| 摘要 |
PURPOSE:To enhance propelling efficiency without generating stern vibration, by a method wherein a pair of two-blade propellers are fitted at positions spaced in the longitudinal direction. CONSTITUTION:The two-blade propellersI, II are fixed to a shaft 1 at positions spaced by a distance l in the longitudinal direction, with a blade phase shift of 90 deg.. By fixing the propellers at the spaced positions, the effect of staggered construction is enhanced and the number of blades is apparently reduced to a half. Accordingly, while the propelling efficiency is substantially as high as that of a two-blade propeller, the stern vibration due to pressure variations becomes substantially as small as that in the case of a four-blade propeller. |
