A boat includes a hull provided with a rear stern hatch located in correspondence with an internal stern compartment of the hull and suitable for opening and closing in correspondence with an aperture of the compartment. The hatch having a body with opposed sides located in correspondence with side walls of the compartment and upper edge and lower edge. The hull having a stern platform that is movable and submersible. The hatch is not provided with any direct connections to the hull, but it is connected to the stern platform to reach, upon opening, a position submersed in the water where the boat is located in the moment when the platform submerges into the water.