Considered by many to be one of the worst maintenance jobs during the Vietnam War First the old tube is readied for removal William Carr Photos The hook-up to remove the tube is made William Carr Photo Next the tube is carefully unfastened and removed William Carr Photo The new tube is readied for placement William Carr Photo The new tube is raised into position William Carr Photo Carefully the new tube is jockeyed into place William Carr Photo Mission accomplished - ready for another 700 rounds William Carr Photo