Novel pressure reducing valve for boat

The novel pressure reducing valve comprises a valve body, a valve cover, a valve seat and a valve clack, the valve seat and the valve clack are arranged in the valve body, the valve cover is connected to the upper portion of the valve body, and an inlet and an outlet are formed in the two sides of the valve body; the valve seat is connected with the valve body in a matched mode, the valve clack is arranged in the valve seat, the top end of the valve clack is exposed out of the valve seat, and the valve clack is vertically and movably connected to the valve seat. A diaphragm is arranged on a middle flange port of the valve body and located above the valve seat and the valve clack. An adjusting spring is arranged in the valve cover above the diaphragm; an upper spring seat connected with the upper end of the adjusting spring and a lower spring seat connected with the lower end of the adjusting spring are respectively arranged at two ends of the adjusting spring; a top port of the valve cover is in threaded conn