Ship Hydrodynamic Appendage Layout for Clear Stern Launch Paths

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Solution Overview

Problem

Existing hydrodynamic appendages at the stern of ships, such as military vessels, pose obstacles to the launching of equipment like towed sonars or boats, leading to potential collisions and mechanical stress due to the need for extended launching systems.

Innovation Solution

The hydrodynamic appendage is designed with a convex leading edge, chevron shape, and movable fins to minimize interference with launching equipment, ensuring a clear launch path and adjustable lift control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a hydrodynamic appendage is positioned at the rear of the stern to optimize its hydrodynamic effect, then the flow of water is facilitated and the vessel is helped to right itself, but it creates an obstacle to the launching of equipment such as towed sonars or boats

Engineering Contradiction:
Improvehydrodynamic performanceVSAvoidequipment launching
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The patent positions the hydrodynamic appendage in the water column below the waterline, separating it vertically from the launching area at the stern. This dimensional separation allows the appendage to maintain its optimal hydrodynamic position while clearing the path for equipment launching operations.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent introduces a launching zone that is spatially separated from the appendage area, creating an intermediary space where equipment can be launched without interference from the hydrodynamic appendage. This intermediary zone resolves the conflict between the appendage's hydrodynamic function and the launching operation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If the launching system is lengthened to launch equipment beyond the hydrodynamic appendage area, then equipment can be launched without collision, but strong mechanical stresses are generated

Engineering Contradiction:
Improveequipment launchingVSAvoidmechanical stress
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

By positioning the appendage in the vertical water column below the waterline, the patent creates horizontal space at the stern for launching operations. This eliminates the need to extend the launching system horizontally beyond the appendage, thereby avoiding excessive mechanical stresses while maintaining safe launching clearance.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Stability of the object's composition

If a hydrodynamic appendage is positioned at the stern to provide lifting force, then the vessel is helped to right itself, but it interferes with the launch path of equipment

Engineering Contradiction:
Improvevessel stabilityVSAvoidlaunch path clearance
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The patent positions the hydrodynamic appendage in the vertical water column below the waterline, separating it from the horizontal launching area at the stern. This dimensional separation allows the appendage to maintain its stability-function while clearing the launch path for equipment.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent divides the stern area into distinct functional zones: a lower water column zone for the hydrodynamic appendage and an upper stern zone for launching operations. This segmentation allows both functions to operate simultaneously without interference.

Inventive Principle:
Principle #1Segmentation

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 design allows safe and efficient launching of equipment by avoiding collisions and reducing mechanical stress, while maintaining hydrodynamic performance and stability.

Implementation Method 1

a hydrodynamic appendage positioned at the rear of the stern of the ship... to provide a forward-directed lifting force component... helps to right the vessel by applying a nearly vertical force directed upwards and forwards

Methodology Applied
Scientific EffectHydrodynamic lift: Aerofoil

Data Source

PatentEP4232350B1Hydrodynamic appendage for a ship, and ship comprising at least one such appendage
Publication Date: 2026.01.21 NAVAL GRP
  • EP4232350B1 patent drawingFigure 1
  • EP4232350B1 patent drawingFigure 2
  • EP4232350B1 patent drawingFigure 3

AI summary

Disclosed is a hydrodynamic appendage (1) which is to be installed on the hull (2) of a ship (3), comprises a trailing edge and a leading edge, and is characterized in that the trailing edge includes at least one concave portion.