PBR MK I
PBR MK II
When the Navy decided to commit river patrol forces to the inland waters of Vietnam, it found itself in need of a small fast patrol craft. The result was the PBR MK I. The boat was 31 ft long and capable of speeds approaching 25 knots. It was powered by two GM 220 Horsepower diesel engines connected by direct drive to a pair of Jacuzzi water jet propulsion pumps. the boat's armament consisted of a twin 50 Caliber machine gun mount in the forward gun tub, a single 50 Caliber machine gun on a stern mount, an M60 machine gun and a Honeywell MK 18 40mm grenade launcher mounted amid ship. In addition each boat was equipped with various small arms; M-79 grenade launcher, Shotgun, mortar, grenades and side arms. The PBR was outfitted with a Raytheon 1900 radar unit and two AN/VRC 46 radios. The PBR drew only two feet of water while at rest and about nine inches of water at full speed. After the initial run of MK I PBRs, the MK II was introduced. Slightly larger and with a lower profile, the only significant difference was the beefed up aluminum gunwales to aid in protecting the boat from being damaged when coming alongside sampans and junks. Eventually there would be 250 PBRs in Vietnam.
The PBR was manned by a four man crew - normally a first class petty officer as boat captain, a gunner's mate, an engineman and a seaman. Each crewman was cross trained in each other's job encase one became unable to carry out his duties. Generally PBRs operated in two boat patrols under the command of a patrol officer who rode one of the boats in addition to the normal crew.
Photo of the Civilian
craft converted to the MK I PBR.