Boat Specifications

Length:	50 foot 1.5 inches
Beam:	13 foot 6.5 inches
Full load draft:	Hull - 3 foot 10 inches, Skegs - 4 foot 10 inches and Navigational - 5 foot 10 inches
Height: (above full draft waterline)	Main deck at pilothouse - 3 foot 8 inches Top of .50 caliber gun tub - 11 foot 6 inches Top of the radar mast - 16 foot 9 inches
Construction: Want to see where these compartents were physically located? Roll your mouse over the underlined terms!	The PCF was divided into seven compartments: forepeak, crew quarters, pilothouse, deckhouse, stowage compartment, engine room and lazarette. - FORE PEAK (Peak Tank) The forepeak was used as a storage area and access to this compartment was through the forepeak hatch located just forward of the pilothouse and in the main deck. - CREW QUARTERS The crew quarters contained berthing for three personnel, storage area for personal equipment and a head. Access to the crew quarters was through either the escape hatch located on the forward main deck or the ladder down from the deckhouse. - PILOTHOUSE The pilothouse was equipped with the necessary controls and indicators to operate the propulsion engines, ac diesel generator, two .50 caliber machine guns (located in the gun tub mounted in the aft center overhead), electrical systems and to navigate the PCF. Access to the compartment was through either port or starboard hatches to the main deck or the ladder up from the deckhouse. Nine fixed windows were mounted in this compartment. A CO2 fire extinguisher was located in the pilothouse. - DECKHOUSE The deckhouse contained berthing for two personnel; galley area with griddle, refrigerator and reefer, sink; radio/radar area with three radios; small arms locker; storage cabinets and two CO2 fire extinguishers. Access to the deckhouse was through the main deck hatch on the aft end of the deckhouse, the ladder down from the pilothouse or the ladder up from the crew quarters. Four operable windows, two on each side, and a single, fixed window in the aft main deck hatch, were mounted in this compartment. - STOWAGE COMPARTMENT (Under Deck) The stowage compartment contained ammunition storage, the forward fuel tank and the two engine control units. The remaining space was utilized for storage. Access to the compartment was through the bilge hatch located in the deckhouse, under the ladder going up to the pilothouse. Three access hatches were provided in the deckhouse, one for the forward fuel tank and two for the ammunition boxes. - ENGINE ROOM The engine room housed the two propulsion engines, ac diesel generator, 2-24v battery sets, storage access for service manuals and tools, exhaust systems for the engines and generator, a five-gallon lube oil can, piping necessary for the bilge system, engine and generator seawater cooling systems, fuel system, 24v dc source of power switch and the ac source of power switch. Access to the engine room was through two hinged hatches on the main deck just aft of the deckhouse. - LAZARETTE STORAGE The lazarette housed the two aft fuel tanks, fresh water tank, steering gear, rudder tillers and two five-gallon lube oil cans. Access to the lazarette was through an access hatch located on the aft port corner of the aft deck. Two soft-patch hatches, on the aft deck, were provided for access to the fuel tanks. The hull and superstructure were of all-welded, 1/4 inch aluminum alloy construction. All deck plating, bulkheads and any other structural members were 5086-H321 aluminum alloy for both sheets and plates. All extrusions were made using 5086-H311 aluminum alloy. Four magnesium anodes were located on the stern, below the water line, and provided the means for reducing underwater electrolytic corrosion.
Paint Scheme:	Original: haze gray overall - factory applied color Vietnam : deck gray with varying amounts of black added, white mortar box lid and a large white star, in a blue circle, on the pilot house roof Riverine: dull green with black camouflage patterns - authorized in May 1970
Weight:	36,913 lbs. empty - 47,047 lbs. with full war load of fuel and ammunition
Displacement:	42,500 lbs.
