Hub 101

To operate effectively, a propeller must spin when driven by, and at the same speed as, the engine's prop shaft. This is done using a "hub system", which connects (adapts) the prop to the propshaft, The hub system also helps provide a level of protection for the engine’s internal components in the event of a hard underwater strike by the propeller.

There are basically two different types of hub systems used in Turbo propellers... the round rubber "pressed-in hub", which is used in a select few of our models, and the "square hub" style, which is used in the vast majority of Turbo props. Regardless of what engine brand you have, with the right Guardian SQ-Lok hub, you’re in the game. Get with your local Turbo propeller dealer for all the details.

Pressed-in Rubber Hub System
Pressed-in Rubber Hub System

These propellers utilize large rubber hubs with a molded-in brass splined insert that are pressed into the much-smaller center of the propeller and are held in place by friction. As this process requires a multi-ton press and specialized alignment tools, this style propeller hubs is not user-serviceable or replaceable. They must be installed and removed by a qualified propeller repair shop. They also dictate the brand and model of engine the propeller can be used on.

Square (Universal) Hub System
Square (Universal) Hub System

For application flexibility and user-convenience, numerous propeller manufacturers today use a “square hub“ type system. These are also known as “universal” hubs. While there are differences between these hub systems in their construction methods and materials used, most are easily interchangeable. If you already have a square-type hub, then all you need is the correct Turbo® propeller for your particular application.

Turbo propellers are designed to use square hubs, and we proudly recommend Guardian SQ-LokTM Hub Systems. The Guardian SQ-Lok hub system is designed for most brands of outboard or stern drive power, from 20hp to 400hp and beyond. Guardian SQ-Lok hubs are designed to take the punishing power and exhaust heat most of today's modern marine engines deliver. Unlike some other square hub brands, they feature heavy-duty construction with a nylon center core (drive adaptor) with a molded-in interlocking brass spline insert for extra strength and durability.

PROP TIP: Although they're tough, it's a good idea to always carry a spare hub. They're easy to install or replace with common tools, and come with the necessary hardware, to help get you moving quickly and easily. Always make sure to use all of the hardware that comes in these kits, even if it means replacing hardware that’s already on the engine.

Download Hub Application Charts Download Hub Application Charts
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