Longitudinally extended floats

A longitudinally extended float, comprising joining means on a first float for detachable longitudinal-side attachment to a substantially identical second float, said joining means being connected to respective opposite first and second longitudinal sides of said first float, said joining means comprising elongated profiles extending substantially parallel to said respective opposite first and second sides, each of the profiles having a generally U-shaped cross-section with leg portions of unequal length, the unequal leg portions comprising a long leg and a short leg, the long leg comprising a back piece which is attached to a respective longitudinal side of said first float, said long leg being connected to said short leg by a bottom portion of said U-shaped profile, said U-shaped profile having an open end opposite the bottom portion, said joining means further comprising a fin member adjacent the open end of said U-shaped profile and substantially parallel to said bottom portion, said fin member being connected to said back piece, and said fin member shielding the open end of the U-shaped profile.