Thruster Well Maintenance System for Floating Vessels
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Solution Overview
Problem
Current methods for maintaining thrusters on deep draft vessels, such as drill ships and semi-submersibles, are costly, require significant downtime, and pose safety risks due to the need for dry docks, heavy lift cranes, and underwater operations by divers or ROVs, which can lead to accidents and equipment loss.
Innovation Solution
A method that allows thruster removal and maintenance while the vessel is floating, using onboard cranes and a thruster well system with multiple clamps and seals to lift and transport thrusters without external assistance, reducing the need for heavy lift cranes, divers, or ROVs, and enabling safer, faster, and more cost-effective maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If thrusters are removed using conventional methods (dry dock, graving dock, external heavy lift cranes), then the thruster can be removed and maintained, but the vessel loses operating time and incurs high costs
Solution Approach 1:
The invention extracts the thruster removal process from the conventional dry dock environment and performs it directly on the floating vessel using onboard equipment. The thruster is removed through a thruster well opening in the hull while the vessel remains afloat, eliminating the need to take the vessel out of service for dockyard maintenance.
Solution Approach 2:
The invention creates a universal maintenance system that can be used on any deep draft vessel with a thruster well opening. The combination of thruster well, clamps, and onboard crane provides a multi-functional solution that handles both the removal and reinstallation of thrusters without requiring specialized external equipment.
2Ease of repair
If thrusters are removed using conventional methods (dry dock, graving dock), then the thruster can be accessed for maintenance, but the vessel must be taken out of water requiring expensive dock facilities
Solution Approach 1:
The invention changes the maintenance dimension from horizontal (vessel moved to dockyard) to vertical (thruster removed through hull opening while vessel remains afloat). The thruster well opening provides vertical access to the thruster from the hull interior, allowing maintenance while the vessel maintains its floating position.
Solution Approach 2:
The invention introduces a thruster well as an intermediary structure between the hull interior and the external water environment. This well provides a controlled passage for removing and reinstalling thrusters, acting as a mediator that enables maintenance access without requiring the vessel to be in a dockyard.
3Ease of operation
If divers or ROV are used for underwater thruster maintenance, then underwater access is achieved, but safety risks increase due to tool drops, clumsiness, and potential equipment loss
Solution Approach 1:
The invention uses buoyancy as a counterweight force to support the thruster during removal and maintenance. Buoyant bags or balloons are attached to the thruster to counteract its weight, allowing it to be safely handled and positioned by the onboard crane without requiring divers to manually support it underwater.
Solution Approach 2:
The invention enables the vessel to perform its own thruster maintenance using onboard equipment (thruster well, clamps, crane) without requiring external assistance from divers or ROV. The vessel serves itself by having all necessary maintenance capabilities integrated into its structure.
4Force
If heavy lift cranes are used for thruster removal, then the thruster can be lifted from the hull, but the cost and operational complexity increase significantly
Solution Approach 1:
The invention enables the vessel to perform its own thruster removal using its existing onboard crane equipment. The vessel serves itself by having all necessary removal capabilities integrated into its structure, eliminating the need for external heavy lift crane support.
Solution Approach 2:
The invention uses buoyancy forces generated by buoyant bags or balloons attached to the thruster to counteract its weight during removal. This reduces the lifting force required from the onboard crane, allowing standard vessel cranes to handle thrusters that would otherwise require specialized heavy lift equipment.
Data Source
AI summary
A method is disclosed herein for lifting thrusters on vessels enabling for on vessel maintenance at sea. The method can include engaging a thruster mounting flange with a thruster well bottom flange; installing alignment guide plates to provide a rough alignment; positioning a seal to provide a connection; installing fasteners to secure the flanges; actuating clamps to secure the flanges while compressing the seal; raising the thruster out of the thruster well; transporting the thruster to a deck of the floating vessel; actuating clamps to hold the flanges; removing the fasteners; flowing water into the thruster well; disengaging the clamps; and lifting the thruster with the lifting means.