Abstract: A large-scale protective device in accordance with the invention comprises an assembly of two types of unit, rigid cylindrical floating towers (3 to 6) and elastic connecting units (7, 8, 9) consisting of elastomer tubes. The generatrices of these elastic connecting units are in contact with vertical stiffeners (10) of the floating towers. These vertical stiffeners also serve to maintain cylindrical deflector rings (11) of the floating towers one above another in a stacked configuration.