HYDRODYNAMIC TANK TESTS OF THE ONE-QUARTER-SCALE HARRAH PLANING CRAFT
Abstract
The results of this study indicate that the craft hull design as represented by the model is sound, and that the reasons for the adverse rolling, yawing, and pitching motions lie primarily in the powering and ruddering systems. It is felt that the remedies to obtain good performance characteristics may be found in the control of the initial unbalance of forces applied to the craft by the aforementioned systems. The adverse nose-down moment may be corrected by the use of a propeller with a higher rake and with proper pitch. A reduction of the propeller shaft angle is also recommended. It is further recommended that the rudder be located away from the propeller cavity so that the rudder area may be fully effective throughout the speed range. Spray strips, attached to the hull at the chines, may be utilized to prevent divergent bow-down attitudes, but these are not considered to be a cure for the basic problem. It is believed that these modifications will serve to measurably improve the operating characteristics of the planing craft. A certain amount of roll and yaw due to torque, however is unavoidable.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1961
- Accession Number
- AD0265107
Entities
People
- S. T. Uyeda
Organizations
- General Dynamics