Abstract: A float having a substantially prismatic and preferably parallelepipedic body, which has corner edge portions provided with corner-connecting elements having eyes and recesses for receiving and interlocking with connecting bolts for connecting a plurality of identical floats in an assembly. In order to increase the strength and stability of the joints between such floats in an assembly consisting of a plurality of layers of such floats, the body of the float is formed at its center with a vertical retaining opening. The opening is adapted to receive a connecting bolt and contains a recessed bearing surface that is engageable by such bolt, a plurality of identical ones of said floats are adapted to be arranged in a plurality of layers in an assembly.