The U.S. Border Patrol in Laredo uses air-boats to patrol the Rio Grande River Valley. 350 horsepower air-boats can navigate waters as shallow as four inches. They are 17 to 27 feet long and usually create sound levels over 140 decibels, comparable to the frequencies emitted by subway trains or artillery fire. Primarily used as a deterrent, warning migrants trying to cross the river of the Border Patrol’s presence, our class got individual “joy” rides during a 7 and a half hour tour of the U.S.-Mexico border.