Here is the Pertinacia which was to become the Seven Phoenix, originally a conventional cable layer  but now one of those very unusual flexible lay ships. This one was built in 2002 and so has the tower on the side of the ship and one assumes that when it is laying a flexible it moves sideways. Amongst the technical info there is the ballast capacity of the vessel which is 5,800 m3, probably needed to offset the tower. Later versions of this ship type have the towers on the centre line. Still amazing. The internet tells us that this craft is currently laid up.

The photo was taken by Tony Poll in 2009 and posted here on 4th May 2020.