In the field of electric boats, breaking through the power bottleneck of a single unit by coordinating multiple outboard motors to achieve high horsepower and high-speed navigation is a core direction that balances environmental protection needs and performance pursuits. Achieving this goal is not a simple stacking of equipment, but requires systematic design from multiple dimensions such as power unit selection, parallel control systems, and hull adaptation optimization, while solving key issues such as power coordination, energy efficiency balance, and operational stability. Combining existing technical achievements and practical cases, this article decomposes the complete path for multiple electric outboard motors to achieve efficient power output.

I. Core Premise: Selection of High-Performance Single Outboard Motors to Lay a Solid Power Foundation

The coordination effect of multiple outboard motors essentially depends on the power quality and energy efficiency of a single unit. Only by selecting high-performance, lightweight, and highly reliable basic units can we achieve a "1+1>2" power gain through parallel operation and avoid dragging down overall performance due to the shortcomings of a single unit.

In terms of motor selection, axial flux motors are preferred over traditional radial flux motors. Their core advantage lies in extremely high power density—taking the axial flux motor of Hub Power as an example, the WAVE300 electric outboard motor equipped with this motor can achieve a powerful output of 300 horsepower, while the system weight is reduced by about 100kg, the volume is reduced by two-thirds, and the overall installation height is lowered by 40%. The lightweight design can effectively reduce hull load, avoid excessive center of gravity caused by multiple motor stacking, improve driving stability, and reduce power loss. In addition, axial flux motors have a fast response speed and can reach full power in 2 seconds, providing support for the instantaneous explosive power of multi-motor coordination.

In terms of motor type, brushless DC motors (BLDC) are one of the optimal choices. Compared with traditional brushed DC motors, BLDC motors eliminate the mechanical brush structure, which not only eliminates noise and wear problems, but also increases motor efficiency to more than 90% and controller efficiency to 95%, with comprehensive energy efficiency improved by more than 20% compared with traditional motors. The efficient energy conversion capability ensures that multiple motors can maintain peak output while controlling energy consumption under high-load conditions, avoiding limited endurance and high-speed duration due to rapid power consumption.

In terms of reliability, products that have passed rigorous environmental verification should be selected. When multiple outboard motors work together, a single unit failure will directly affect the overall power balance. Especially in the marine environment, salt spray corrosion and high-frequency vibration are the main hidden dangers. Outboard motors with 1000-hour salt spray durability can effectively ensure the stable operation of the multi-motor system under complex working conditions.

II. Core Key: Intelligent Parallel Control System to Achieve Power Coordination

The core technical barrier of multiple electric outboard motors lies in coordination control—the traditional independent control method requires adjusting the speed of each unit one by one, which is cumbersome to operate and prone to speed deviations, leading to power internal consumption, hull vibration, and even performance degradation. Through a professional parallel control system, multi-motor speed synchronization, load balancing, and intelligent regulation can be realized to maximize the coordinated power release.

1. Hardware Architecture: CAN Bus + Industrial Computer to Build a Unified Control Network

The hardware core of the parallel system is to establish an efficient signal transmission and control link. It is recommended to use CAN bus to interconnect multiple outboard motors with industrial computers to form a distributed control network. The CAN bus has the advantages of fast transmission speed, strong anti-interference ability, and multiple connectable nodes, which can ensure real-time synchronization of speed commands and operating status signals between the industrial computer and each outboard motor, avoiding coordination errors caused by signal delay.

The system composition should include a signal transmitter, an industrial computer, and control units of each outboard motor: the signal transmitter is responsible for receiving speed commands from the operator; the industrial computer, as the core processing unit, conducts real-time monitoring and command optimization of the operating status of all outboard motors; each outboard motor executes commands and feeds back status through its own control unit, forming a closed-loop control.

2. Control Logic: Speed Synchronization + Fault-Tolerant Protection to Ensure High Efficiency and Stability

To achieve power coordination, the control system must follow three core logics: "unified speed, priority judgment, and fault-tolerant protection". First, multiple outboard motors must maintain the same speed to avoid power conflicts—when the operator inputs a command through the signal transmitter, the industrial computer uniformly judges the commands received by each outboard motor; if a single outboard motor receives a command, it synchronizes the command to all equipment; if multiple outboard motors receive different commands, it automatically takes the highest speed value as the unified control signal to ensure maximum power output.

The fault-tolerant protection mechanism is an important guarantee for system stability. Set a lower speed threshold (such as 1200rpm); when the input command speed is lower than the threshold, the system automatically cancels the command or operates at the lower threshold speed to prevent abnormal motor start-stop caused by misoperation. At the same time, the industrial computer real-time monitors the current, temperature, and vibration parameters of each outboard motor; if a single unit fails, it immediately cuts off its power output and adjusts the load distribution of the remaining equipment to avoid fault spread and ensure the basic driving capacity of the hull.

