Aiming at the cathodic protection monitoring technique for large scale floating structures, the pseudo-noise inverse analysis method for the estimation of the electropotential distribution on the surface of floating structures based on the measured potential data in sea water is proposed. Considering the fact that the errors in the measurement are unavoidable in practice, the unknown pseudo-noise variables are introduced into the simultaneous algebraic equations obtained by the boundary element method for the cathodic protection problem, so that the errors induced by the ill-posed matrix in the inverse analysis procedure are controlled successfully, and therefore a rational potential distribution on the surface of the floating structure can be estimated from the measured potential data in sea water. A series of simulating calculations for the floating structure model by changing the noises in the simulated input potential data in sea water show good stability of the inverse solutions with the proposed method, and it may be concluded that the potential distribution on the surface of the floating structure can be reliably estimated from the measured potential data in sea water when the measurement error is less than 10 mV.
For large scale floating structure such as a marine floating air port, covering method with : some anti-corrosion materials such as titanium(Tadokoro et al 1992) and cathodic protection technique(John et al 1977) can be employed to prevent its corrosion in the severe corroding environment, so that a service life of 100 years is expected. Based on the developed cathodic protection techniques for general marine structures, it is possible to make a reasonable design of the cathodic protection system for the submerged part of a large scale floating structure. During the long service life, however, the protection state of the floating structure surface will surely change due to many factors, such as the damage of the sacrificial anodes, marine growth on structural surface, etc..
