Cathodic Protection Calculator

Calculate sacrificial anode requirements for hull corrosion protection

Total submerged surface area of the hull below the waterline. Can be estimated from LOA, beam, and draft.
sq ft
Steel requires the most protection current. Aluminum needs less but is more sensitive. Fiberglass needs protection for underwater metals (shafts, props, thru-hulls).
Salt water is most corrosive and requires more protection. Brackish is intermediate. Fresh water is least corrosive.
Zinc: standard for salt water. Aluminum: works in all waters, longer life. Magnesium: required for fresh water, highest output.

Results

Current RequiredmA
Anode Weight Neededlbs
Number of Anodes
Replacement Intervalmonths
References: ABYC E-2, MIL-DTL-24779C. Steel current density: 5-15 mA/sq ft in seawater. Zinc capacity: 372 Ah/lb, aluminum: 1108 Ah/lb, magnesium: 500 Ah/lb.