Combined propulsion using electric outboard motors and rim-driven thrusters is a preferred solution for small vessels, unmanned surface vehicles, and working boats to achieve high efficiency, low noise, and high maneuverability. The complementary advantages of the two systems can significantly improve endurance, controllability, and reliability through proper installation, coordinated control, and scenario-based operation.

1. Equipment Characteristics and Combined Advantages

1.1 Core Characteristics

electric outboard motor: Easy installation, flexible steering, simple maintenance, suitable for main thrust and heading control.

Rim-driven thruster: Shaftless, gearless, direct-drive high efficiency, low noise and anti-winding performance, ideal for auxiliary thrust, precise positioning, and low-speed operation.

1.2 Core Advantages of Combination

Thrust superposition for improved acceleration and heavy-load capacity

Dual-unit redundancy for enhanced navigation safety

Balanced high and low-speed performance, more energy-efficient cruising and precise operation

Low noise and anti-winding design suitable for fishery, scientific research, and water operations

2. Installation and Layout Methods

2.1 Installation Position

Main propulsion: electric outboard motor mounted at the stern center for primary power and steering.

Auxiliary propulsion: rim-driven thrusters installed on both sides of the stern or bow for auxiliary thrust, lateral movement, or positioning.

Maintain symmetrical thrust centerlines to avoid yaw and energy loss.

2.2 Mechanical Installation Requirements

Outboard motor: Firmly fixed on the transom, adjust anti-ventilation plate height to avoid cavitation.

Rim-driven thruster: Fully submerged, kept horizontal, with watertight cable protection.

Maintain sufficient distance between the two units to prevent flow interference.

2.3 Electrical System and Power Supply

Use the same type of high-voltage lithium battery packs with dedicated BMS and main switches.

Lay cables separately with waterproof, wear-resistant, and anti-corrosion treatment.

Install insulation and short-circuit protection; do not plug or unplug underwater connectors while powered.

3. Coordinated Control and Operation Methods

3.1 Control Modes

Master-Auxiliary Mode (Recommended)

Outboard motor: Main control of speed and direction

Rim-driven thruster: Auxiliary thrust, stability, and fine adjustment

Synchronous Mode

Both units run at the same speed and direction for maximum thrust and efficiency during straight cruising

Independent Mode

Separate control for in-situ turning, lateral translation, and precise mooring

3.2 Standard Operation Procedure

Power-on self-test: Check voltage, communication, and fault alarms

Low-speed running-in: Operate at low power for 1–2 minutes

Starting: Activate the outboard motor first, then gradually turn on the rim-driven thruster

Steering: Mainly controlled by the outboard motor, assisted by the rim-driven thruster for correction

Deceleration: Reduce power of the rim-driven thruster first, then the outboard motor

Shutdown: Stop units sequentially, check for leaks and fasteners

3.3 Key Operating Skills

Straight cruising: Balanced output from both units to improve efficiency and range

Heavy load / headwind: Full power from both units to maintain stable speed

Mooring / operation: Idle the outboard motor, use the rim-driven thruster for fine positioning

Anti-winding: Stop the rim-driven thruster immediately if entangled; do not force forward/reverse rotation

4. Optimal Application Solutions by Scenario

5. Maintenance and Safety Specifications

Rinse salt and debris after each use; check fasteners and seals

Regularly inspect cable watertightness, motor insulation, and bearing conditions

Avoid long-term full-load operation of a single unit; prefer combined output

Reduce use of rim-driven thrusters in rough sea conditions to prevent impact damage

Long-term storage: Store in dry place, keep fully charged, recharge monthly

6. Applicable Vessel Types

Small fishing boats, inflatable boats, and speed boats

Unmanned surface vehicles, monitoring boats, and working boats

Inland water traffic boats and light yachts

Special vessels requiring high quietness and efficiency

Summary

The electric outboard motor + rim-driven thruster is a highly efficient propulsion solution with 1+1>2 performance:

The outboard motor handles maneuverability and main thrust, while the rim-driven thruster ensures efficiency, quietness, and precision.

Following the logic of “master-auxiliary coordination, synchronous cruising, and independent fine adjustment” achieves comprehensive improvements in endurance, controllability, and reliability.