Full-Scale Measurements of High Speed Passenger Ferry Performance and Wake Signature

Intensive field research tests were conducted with innovative high speed foil-assisted catamarans and air- entrainment/surface effect hull designs to provide wake wash and vessel performance data for development and validation of wake prediction models and to provide full-scale baseline data for advancing the hull designs. The trial data and models enable a detailed assessment of vessel performance in terms of operation efficiency and wake wash generation which are being extended to assess the potential shore impacts from candidate hull types in environmentally sensitive areas, such as Rich Passage in Puget Sound, and to the design of a new generation of low impact passenger vessel. In the past, wake and vessel optimization studies have focused on the use of small-scale laboratory studies and computational fluid dynamics modeling to develop data for design purposes. However, high speed vessels operating at super-critical speeds are particularly difficult to accommodate in most laboratories because of the need for large facilities both in terms of length, to accommodate a high speed tow carriage, but also in terms of width, to accommodate the development of the wake patterns which develop at super-critical Froude numbers. Also because of the scaling required in the laboratory, differences in wake energy and spectral signature between test conditions and hull variants may be within the level of detection of instrumentation. Computational modeling studies are also limited by a paucity of full-scale data for validation. Therefore, detailed trials were conducted at full scale with state of the art vessels as a precursor to advancing hull design. The wake measurements allow an examination of the relationships between vessel wake parameters (including maximum wake height and energy) and spectral shape as a function of distance from the vessel sailing line for a range of vessel operating conditions. Results from detailed trials of 3 state-of-the-art foil assisted catamarans and 2 surface effect designs are presented and compared with measurements from conventional catamaran designs.