Electric Watercraft Motor-Battery Layout for Reduced Hydrodynamic Drag
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Solution Overview
Problem
Recreational watercraft with electric propulsion systems face increased hydrodynamic drag due to their lower position in water, leading to reduced range and difficulty in getting on plane, especially in large vessels like pontoons, as they consume energy at a high rate and are constrained by non-optimal battery pack placement.
Innovation Solution
A watercraft design with an electric propulsion system where the electric motor and battery are positioned forward and rearward, respectively, to balance weight distribution, and a propulsion shaft extends into a channel in the hull to minimize drag, with components being waterproof and buoyant material added for buoyancy, reducing construction complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If electric propulsion system is installed in watercraft, then environmental friendliness and quiet operation are improved, but weight increases causing the watercraft to sit lower in water and increasing hydrodynamic drag
Solution Approach 1:
The patent applies counterweight by positioning the heavy battery pack at the rear of the watercraft to balance the weight distribution. This rearward placement of the battery compensates for the forward position of the electric motor, creating a balanced weight distribution that helps the watercraft achieve proper trim and reduces hydrodynamic drag.
2Ease of manufacture
If battery packs are placed in existing storage spaces, then retrofitting complexity is reduced, but weight distribution becomes non-optimal and ability to get on plane decreases
Solution Approach 1:
The patent moves the battery pack from traditional side-mounted storage locations to a rearward position beneath the deck, utilizing the vertical and longitudinal dimensions of the hull space. This dimensional repositioning allows for optimal weight distribution while still fitting within the existing hull structure, thereby improving planing capability without requiring complete redesign.
3Stability of the object's composition
If electric motor is positioned forward for optimal weight distribution, then weight balance improves, but propulsion shaft length increases and construction complexity increases
Solution Approach 1:
The patent employs a flexible or articulating propulsion shaft that can accommodate the increased length and angular changes required by the forward motor position. This dynamic shaft design allows the propulsion system to maintain proper alignment between the motor and propeller while accommodating the extended distance, thus enabling optimal weight distribution without excessive construction complexity.
4Loss of energy
If hull surface area in water is reduced to decrease drag, then energy consumption decreases, but buoyancy is reduced and weight support capability decreases
Solution Approach 1:
The patent implements local quality by designing the hull with a reduced wetted surface area in the regions that contact water during planing, while maintaining sufficient buoyant volume in the upper portions of the hull. This localized optimization allows the hull to minimize drag during operation while still providing adequate buoyancy to support the watercraft's weight, particularly the heavy electric propulsion components.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design enhances weight distribution and reduces drag, improving the watercraft's ability to get on plane and increase range by optimizing the placement of electric components and maintaining buoyancy.
Implementation Method 1
Waterproof buoyant material is further included to aid in increasing buoyancy
Data Source
AI summary
A watercraft including a hull including a bottom surface, a channel being defined by the bottom surface; a deck disposed above the hull; a battery disposed in a rear portion of the watercraft below the deck; an electric motor disposed in a forward portion of the watercraft, the electric motor being disposed above the bottom surface of the hull and below the deck, the electric motor being electrically connected to the battery; a propulsion shaft operatively connected to the electric motor at a front end of the propulsion shaft, the propulsion shaft extending downward and rearward from the electric motor, the propulsion shafting passing through the bottom surface of the hull and extending into the channel; a propeller connected to a rear end portion of the propulsion shaft; and a rudder pivotally connected to at least one of the hull and the deck.