Helper Vessel Ship Positioning Offshore Transfer
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Solution Overview
Problem
The challenge in transferring fluid cargo offshore is exacerbated by difficult weather and wave conditions, which complicates the positioning and mooring of ships alongside floating offshore storage facilities, leading to inefficiencies and safety concerns, particularly with existing tug-based systems that struggle in high waves and currents.
Innovation Solution
A method and system utilizing a helper vessel connected to the ship, which applies thrust to facilitate sideways movement and positioning, allowing the ship to be brought into a side-by-side configuration with the storage facility without the need for mooring lines, using a dynamic positioning system and propellers to control movement and heading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If tugs are used to push the ship sideways toward the mooring position, then the ship can be positioned alongside the storage facility, but significant roll motions occur and propeller ventilation reduces efficiency in high waves
Solution Approach 1:
A helper vessel is introduced as an intermediary between the ship and the storage facility. The helper vessel pushes the ship sideways while the ship's own propellers provide forward thrust, eliminating the need for traditional push tugs and their associated roll motions and ventilation problems. The helper vessel acts as a mediator that transfers the pushing force without requiring the ship to be beam-on to waves.
Solution Approach 2:
The mooring operation is segmented into two independent functions: sideways movement is provided by the helper vessel, while forward movement is provided by the ship's own propellers. This segmentation allows each function to be optimized independently, with the ship maintaining its heading for efficient propulsion while the helper vessel handles the lateral positioning.
2Reliability
If multiple tugs are positioned nearby for emergency escape, then quick removal from the storage facility is possible, but the operation becomes complex and time-consuming
Solution Approach 1:
The ship's own propulsion system is utilized to assist in the mooring operation. By having the ship's propellers provide forward thrust while the helper vessel provides sideways movement, the system reduces dependency on external tug vessels for both routine mooring and emergency escape operations, simplifying the overall system complexity.
3Force
If the ship is rolling during mooring, then high mooring line loads are imparted, but slosh damage occurs in the tank containment system
Solution Approach 1:
The helper vessel serves as an intermediary that provides the sideways pushing force without requiring the ship to roll. This eliminates the harmful rolling motion that causes both high mooring line loads and slosh damage in the tank containment system, while still achieving the necessary lateral positioning.
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 approach enables efficient and stable side-by-side transfer of fluid cargo, reducing roll motion and sloshing risks, and allows for quick emergency disengagement, potentially eliminating the need for tugs and improving safety and operational efficiency in challenging weather conditions.
Implementation Method 1
The propeller may be rotated to generate thrust, so as to push or urge the ship with a component of force sideways toward and/or against the floating storage facility
Data Source
AI summary
A method is for performing an approach to position a ship in side-by-side configuration alongside a floating offshore storage facility, for transfer of fluid cargo between the floating offshore storage facility and the ship. The method may comprise connecting a helper vessel to the ship, moving the ship on an approach path toward the floating offshore storage facility using the helper vessel, and obtaining a component of sideways movement of the ship by applying thrust from the connected helper vessel, to facilitate moving the ship on the approach path and position the ship in the side-by-side configuration. The ship can be brought into the side-by-side configuration alongside the floating offshore storage facility, at least one transfer pipe can be connected between the ship and the floating offshore storage facility, and communication can be opened through the transfer pipe to communicate fluid cargo between the ship and the storage facility.