The underwater observation device comprises two segments, one of which is underwater (1) , located below the water surface, on which are mounted glass portholes (4) and the dimensions of which allow a corresponding number of observers to be seated there (3). ) - one, two and more. The other segment (2) is overhead and is located on the water surface, as the two segments are connected by an air duct comprising two pipes (8 and 9). The underwater segment (1) has an aerodynamic shape - ellipsoidal, cylindrical or spherical, with glass portholes (4) located on its two opposite horizontal sides, and in the central upper and lower part of the segment (1) there may also be portholes (4). ). On the one of the horizontal sides of the segment (1) there is a hermetically closable hatch (5) with dimensions sufficient for coming in and out of the observers (3). On the lower outer side of the segment (1) is fixedly mounted one axle (6) at the front and rear, with a length of not less than two diameters of the underwater segment (1), as at the ends of each axle (6) there is one wheel (7). The pipes (8 and 9) of the air duct are fixed in the front and rear part of the segment (1), protruding above the water surface, and their length determines the immersion depth of the segment (1) with the observers (3). They are supplied with fresh air for breathing with atmospheric pressure from the front pipe (8), and the exhaust air exits through the rear pipe (9), assisted by a fan (10), while the flow of fresh air is controlled by the speed of rotation of the fan (10). The total weight of the segment (1) along with the observers (3) and the pipes (8 and 9) is greater than the buoyant force vertically displacing it. The surface segment (2) is a hermetically sealed volume filled with air at atmospheric pressure as the dimensions and volume of this segment (2) are such that its lifting buoyant force is greater than the total weight of the segment (1) together with the observers. (3) and pipes (8 and 9). The two pipes (8 and 9) pass freely through symmetrical openings (11 and 12) in the surface segment (2), and in their upper part are fixed clamps (13 and 14), determining the depth of immersion of the segment (1). The movement of the underwater observation device is carried out with a surface vessel (15) connected to the segment (1) with a cord (16), in which there is a built-in cable for communication of the observers (3) with the driver of the vessel (15).
