Wave-compliant, bottom tension boom

Abstract

A bottom tension boom for collecting floating material, such as an oil spill upon a body of water, has a barrier containing an upper or freeboard portion, a lower or skirt portion which is submerged in and extends downwardly into said body of water, and pleats or slack portions which extend generally vertically across the barrier. A plurality of flotation elements is attached to the freeboard portion of the barrier and thereby supports the barrier as a whole upon the water. A lattice containing a plurality of strands made from an extensible material is attached to the skirt and extends downwardly therefrom. The lower portion of the lattice is connected to a bottom tension line which is shorter in length than the corresponding portion of the barrier. The boom is towed by tow lines connected solely to the bottom tension line and effects a backward skirt inclination with respect to the position of the bottom tension line. The extensible strands of the lattice are positioned at a non-vertical angle, generally at a 10.degree. to a 40.degree. angle, with respect to the bottom tension line and the skirt to produce a geometric lattice which amplifies the strand material extensibly and acts as a soft spring so that excellent wave compliance is obtained in that the bottom tension tow line remains relatively stationary, while the flotation elements move freely up and down, backward or forward, and to and fro (laterally) with the waves or water surface.