The hub is a component that connects the propeller blades and it is on the ship's exterior. The blades rotate through the water as the hub spins. It is located to the marine shaft through the stern tube and surrounding bearings for torque transfer. It must be adequately lubricated to prevent friction within the stern tube. Saltwater cavitation affects the propeller and the hub. It may lead to structural damage, could affect the vessel's response to maneuvers, and steering to be unpredictable. HMS Hubs, Inc. can provide you wide variety of precision-produced Marine Propeller Hubs. Hub Mercury for 18 to 25 hp by HMS Hubs built of high-strength metal and composite material. With Max. Inside Dia.: 0.740" and *1 7/16" hub cavity. Key Features High strength materials for durability Built with corrosion-resistant materials that can withstand cavitation Smooth operation and top performance hub Reliable and perfect replacement hub for Mercury with 18-25 hp Specifications BRAND: HMS HUBS SKU: VS-3 UPC: VS-3 Weight:0.70 LBS DRIVE TYPE:10 Spline HUB TYPE: Rubber Spindle length: 3.830" (~3 13/16") Flange Dia.: 1.420" Rubber O.D.: 1.640" Uses Wear Ring: none Rubber Duro: 70 Spline count: 10 spline Force, Chrysler 25 hp* Engine ApplicationForce Force, 25 hp 1995-1998 3 1/4" gearcase Mercury Mercury 9.9-25 hp 1980-early manufacture propellers