Rotating Pod Propulsion for Vessel Efficiency
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Solution Overview
Problem
Large water-displacement vessels face challenges in maintaining optimal operating conditions when lightly loaded, as the reduced water contact area increases flow resistance, leading to higher speeds or lower consumption, and require ballast to prevent riding higher, which affects propulsion efficiency.
Innovation Solution
A rotatable pod drive system with a non-vertical axis of rotation and a non-perpendicular propeller shaft, featuring an annular jet pipe that adjusts its position and direction of rotation to ensure effective propulsion both with a large and small draught, allowing the propeller to operate below the water surface even when lightly loaded, using a combination of angle adjustments and reverse rotation to minimize air suction and maximize water intake.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the vessel is lightly loaded, then the water contact area decreases and flow resistance decreases, but the vessel rides higher and propulsion efficiency deteriorates
Solution Approach 1:
The pod drive system is made dynamically adjustable through rotation about a non-vertical axis, allowing the propeller shaft to change its angle relative to the horizontal plane. This dynamic repositioning enables the system to adapt to varying loading conditions, maintaining optimal propulsion efficiency whether the vessel is heavily or lightly loaded by adjusting the propeller's operational angle to compensate for changes in water contact area and resistance characteristics
2Productivity
If ballast is added to maintain optimal operating conditions when lightly loaded, then propulsion efficiency improves, but the vessel weight increases
Solution Approach 1:
Instead of changing the vessel's weight by adding ballast, the invention changes the operational parameters of the pod drive system. By rotating the pod drive about a non-vertical axis, the system adjusts the propeller shaft's angle and position relative to the water surface, thereby modifying the hydrodynamic parameters to maintain optimal propulsion efficiency without adding weight to the vessel
3Productivity
If the propeller shaft is arranged horizontally for optimum thrust, then propulsion efficiency is maximized, but the system cannot adapt to varying loading conditions
Solution Approach 1:
The pod drive system transitions from a fixed horizontal configuration to a dynamic system that can rotate about a non-vertical axis. This allows the propeller shaft to change its orientation relative to the horizontal plane, enabling adaptation to varying loading conditions while maintaining high propulsion efficiency through optimal angular positioning in each operating state
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
Enables efficient propulsion of vessels with minimal ballast, allowing for sailing with a low draught without compromising propulsion efficiency, as the propeller and jet pipe design effectively manage air and water flow, ensuring effective operation across varying loading conditions.
Implementation Method 1
a propeller shaft (5) which protrudes through the housing (4) and to which a propeller (6) is attached, wherein said propeller shaft (5) defines a first axis
Implementation Method 2
the direction of rotation of the propeller shaft (5) in the forward position is adjustable in such a way that the jet pipe (17) has a water-suction effect
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to a vessel and a method for driving a vessel. Said vessel is provided with a pod arranged at the rear side thereof which is arranged rotatably with respect to the vessel. Rotation is effected about an axis which deviates slightly from the vertical. According to the invention, the axis of the propeller shaft forms an angle which is smaller than 90? with the axis of rotation of the pod. As a result of this combined positioning of the rotation shaft of the pod and the positioning of the propeller shaft, the axis of the propeller shaft with respect to the horizontal will vary when the pod is rotated depending on the rotation position of the pod. This permits optimum adaptation to the various operating conditions of the propeller position.