Education... photographic identification of electrolysis.
Fit the SeaBis System - its the most economic way for you to protect your installation.
Winch.
Note:
The paint below the anode has been removed by electrolysis. The anode was prevented from producing any protection by the electrolysis current.
The winch was mounted on a wooden base to a metal deck. Whenever moisture entered the wood (in the mornings from over night dew) it's insulation failed. Resolved by coating the wood with two pack epoxy paint. Non porous paint, while new and continuous, is an insulator. The base will be replaced with very tough plastic at next refit.