Moored beside Clarendon Dock, the AMT Explorer barge ( left ) and mothership Cable Enterprise ( on right, owner of the white superstructure ) each fitted with a cable carousel ( the canvas-shrouded blue metal structure ). According to the owner's web site, the carousels have respective capacities of 7,000 and 4,000 tonnes.
Also visible to port of Cable Enterprise is MCS Ailsa, a maritime construction support craft described here.
I wonder what their mission will be; William commented on the rather low freeboard, even without load, which would seem to preclude deep-sea operations.
Update: from this I learn that the Explorer is currently involved with offshore wind farm projects, presumably laying the conductor back to the mainland.
Circled in the sky is the PSNI's EC 145, which seemed quite interested in the scene.
Should any of the linked web sites fail I have cached the data sheets for Explorer, Enterprise and Ailsa.