抄録
The mathematical calculation of the seawater resistance between rudder, propeller shaft and zinc anode of FRP Ship was performed with the interest to the corrosion protection of the boat. In the calculation, the rudder and the zinc anode, which were perpendicular each other, were converted into parallel plate condenser by the conformal transformation. The mathematical expression of the seawater resistance between the rudder and the zinc anode was obtained by the field mapping method, thus R0=ρ⋅K1′/K1 for the zinc anode of infinite area and R=f1⋅f2⋅R0 for that of finite area, where f1 and f2 indicate the seawater resistance coefficient on the X Z plane and XY plane respectively, ρ the resistivity of seawater, and K1 and K1′ indicate length and distance of electrode. A similar equations were also obtained for seawater resistance between the propeller shaft and the zinc anode. The results of the calculations were found to be in good agreement with the values measured on FRP Ship in real condition.
