RECTANGULAR HARNESS ANODE

Function and technical context

Rectangular sacrificial anodes for Arneson systems are the galvanic shield for submerged components in the surface transmission. Made of zinc or aluminum alloy depending on the navigation environment, they act as a negative electrode in the galvanic pair, attracting electrolytic corrosion and thus protecting the noblest metal parts of the Arneson drive—shafts, propellers and casings—against the attack of salt, brackish or fresh water. Without a healthy anode, galvanic corrosion silently degrades the transmission's structural parts, necessitating major repairs or even complete replacement of the drive.

When to replace this part?

The most obvious symptom of a depleted anode is the visible reduction in its mass: when the anode has lost between 50% and 60% of its initial volume it must be replaced immediately, regardless of the time elapsed since the last replacement. In boats that navigate in salt water or with high electrical activity at the mooring, inspection every six months or at the beginning and end of each season is the practice recommended by nautical maintenance professionals. Replacing the Arneson anode preventively is the cheapest possible investment compared to the cost of repairing a corroded shaft or drive at sea.