An assembly for a watercraft according to an example of the present disclosure includes, among other things, a flotation device defining an elongated slot extending between opposed ends of the flotation device, and an elongated mount that has first and second flanges extending outwardly from a bracket body. The first flange is configured to be mechanically attached to a frame, and the second flange is slideably received in the elongated slot to secure the flotation device. A method of assembly for a watercraft is also disclosed.