Zinc Anode Sizing Calculator
Calculate sacrificial anode requirements per ABYC E-2 cathodic protection standards
Anode Requirements
Recommended Anode Type
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Total Anode Weight Needed
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Hull Anodes
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Shaft Collar Anode
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Prop Nut Anode
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Trim Tab Anodes
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Protected Surface Area
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Current Density
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Anode Material Selection
| Material | Water Type | Capacity |
|---|---|---|
| Zinc | Salt water only | 354 A-hr/lb |
| Aluminum | Salt & brackish | 1,108 A-hr/lb |
| Magnesium | Fresh water only | 500 A-hr/lb |
Cathodic Protection Guidelines
Anode Placement
Hull anodes should be evenly distributed along the waterline, typically at stern, midship, and bow positions.
Shaft anodes (collar type) protect the shaft and prop. Position close to the strut or shaft log.
All anodes must have clean metal-to-metal contact with the hull bonding system.
Replacement Criteria
Replace anodes when 50% consumed (ABYC E-2 recommendation). Never let anodes deplete completely.
Zinc anodes that turn white or powdery in salt water may indicate stray current or wrong anode type.
Never mix anode types on the same vessel - this creates galvanic cells between anodes.