Adjustable Flap for Partially Submerged Propeller Wake Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing marine drive systems with partially submerged propellers face inefficiencies at intermediate speeds, leading to reduced maneuverability and speed range, as the propeller does not maintain optimal submerged conditions, and modifications to the hull can negatively impact performance.
Innovation Solution
Incorporating a flap between the transom and propeller to intercept and direct the wake wave, adjusting the propeller's immersion and optimizing its operation at lower speeds, while maintaining efficiency at rated cruise speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the propeller operates in partially submerged configuration at lower speeds, then the watercraft achieves better maneuverability and efficiency, but the propeller cannot maintain optimal submerged conditions across all speed ranges
Solution Approach 1:
The patent employs dynamic adjustment of the propeller immersion depth through a adjustable support structure, allowing the propeller to transition between partially submerged and fully submerged configurations based on operating speed. This dynamic adaptation enables the system to maintain optimal propeller efficiency across the entire speed range, resolving the contradiction between adaptability and productivity.
2Speed
If the watercraft speed increases to rated design speed, then the wake wave moves away from the transom, but the propeller becomes completely submerged or in intermediate configuration losing optimal efficiency
Solution Approach 1:
The adjustable support structure enables dynamic repositioning of the propeller relative to the transom as speed changes. At higher speeds, the propeller can be adjusted to maintain optimal partial submersion despite the wake wave moving away, preserving propeller efficiency across the full speed range.
3Productivity
If the propeller is positioned for optimal operation at rated speed, then efficiency is maximized at cruise speed, but maneuverability and efficiency at intermediate speeds are limited
Solution Approach 1:
The system allows dynamic adjustment of propeller immersion depth, enabling optimal configuration at both cruise speed and intermediate speeds. This eliminates the need to compromise between cruise efficiency and intermediate speed maneuverability, as the propeller can be repositioned according to operating conditions.
4Productivity
If the transom is modified to improve wake wave direction, then propeller operation at lower speeds improves, but performance at cruise speed and maneuverability are negatively influenced
Solution Approach 1:
Instead of permanently modifying the transom structure, the patent extracts the wake wave direction control function to a separate, adjustable component - the flap or baffle element positioned between the transom and propeller. This removable element can be adjusted or removed as needed, improving lower speed operation without permanently compromising cruise performance or maneuverability.
Solution Approach 2:
The patent introduces an intermediary element (flap/baffle) between the transom and propeller to control wake wave direction. This intermediary can be adjusted to optimize wake direction at lower speeds without permanently altering the transom structure, thereby preserving overall performance and maneuverability across all operating conditions.
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 flap effectively directs the wake wave to enhance propeller efficiency at lower speeds, allowing for better maneuverability and maintaining optimal operation across a wider speed range without affecting cruise speed performance.
Implementation Method 1
a flap between the transom and the propeller, positioned so as to intercept the wake wave when the watercraft travels at speed lower than the rated speed
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
A partially submerged propeller drive system (1), of the kind having a partially submerged propeller placed at the transom (T) of a watercraft provided with one or more propellers (2) mounted at the lower part of the transom (T) of a watercraft (S), with the drive shaft projecting astern, allows a more effective directing of the wake wave, so as to achieve at the propellers a working condition at lower speeds nearer to ideal one, partially submerged and at a lower pressure, preventing them to be affected at the rated cruise speed designed for the watercraft and comprises, at each drive shaft, a flap (100) between the transom (T) and the propeller (2), positioned so as to intercept the wake wave (W), when the watercraft (S) moves at a speed lower than the rated speed.