Castoro Sei

The Castoro Sei (Italian for Beaver Six) was a column-stabilized semi-submersible pipelay vessel. She had 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 in the Baltic Sea, south-east of Gotland on contract to Nord Stream, March 2011
History
Name	Castoro Sei
Owner	Saipem[1]
Operator	Saipem
Port of registry	Nassau, Bahamas
Builder	Fincantieri, Italy
Yard number	4334
Laid down	20 May 1975
Completed	1978
Identification	Call sign C6DF4 IMO number: 8758603 MMSI number: 308162000
Fate	Scrapped Aliaga, May 2022
General characteristics
Tonnage	31,506 GT
Length	152 m (499 ft)[1]
Beam	70.5 m (231 ft)[1]
Draught	15.5 m (51 ft)[1]
Depth	29.8 m (98 ft)
Speed	5.8 knots (10.7 km/h; 6.7 mph)[2]
Crew	330[1]

The Castoro Sei was equipped with 2 rotating gantry cranes of 134 tonnes capacity, three 130 tonnes pipe tensioners and a 400 tonnes abandon and recovery winch for pipelaying. She provided accommodation for 354 people.^[1]

The firing line comprises the fixed pipelay ramp, enclosed in the central housing, running along the longitudinal centreline of the vessel. It is connected to an internal and external ramp, both of which have adjustable inclination to facilitate pipelay in varying water depths. A ramp extension unit is available for use in deep water or for severe seabed conditions.^[1]

The Castoro Sei was built in 1978 by Fincantieri at Trieste yard, and was owned and operated by Saipem. Her port of registry was Nassau, in the Bahamas.

It has been used for laying a number of pipelines in the Black Sea, North Sea and Mediterranean Sea, including Blue Stream, Greenstream, Medgaz, Trans-Mediterranean, Europipe II, and BBL pipelines.^[3][4][5][6] The vessel also laid most of the Nord Stream 1 pipeline in the Baltic Sea.^[7][8]