Usually 2 – 3 years after Drydocking, anodes wasted and replacement is necessary.
Depends the LOA of the vessel, we replace 20 – 60 pieces aluminum anodes by welding or by bolts.
Photo : Anode replacement by U/W welding at bilge keel flat bar.
For vessels equipped ICCP, we replace only at locations like Bow (stern) Thruster, Rudder etc.