Abstract: The present invention provides an unmanned watercraft capable of sufficiently cooling equipment that generates a large amount of heat, capable of cooling such equipment without using energy in the watercraft, and capable of improving mean time between failures (MTBF) of a cooling device. An unmanned watercraft 1 has a cooling structure CS for cooling a central processing unit CPU1 for image recognition and a central processing unit CPU2 for control that constitute a central processing unit CPU as a heat-generating body. The cooling structure CS includes a waterproof container 7 that accommodates the heat-generating body (an insulating envelope that surrounds the heat-generating body in an electrically insulated state). The waterproof container 7 is arranged outside a submerged part 3 of the unmanned watercraft 1 so as to be in contact with water present outside the unmanned watercraft 1, the submerged part 3 being submerged in water.

Abstract: There are provided a shell of a pressure-resistant container that is made of ceramics, is used for a pressure-resistant container formed with a through hole, and can be made higher in strength and lighter in weight, as well as to provide a pressure-resistant container and an exploratory apparatus. A shell of a pressure-resistant container includes a shell portion and a thick-walled portion. The shell portion is made of ceramics and has a convexly-curved surface. The thick-walled portion is made of ceramics, continues into the shell portion, is larger in thickness than the shell portion, and has a through hole penetrating through the thick-walled portion in a thickness direction thereof.

Abstract: There are provided a shell of a pressure-resistant container that is made of ceramics, is used for a pressure-resistant container formed with a through hole, and can be made higher in strength and lighter in weight, as well as to provide a pressure-resistant container and an exploratory apparatus. A shell of a pressure-resistant container includes a shell portion and a thick-walled portion. The shell portion is made of ceramics and has a convexly-curved surface. The thick-walled portion is made of ceramics, continues into the shell portion, is larger in thickness than the shell portion, and has a through hole penetrating through the thick-walled portion in a thickness direction thereof.

Abstract: There is a problem in that a gas pressure in an oxygen container of an oxygen supply device is high, thereby causing a mounting cost for charging gas into the oxygen container. Further, there is also a problem in terms of safety at a time of operation.