Vessel Drag Reduction via Water Shield Outlets
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Solution Overview
Problem
Current solutions for reducing parasitic drag in marine vessels, such as grids and scallop fairings, are either ineffective or unreliable, and existing methods like mechanical covers or inflatable bags are not robust enough, leading to increased energy consumption and resistance.
Innovation Solution
A system that includes water outlets arranged at the junction between the hull and openings in the vessel, creating a water shield to reduce drag by controlling water flow and minimizing parasitic resistance, which can be retrofitted to existing vessels without moving parts on the outer surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If grids are installed at thruster tunnel openings to reduce parasitic drag, then drag reduction is achieved, but transverse thrust is reduced
Solution Approach 1:
The invention extracts the water flow control function from passive grids and implements it through active water outlets that inject water streams. This removes the harmful drag-reducing grids while maintaining their beneficial drag reduction effect through an alternative mechanism that does not interfere with transverse thrust generation.
Solution Approach 2:
The invention introduces water streams as an intermediary substance to control the flow patterns around thruster tunnel openings. These injected water streams act as a mediator between the hull and the external water flow, modifying the boundary layer and reducing parasitic drag without physically blocking the openings or interfering with thruster operation.
2Object-affected harmful factors
If mechanical covers or inflatable bags are used to close thruster tunnel openings, then parasitic drag is reduced, but reliability and robustness decrease due to moving parts and locking mechanisms
Solution Approach 1:
The invention replaces mechanical cover systems with hydraulic/jet-based water outlets. Instead of using mechanical parts that move, lock, and seal physical covers, the system uses controlled water streams to achieve drag reduction. This substitution eliminates moving parts, locking mechanisms, and seals, thereby dramatically improving reliability and robustness.
Solution Approach 2:
The invention employs hydraulic principles by using controlled water streams injected from outlets at the thruster tunnel openings. The water flow is controlled through hydraulic systems (pumps, valves, nozzles) to create the desired flow patterns for drag reduction without any mechanical moving parts in the drag reduction mechanism itself.
3Object-affected harmful factors
If scallop fairings are installed aft of appendages, then parasitic drag is reduced minimally, but device complexity increases
Solution Approach 1:
The invention extracts the drag reduction function from complex external fairings and relocates it to the hull surface itself through water outlets. This eliminates the need for separate scallop fairing structures and their associated mounting, sealing, and maintenance complexity.
Solution Approach 2:
The water outlets serve multiple functions: they can control flow patterns for drag reduction, they can be integrated with existing hull structures, and they can be adjusted or controlled dynamically. This multi-functionality replaces the single-purpose scallop fairings with a more versatile system that reduces overall device complexity.
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 system effectively reduces vessel resistance by more than 3% and provides a reliable, sturdy solution that maintains transverse thrust, overcoming the limitations of prior art methods.
Implementation Method 1
creating a water shield to reduce drag by controlling water flow and minimizing parasitic resistance
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
Disclosed is a system (300A) for reducing drag of a vessel (100), the vessel comprising a hull having a portion below waterline, wherein the hull comprises at least one opening (336, 338) in the portion below waterline, and wherein the system (300A) comprises at least one water outlet (402) arranged at the at least one opening (338) and means (302) for feeding water to the at least one water outlet.