Knowing that patrolling coastal and river waterways during a conflict in Vietnam was going to be extremely hazardous the U.S. Navy searched for a boat design that could be quickly produced and employed. One chosen was a fiberglass-hulled pleasure craft built by Modutec Marine in Seattle Washington. The Patrol Boat River or PBR as it was known militarily became one of the most successful weapons systems used in Southeast Asia. It was 31″ 11″ long 11 7″ wide and 9″9″ high above the waterline. It displaced 8 3/4 tons loaded drawing two feet of water. It’s crew of four was armed with a pair of .50 cal gun or grenade launcher mounted on a tripod in the fantail plus a single M-60 on a pipe mount bolted to one of the amidships splinter shields.