McGard Stern Drive Lock
McGard Stern Drive Locks: Purpose-Built Marine Anti-Theft Protection
A stern drive is one of the most valuable and vulnerable components on an inboard/outboard boat — and replacing one after theft can cost thousands of dollars. McGard, widely recognized as the nation's leading manufacturer of mechanical anti-theft devices, applies the same engineering discipline it has refined in the automotive world to a complete line of stern drive locks purpose-built for the marine environment.
How McGard Stern Drive Locks Work
The installation couldn't be simpler: you replace one of the stern drive mounting nuts with a McGard lock. There are no special tools required beyond what you'd already use for routine drive maintenance. Despite this straightforward installation, the security technology inside is far from simple.
The lock features McGard's patented free-spinning collar — an innovative design that prevents gripping tools from loosening the lock, effectively thwarting theft attempts while allowing you to use your boat without removing the lock. This means would-be thieves are stopped cold even when using pipe wrenches or locking pliers, the go-to tools for quick marina theft.
Materials Built for the Marine Environment
Saltwater, UV exposure, and constant moisture make material quality non-negotiable on the water. Each lock is precision-machined from high-grade stainless steel and through-hardened for exceptional durability and corrosion resistance in harsh marine environments. The through-hardening process — treating the metal throughout its entire cross-section rather than just the surface — ensures the lock resists both the elements and any physical attack simultaneously.
Each set includes one locking lug, a unique key for secure access, and a protective cover to shield the lock from corrosion and debris. The unique key pattern means no two McGard locks share the same code, giving every boat owner individualized security.
Wide Compatibility Across Major Stern Drive Brands
McGard offers stern drive lock sets in single and twin configurations to match virtually any popular outdrive setup. Compatible applications include MerCruiser Alpha, Bravo I–III (including X and XR), Blackhawk, OMC Cobra and King Cobra, and Volvo SX and DP-S single drives. Theft protection is also available for Yamaha stern drives , with thread-specific sizing ensuring a precise, factory-quality fit for each platform.
Whether you have a single outdrive weekend cruiser or a twin-drive performance boat, these locks fit directly onto the stern drive mounting nuts without requiring removal during boat operation — so security never gets in the way of time on the water.
OEM-Grade Quality You Can Trust
McGard stern drive locks are proudly made in the USA to meet stringent OEM specifications, making them a trusted solution to safeguard your valuable stern drive investment. For boaters who take their equipment seriously, McGard delivers the same confidence ashore as it does on the water.