Question

Explain the purpose of fitting external anodes to a ships hull.

b) i) sketch a method of securing external anodes to the ship hull.

ii) Show, with the aid of a sketch , where external anodes are placed.

iii) Explain how it may be ascertained that anode replacement is necessary.

Answer.

a) The purpose of fitting external anodes to a ships hull is to protect it against corrosion by using a metal such as aluminum or zinc to form anode of the corrosion cell, in preference to the cathodic steel of the ships hull.

b)

i)sketch

ii)sketch

iii) It can be ascertained that anode replacement is necessary by having an underwater inspection, and checking the amount of anode material left. But generally anodes are designed to last from drydock to drydock, the size of anode used is determined by that length of time.