The present invention relates to a sail for a submarine. The sail for a submarine comprises masts arranged therein and upper and lower structures. The upper structure comprises lightweight frames and buoyancy walls. The lower structure is formed of a lightweight member. A separation part is formed between the lower structure of the sail and a pressure hull. The sail and the pressure hull are coupled by coupling units while the separation part is charged with epoxy resin and a hardener. The sail for a submarine according to an embodiment of the present invention can have excellent restoration in sailing since the upper structure of the sail positioned in the upper part of a submarine is lighter than an existing sail structure and is formed of a buoyancy member. Also, the present invention can prevent galvanic corrosion with the aluminum frames by enhancing the loading structure of the sail loaded on the pressure hull.
