| 摘要 |
PURPOSE:To improve propulsion resistance and following-wake gain by positioning the max. width part of a stern bulb which largely projects from the radius of a propeller, under the axis line of the propeller and setting the projection area of the longitudinal section of the stern bulb over 60% of the product of the length of projection and the height of the propeller shaft. CONSTITUTION:The length L1 of the projection part of a one-axis stern bulb is made larger than Dp/2, namely the radius of a propeller, and the position (h2) of the max. width part of the bulb is positioned below the height (h1) of the propeller shaft, and an S-shaped frame line is formed in the joint part between the rear part of a hull and the bulb projection part. Further, the area (oblique line part) of projection of the projection part of the stern bulb under the center line 7 of the propeller shaft, for the section taken along the center line of the hull is allowed to occupy 60% or more of the product of the length L1 of the projection part of the stern bulb and the height (h1) of the center line of the propeller shaft 5. Therefore, the increase of the resistance due to the operation of the propeller is improved, and the propulsion efficiency can be improved by obtaining the following-wake gain.
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