PGS Ramform W-Class Vessels, Norway

Key Data

W-Class 3D seismic vessels are the fifth generation of the Ramform series. Owned by Petroleum Geo-Services (PGS), the Ramform series is believed to be the most advanced seismic fleet of vessels in the world. Eight Ramform vessels are currently operational globally. Seven of these are owned and operated by PGS.

"The unique hull shape of the Ramform Class was originally drawn from Marjata, a Norwegian electronic intelligence (ELINT) collection vessel."

PGS signed a contract with the Japanese shipbuilder Mitsubishi Heavy Industries in April 2011 to construct two Ramform W-Class vessels. The contractual agreement also includes an option for two more vessels, to be built within one year of signing of the final contract. Construction cost, including commissioning and seismic package of each of the new generation Ramform ships, is estimated to be $250m.

Ramform W-Class vessels will be constructed at MHI's Nagasaki Shipyard as per DNV's classification standards. The first vessel is anticipated to be delivered in the first half of 2013.

The delivery of the second vessel is planned to take place in the second half of 2013. If PGS exercises its option, two additional vessels will be delivered in 2015.

With new generation Ramform vessels, PGS aspires to strengthen its hold in the three-dimensional seismic acquisition business.

Unique hull design of PGS's next generation Ramform series ships

The unique hull shape of the Ramform Class vessels was originally drawn from Marjata, a Norwegian electronic intelligence (ELINT) collection vessel. The curved waterline of Ramform ships allows them to achieve stable motion.

"Eight Ramform vessels are currently operational globally. Seven of these are owned and operated by PGS."

The immense back deck of the vessel facilitates installation of a number of pieces of equipment. Streamers and source arrays can be handled efficiently and safely from two separate deck levels, while a work boat can be operated from protected areas at the waterline.

The 5G Ramforms will have wider hull form compared to the existing series. With the wider hull design, PGS intends to deploy ultra-wide streamer tows to acquire higher resolution data and higher streamer counts.

Streamers will be towed from the vessel's stern via multiple streamer cables (up to 24), each measuring thousands of metres in length. The two W-Class vessels will be installed with ballast systems, each rated at 400m³/h, supplied by Optimarin. Each vessel will be equipped with two davits to be supplied by Vestdavit.

The vessels will also feature a helicopter deck capable of handling Super Puma / EH-101 type helicopters.

Technical specifications and capacities of Petroleum Geo-Services' vessels

The new 5G Ramforms will have an overall length of 104.2m and width of 70m. Design draught of the vessels will be 6.4m.

Fuel capacity of 6,000 cubic metres will allow marine operation of the vessels continuously for 150 days. The transit speed of the vessels will be 16kt.

The vessels will be capable of accommodating 80 people. There will be 60 single and ten double cabins onboard.

Propulsion for the fifth generation W-Class 3D seismic vessels

The new Ramforms will be outfitted with diesel-electric propulsion system. The power plant will be comprised of six main engines, each capable of generating 3,840kW. The main propulsion system will include three controllable pitch propellers (CPP) with nozzle and propeller shafts.

The propulsion and electrical systems for the first two vessels will be supplied by ABB under a $24m contract.

Communication and infotainment system from Ulstein Power & Control

Ulstein Group's Ulstein Power & Control will supply the communication and infotainment system for the new W-Class ships being built for PGS. The delivery package also includes on-demand internet protocol television (IPTV), a redundant public address system, CCTV and a battery-free telephone.

Back-deck handling systems for the Norwegian Ramform series vessels

The complete-back deck handling systems for the two PGS W-Class vessels of the Ramform series will be delivered by Evotec. Evotec's scope of delivery includes auxiliary handling systems, streamer handling systems, wide tow deflector handling systems, gun handling systems, hydraulic power units, lead in handling systems and a radio remote control system

Ramform W-Class vessels have wider hulls compared to the existing series.

Andrew Loh (Ulstein Asia) and Edgar Eidsvik (Ulstein Power & Control).

Ramform Explorer, launched in 1995, was the first vessel in the series.

The unusual hull form was drawn from Marjata, a Norwegian naval intelligence vessel.