3. Intelligent Optimization: Dynamic Adaptation to Working Conditions to Improve Energy Efficiency Ratio

Introducing an intelligent control system (such as ExploMar's self-developed SmartCaptain system) can realize dynamic adaptation and optimization of the ship, motor, and propeller. Based on real-time working conditions such as hull speed, load change, and water flow resistance, the system automatically adjusts the power output ratio and speed of each outboard motor to minimize energy consumption while maintaining high speed. For example, in the Monaco Energy Boat Challenge, the multi-motor combination equipped with this system completed the 16-nautical-mile race in 29 minutes with 40% power remaining, and reached a maximum speed of 42 knots in the 3-hour endurance race, fully verifying the role of intelligent regulation in improving energy efficiency and performance.

III. Auxiliary Optimization: Hull and Supporting System Adaptation to Reduce Power Loss

The power output of multiple outboard motors can be fully converted into high-speed performance only by relying on an adapted hull and supporting system. If there are adaptation shortcomings, even with sufficient power, the speed improvement will be limited due to excessive resistance and energy waste.

1. Hull Design: Lightweight + Low Resistance to Optimize Power Transmission

Hull weight is a key factor affecting high-speed performance. Multiple outboard motors themselves will increase equipment weight, so the hull should be made of lightweight materials (such as carbon fiber, high-strength aluminum alloy), and the structural design should be optimized to reduce weight. For example, the energyX 6.3 carbon fiber RIB participating in the MEBC race achieved extreme high-speed performance by virtue of its lightweight hull and adaptation to multiple WAVE300 outboard motors.

The hull line type should adapt to the multi-motor power characteristics, and adopt a low-resistance design to reduce water flow interference—optimize the flatness of the hull bottom to reduce eddy current generation; reasonably design the draft depth to ensure that the propeller is fully submerged in water while avoiding increased resistance due to excessive submersion. At the same time, the installation positions of multiple outboard motors should be symmetrically distributed to avoid hull deviation caused by excessive power on one side, which affects driving stability and power transmission efficiency.

2. Propeller Adaptation: Precise Matching with Power to Improve Thrust Conversion

As the terminal of power output, the design of the propeller directly affects the power conversion efficiency. When multiple outboard motors work together, it is necessary to select a propeller that is accurately matched with the motor speed and torque curve, focusing on optimizing the diameter, pitch, number of blades, and shape: large-diameter propellers are suitable for low-speed and high-thrust scenarios, while small-diameter and high-pitch propellers are more suitable for high-speed conditions; multi-blade design can improve propulsion stability and reduce power loss caused by water flow impact. At the same time, it is necessary to ensure that all outboard motors are equipped with propellers of the same specification to avoid power internal consumption due to thrust differences.

3. Battery System: High Energy Density + Stable Discharge to Ensure Continuous Power

Multiple high-horsepower outboard motors have extremely high requirements for battery energy density, discharge rate, and stability. Lithium batteries (such as lithium iron phosphate batteries) are preferred over traditional lead-acid batteries. They have higher energy density, lighter weight, and can maintain stable voltage output under high load, ensuring that the motor continuously obtains peak power support. The battery capacity should be reasonably configured according to the total power of multiple motors and endurance requirements, and the charging management system should be optimized to improve charging efficiency to meet the needs of high-intensity racing or operation scenarios.

IV. Practical Verification and Precautions

The high-horsepower and high-speed scheme of multiple electric outboard motors has been verified in professional competitions. In the 2025 Monaco Energy Boat Challenge, the ship equipped with multiple WAVE300 electric outboard motors suppressed opponents throughout the offshore race, achieved the first finish, and showed stable extreme condition output capacity in the endurance race, proving the feasibility of this technical path.

Two points should be noted in practical application: first, balanced load distribution—when starting the parallel system, the speed should be gradually increased and the load adjusted to avoid overloading a single unit; second, regular maintenance and calibration—regularly check CAN bus signals, motor status, and propeller wear to ensure control system accuracy and equipment reliability.

Conclusion

Achieving high horsepower and speed with multiple electric outboard motors is the result of the coordination of three core elements: high-performance power units, intelligent parallel control, and hull adaptation optimization. Based on axial flux motors and BLDC motors as the power foundation, building a unified control network through CAN bus + industrial computer, and matching with lightweight low-resistance hull and highly adaptable supporting systems, can not only break through the power limit of a single unit, but also maintain an efficient, stable, and environmentally friendly operating state. With the continuous iteration of electric boat technology, multi-motor coordination systems will be more widely used in racing, leisure, operation and other scenarios, promoting the performance upgrade of green water travel.