Retractable Marine Propeller Drive Assembly for Shallow Water Navigation
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Solution Overview
Problem
Marine vessels face challenges in navigating shallow waters and transporting over land due to propeller damage risks and height constraints, as existing propulsion systems are not adaptable for reduced size or height.
Innovation Solution
A propeller drive assembly with a retractable propeller drive unit and electric drive means that allows precise control of propeller shaft rotation, enabling the propeller to be positioned within the hull for reduced exposure and compact housing, facilitating safer navigation and transportation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the propeller drive unit is made retractable to reduce propeller exposure, then the risk of propeller damage is reduced, but the device complexity increases
Solution Approach 1:
The propeller drive unit is made dynamically movable between deployed and retracted positions along the longitudinal axis. The suspension mechanism allows the drive unit to move forward and backward, enabling the propeller to be positioned inside or outside the hull as needed, thus reducing damage risk while maintaining operational flexibility
Solution Approach 2:
The propulsion system is divided into separable components: the hull, the propeller drive unit, and the suspension mechanism. This segmentation allows the drive unit to be independently moved and positioned, enabling it to be retracted into the hull for protection while maintaining the integrity of the overall system
2Length of moving object
If the propeller drive unit is retracted into the hull to reduce height, then the vessel can pass under low-clearance bridges, but the device complexity increases
Solution Approach 1:
The propeller drive unit is made dynamically movable between deployed and retracted positions along the longitudinal axis. The suspension mechanism allows the drive unit to move forward and backward, enabling the propeller to be positioned inside or outside the hull as needed, thus reducing damage risk while maintaining operational flexibility
Solution Approach 2:
Instead of reducing height in the vertical dimension, the solution moves the propeller drive unit forward in the longitudinal dimension. By retracting the drive unit into the hull, the vertical height is reduced while the horizontal positioning is adjusted, effectively solving the bridge clearance problem through dimensional transformation
3Reliability
If the propeller is rotated to predetermined position to minimize exposure, then the risk of propeller damage is reduced, but the device complexity increases
Solution Approach 1:
Before the propeller drive unit is retracted or before the vessel enters shallow water, the control system rotates the propeller shaft to a predetermined position where the propeller blades are aligned to minimize exposure. This preliminary action prepares the propeller for the upcoming conditions, reducing damage risk through advance positioning
Solution Approach 2:
The mechanical rotation of the propeller shaft is replaced with an electric drive means that can precisely control and position the propeller at predetermined rotational angles. This substitution enables accurate blade positioning to minimize exposure while simplifying the control mechanism through electric actuation
Data Source
AI summary
A method of controlling a propeller drive assembly attachable to a hull of a marine vessel, said propeller drive assembly comprising a propeller drive unit and a housing for attachment to a hull of the marine vessel on an inside of the hull. The housing defines an inner space and an opening through which at least a portion of the propeller drive unit is movable into and out of the inner space. The propeller drive assembly comprises a suspension mechanism attached to the housing and configured to suspend the propeller drive unit, wherein the suspension mechanism is adapted to move the propeller drive unit between a stowed position and a deployed position. The method comprises a first step comprising triggering rotation of each propeller shaft such that the respective propeller shaft reaches a respective predetermined rotational position and stops at the respective predetermined rotational position, and a second step comprising triggering movement of the suspension mechanism from the deployed position to the stowed position. Each propeller shaft is provided with a respective propeller, and wherein the respective predetermined position of each propeller shaft is such that each respective propeller is at least partly confined within the inner space of the housing when the propeller drive unit is in the stowed position.