Engines: Propellors:	Two (2) General Motors 12V71"N" Detroit marine diesels; port model #7122-3000, starboard model #7122-7000, each equipped with two 4-71 blowers and rated at 480 horsepower, when using the N70 type injectors, SM-118 Hydraulic Marine Gear Clutch with 1.15:1 reduction gears and driving two counter-rotating bronze screws. Two (2) 28x27 inch/pitch, 2.25" bore; one right hand rotation, one left hand rotation (factory configuration). Propellor tests were conducted on 23/24 July 1970 at Cam Ranh Bay, with PCF 58, to compare overload conditions on the 12V71 engines, using the 28x27 inch/pitch vs. 28x25 inch/pitch screws. Using the 28x27 screws, overload conditions occurred at 2000 rpm. No overload conditions were observed, at any speed, when using the 28x25 propeller, however a loss of about one knot in speed was prevalent at all speed changes. PCF 58 was loaded out to weigh 50,000 lbs and 47,500 lbs on each test run. Approval was granted to equip all PCFs with the 28x25 propellers, as a result of these tests.
Electrical:	24 volt batteries provided the main source of electrical power, including main engine starting, general purpose lighting, search lights, navigational lights, radar and the URC-58 radio (alternate mode). There were two (2) 24 volt battery banks, each charged by its own alternator. The port bank was a standby 24 volt supply, while the starboard bank was used for general boat power. In an emergency, these banks could be put in a parallel mode configuration, to ensure operation of vital equipment. 120 volt 60 cycle AC, single phase electrical power, was used for operation of the URC-58 radio, signal light, reefer equipment, cooking outlet and griddle. It was supplied by a small diesel powered generator. - 3.0kw Onan, model 3DJA-1E 2236, 120 volt, 25 amp, AC generator, air cooled, used in the early boats - 6.0kw Onan, model 6MDJB-3R, 120 volt, 50 amp, AC generator, water cooled, used on the later boats and retrofitted to the early boats during major overhauls (this allowed the use of all AC electrical equipment at one time)
Electronics:	Decca D202 (X-band, 3cm) surface search radar, maximum range scale of 24 miles, with fixed range rings and a relative bearing presentation. Range discrimination was 30 yards, on the 1.5 mile scale, with a bearing accuracy of 1 degree. Maximum detection range of a small wooden junk was 3 miles, with an estimated 90% detection of small junks at 1 mile. In average sea conditions, a 90% detection rate, for steel hulled trawlers, could be assumed at 5 miles. Power consumption was 200 watts DC only. Raytheon 1900ND surface search radar was installed on a limited number of boats, equipped with breakaway radar masts, that could be lowered to clear low bridges. Raytheon DE176A Fathometer - dual range (240 foot maximum depth) AN/URC-58 SingleSideBand radio, 2 to 15 Mhz, could operate on upper sideband, lower sideband, AM or CW. Output was 100 watts. This was the PCFs primary communications equipment and was used to guard the M/T reporting net (S-3) for long range - boat to base communications. This radio normally operated on 120 volts DC power but could be operated on 24 volt DC if necessary. PCFs 17 and above, had a remote speaker and microphone installed in the pilothouse. AN/VRC-46 FM radio, 30.00 to 79.95 Mhz (short range - boat to boat or boat to shore for coordination with other units), installed on all boats during 1967. AN/PRC-10/25 FM, 30.00 to 79.95 Mhz portable field radio (used by off boat inspection parties and to coordinate with other units ashore). AN/PRC-41 UHF portable radio (surface to air communications). Installed on all boats between March and May 1970, prompted by aircraft sinking of PCF-19 in June 1968. AN/URC-4 Survival/Emergency radio PSYOPS warfare amplified loud-hailer system, AN/UIH-5, included both a microphone and tape recorder, range of approximately 1800 yards, and were installed during 1967, in concert with the removal of the top mounted searchlights.
