ANODE SHAFT 1-1/4`` ALUMINUM

Function and technical context

The shaft anode is a cathodic protection element that is installed directly on the tailshaft of the boat, acting as an electrochemical sacrifice to protect the submerged metal parts—propeller, horn, rudder and hull—against galvanic corrosion. This aluminum model is designed specifically for 1-1/4-inch diameter shafts, adjusting precisely with set screws to ensure permanent electrical contact and safe tight torque. The aluminum alloy used in the CMX-5A is the recommended technical choice for salt and brackish waters, where it offers superior electrochemical performance to zinc in terms of active sacrifice potential. If this component deteriorates completely without being replaced, galvanic currents will directly attack the metal surfaces of the propulsion system, causing deep corrosion of the shaft, propeller and stainless steel or bronze fittings, with the consequent risk of structural failure and water ingress.

When to replace this part?

Shaft anodes should be inspected at least at the beginning and end of each nautical season, and replaced when they have lost approximately 50% of their mass, since below that level their cathodic protection capacity is seriously compromised. A clear symptom that the anode has exhausted its useful life is the appearance of pitting, orange stains or superficial corrosion on the shaft or propeller, indicators that the galvanic protection is no longer effective. As a professional standard, it is recommended to replace all the anodes of the propulsion assembly simultaneously and preventively at each annual tune-up, thus avoiding costly breakdowns in areas that are difficult to access during the navigation season.

Compatibility table