Lifting Body Ships - "HYSWAC"

Based on the success of MIDFOIL, Navatek received funding from the Office of Naval Research to convert an existing Navy Surface Effect Ship (SES) to a lifting body ship. Work on this $18 million project began in 2000 and resulted in the U.S. Navy technology demonstrator craft called HYSWAC ®. The SES-200 provided the parent hull of the HYSWAC, reducing project costs. During the two-year project, Navatek removed the existing SES air lift system and all related components, and installed a 170-ton Navatek underwater lifting body incorporating a new propulsion drivetrain (engines, gearboxes, shafts and propellers) within the lifting body. This allows the craft to be operated with variable immersion as speed increases with the parent hull fully out of the water at maximum speed. An aft crossfoil was also added for pitch and roll control, along with a proprietary Navatek advanced ride control system (ARCS).

Launched in June 2003 at Pacific Shipyards International, the 160-foot, 30+ knot HYSWAC, namedSea Flyer, has a full-load displacement of 340 LT. Durring successful sea trials in Summer 2004, Sea Flyer confirmed on a large scale the three major benefits of underwater lifting bodies verified through CFD studies and on the earlier, small-scale, 52-ton MIDFOIL.