The Castoro Sei (Italian for Beaver Six) is a column stabilized semi-submersible pipelay vessel. She has an overall length of 152 metres (499 ft), a width of 70.5 metres (231 ft) and an operating draught of 7.8 to 15.5 metres (26 to 51 ft). The Castoro Sei is equipped with 2 rotating gantry cranes 134 tonnes capacity, three 130 tonnes pipe tensioners and a 400 tonnes abandon and recovery winch for pipelaying. She provides accommodation for 354 people. The Castoro Sei was built in 1978 by Fincantieri at Trieste yard, and is owned and operated by Saipem. Her port of registry is Nassau, Bahamas.