Design and Evaluation of a Highly Skewed Propeller for a Cargo Ship
DAVID W TAYLOR NAVAL SHIP RESEARCH AND DEVELOPMENT CENTER BETHESDA MD
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The design process and model evaluation of a highly-skewed propeller for a modern cargo ship are given. The design process is discussed in detail, including considerations of cavitation, mean and fatigue strength, and propeller-excited vibratory forces. Model experimental results are presented which tend to confirm the design process and to show that the highly skewed propeller possesses prouplsion performance comparable to the propeller now fitted to the ship, delays the inception of cavitation by two knots, has less tendency towards cavitation erosion than the fitted propeller, and possesses adequate strength for ahead and steady astern operation. Calculations, using unsteady lifting-surface theory, indicate that the highly skewed propeller will reduce blade-frequency thrust and torque by 90, will reduce blade-frequency transverse horizontal bearing force by 60, and will increase blade-frequency vertical bearing force by 2, compared to the propeller currently installed on the ship.
- Marine Engineering