Greatship Rohini is a DP-Class II ROV Support Vessel (ROVSV), capable of supporting offshore exploration and production operations. Its construction started in July 2009 and delivery took place in December 2010. The vessel has been built in accordance with Lloyd’s Environmental Protection & Crew Comfort notations and in compliance with the new SPS Code 2008. The SPS Code prescribes safety guidelines to be used in the design of special purpose ships (SPS).
Greatship Rohini is the third in a series of four vessels built by Colombo Dockyard, Sri Lanka for Greatship (India) Limited (GIL), a subsidiary of The Great Eastern Shipping Company of Singapore. Greatship Rekha, Greatship Ramya and Greatship Rashi are the other three vessels in the series.
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The construction of Greatship Rohini required an investment of about $26m. The vessel has been chartered to a Brazilian oil company Petrobras for deployment in exploration activities.
Greatship Rohini design
The vessel is of R Class design which was developed by Singapore-based Sea Tech Solutions International. Apart from performing regular functions of a platform supply vessel (PSV), the R Class vessels can also be used for conducting inspection, geophysical and geotechnical, and maintenance and repair services.
The vessels are designed for a 50t crane or A Frame and are fitted out to support two work class remotely operated vehicles (ROVs). The lower level and deck head windows are fitted to ensure clear view to the aft deck and aft overhead. The sewage treatment plant integrated on the ship can serve 50 persons.
Overall length of the vessel is 78m. Length between perpendiculars is 78m, while moulded breadth is 17m. Moulded depth is 8m and maximum loaded draft is 6.30m.
Deadweight of the vessel at 6.3m draft is 3,700t. Net tonnage and gross tonnage are approximately 967 and 3,226t respectively. The vessel has a deck area of 725m² and its deck strength of 5t/m², enabling it to hold 1,200t of cargo.
Dry bulk can be discharged at the rate of 2 x 25m³/min at 5.6bar, fresh water at 2 x 100m³/hr at 9bar, ballast / drill water at 2 x 100m³/hr at 9bar, liquid mud / brine at 3 x 75m³/hr at 9bar, base oil at 1 x 90m³/hr at 9bar, fuel oil at 2 x 100m³/hr at 9bar and methanol at 2 x 75m³/hr at 9bar.
With its auxiliary launch and recovery systems (LARS), the ROV will help to perform various operations such as extraction of hydrocarbon samples, inspection of pipe lines and well-head, and repairs and modifications of sub-sea structures.
Accommodation
A total of 50 fully air conditioned berths are available for accommodation in six one-man cabins and 22 two-man cabins. Two hospital beds and two separate offices are available for charters and ROV.
Propulsion
The vessel has two main engines. Each of these is capable of generating 2,320kW. Propulsion is attained by two controllable pitch propellers (CPP). Of the total five auxiliary engines, two are shaft generators capable of generating 1,600kW each, two are diesel generators capable of generating 460kW each, and one is a 90kW emergency generator. The auxiliary engines have a three phase supply system with 400V.
The two tunnel bow thrusters, each rated at 900KW, and two tunnel stern thrusters, each rated at 400kW, help in achieving good manoeuvrability and station keeping.
Equipment
The deck equipments include two capstans, each of 8t capacity, two tugger winches, each of 10t capacity, and one provision crane of 3t capacity. Anchoring equipments include one anchor / mooring winch, two anchors, each with 1,700kg lifting capacity, and 330m x 42mm (diameter) chain cables on each side.
ROV operation is carried out with the help of removable bulwarks, store or workshop available on main deck, deck sockets and ROV plug-in.
The Converteam-made DP system is of class II and its signal reception is suitable for L1/L2 and GLONASS satellite navigation system. Transponder winches of the DP system can perform launch / recovery up to a depth of 3,000m.
Navigation and communication
Navigation equipments include Dual ECDIS electronic charts and navigational watch alarm which complies with International Maritime Organization (IMO) recommendations for bridge navigational watch alarm system (BNWAS). INMARSAT satellite mobile is used for fax, data and voice correspondence.