Miscellaneous Equipment:	Danfort/White magnetic compass - installed on pilothouse console Hand held observers magnetic compass 6 inch portable search light - visible at 4 mile range, when used from the guntub Spotlight - used to illuminate targets at 250 to 300 yards range, mounted on pilothouse roof and controlled from inside the pilothouse by the boat driver
Armament:	- Twin .50-caliber Browning machine guns, with heavy barrels, on a Mark 17/Mod 1 manually operated, twin-scarf-ring mount. Capable of firing at 450-550 RPM and equipped with ammo cans for 500-600 rounds per gun. All located on the boat centerline, in a guntub, mounted on top of the pilothouse and designated "mount 51." The maximum range of these guns was in excess of 7,000 yards. Experience showed that the effectiveness was poor in excess of 2,000 yards but that it improved with decreasing range and that its accuracy was excellent at 1,000 yards or less. Typically 20 to 25,000 rounds of .50 caliber ammunition were carried onboard the PCF. - 81mm Mark 2/Mod 0, trigger fired mortar with a .50-caliber, semi-automatic capable, Browning machine gun, with heavy barrel, fixed atop it, and equipped with an ammo can for 100 or 300 rounds. All mounted to an on centerline fantail tripod and designated "mount 52." It was also referred to as the "over and under weapon." - Range of the 81mm mortar was 3,940 yds. elevated, and 1000 yds. direct fire. - Trigger fired capacity was 10 rounds per minute, drop fired 18 rounds per minute. Typical 81mm ammunition load carried on board, in the stern mounted ready service locker and two main cabin floor lockers was: - High Explosive w/Point Detonate fuse - 80 rounds - White Phosphorus w/Point Detonate fuse - 15 rounds - Flechette (Mark 120/Mod 0) added to the allowance in November 1970 - Illumination w/Time fuse - 20 rounds - Proximity (Variable Time) fuse - 8 per boat - Mark 19, 40mm, belt feed, grenade launcher, was installed on the bow of 26 boats, in November/December 1970 time frame. - various crew member weapons, to include: M-60 machine guns, M-79 grenade launchers with (illumination, high explosive, flechette and 00 buckshot) rounds, M-14 and or M-16 rifles, 12 gauge Ithaca riot gun, .38 caliber or .45 caliber pistols, various types of hand grenades (fragmentation, concussion - M3A1, thermite and red, yellow and green smoke), very pistols (flare gun) and at times, some C-4 explosive. In May 1968, action was taken to provide protection for mount 51 and the fantail of the PCF. Flack jackets were initially draped over the fantail lifelines and air crewman armor was installed around mount 51. In May 1970, 25 sets of fantail armor protection (3/8" thick, fiberglass/ceramic armor, Bonded Woven Roving), was installed on PCFs involved in riverine operations.
Speed:	32 knots, designed maximum
Turning radius:	75 yards when cruising at 20 knots
Stopping distance:	2 1/4 boats lengths (112') in 9 seconds, from maximum speed
Fuel:	800 gallons, diesel or JP-5 in an emergency, in three fuel tanks (2 aft, 1 amidships) There were no fuel transfer pumps. PCFs 1 -16 engines could draw fuel from their own tank or the centerline tank. PCFs 17 and higher could draw fuel from any tank.
