Abstract: A hydrofoil craft includes a hull including a bottom that spreads from a bow to a stern; and a hydrofoil mechanism provided on the bow side of the hull. The hull further includes an accommodating recess formed therein, and the accommodating recess is recessed toward the stern side between the bow and the bottom to accommodate the hydrofoil mechanism. A retreat surface is formed between the bottom and a recess main surface facing the bow side in the accommodating recess, and the retreat surface extends toward the stern side in a downward direction and is connected to the bottom.

Abstract: A hydrofoil craft includes: a hull including a bottom that spreads from a bow to a stern; and a hydrofoil mechanism provided on the bow side of the hull. The hull includes an accommodating recess formed therein, the accommodating recess being recessed toward the stern side between the bow and the bottom to accommodate the hydrofoil mechanism. A retreat surface is formed between the bottom and a recess main surface facing the bow side in the accommodating recess, the retreat surface extending toward the stern side in a downward direction and being connected to the bottom.

Abstract: To provide a non-spherical tank which includes: a circular cylindrical portion; a top portion disposed continuously with an upper side of the circular cylindrical portion; and a bottom portion disposed continuously with a lower side of the circular cylindrical portion, wherein the top portion includes: a spherical shell portion which is formed of a portion of a spherical body having a radius R1, and is disposed at an upper end of the top portion; and a toroidal portion which is disposed continuously with the upper side of the circular cylindrical portion and with a lower side of the spherical shell portion respectively, and is formed of a portion of a spherical body having a radius R2 smaller than the radius R1, and an expression 1.0<R/H1<1.5 is satisfied. Here, “R” denotes a radius of the circular cylindrical portion, and “H1” denotes a height of the top portion in a vertical direction.

Abstract: To provide a non-spherical tank which includes: a circular cylindrical portion; a top portion disposed continuously with an upper side of the circular cylindrical portion; and a bottom portion disposed continuously with a lower side of the circular cylindrical portion, wherein the top portion includes: a spherical shell portion which is formed of a portion of a spherical body having a radius R1, and is disposed at an upper end of the top portion; and a toroidal portion which is disposed continuously with the upper side of the circular cylindrical portion and with a lower side of the spherical shell portion respectively, and is formed of a portion of a spherical body having a radius R2 smaller than the radius R1, and an expression 1.0<R/H1<1.5 is satisfied. Here, “R” denotes a radius of the circular cylindrical portion, and “H1” denotes a height of the top portion in a vertical direction.

Abstract: Provided is a wind power generator equipped with a circulating passage including a downward passage through which air in a nacelle flows downward from the nacelle through a tower and an upward passage through which the air that has flowed downward flows upward through the tower into the nacelle; and a heat exchanger part configured to exchange heat between the air and outside air at an intermediate portion of the circulating passage, wherein the upward passage is thermally insulated.