the 3rd battalion of the 7th special forces had been in panama almost a year now and my weekly demonstration class on jungle river crossings , theoretically just another redundant exercise designed to keep us fit between southeast asian assignments , never failed to draw a small group of green berets who took bets on how long it would take me to make the crossing , how close i would come to the target take-out point on the opposite bank , or if i would get across at all .