ROV Deployment with Suspended TMS and Short Umbilical
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Solution Overview
Problem
Existing methods for deploying remotely-operated vehicles (ROVs) from vessels are limited by the weight-bearing umbilical, requiring specialized vessels and equipment, and are complex, restricting deployment to shallow waters or needing permanent installations.
Innovation Solution
A method involving a mobile ROV support unit with a TMS/ROV assembly, using a crane to lift the assembly outboard, deploying the ROV underwater while the TMS remains suspended, allowing the ROV to operate independently via a tether, and utilizing a short umbilical managed by a single winch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a dedicated A-frame with TMS is used for ROV deployment, then the ROV can be deployed and operated underwater, but the umbilical must bear the weight of the TMS/ROV assembly which limits deployment depth and requires specialised vessels
Solution Approach 1:
The system divides the ROV deployment function into separate components: a mobile support unit that can be transported on ordinary vessels, and a crane system already present on the vessel. This segmentation eliminates the need for dedicated A-frames and TMS installations on the vessel itself, allowing ordinary vessels to perform ROV deployments without permanent modifications
Solution Approach 2:
The mobile support unit serves multiple functions: it carries the ROV, provides the TMS, and can be rapidly deployed and removed from different vessels. This universal platform can be used on any vessel with a crane, making the system adaptable to various vessel types without requiring specialised ROV support vessels
2Ease of operation
If the umbilical bears the weight of the TMS/ROV assembly, then the ROV can be lifted and deployed, but the thickness of the umbilical limits the depth to which the assembly can be delivered
Solution Approach 1:
The weight-bearing function is extracted from the umbilical and transferred to the crane system. The umbilical now only needs to provide power and data connections, not support the weight of the TMS/ROV assembly. This allows the use of lighter, more flexible umbilicals that can be deployed to greater depths without being limited by weight-bearing requirements
Solution Approach 2:
The crane acts as an intermediary that handles the weight-bearing function during deployment. The crane lifts and positions the mobile support unit with the ROV, while the umbilical merely provides electrical and data connections. This intermediary approach separates the weight support function from the umbilical, enabling deeper deployments
3Reliability
If permanent installation and specialised vessel are used for moonpool deployment, then higher sea states can be coped with, but dedicated structures and equipment on the deck are required which militates against the use of vessel of opportunity
Solution Approach 1:
The system transitions from static permanent installations to a dynamic, mobile support unit that can be rapidly deployed and removed. The mobile support unit adapts to different vessel configurations and can be stowed when not in use, providing flexibility for vessels of opportunity while maintaining deployment capability in various sea conditions
Solution Approach 2:
The mobile support unit is self-contained with its own TMS, power systems, and control equipment. It does not require permanent vessel modifications or dedicated deck structures, allowing it to be deployed on ordinary vessels without requiring the vessel to be specially equipped for ROV operations
Data Source
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AI summary
An ROV docked to a tether management system (TMS) is lifted outboard into water beside a vessel while deploying an umbilical that effects communication with the ROV via a tether of the TMS. After undocking the ROV to swim away from the TMS while deploying the tether, the TMS is suspended over the water while the ROV performs a subsea mission. A mobile or transportable ROV support unit can be positioned on a deck of a vessel of opportunity to facilitate deployment of the ROV, the TMS and the umbilical and to control the ROV during the mission.