Abstract: A boom for collecting material floating on the surface of a body of water comprises a first collapsible tube which can be stored either as flat layers of folded material or by rolling it on a roller. Transverse seals are provided along the length of the tube to provide a longitudinal sequence of compartments. A reactant body is disposed in at least one compartment, and being capable of producing an inflating gas. The reactant body is disposed within a pouch which is frangible under pressures applied by rollers or the like during the deployment of the boom from its stored condition. In a modification, a small collapsible tube is provided in longitudinally secured relationship to the first tube and the interior of the small tube is provided with fluid connections to each of the successive compartments.