I used a CAPAC system but it is a PITA. I wondered why the previous owner had disconnected it so I tried it for a year and abandoned it too.
Firstly it uses 12 volt
power so unless you are a cocktail boat, keeping
batteries up becomes a problem. Second, it concentrates the protection at a limited number of electrodes that attempt to cover the whole
hull. With enough voltage to get the correct level of protection as measured by the control cell location, the areas around the electrodes becomes over protected. The DC current in this area causes
ELECTROLYSIS in the seawater forming Chlorine gas bubbles which will eat the antifouling
paint off the adjacent hull and bleach color out in streaks rising to the surface.