Range:	@800rpm - 8.1 knots - 8 gallons per hour - 840 nautical miles - 100+ hours endurance @1000rpm - 9.8 knots - 10 gallons per hour - 780 nautical miles - 80 hours endurance @1200rpm - 11.2 knots - 18 gallons per hour - 600 nautical miles - 44 hours endurance @1400rpm - 13.6 knots - 20 gallons per hour - 540 nautical miles - 40 hours endurance @1600rpm - 17.6 knots - 28 gallons per hour - 400 nautical miles - 28.5 hours endurance @1800rpm - 20.5 knots - 50 gallons per hour - 320 nautical miles - 16 hours endurance @2000rpm - 23.5 knots - 75 gallons per hour - 250 nautical miles - 10.7 hours endurance Actual engine RPM versus speed data varied widely from boat to boat depending on the type of fuel used, loading of the boats, and calibration of the remote engine tachometers. The height of the sea significantly curtailed the speed capabilities of the PCF. This effect varied with the course of the PCF relative to the direction of the seas. Average estimates of the most limiting conditions on a PCF, heading directly into the seas, without violent pounding, are listed below: 0'-2' seas, 0-12 knot wind, 1850 max RPM, 21.0 knot speed, 21.0 knot speed over all 3'-4' seas, 12-15 knot wind, 1200 max RPM, 11.2 knot speed, 10.5 knot speed over all 5'-6' seas, 15-18 knot wind, 600 max RPM, 6.3 knot speed, 4.5 knot speed over all
Potable Water:	60 gallons

Length:	51 foot 3.75 inches
Beam:	13 foot 7 inches
Full load draft:	Hull - 3 foot 10 inches, Skegs - 4 foot 10 inches and Navigational - 5 foot 10 inches
Construction: Note:	hull/superstructure were of all-welded, 1/4 inch aluminum alloy construction All deck plating, bulkheads, and other structural members were 5086-H321 aluminum alloy for both sheets and plates. All extrusions were made using 5086-H311 aluminum alloy. Two magnesium anodes were located on the stern, below the water line, and provided the means for reducing underwater electrolytic corrosion. Bow height was raised by one (1) foot and the pilothouse was moved aft by approximately three (3) feet, from the Mark I construction plans design
Weight:	34,934 lbs. empty - 45,093.8 lbs. with full war load of fuel and ammunition
Displacement:	43,035 lbs.
Engines: Propellors:	Two (2) General Motors 12V71"N" Detroit marine diesels; port model #7122-3000, starboard model #7122-7000, each equipped with two 4-71 blowers and rated at 480 horsepower, when using the N70 type injectors, MG-512, Twin Disk, Hydraulic Marine Gear Clutch with 1.5:1 reduction gears and driving two counter-rotating bronze screws. Each engine was equipped with an MP130R, 180 gpm bilge pump. Two (2) 28x26 inch/pitch, 2.25" bore; one right hand rotation, one left hand rotation (factory configuration).
Electrical: DC AC	5 - 12 vdc batteries (Delco 761 - 205 amp hour) provide the main source of electrical power, including main engine starting, load and AC generator start. They were arranged as (2) 24 volt battery banks, each charged by its own alternator. The DC system was a two wire, ungrounded system. - 6.0kw diesel Onan generator, model 6MDJB-3, 120 volt, 50 amp, 60 Hz AC, water cooled.
Electronics:	Decca D202 (X-band, 3cm) surface search radar, maximum range scale of 24 miles, with fixed range rings and a relative bearing presentation. Range discrimination was 30 yards, on the 1.5 mile scale, with a bearing accuracy of 1 degree. Maximum detection range of a small wooden junk was 3 miles, with an estimated 90% detection of small junks at 1 mile. In average sea conditions, a 90% detection rate, for steel hulled trawlers, could be assumed at 5 miles. Power consumption was 200 watts DC only. Raytheon DE-736 Fathometer - dual range (240 foot maximum depth) AN/URC-58 SingleSideBand radio, 2 to 15 Mhz, could operate on upper sideband, lower sideband, AM or CW. Output was 100 watts. This was the PCFs primary communications equipment and was used to guard the M/T reporting net (S-3) for long range - boat to base communications. This radio normally operated on 120 volts DC power but could be operated on 24 volt DC if necessary. AN/VRC-46 FM radio, 30.00 to 79.95 Mhz (short range - boat to boat or boat to shore for coordination with other units).
Fuel:	828 gallons, diesel or JP-5 in an emergency, in three fuel tanks (2 aft - 279 galllon capacity, 1 amidships - 270 gallon capacity)
Potable Water:	51 gallons in a rectangular stainless steel tank