McGard Propeller Lock

Why McGard Propeller Locks Are the Gold Standard in Marine Security

When a quality marine propeller can cost hundreds — sometimes thousands — of dollars, protecting it from theft isn't optional. McGard has been engineering precision security hardware since the mid-1960s, and their expertise translates directly into their line of propeller locks — widely regarded as some of the most effective marine theft-prevention devices available.

McGard entered the marine market in the early 1980s, recognizing that boat propellers, outboard motors, stern drive units, and trailer wheels all needed dependable theft protection. Decades later, that commitment to marine security remains a core part of the McGard identity.

Built to Resist Attacks and the Elements

McGard propeller locks aren't just deterrents — they're engineered to defeat real-world theft attempts. A free-spinning collar will turn if attacked by gripping tools without loosening the lock, and the entire assembly is constructed of naval brass and hardened stainless steel for maximum security. That combination of materials isn't accidental: naval brass resists corrosion in saltwater environments, while hardened stainless steel stands up to physical force.

Since 1966, McGard has become known for its unique product designs, and once installed, the McGard propeller lock offers 24-hour protection during use, storage, and transit. Whether your boat is docked at a marina, trailered in a parking lot, or out on the water, the lock is working.

Wide Compatibility Across Major Engine Brands

One of the standout strengths of McGard's propeller lock lineup is its broad application coverage. The product line spans a variety of thread sizes and engine families, including:

• MerCruiser Alpha I, Bravo I (including X and XR), TRS, Vazer, OMC Cobra and King Cobra, Mercury/Mariner 70 hp and larger (2-stroke), Mercury 40 hp and larger (4-stroke), Optimax 75 hp and larger, Verado 135 hp and larger, and Johnson/Evinrude 150 hp and larger (2-stroke).
• Yamaha stern drives (all), Honda 75 hp and larger, Suzuki 40 hp and larger, Yamaha 115 hp and larger, and Johnson/Evinrude 150 hp and larger (4-stroke).
• Johnson/Evinrude 40–140 hp (2-stroke) applications via dedicated thread sizing.

McGard notes that thread sizes can change by manufacturer, so verifying the correct thread size and application before installing locks is always recommended. This attention to fitment accuracy reflects the precision-engineering heritage the company has maintained since its roots in aerospace machining.

The McGard Difference: Security Engineering Expertise

McGard is the nation's leading manufacturer of mechanical anti-theft devices , and that leadership comes from decades of refining security hardware across automotive, industrial, and marine segments. McGard offers the most complete line of marine security fasteners in the industry, machined from stainless steel and naval brass and built to withstand the demands of a harsh marine environment.

For boaters who have invested in a premium propeller, pairing it with a McGard propeller lock is a straightforward way to protect that investment — on the water, on the trailer, and in storage. Browse the full selection of propeller locks or explore everything McGard has to offer across their marine and automotive security lineup.