the risks of interference with other metal structures (boats in the harbours, etc). For boats hulls, the impressed current anodes are installed on the hull, in the centre of a dielectric screen (shield) in order to avoid too high densities of protection current in the immediate vicinity of the anode (risk of over-protection). 

The galvanic anodes are mainly made from aluminium alloys (Al-Zn-In), from zinc (with controlled composition) or from magnesium. They are fixed on the structure thanks to a system which facilitates their replacement if necessary when they are consumed. For the offshore structures, the calculation relating to the anodes (mass, number) is carried out to cover the lifespan of the work.