The history of the garment making and fiber industry in Antalya means Damen can source directional glass fiber from local suppliers. The company typically gets glass fiber from Turkish company Metyx, a manufacturer of unidirectional, multi-axial and hybrid reinforcement fabrics. Metyx recently announced an increase in its knitting production lines in Turkey to supply an additional 12,000 metric tons of glass and fiber multiaxial fabric knitting capacity to the industry.

Molds for the Waterbus 2407’s modular segments are made by Damen in Antalya using a 3-D milling machine. Manufacturing begins with placement of multiaxial glass fibers into the mold for the outer skin without using a gel coal. “It does mean additional lamination of the outer skin, but we save some 2 kilos per square meter of weight, which is substantial,” notes Paš.

Following placement of core and multiaxial fibers for the inner skin but before impregnation, the construction is placed in a vacuum bag for compaction of the dry fibers and core at an air pressure of 9 tons per square meter (1,843 pounds per square foot), limiting or eliminating gaps between the fibers and core. One-shot vacuum-assisted resin infusion impregnates the core and fibers with epoxy resin.

“Ninety-five percent of the composite components for the Waterbus are handled with one-shot infusion. Vacuum infusion reduces the amount of resin needed, leading to a high-fiber, lower-weight component that helps to prevent water penetration,” says Paš. “We use a computer controlled mixing machine to consistently define the ratio between resin and hardener. With the quantity of resin we process every year, the automation has paid off in less than two years.” The result, he says, is efficient, standardized serial production with a 6-month delivery schedule for the Waterbus – 30 percent shorter than for a comparable metal-welded vessel.

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Workers at Damen Shipyards lower a GFRP catamaran hull onto a support stand. Photo Credit: Damen Shipyards

Paš says the use of composites also contributes to the Waterbus 2407’s versatility. “If we want to build efficiently, composites allow for more changes than the aluminum or steel alternative,” Paš says. The modular design of the hulls and deck can be lengthened based on the passenger count specified. The catamaran design provides a large platform to maximize the number of seats, giving operators higher revenue per trip. The composite platform also can be fitted with different finishing styles and levels depending on end use, ranging from benches for basic urban public transportation to luxury finished interiors for sightseeing, dinner cruising, business conferences or lounging.