Mussel Float Damping Plate and Keel for Wave Stability

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Solution Overview

Problem

Existing floats used for suspending mussel crop ropes in marine environments are unsuitable for open waters, as they become submerged and unstable under large waves, leading to the risk of mussels being shaken off due to buoyant forces and potential collapse.

Innovation Solution

A float design featuring a hollow shell with an airtight interior and a damping means that extends laterally to dampen buoyant, rolling, and pitching movements, combined with a keel to minimize rolling, and a valving system for pressurization to enhance stability, allowing secure mooring and reduced risk of mussel loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional floats are used in open unprotected waters, then the floats can be submerged under large waves, but the floats become unstable and may collapse or propel mussels from crop ropes

Engineering Contradiction:
Improvefloat stabilityVSAvoidwave-induced buoyant forces
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The float incorporates a damping mechanism with a piston moving in a cylinder filled with viscous fluid, allowing the float to dynamically respond to wave forces. The piston can move vertically within the cylinder, providing controlled resistance to buoyant forces while maintaining float stability during submersion and emergence cycles

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The damping mechanism changes the effective damping parameter of the float system by using viscous fluid resistance that varies with piston velocity. This provides higher resistance during rapid movements (wave impacts) and lower resistance during gradual movements, stabilizing the float under varying wave conditions

Inventive Principle:
Principle #35Parameter changes

2Force

If the floats are made buoyant to support crop ropes, then the floats can suspend mussels in water, but the buoyant force propels floats out of water to heights above four metres during wave action

Engineering Contradiction:
Improvebuoyant upward forceVSAvoidpropulsion of floats out of water
Core Design Contradiction:
ForceVSObject-affected harmful factors

Solution Approach 1:

The damping mechanism is pre-configured with viscous fluid in the cylinder that provides cushioning resistance before the float is propelled upward by wave action. This beforehand cushioning reduces the acceleration and maximum height of float emergence, preventing mussels from being shaken off while still allowing the float to rise naturally with wave energy

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Stability of the object's composition

If the floats are submerged to depths of up to twenty metres under stormy waves, then the floats can remain in position, but the floats may collapse under water pressure

Engineering Contradiction:
Improvefloat position stabilityVSAvoidfloat structural strength
Core Design Contradiction:
Stability of the object's compositionVSStrength

Solution Approach 1:

The damping mechanism allows the float to dynamically adjust to pressure changes during submersion. The piston movement provides controlled resistance that prevents sudden collapse while allowing gradual compression, and enables the float to slowly return to its original shape when rising, maintaining structural integrity under varying pressure conditions

Inventive Principle:
Principle #15Dynamics

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 float effectively minimizes the impact of wave-induced buoyant forces, preventing excessive upward propulsion and potential collapse, thereby reducing mussel loss and ensuring stable operation even in stormy conditions, while also reducing the risk of mooring rope damage.

Implementation Method 1

a hollow shell defining an airtight hollow interior region

Methodology Applied
Scientific EffectBuoyancy: Archimedes' Principle (Buoyancy)

Implementation Method 2

a damping means for damping buoyant movement of the hollow shell in water in a generally vertical direction

Methodology Applied
Scientific EffectDamping: Damping

Data Source

PatentEP2520163B1A float and a floatable structure
Publication Date: 2014.07.16 RODICON
  • EP2520163B1 patent drawingFigure 1
  • EP2520163B1 patent drawingFigure 2
  • EP2520163B1 patent drawingFigure 3

AI summary

A float (1) comprising a hollow pneumatically pressurisable ovoid shell (5) is provided with a damping plate (12) extending laterally outwardly around the shell (5) for damping vertical upward and downward movement of the float in water during stormy conditions, thereby minimising the effect of the buoyant upward propulsion force acting on the float when the float is submerged in stormy conditions. A keel (18) extends downwardly from the float (5) for minimising rolling movement of the float (1). A pair of coupling plates (22) extending from front and rear ends (19,20) of the shell (5) facilitate coupling of the float (1) between a pair of spaced apart tethering ropes used in mussel growing. A plurality of the floats (1) may be secured between a pair of spaced apart tethering ropes at spaced apart intervals along the tethering ropes for supporting the tethering ropes so that crop ropes impregnated with mussel spawn may be suspended from the tethering ropes for growing mussels. A navigational buoy (60) is also disclosed, which comprises a lower float (61) and a pillar (62) extending upwardly therefrom for carrying navigational and other instrumentation.