Here is a bit of history. The Castoro 7 is a pipelayer, or was a pipelayer which was scrapped earlier this year at Alang, after 41 years at work. It entered service as the Viking Piper in the mid 1970s - see photograph below when it was fully employed laying pipe all over the North Sea.

At that time the British supply vessel operator OIL built a pipe carrier specially to service it, probably the first offshore vessel with all aft accommodation. However, once the two craft got together the Oil Challenger's superstructure kept hitting the side of the Viking Piper, and so it was retired and lay in the River Tay for a year or so - still on hire.   

Main photo by Andriy Kalov in 2012 and the second one by Victor Gibson some time in the 1970s (together with the Maersk Beater and the Ninian Central Platform). Posted here on 14th November 2016