BoatHowTo · video

What this video covers

Aluminum saildrive legs suffer severe galvanic corrosion when electrically connected to more noble metals like bronze propellers, steel dock components, or other boats via a shore power grounding wire.0:38 Because aluminum sits high on the galvanic series, the drive leg acts as a sacrificial anode for these connected metals, often resulting in total unit failure within one or two seasons.Watch To prevent this, install a galvanic isolator or an isolation transformer to break the electrical path between the boat’s grounding system and the shore power ground.1:59 If the drive leg remains connected to the engine and the boat’s DC negative bonding circuit, ensure the leg has dedicated sacrificial anodes and maintain the unit's protective paint coating to minimize exposed aluminum.3:50 Volvo Penta units avoid this issue through a patented system that electrically isolates the drive leg from the engine and the rest of the boat.3:06 Yanmar and other manufacturers explicitly state that drive leg anodes protect only the leg itself, not the broader vessel.4:28 Proper isolation and anode maintenance prevent rapid, expensive structural degradation of the drive unit.4:04

More from BoatHowTo

Boat ELECTRIC PROPULSION with only LEAD ACID Batteries ?? | Ask The Expert with NIGEL CALDERSep 2026MaxProp: More Pitch in Reverse than in Forward? 🤔 | Ask The Expert with NIGEL CALDERSep 2026Common Ground Point with Isolated Saildrives | Ask The Expert with NIGEL CALDERSep 2026How to keep you TANK CLEAN in the days of BIODIESEL.. | Ask The Expert with NIGEL CALDERAug 2026

From BoatHowTo — see the channel’s boat, crew, and every analyzed video.

The Sailing Directory Newsletter

One email with the fleet's best finds — the moments, boats, and stories worth your watch time. Enter your own address to get your own copy.