Conventional vertical barrier booms are ineffective in currents in excess of approximately 0.7 knots when placed at right angles to the current. The PACE boom is a horizontal boom that is effective in medium to fast currents and has successfully been tested on the St. Lawrence River in currents of 2.5 knots.
It is a hydrodynamically effective horizontal oil boom that utilizes the natural forces of flowing water to contain spilled oil and/or direct it for recovery. A section of boom consists of two parallel flotation devices each 15 m in length and joined by a suspended segment of netting fastened to a fabric through which water passes but not oil. In operation, interconnected sections of boom are placed across the current in such a manner that surface oil flows under the first flotation device, up through the netting, and over the fabric where it is trapped against the second flotation device. A tangential flow produced between the floats carries the oil across the current to a recovery area.