What Are Zincs/Anodes and When Should You Replace Them?
Sacrificial anodes (zincs in saltwater, aluminum in brackish, magnesium in fresh) corrode in place of your aluminum lower unit. Lose your anodes and electrolysis eats the casing in months.
Skip the maintenance headache.
Monthly turnkey care for $149* — we run your batteries, flush, check anodes, and remind you what's due. Members save 10% on all repair work.
Where they live on your boat
- Powerhead — under the cowling, often forgotten
- Mid-section / leg — bolted plates and trim-tab
- Bracket / transom — separate from outboard plate
- Trim cylinders — small button anodes
- Lift, props, shaft — if you keep the boat in slip
When to replace
Rule of thumb: replace at 50% mass loss. In the Indian River Lagoon and Sebastian Inlet area, that's typically every 6-9 months for trailered boats and every 4-6 months for lift-kept boats. Slip-kept boats get checked every 90 days.
FAQs
How do I know if my anodes are working?
Healthy anodes look rough, pitted, and chalky. Smooth, shiny anodes are passivated and need to be replaced even if they look 'new'.
Need this done on your boat?
Fastest turnaround shop in Vero Beach. Call, text, or request a quote online — we'll get you on the schedule.
Related Guides
The lagoon is brackish but corrosive — what to flush, rinse, and inspect after every trip to make your boat last 20 years instead of 8.
Water pump, thermostats, anodes, and a full 100-hour service rolled in. Why the 300-hour interval is the most important service you'll do on an outboard.