One of the most intriguing of the United States Navy's crafts during the Vietnam War arguably was the PBR (or "Patrol Boat, Riverine" though also sometimes known as "Pibber"). The low-draft, high-speed river-borne craft was used for basic river patrol, river traffic searches and special forces insertion in an attempt to disrupt enemy riverine highways from supplies, ammunition and the like. The boat, the centerpiece for River Patrol Force, Task Force 116, could be fitted with a plethora of armament and was very effective in its intended role.
Design of the PBR centered around its propulsion of twin Detroit Diesel diesel engines which generated up to 220 horsepower. These engines drove twin Jacuzzi Brothers waterjets that allowed the PBR speeds in excess of 28 knots. The rigid hull was constructed of fiberglass and produced a shallow draft, allowing the PBR elements to traverse portions of the Delta where other Navy craft could not enter. Accommodations amounted to a standard load of four personnel with one usually consisting of an interpreter for dialogue and navigational purposes. Ceramic-based armor allowed for some protection for the cabin where three of the crew and their fellow passengers resided. A forth crewmember mounted the separated forward armament tub at the bow.
Armament consisted of a myriad of weapons combinations based on experience and practice. The forward bow turret was usually armed with twin 12.7mm (.50 caliber) M2HB Browning heavy machine guns. A pintle mounting amidships could hold a Mark 19 40mm grenade launcher or a single M60 7.62mm (.30 caliber) belt-fed machine gun. The rear pintle mounted (protected by ceramic shields) could mount a single 12.7mm or 7.62mm machine guns. Additional armament for the boat consisted of mortar launchers, 20mm cannons and flamethrowers, the latter of which produced impressive results against the straw and thatch structures found throughout the region. The standard armament of the PBR could also be augmented by whatever personal weapons were carried by the crew.
The PBR appeared in two marks known simply as Mark I and Mark II. The most differentiating feature between the two was that the Mark II series was fitted with a longer hull. The PBR plays a large role in the Hollywood motion picture Apocalypse Now. PBR's served the United States Navy up until 1995.