The composite catamaran has an unusually shallow draft of just 0.6 meters - this was one of PGS' prime requirements.
Swede Ship Marine has over 100 years experience in shipbuilding. In 1990, it had six yards in Scandinavia - four in Sweden and two in Norway. For a time, the company had interests in the offshore platform market - for example, the massive accommodation module for Norsk Hydro's Oseberg C platform was delivered from its Westmarin yard near Kristiansand in Norway in 1991.
Since then, the company has condensed its operations into three yards in Sweden and focused on one of its key strengths, the building of lightweight craft, mainly for the military and coast guard services. The Djupviks yard near Gothenburg has been building in aluminum for over 50 years and this is still a main business line. The company also took an early interest in the design and build of composite vessels, this time at its yard in Hunnebostrand further up the west coast. It now enjoys international renown in this area of marine technology, supplying vessels in GRP and more advanced composites, which have either a single or sandwich layer construction.
This reputation influenced PGS when it was looking for a boat builder to provide a series of shallow draft seismic vessels to operate in areas such as the Caspian. Swede Ship came up with a twin-hulled catamaran made of a fiber-reinforced vinyl ester composite sandwich, incorporating a special PVC distance material. The stiffness this combination provides means there is no need for longitudinal or horizontal spars in the construction. The vessel is double-bottomed and has no keel.
The weight of composite in the approximately 20 meter by 7 meters vessel is just under 10 tons. Total maximum weight of the vessel is around 70 ton, while the minimum draft is just 0.6 meters, as designated by PGS. Twin 490 HP Scania diesels power water jets giving a maximum speed of 15 knots, although the primary reason for their selection was their ability to deliver high power at low speeds.
Large working space
The vessel has a number of features which make for ease of operation. Despite its size, it has 140 sq meters of working space, which will withstand loads of up to 3 ton/sq meters. The inherent thermal properties of the composite, as well as additional mineral wool insulation, ensure a condensation-free environment, although air conditioning has also been fitted to protect the sensitive electronic equipment the vessel will be carrying.
The first vessel was delivered in 1999 and the second in April of this year. They cost in the region of US$2 million each. Swede Ship is hopeful of winning an order from PGS for four more vessels of the same type.
For more information contact Carl Gisaeus, Swede Ship Marine. Tel: +46 304 679550, Fax: +46 304 662575, E-mail: firstname.lastname@example.org