PURPOSE: To save the labor required for manufacturing a lounge and a float separately and facilitate positioning and installation of each by allowing the lightweight material made of foamed body to be closed in the outer shell made of FRP and integrally forming the lounge and the float.

CONSTITUTION: The lounge material as the constituting elements in the longitudinal direction of a small vessel made of FRP of constituted so that the lightweigth material made of foamed body 75 is closed in a recess of the outer shell 76 made of FRP, and a lounge and a float are formed integrally. Therefore, the labor required for manufacturing the lounge and the float separately can be saved, and positioning and installation of the float can be performed concurrently with that of the lounge, and manufacturing can be facilitated.