Rotatable Vertical Tail Wing for Ship Resistance Reduction
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Solution Overview
Problem
Conventional transport ships with large structures over the water line, such as pure car carriers and container ships, face challenges in reducing both air and underwater resistance while maintaining cargo-holding functionality, as existing solutions either neglect air resistance or increase underwater resistance when correcting for swinging moments caused by wind.
Innovation Solution
The design incorporates a nearly hollow semispherical bow shape to decrease air resistance, a vertically rising tail with a chimney to reduce underwater resistance, and a rotatable vertical tail wing to convert lift into thrust, addressing both air and underwater resistance effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a large structure is provided over the water line to hold cargos, then the cargo-holding function is improved, but the air resistance increases
Solution Approach 1:
The bow is formed in a hollow semispherical shape to streamline the airflow and reduce air resistance. The curved surface allows air to flow smoothly over the structure rather than creating turbulent eddies, thereby reducing the harmful aerodynamic forces while maintaining the necessary cargo volume.
2Stability of the object's composition
If the rudder is adjusted to correct the swinging moment caused by aslant head wind, then the ship's course stability is improved, but the underwater resistance increases
Solution Approach 1:
The vertical tail wing is positioned and shaped to preliminarily counteract the swinging moment before it fully develops. By having the vertical tail wing work as a flap or aileron on the front hinge, the ship can correct its course earlier and with less rudder adjustment, thereby reducing the underwater resistance associated with continuous rudder corrections.
3Use of energy by moving object
If a vertical tail with rotatable wing is provided to convert lift into thrust, then the fuel consumption is reduced, but the device complexity increases
Solution Approach 1:
The vertical tail structure serves multiple functions: it acts as a stabilizer, a rudder, and a wind-powered thrust generator. The rotatable vertical tail wing can function as a flap or aileron depending on the sailing conditions, allowing the same structure to address both stability and propulsion needs, thereby reducing overall device complexity despite the added rotational capability.
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
This design significantly reduces air resistance and underwater resistance, facilitating easier navigation and cargo operations while maintaining energy efficiency and reducing fuel consumption.
Implementation Method 1
forming the structure over the water line in the upper bow portion in at least a nearly hollow semispherical shape, a nearly quarter-spherical shape, holding the bridge and the like in this portion to decrease the air resistance
Implementation Method 2
decreasing the underwater resistance which was so far produced by the rudder adjustment (check helm), and decreasing the underwater resistance of the hull by, further, utilizing the wind force as a thrust relying upon the lift produced by the vertical tail wing
Implementation Method 3
providing a vertical tail of a symmetrical shape in cross section on the stern incorporating the chimney of the engine therein, the vertical wing being rotatable and adjustable and, as required, the rear end thereof working as a flap or an aileron of the front hinge, and, further, adding the leading flap to the vertical tail to cancel the swinging moment imparted to the hull by the aslant head wind or the side wind
Data Source
Figure 1~2A
Figure 2B~4
Figure 5~6
AI summary
Transport ships having a relatively large structure over the water line, such as a pure car carrier, container ship and a passenger ship tend to receive the air resistance during the sailing. When sailing aslant against the wind, check helm had to be effected so far to cancel the swinging moment causing an extra increase in the underwater resistance. A low-fuel-consumption transport ship of the invention has a structure over the water line, comprising the bow of a shape integral with the bridge of a hollow nearly semispherical to quarter-spherical shape or a partly cylindrical shape which is smoothly continuing to the stern to decrease the air resistance. The low-fuel-consumption transport ship further has a vertical tail incorporating a chimney and is rotatable on the uppermost stern deck to cancel the swinging moment in the air, without almost requiring check helm and, therefore, decreasing the underwater resistance.