SHIP'S STERN BULB

摘要

This invention relates to the propulsion of self-propelled vessels, and in particular to the form of a ship's stern. The invention describes a new and distinctive form of bulbous-shaped stern form which, unlike other stern bulbs developed to date, does not fair into the hull, instead intersecting it to create a sharp discontinuity between surfaces. This discontinuity creates a turbulent zone along the said intersection, allowing the wake to reorganize and to follow in a desired pattern the bulb's shape in the proximity of the propeller. Thus a more uniform wake field is formed within the propeller disc, consequently improving propeller efficiency and reducing propeller induced vibration. These effects, which result in improved quietness and overall efficiency of a running propeller, along with other improved characteristics, have been confirmed by a preliminary series of model tests. The form of the bulb, and its attendant benefits, are described on the following pages.