Hydradrive HD-108 Constant Velocity Propeller Shaft Drive Kit with Thrust Bearing and Adapter

Hydradrive HD-108 Constant Velocity Propeller Shaft Drive Kit with Thrust Bearing and Adapter

The Hydradrive HD-108 Constant Velocity Propeller Shaft Drive Kit is a marine propulsion transmission system designed for engines up to approximately 50 HP. The assembly combines a homokinetic (constant velocity) drive shaft, a self-aligning thrust bearing and a gearbox adapter to provide flexible power transmission between the marine gearbox and propeller shaft.

The system accommodates angular misalignment between the gearbox and propeller shaft while transferring propeller thrust directly to the vessel's hull through the dedicated thrust bearing and its mounting arrangement. This configuration allows the engine to be installed on softer vibration-damping mounts.

Key Features

• Constant velocity drive: Homokinetic shaft with two joints for transmitting torque between misaligned shaft connections.
• Integrated thrust bearing: Transfers propeller thrust directly to the hull through vibration-damping mounting bushes rather than the engine.
• Vibration and noise reduction: Designed to reduce transmitted noise and vibration by up to 90%.
• Self-aligning bearing: Simplifies shaft alignment and installation.
• Flexible installation: Accommodates angular misalignment of up to 2 × 8°, depending on shaft speed.
• Variable-length drive shaft: CV shaft length of 155 ± 25 mm.
• Shaft clamping connection: Secure attachment to the cylindrical propeller shaft end.
• Complete installation set: Includes CV shaft, thrust bearing with clamping hub, selected adapter and fastening hardware.

Technical Specifications

Angular Misalignment and Shaft Speed

The maximum installation angle of each constant velocity joint depends on the operating speed of the propeller shaft.

The maximum specified shaft speed of 5000 RPM does not imply that the maximum 8° joint angle is permissible at that speed. The operating angle must be selected according to the actual shaft speed.

Kit Contents

• Hydradrive constant velocity drive shaft
• Self-aligning thrust bearing with propeller shaft clamping hub
• Gearbox adapter, selected for the installation
• Mounting bolts, nuts and locking components

Available Shaft Diameters

The HD-108 system is suitable for the following propeller shaft diameters:

• 20 mm
• 25 mm
• 30 mm
• 1"
• 1 1/4"

Thrust Transmission and Vibration Isolation

The Hydradrive HD-108 uses a dedicated thrust bearing to transfer propeller thrust to the hull instead of transmitting it directly through the engine and gearbox mountings. The thrust bearing is supported through vibration-damping bushes, allowing softer engine mounts to be used.

The constant velocity drive shaft compensates for angular displacement between the gearbox and propeller shaft. Its variable-length configuration accommodates differences in the installation distance between the two connections.

Operating Load Considerations

The specified shaft torque and thrust ratings are intended for pleasure craft applications operating at full load for fewer than 100 hours. For commercial applications, 60–80% of the stated values should be considered the maximum permissible loading, according to the supplied manufacturer information.

Selection and Installation

Before ordering the Hydradrive HD-108, the following installation information must be confirmed:

• Engine power: Rated engine output.
• Maximum shaft speed: Operating RPM of the propeller shaft.
• Gearbox: Manufacturer, model and reduction ratio.
• Gearbox output flange: Bolt circle diameter and centering diameter.
• Propeller shaft diameter: Required thrust bearing clamping hub size.
• Installation geometry: Available installation length and angular alignment.

The gearbox adapter is selected according to the output flange configuration. The appropriate propeller shaft clamping connection must also be specified when ordering.