PROBABILISTIC INSTABILITY AND RESPONSE OF SURFACE SHIPS.
Final rept. Feb 66-Sep 67,
NOTRE DAME UNIV IND DEPT OF ENGINEERING SCIENCE
Pagination or Media Count:
The first part of report is concerned with the probability of instability on a straight course of ships moving in a lateral plane. The hydrodynamic coefficients in the differential equations of motion are considered to be random variates. A criterion for the probability of instability is derived, which is then applied to a MARINER type ship which is known to be near a state of marginal stability on a straight course. The second part of report discusses the probability density functions of the heading rate in a turning maneuver when one or more steering indices are random variates. In particular, the probability density functions are derived for the heading rate response of a ship with a step-type rudder input. The theoretical results are applied to a small cargo ship. It is shown that at very large values of time, the probabilistic response differs considerably from the deterministic response. A procedure for predicting the response in terms of the dimensions and displacement of a ship is also developed and discussed. This procedure appears to be a promising design approach which facilitates the maneuvering capabilities of preliminary designs. Author
- Marine Engineering
- Fluid Mechanics