PLANING HULL SEAKEEPING IN IRREGULAR HEAD SEAS
UDC 629.5.017/018.71 Summary The paper presents the results of planing hull seakeeping tests in irregular seas. The tested model belongs to a small systematic series developed at the University of Naples; it is a prismatic hull very similar to the well-known Fridsma’s models. The 16.7 degrees deadrise angle, length-to-breadth and load coefficient are representative of modern hull forms of pleasure boats. Tests in irregular waves have been performed at three speeds for one displacement in three sea states. The measured heave, pitch, acceleration at the centre of gravity and at bow have been analysed in the time domain and the results are presented in terms of significant values (the mean of 1/3 rd highest values). They are given in tabular and graphical form. Furthermore, the obtained results are commented with respect to the state of the art in planing hull seakeeping, and compared with the available experimental data from literature. The conclusions highlight the applicability of these data in design practice, commenting on trends and the range of significant parameters.
CHARACTERISTICS OF A SERIES OF HIGH SPEED HARD CHINE PLANING HULLS-PART II: PERFORMANCE IN WAVES
An experimental investigation into the performance of high speed hard chine planing hulls in irregular waves has been conducted. A new series of models representative of current design practice was developed and tested experimentally. Measurements of the rigid body motions and accelerations were made at three speeds in order to assess the influence of fundamental design parameters on the seakeeping performance of the hulls and human factors performance of the crew, with an aim to provide designers with useful data.
ROUGH WATER PERFORMANCE OF HIGH LENGTH TO BEAM RATIO PLANING BOATS
Experiments were conducted in waves with several constant deadrise models to assess the rough water performance of high length to beam ratio planing craft. Several models with L/b=7 and one with L/b=9 were run in waves to determine the effects on performance of basic design parameters such as speed length ratio, loading coefficient, wave height to beam ratio, deadrise angle, trim angle and length to beam ratio. Charts have been prepared for estimating the pitch and heave motions, vertical accelerations and added resistance in waves of the high L/b craft. Two problems encountered with the models which may present obstacles in the design of high length to beam ratio craft were the extremely high impact loads as indicated by the high impact accelerations and large quantities of water over the deck resulting from the bow plowing through wave crests. (Author)