Editing Patrol Craft Fast (section)

==Service==
{{more citations needed section|date=April 2023}}

Most of the 193 PCFs built were used by the U.S. Navy in Vietnam and the two training bases in California. About 80 of the boats constructed were sold or given away to nations friendly to the United States. The original training base for Swift Boats was at [[Naval Amphibious Base Coronado]].

In 1969, training was moved to [[Mare Island]] near [[San Pablo Bay]], California, where it remained for the duration of the war. Though not a deep water boat, PCF training boats frequently transited from Mare Island, through the [[Golden Gate Bridge]] to cruise either north or south along the Pacific Ocean coastline. ''PCF-8'' sank in a storm off [[Bodega Bay]], California in December 1969. This was the only Swift Boat lost during training operations. No crewmen were lost in the event.

The most frequent training area for the [[Mare Island]] units was the marshland that forms the northern shoreline of San Francisco Bay. This area, now known as the [[Napa Sonoma Marshes]] State Wildlife Area, was also used by [[United States Navy Reserve]] unit PBRs) up until 1995, when Mare Island was scheduled for base closure.

===Vietnam War service===
[[File:Fast Patrol Crafts operating up a river 2.jpg|thumb|PCFs carry a group of South Vietnamese marines up a narrow canal for insertion.]]

The first Swift Boats arrived in South Vietnam in October 1965. The boats were initially used as coastal patrol craft in [[Operation Market Time]], interdicting seaborne supplies on their way to the [[Viet Cong]] (VC) and [[People's Army of Vietnam]] (PAVN) forces in South Vietnam. However, the design's shallow draft and low [[Freeboard (nautical)|freeboard]] limited their seaworthiness in open waters. These limitations, plus the difficulties being encountered in the interior waterways by the smaller, more lightly armed [[Patrol Boat, River|PBRs]], led to the incorporation of Swifts to patrol the {{convert|1,500|mi}} of rivers and canals of Vietnam's interior waterways.<ref>Symmes ''War on the Rivers'' p. 95</ref><ref name=MMSD>{{cite web|url=http://sdmaritime.org/visit/the-ships/pcf-816-swift-boat/|title=PCF 816 Swift Boat|work=Maritime Museum of San Diego|access-date=2015-07-06|archive-url=https://web.archive.org/web/20150906143240/http://sdmaritime.org/visit/the-ships/pcf-816-swift-boat/|archive-date=2015-09-06|url-status=live}}</ref> Swift Boats continued to operate along the Vietnamese coastal areas, but with the start of Admiral [[Elmo Zumwalt]]'s "[[Operation Sealords|SEALORDS]]" riverway interdiction strategy, their primary area of operations soon centered upon the [[Cà Mau Peninsula]] and the [[Mekong Delta]] area in the southern tip of Vietnam.<ref name=MMSD/> Here they patrolled the waterways and performed special operations, including gunfire support, troop insertion and evacuation, and raids into enemy territory.<ref name=MMSD/>

The Mekong Delta is composed of ten thousand square miles of marshland, swamps and forested areas. The region is interlaced by rivers and canal ways.  Controlled by the VC, the interior waterways of the Mekong Delta were used to transport supplies and weapons.

Swift Boats generally operated in teams of three to five. Each boat had an officer in charge, one of whom would also be placed in overall charge of the mission. Their missions included patrolling the waterways, searching water traffic for weapons and munitions, transporting South Vietnamese marine units and inserting Navy [[SEAL]] teams.

When the Swift Boats began making forays up the waterways into the interior of the delta, they initially took the carriers by surprise, causing them to drop their materials and run off into the overgrowth.  Occasionally a short firefight would break out. As it became clear that control of the waterways was being contested, the VC developed a number of tactics to challenge the U.S. Navy. They set up ambushes, built obstructions in the canals to create choke points and began to place mines in the waterways.

For the Swifts, coming back down river was always more dangerous than going up river. The passage of a patrol assured their eventual return, providing an opportunity for the VC. Ambushes were typically short lived affairs, set up at a river bend or in a narrow canal that restricted the maneuverability of the boats.<ref>Symmes ''War on the Rivers'' p. 148</ref>  A wide variety of portable weapons were used in attacks, including [[recoilless rifle]]s, [[RPG-2|B-40 rockets]], [[DShK|.50 caliber machine guns]] and [[AK-47]]s, often fired from behind earthen bunkered positions.<ref>Symmes ''War on the Rivers'' p. 136</ref> Engagements were brief and violent, with the ambushers often slipping away into the undergrowth when the boats located the source of attack and began to concentrate their return fire. When attacked the boats would accelerate out of the hot zone, turn and then return as a group, firing as many of their guns as they could bring to bear. They would power past the ambush point, turn and return to attack again until the ambushers were either killed or slipped away. Though most cruising and patrolling was done at 8 to 10 knots, the boats could reach a top speed of 32 knots. Thick brush and vegetation in the delta provided excellent cover for the escaping ambushers. Casualties taken among the river crews were high. Casualties suffered among the VC were difficult to assess, as they would take their dead and wounded away from a firefight. Discovering newly dug graveyards was one of the few ways to confirm VC losses.<ref>Symmes ''War on the Rivers'' p. 173</ref>

