TECHNICAL EVALUATION OF THE SES‐200 HIGH LENGTH‐TO‐BEAM SURFACE EFFECT SHIP

Abstract

ABSTRACTRecent Navy surface effect ship (SES) research has been aimed at achieving efficient operation at task force speeds without compromising the SES advantage of operating at higher speeds. Results showed that this objective could be achieved by designing ships with higher length‐to‐beam ratios than the previous generation of Navy SES. These ships are typically referred to as “High Length‐to‐Beam SES”.This paper describes an extensive program undertaken by Naval Sea Systems Command (NAVSEA) to validate this research and demonstrate high length‐to‐beam SES capabilities. Under this program a 110 ft commercial SES was procured and stretched from a length‐to‐beam of 2.65 to 4.25 by installing a 50 foot hull extension amidships. This ship is the SES‐200; it is the only large high length‐to‐beam SES in the world.A brief history of the SES‐200 is provided, and the use of standard marine construction and systems in this ship is described.A synopsis of the SES‐200 Technical Evaluation Program completed in the Chesapeake Bay and Atlantic Ocean is given, and results of performance, seakeeping and maneuvering tests are presented.The effect of cushion length‐to‐beam proportions on both cushion wave making resistance and total SES resistance is explained. Performance test data are presented to show that the advantages of high length‐to‐beam design have been validated. Full power operation in heavy weather at all headings is demonstrated, and heavy weather motion responses are compared to Navy surface ship criteria to show that limits are satisfied for both high and low speed operation. Directional stability and maneuvering test results are cited for both normal operation and impaired situations.Implications of high length‐to‐beam technology relative to multithousand ton ship design are discussed. The speed and seakeeping capabilities that SES in this size range offer are indicated by scaling SES‐200 test data.