Abstract: A lift-propulsion assembly and a watercraft. The watercraft includes a buoyant body having upper and lower surfaces on respective upper and lower sides thereof; a lift-propulsion system including a mast connected to the buoyant body, the mast having a proximal end and a distal end, the mast extending from the lower side of the buoyant body; and the lift-propulsion assembly. The assembly includes an assembly frame connected to the distal end of the mast; a propulsion unit for providing thrust to the watercraft, the propulsion unit being connected to the assembly frame; a hydrofoil for providing lift to the watercraft, the hydrofoil being selectively connected to the assembly frame; and a manually-operable attachment system connecting the hydrofoil to the assembly frame.

Abstract: The lens is made by injection molding in a mold through the injection of molten plastic material in at least three injection shots using a multistep process. It includes a first outer lens part, a second outer lens part and a lens core part forming an interior of the lens. The lens core part is embedded between the first and second outer lens parts. The lens core part is divided into at least two subparts separated at least partially by at least one elongated slot extending across the lens core part between the first and second surfaces of the lens core part. The slot or slots made through the lens core part are filled and fused with the plastic material of the first outer lens part.