Instructions / Assembly

This data is internal to Brunswick.
Solas and Rubex
The Solas and Rubex brands use rubber hubs to dampen both shifts into gear and impacts with submerged objects, softening shock to
the prop shaft and the lower unit's other valuable internal parts. For everyday boating, we use squeeze casting to make less porous and
stronger aluminum blades, which can therefore be thinner throughout the profile for better efficiency that benefits fuel economy,
acceleration, and top speed. For boaters with performance in mind, we have high rake stainless steel designs with aggressive, low drag
blade profiles and adjustable venting.
Installation Guides: https://www.rubexprops.com/propulsion/propeller-hubs/
Understanding Boat Propeller Assemblies
An interchangeable hub propeller assembly
On the Prop Shaft
A typical recreational boating propeller is mounted on a splined prop shaft with a thrust washer, spacer, washer and nut, with some
provision to keep the nut from turning loose, such as tabs on the washer or an additional cotter pin. There are exceptions, like the shear
pin systems that were once widespread, but now most are as discussed here.
Various thrust washer shapes. Not all are splined.
Thrust Washer
The thrust washer is mounted on the prop shaft, between the lower unit and the propeller, and it may or may not have splines. It’s an
important component of a boat propeller’s installation, because it fits the shaft in such a way that will not allow either itself or the
propeller to move forward under thrust, thereby transferring thrust to the shaft and protecting the gear housing and its seal from
contacting the rotating propeller.
A matching taper on the prop shaft and the washer is one effective design that stops a thrust washer from moving too far forward.
The thrust washer also helps to keep the propeller centered on the shaft when the soft inner prop hub fails to do so under adverse high-
torque conditions.
A Rubex interchangeable rubber hub (left) and a pressed rubber Solas hub.
Hub
Inserted in the prop is a splined inner hub, which serves as a shock absorber between the prop blades and the shaft. A good prop hub
should keep the propeller precision-centered on the prop shaft, dampen vibrations and help protect the shaft from the severe shock of
striking a submerged object with the propeller.
There are two basic types of hub (in addition to some rare specialty hubs): a pressed rubber hub or an interchangeable hub. The
pressed hub is semi-permanently forced into position by a high pressure press in a prop shop. By contrast, the interchangeable hub is
easily inserted by the prop installer. Each propeller is designed to use one type or the other. While pressed hubs are made of rubber,
interchangeable hubs are sometimes made of a more rigid material, but we find that rubber interchangeable hubs offer better vibration
dampening.