A method and a device for receiving a High-Definition Multimedia Interface signal from an HDMI source via a first HDMI interface is disclosed. The bar further comprises first and second flat sections configured to contact a futon to support the futon in a selected position and a bight coupled to the first and second flat sections to reinforce the first and second flat sections when a load is applied to the futon. A lock member includes a strap-engaging locking part. Also outboard motor actuators are individually operated to regulate the relative angles between the outboard motors, thereby enhancing both straight course-holding performance and turning performance.