Encyklopedia jachtów
Cathodic protection
Cathodic protection on yachts: sacrificial anodes versus active systems, survey reading, and FairHelm limits on claiming remaining life from photos.
Co to jest
Cathodic protection is the practice of making underwater metals the cathode in a corrosion cell, usually with sacrificial anodes or, less often on leisure boats, impressed-current hardware.
Anchor
On Baltic and North Sea cruisers FairHelm mostly meets zinc or aluminium anodes on shafts, saildrives, and thrusters. Active systems appear on some metal hulls and commercial craft, not as a default on GRP production boats.
FairHelm judgment
FairHelm judgment: treat protection as a circuit, not a sticker. Missing anodes, painted anodes, broken bonding straps, and long shore stays without isolation beat glossy "recently antifouled" claims.
Limits
We do not invent universal change intervals or amp ratings. Alloy must match water type. Ask a surveyor or marine electrician for the boat in front of you.
Najczęściej zadawane pytania
Q: Is cathodic protection only zinc anodes?
A: No. Anodes are the common leisure method. Bonding and shore isolation belong in the same story.
Q: Do GRP boats need cathodic protection?
A: Yes for underwater metals: shaft, prop, saildrive, thruster, bronze fittings. The laminate itself is not the metal at risk.
Q: Can I judge anode life from listing photos?
A: Only roughly. Size, waste, and access matter. Do not buy on photo guess alone.