Galvanic isolation

General
Description: Galvanic corrosion is an electrochemical process in which one metal corrodes when it is in electrical contact with another, different metal, and both are in the presence of an electrolyte.
Recommendation: Test your system annually
Documents
Presentation Marine Galvanic Corrosion Made Easy: File:Marine Galvanic Corrosion Made Easy.pdf
Electrolysis Blocker Datasheet: File:Shore Power Electrolysis Blocker.pdf
Links
Cathodic testing procedure: External Link

Potential causes galvanic corrosion

• Erosion of saildrive
  
• Erosion of propellers
  
• Erosion of rudder stock
  
• Erosion of thru hulls
  
• Prop-speed/saildrive paint flaking off
  
• Bottom paint around thruhulls flaking off
  

Risk Factors

• Depleted zinc anodes not replaced
  
• Connection to shore power
  
• Wiring issues
  

Best practices shore power

• Have an isolation transformer installed OR
  
• Have a electrolysis blocker installed