ONR Tumblehome course keeping and maneuvering in calm water and waves

Abstract

This paper discusses the maneuvering performance of the Office of Naval Research Tumblehome (ONRT) surface combatant model in waves. Maneuvering tests in calm water and regular waves using free-running model were conducted at the IIHR wave basin, The University of Iowa. Ship trajectories and 6DOF motions/velocities were obtained for all tests. Course keeping tests were performed in 8 variable headings for three wave lengths and harmonic analysis were done for measured variables. The 1st harmonic amplitude of pitch and heave have maximum value in head waves and beam waves, respectively. Other amplitudes except for these two have maximum value at stern quartering waves. Zigzag and turning tests were performed in calm water and in waves. Maneuvering characteristic parameters such as 1st and 2nd overshoot angles, advance and tactical diameter in calm water were evaluated based on the International Maritime Organization (IMO) criteria. Maneuvering characteristic parameter of zigzag and turning in waves were also evaluated and compared to those of S-175 and Very Large Crude Carrier (VLCC). It is confirmed that ONRT satisfies IMO criteria and has higher maneuverability than S-175 and VLCC due to its slender hull with the twin-rudder twin-screw.