Dynamic Power Allocation for Floating Vessel Yaw Tracking

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Solution Overview

Problem

Semi-submersibles currently available are unable to react fast enough to the yaw motions of turret moored floating platforms due to their size and power imbalances, leading to challenges in maintaining position and performing maintenance operations without disrupting the platform's operations.

Innovation Solution

A floating vessel system that dynamically allocates 20-35% of its total power as residual thrust to react to the yaw motions of a turret moored floating vessel, using a computer system to calculate and control the power distribution among engine thrusters, ensuring the vessel remains connected and stable alongside the turret moored platform.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If semi-submersibles are made larger and heavier to accommodate more features, then the vessel can carry more equipment and facilities, but the vessel cannot react fast enough to the yaw motions of the turret moored platform

Engineering Contradiction:
Improveequipment capacityVSAvoidresponse speed to yaw motions
Core Design Contradiction:
Quantity of substanceVSSpeed

Solution Approach 1:

The patent applies dynamics by making the power allocation adjustable and adaptive rather than fixed. The system dynamically reallocates power between station-keeping thrusters and yaw-motion compensation thrusters based on real-time operational needs, allowing the vessel to respond quickly to platform movements while maintaining station-keeping capability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the parameter of power distribution dynamically. By varying the power allocation ratio between different thruster groups according to the platform's yaw motion state, the vessel can optimize its response characteristics without changing its physical mass or size.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If more power is allocated to station-keeping to withstand harsh weather, then the vessel can maintain position in rough seas, but no power remains to react to yaw motions of the platform

Engineering Contradiction:
Improvestation-keeping capabilityVSAvoidability to follow yaw motions
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The system uses dynamic power allocation that adjusts in real-time based on the operational context. When the platform requires yaw motion compensation, power is dynamically shifted from station-keeping thrusters to the thrusters responsible for following the platform's motion, enabling both functions to operate effectively.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The power allocation operates in periodic cycles, alternating between station-keeping priority mode and yaw-motion compensation mode based on the platform's operational state, allowing the system to switch between different functional priorities as needed.

Inventive Principle:
Principle #19Periodic action

3Ease of repair

If the floating vessel disconnects from the turret moored platform for maintenance, then maintenance operations can be performed, but the platform loses earnings due to downtime

Engineering Contradiction:
Improvemaintenance accessibilityVSAvoidplatform downtime
Core Design Contradiction:
Ease of repairVSLoss of time

Solution Approach 1:

The floating vessel acts as an intermediary maintenance platform that can operate independently while maintaining connection to the turret moored platform. This intermediary system allows maintenance personnel and equipment to access the platform without requiring the platform itself to disconnect or shut down, enabling concurrent operation and maintenance.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP2989000B1A system and method for dynamically positioning a floating vessel alongside a turret moored floating vessel
Publication Date: 2019.10.16 KEPPEL OFFSHORE & MARINE TECH CENT PTE LTD
  • EP2989000B1 patent drawingFigure 1~2
  • EP2989000B1 patent drawingFigure 3
  • EP2989000B1 patent drawingFigure 4

AI summary

A rapid transition floating vessel that is able to follow the yaw motions of a turret moored floating vessel is provided. The rapid transition floating vessel includes a system and processes for dynamically positioning the floating vessel alongside a turret moored floating vessel whereby the floating vessel remains at a safe distance while being connected to the turret moored floating vessel. This is achieved by the floating vessel following the yaw motions of the turret moored floating vessel as the turret moored floating vessel weathervanes about a centre of the turret moorings.