Retractable Bow and Stern Thruster for Drag Reduction
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Solution Overview
Problem
Conventional bow and stern thrusters for boats are expensive to install and maintain, require hull modifications, and are prone to corrosion, fouling, and increased drag, making them inaccessible for frequent cleaning and vulnerable to damage.
Innovation Solution
A self-contained thruster apparatus with electric motors, batteries, and a wireless controller, integrated into a housing that can be deployed and retracted using a sliding car mechanism along a track or guy line, allowing for secure attachment and removal from the hull without underwater connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional tunnel thruster is installed through hull modifications, then the boat gains thruster functionality for tight quarters handling, but the boat experiences increased hydraulic drag and requires frequent haul-outs for maintenance
Solution Approach 1:
The thruster is mounted on a sliding car mechanism that allows it to move between a deployed position (for thruster operation) and a retracted position (above waterline to reduce drag). This dynamic positioning resolves the contradiction by enabling the thruster to be underwater only when needed for maneuvering, while remaining above water during normal cruising to minimize hydraulic drag.
Solution Approach 2:
The thruster system is separated from the hull structure, allowing independent movement and positioning. The sliding car mechanism divides the system into movable (thruster) and stationary (hull mounting) components, enabling the thruster to be positioned optimally for both performance and drag reduction.
2Adaptability or versatility
If a conventional tunnel thruster is installed through hull modifications, then the boat gains thruster functionality, but the installation cost and complexity increase due to required hull work and electrical routing
Solution Approach 1:
The thruster system is divided into self-contained modules (thruster unit, sliding car, mounting brackets) that can be installed independently without requiring complex hull modifications. The electrical system is segmented with battery packs mounted separately and wired through accessible deck locations, eliminating the need for complex underwater electrical routing.
Solution Approach 2:
The thruster is extracted from the traditional integrated tunnel configuration and mounted externally on a sliding mechanism. This extraction allows the thruster to be installed without cutting tunnels through the hull, using instead simple through-hull fittings or deck-mounted brackets that are much easier to install.
3Power
If the thruster components are positioned underwater for optimal performance, then the thruster can provide effective thrust, but the components become vulnerable to corrosion, fouling, and damage from marine life and debris
Solution Approach 1:
The sliding car mechanism enables the thruster to dynamically change its position between underwater (for thrust) and above-water (for protection). This resolves the contradiction by allowing the thruster to be submerged only during brief periods when maneuvering is needed, while remaining protected above the waterline during extended periods of normal operation.
Solution Approach 2:
The thruster operates in periodic cycles - deployed underwater for brief thrust periods, then retracted above water for extended protection periods. This periodic deployment minimizes exposure to corrosive and damaging marine environments while maintaining thrust effectiveness when needed.
4Ease of repair
If the boat is hauled out of the water frequently for thruster maintenance, then the thruster components can be cleaned and maintained, but the boat owner experiences increased time loss and operational disruption
Solution Approach 1:
The sliding car mechanism allows the thruster to be easily moved between deployed and retracted positions, providing accessible positioning for maintenance without requiring the boat to be hauled out. The thruster can be positioned above the waterline while the boat remains afloat, enabling routine maintenance to be performed at the dock.
Solution Approach 2:
The system is designed to be easily serviceable by the boat owner without requiring professional boatyard facilities. The sliding car mechanism and modular construction allow owners to perform routine cleaning and maintenance themselves by simply positioning the thruster above water at the dock, eliminating the need for costly and time-consuming haul-outs.
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
Eliminates the need for hull modifications, reduces drag, prevents corrosion and fouling, and allows for easy maintenance by retracting the thruster above the waterline, significantly lowering installation and ownership costs.
Implementation Method 1
A sliding car is provided that moves along a guide device with a portion above the waterline and a portion below the waterline
Implementation Method 2
The thruster apparatus includes one or more electric motors operatively coupled with one or more propulsion devices, the one or more electric motors configured to drive one or more propulsion devices
Data Source
AI summary
A bow and stern thruster apparatus includes a motor, a propeller, a battery, a radio receiver, control logic, and power driver circuitry; together forming a fully integrated thruster unit that slides up and down along a guide device to a hull attachment fixture near the water line of a boat. The deployed thruster unit can act as a bow or a stern thruster depending on where the guide device and attachment fixture are mounted to the boat. The thruster unit is retracted by raising it along the guide device to be stowed well above the water line, or to be removed entirely from the hull.