Introducing Hill Marine’s New Patented Split Loc Propeller Nut
For years, one of the most common calls we’ve received at Hill Marine has been from boaters who lost a propeller because the retaining nut backed off. Whether it’s on a high-horsepower catamaran, a tritoon, or a weekend performance boat, a loose propeller nut can quickly turn into an expensive and frustrating problem.
The marine industry’s traditional answer has been the standard nylon locking nut, commonly known as a nyloc. Some competitors have also attempted to solve the issue with double-nut systems. While these methods may work in certain applications, they still leave room for failure, especially in the high-performance boating world where vibration, torque, and constant load changes push hardware to the limit.
The problem with most so-called “double-nut” systems is simple: for a true double-nut setup to properly lock, you must be able to hold and reverse the first nut into the second nut to create opposing pressure. On roughly 90% of overhub and through-hub propeller applications, that simply isn’t possible due to limited access behind the propeller. In many cases, the second nut is doing little more than acting as a jam nut without achieving the true locking effect required.
That’s where the new Hill Marine Patented Split Loc Nut changes everything.
After years of development, testing, redesigning, and refining, Chad Hill has brought a completely new locking system to market. Multiple prototype versions were built and tested extensively before arriving at the final production design. From our tritoon equipped with a 300 horsepower outboard to high-performance catamarans with over 500 horsepower, the Split Lock Nut has endured hundreds of confidential test hours in real-world conditions.
The results have been extremely promising.
The secret behind the Split Loc design is how it interacts with the propeller shaft threads once tightened. Rather than relying solely on nylon resistance like a standard nyloc, the Split Lock Nut intentionally distorts and conforms to the threads as torque is applied. This creates a mechanical locking effect that resists loosening under vibration and extreme load conditions similar in principle to a Stover-style lock nut, but engineered specifically for marine propeller applications.
The result is a more secure connection, improved reliability, and added peace of mind for performance boaters who demand confidence every time they hit the throttle.
At Hill Marine, innovation has always been about solving real problems boaters face on the water. The new patented Split Loc Nut represents the next step in propeller retention technology, and we’re excited to finally bring it to market after years of development and testing.
This is more than just another propeller nut it’s a purpose-built solution designed for the realities of high-performance boating.
Youe would be "nuts" not to use one of these!!