43m 59sLength

The Most Feared Gunboat You Never Knew Existed - Full Documentary Patrol Boat, River or PBR, is the United States Navy designation for a small rigid-hulled patrol boat used in the Vietnam War. They were deployed in a force that grew to 250 boats, the most common craft in the River Patrol Force, Task Force 116, and were used to stop and search river traffic in areas such as the Mekong Delta, the Rung Sat Special Zone, the Saigon River and in I Corps, in the area assigned to Task Force Clearwater, in an attempt to disrupt weapons shipments. The boats were powered by dual 180 hp (115 kW) Detroit Diesel 6V53N engines with Jacuzzi Brothers pump-jet drives. The boats reached top speeds of 28.5 knots (53 km/h 32 mph). The PBR was a versatile boat with a fiberglass hull and water jet drive which enabled it to operate in shallow, weed-choked rivers. It drew only two feet of water fully loaded. The drives could be pivoted to reverse direction, turn the boat in its own length, or come to a stop from full speed in a few boat lengths. The PBR was manufactured in two versions, the first with 31 foot length and 10 foot, 7 inch beam. The Mark II version 32 feet (9.8 m) long and one foot wider beam had improved drives to reduce fouling and aluminium gunwales to resist wear. Typical armament configuration included twin M2HB .50 caliber (12.7 mm) machine guns forward in a rotating shielded tub, a single rear M60, one or two 7.62 mm light machine guns mounted on the port and starboard sides, and a Mk 19 grenade launcher. There was also a full complement of M16 rifles, shotguns, .45 ACP handguns, and hand grenades. Some had a "piggyback" arrangement, a .50 cal machine gun on top of an 81mm mortar; others had a bow-mounted Mk16 Mod 4 Colt 20 mm automatic cannon, derived from the AN/M3 version of the Hispano-Suiza HS.404 and also found on the LCMs and PBRs. What the boats benefited in heavy firepower they lacked in armor or shielding. Although the .50 cal machine guns had some ceramic armor shielding and the Coxswain's flat had some quarter inch thick steel armor plate, the boats were designed to rely on rapid acceleration, maneuverability, and speed to get out of tight situations.