游艇百科
Sacrificial anode
Sacrificial anodes on sailing yachts: galvanic protection, survey checks, and FairHelm limits on guessing remaining life from photos.
这是什么
A sacrificial anode is a more active metal (often zinc, aluminium, or magnesium by water type) bonded so it corrodes instead of propellers, saildrives, shafts, or thru-hulls.
Anchor
Nordic marina winters, shore-power earth faults, and mixed metals change wear. FairHelm expects anodes on shaft, saildrive, and sometimes keel or thruster tunnels when those metals are present.
FairHelm judgment
FairHelm judgment: missing, painted-over, or fully wasted anodes are negotiation and survey flags. Fresh anodes alone do not prove the bonding circuit is sound. Ask what was replaced and whether the boat sits on shore power with isolation.
Limits
We do not publish invented amp-hours or "change every N months" as universal law. Water salinity, marina earthing, and alloy choice change life. Follow the surveyor and maker guidance for that installation.
常见问题
Q: Are zinc anodes always correct in fresh water?
A: Not always. Alloy must match water type. Wrong alloy can protect poorly.
Q: Does a new anode mean the boat is safe from electrolysis?
A: No. Check bonding, shore-power isolation, and other metal pairs.
Q: Can I paint anodes to keep them looking tidy?
A: No. Paint blocks them. They must stay bare metal in the water.