Ship Pitch Stabilization - Progress and Prognosis.
Abstract
The problem of pitch stabilization of ships is considered for different vessels of varying size, with application to both commercial and military craft. The various operational benefits of pitch stabilization are described, together with the history of prior efforts applied to this problem area by use of hydrodynamic force elements (i.e., fins or other lifting surfaces), including a discussion of the limiting hydrodynamic phenomena and vessel behavior that have inhibited the use of pitch stabilization with fins. Efforts to overcome some of these limiting features involve approaches using hydrodynamic lifting surfaces in a different manner. These approaches consider fin location in the stern region; the effect of the propeller race; specific types of control system command rules; and the use of special high lift hydrofoils dependent on flow control. Results of the program to date are presented, based upon theoretical analysis and actual demonstration on a small vessel at sea. The beneficial results obtained on a 12.80 m (42 ft) cabin cruiser when equipped with controlled fins in at-sea tests in the Pacific Ocean support the basic concept of achieving useful pitch stabilization of ships in a seaway. Keywords include: Canted rudders, Pi rudder system, Vertical plane motions, Circulation control, Full-scale trials, Control system design, and Cavitation/ventilation.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1984
- Accession Number
- ADA150153
Entities
People
- A. E. Baitis
- Andrew Clark
- G. Gaudin
- P. Kaplan