Method for reducing frictional resistance of hull, frictional resistance reducing ship using such method, and method for analyzing ejected air-bubbles from ship

Abstract

A method for reducing frictional-resistance at a hull (,) of a ship (,), characterized in that the method comprising a step of ejecting micro-bubbles (,) having predetermined diameters; wherein the micro-bubbles (,) are ejected into water from a position adjacent to the starting point of desired stream line (F.L.) of water and from the position where the static pressure is low; the stream line (F.L.) being directed, from the submerged shallow position at a stem portion (,) of the ship's hull (,), to the ship's bottom (,) along both side surfaces of the ship's hull (,), so that the ejected micro-bubbles (,) are transferred to the ship's bottom (,) along the stream line (F.L.); whereby the micro-bubbles (,) are distributed at at least a part of the circumferential area of the submerged portion of the hull (,), thus reducing frictional-resistance at a hull (,) of a ship (,) while cruising.