Abstract: A marine vessel capable of improving propulsion efficiency for the entire operation of the marine vessel. In the marine vessel, which includes a hull and a propeller provided on a stern side of the hull, n2D/?(Bd) is 4 or more and 35 or less, in a case where n is the number of the propeller, D is a diameter of the propeller, B is a water line breadth of the hull, and d is a draft of the hull.

Abstract: To provide a marine vessel capable of improving propulsion efficiency for the entire operation of the marine vessel. In a marine vessel including a hull and a propeller provided on a stern side of the hull, n2D/?(Bd) is 4 or more and 35 or less, in a case where n is the number of the propeller, D is a diameter of the propeller, B is a water line breadth of the hull, and d is a draft of the hull.

Abstract: A ship air lubrication system of an external installation type has good efficiency. An air ejecting unit includes an ejecting side chamber installed in a ship bottom of a ship and having air ejecting holes formed in a surface opposite to the ship bottom on a lower side, and a supply section which supplies air into an inner space of the ejecting side chamber. When the air in the ejecting side chamber is ejected from the air ejecting holes, the air is sheared by an external water stream, and small air bubbles are supplied to the ship bottom.

Abstract: An air lubrication system of an outer installation type has good efficiency. An air recovering device includes a recovery side chamber provided on a bottom of a ship on a stern side from an air ejecting device which supplies air bubbles to the ship bottom. The recovery side chamber includes air intake holes formed in a portion of the recovery side chamber opposite to the ship bottom through a gap. The air recovering device also includes a recovering section recovering air inside a recovery side chamber. The air bubbles acquired from the air intake holes are accumulated inside the recovery side chamber to generate pushing pressure so that air can be smoothly recovered from the recovering section.

Abstract: A ship air lubrication system of an external installation type with good efficiency is desired to be provided. An air ejecting unit includes an ejecting side chamber installed in a ship bottom of a ship and having air ejecting holes formed in a surface opposite to the ship bottom on a lower side; and a supply section which supplies air into an inner space of the ejecting side chamber. When the air in the ejecting side chamber is ejected from the air ejecting holes, the air is sheared by an external water stream, and small air bubbles are supplied to the ship bottom.

Abstract: It is desired to provide an air lubrication system of an outer installation type with a good efficiency. An air recovering device includes a recovery side chamber provided on a bottom of a ship on a stern side from an air ejecting device which supplies air bubbles to the ship bottom, and comprising air intake holes formed in a portion of the recovery side chamber opposite to the ship bottom through a gap; and a recovering section recovering air inside a recovery side chamber. The air bubbles acquired from the air intake holes are once accumulated inside the recovery side chamber to generate pushing pressure occurs so that air can be smoothly recovered from the recovering section.

Abstract: An air lubrication apparatus of a ship includes an air ejecting unit and a restraining section. The air ejecting unit ejects air from the ship bottom. The restraining section restrains relative reduction of a thickness of an air layer which covers a center line region of the ship bottom.