C-DART

Overview

For further information on the current status of this development, please contact the Lead Applicant.  

The C-DART Quick Connection System (QCS) is a combined mooring and electrical connection device for rapid deployment and recovery of moored, electromechanical marine devices, such as wave energy converters (WECs). Its design permits both electrical and mechanical connections to be made remotely of the towing vessel.

The C-DART QCS has two primary elements: a surface buoy, permanently connected to a mooring system and subsea electrical cable; and a device mooring / towing hawser that incorporates an electrical cable and an interfacing QCS connector.

The C-DART QCS offers a reliable solution for electrical and mooring connections using a simple, practical marine operation. When compared to the current state of the art, it offers a significant reduction in manual intervention as well as an increased operational weather window and a reduced deployment and recovery duration. These key characteristics will enable a step-change reduction in the cost of deploying and recovering devices and will reduce the EHS risk exposure of undertaking the associated marine operations.

During Stage 1 of the WES QCS programme, both the mechanical and electrical design and the marine operations concepts were developed to ensure a feasible and cost-effective solution.

C-DART is a novel system that allows quick connection and disconnection between a WEC and an offshore buoy, providing an inexpensive, effective, and robust means to make both a mechanical mooring and electrical connection. This allows for rapid turnaround for both planned and unplanned maintenance away from the deployed site.

C-DART employs a novel method of catching and connecting a horizontal surface mooring hawser and electrical jumper to the offshore buoy, using conventional workboats. Disconnection is achieved with a separate retrieval towline, using a similar catch and connect method. The C-DART system is designed to operate without requiring actuators, stored energy or backup power.

The process is not reliant upon divers, ROVs or offshore lifting, and does not require the close interaction of boats, WECs or other floating bodies. 

During Stage 2, the project focused on advancing the design and the understanding through test cases which applied the C-DART technology to both a wave and floating tidal device. This analysis examined extreme operational and survival loads, as well as detailed assessments of marine operations for connection and disconnection.

Longer term, it is anticipated that this technology can be used in many different markets and at many different scales, making it applicable for a wide variety of uses.

The C-DART connects into spar buoy, and offers 4 main advantages:

• Significantly reduce HSE risk: No ROVs, divers, high risk deck operations, personnel transfers or close proximity vessel operations
• Increase the operational weather window to allow operations in 2m wave height (Hs), 1m/s tidal flow and hours of darkness
• Improve reliability with a passive connection: No actuators, stored energy systems, complex mechanisms or control systems
• Simple integration with devices: Only existing pad eyes and electrical cable interface, no negative performance impact, potential to provide upstream flow measurement to provide yield improvement and loads reduction

During Stage 3, the project continued to de-risk the design and demonstrate its effectiveness by testing specific aspects of the technology using 4 different test and demonstration rigs. These included a wave tank test, a full-scale wooden geometry mock-up, a marine operations test and virtual prototyping. The outcomes from the testing have fed into the creation of design solution for 2 marine applications.

The system can be used not only by developers within the wave and tidal industries, but it is also suitable for electric and hydrogen vessel charging, and for remote ROV / AUV connections

This collaborative project also brings together technologies from the NWEC, Control Systems and QCS programmes run by Wave Energy Scotland in order to investigate a wide range of potential impacts and step changes in the wave energy sector.