The first Swift Boat to be lost during the war was ''PCF-4'', which was lost to a mine in 1966. Two boats, ''PCF-14'' and ''PCF-76'', were lost in rough seas at the mouth of the Cua Viet River near the [[Vietnamese Demilitarized Zone|DMZ]], and a third, ''PCF-77'', was lost in a rescue effort during a [[monsoon]] at the mouth of the [[Perfume River]] on the approach to [[Huế]]. All three of these boats were lost in 1966. ''PCF-41'' was lost that same year in an ambush when it was hit by fire from a 57&nbsp;mm recoilless rifle. Its controls destroyed and coxswain killed, it ran aground at speed. When the crew ran out of ammunition it had to be abandoned.<ref>{{cite web|last= Wasikowski|first= Lawrence J.|url= http://www.swiftboats.net/stories/pcf41.htm|title= Coastal Squadron One; 22 May 1966 Sinking of ''PCF-41''|date= April 26, 2008|access-date= July 13, 2018|website= swiftboats.net|archive-url= https://web.archive.org/web/20150924112325/http://www.swiftboats.net/stories/pcf41.htm|archive-date= 24 September 2015|url-status= live}}</ref> It was recovered the next day but was too badly damaged to be repaired, so was salvaged instead.

''PCF-43'' was lost to a rocket attack in 1969.<ref>Symmes ''War on the Rivers'' pp. 120-122</ref> Several other Swift Boats had been lost to river mines, but had been salvaged and either repaired or used for spare parts.

When Vietnamization was implemented, several Swift Boats were turned over to the South Vietnamese Navy.<ref>{{cite web | url=https://www.history.navy.mil/content/history/museums/nmusn/explore/photography/ships-us/ships-usn-p/patrol-craft-fast-pcf.html | title=Patrol Craft, Fast (PCF) }}</ref>

==== Controversy over loss of ''PCF-19'' ====
{{Infobox military conflict
| conflict    = Sinking of PCF-19
| width       = 370px
| partof      = [[Operation Market Time]], [[Vietnam War]]
| date        = June 16, 1968<br />~0030 - 0400 hours ([[UTC+07:00]])
| place       = [[Bến Hải River|Bến Hải]] & Cửa Việt Rivers, [[South Vietnam]]
| territory   = 
| result      = Determined to be a [[friendly fire]] incident due to an unrelated incident in the same area the next day
| combatants_header = 
| combatant1  = {{flagicon|Vietnam}} [[North Vietnam]]
| combatant2  = {{flag|United States}}
| commander1  = Unknown
| commander2  = [[Lieutenant (junior grade)|LTJG]] John Davis<br />LTJG Peter Snyder<br />LTJG Ronald Fritz<br />[[Colonel (United States)|Col]] Dominic Damico
| strength1   = 2-4 [[Mil Mi-4|Mi-4 helicopters]]<br />1 unknown [[fixed-wing aircraft]]
| strength2   = 2 PCFs<br />1 [[USCGC Point Dume (WPB-82325)|point-class cutter]]<br />1 [[McDonnell Douglas F-4 Phantom II|F-4 Phantom II]]
| strength3   = 
| casualties1 = 1 helicopter allegedly damaged	
| casualties2 = 1 PCF destroyed<br />5 killed<br />2 wounded
| campaignbox = 
}}
On the night of 15/16 June 1968, U.S. marine aircraft spotters on the ground began reporting unidentified helicopters near the DMZ. The first report stated that four helicopters had been detected and were proceeding toward [[Cồn Cỏ District|Tiger Island]], just off the North Vietnamese coast at an altitude of {{convert|700–1,000|ft}}. These spotters observed the aircraft visually, using [[Starlight Scope]]s and by radar. Over the course of the night, Air Force pilots reported 19 additional helicopter sightings. On this same evening the guided missile heavy cruiser {{USS|Boston|CAG-1|6}}, operating near the
DMZ, also began reporting helicopter activity in the vicinity of [[Bến Hải River|Bến Hải]], Cap Lay and Tiger Island. At 00:10 on the 16th, an unidentified aircraft fired three rockets or missiles at ''Boston'', but none hit the vessel.<ref name=Sherwood>{{cite book|last=Sherwood|first=John|title=War in the Shallows: U.S. Navy and Coastal and Riverine Warfare in Vietnam 1965-8|publisher=Naval History and Heritage Command|year=2015|isbn=9780945274773|url=https://www.history.navy.mil/research/publications/publications-by-subject/war-in-the-shallows.html}}{{PD-notice}}</ref>{{rp|240}}

At 01:00 on 16 June 1968 in the same area, ''PCF-19'' was struck by two missiles, one struck the cabin just below the pilothouse on the port side, the other hit the engine room. The boat sank in four minutes. Four of its crewmen were killed, and two others badly injured.<ref>Steffes, p.68-71, official U.S. Navy OinC (Officer In Charge) PCF-12 After Action Report</ref><ref name=Sherwood/>{{rp|240}} The remaining crew managed to swim free from the sinking craft and cling to a life raft until {{USCGC|Point Dume|WPB-82325|6}} arrived on scene at 01:30. As soon as the survivors were on board, ''Point Dume'' departed the scene to drop them off at the [[Cua Viet Base]] for a medevac to Danang. In the meantime, the crew of ''PCF-12'', which had arrived on the scene at 01:50 to continue the search for survivors, noticed illumination rounds being fired that were not their own. Opting to investigate, the officer in charge ordered the boat to speed to the Cua Viet River. When ''PCF-12'' was {{convert|3|mi}} from the river mouth, crewmembers observed two sets of aircraft lights off the port and starboard beam, about {{convert|300|yd}} away and {{convert|100|ft}} above the water. The boat commander immediately got on the radio and requested permission to engage the aircraft. At 02:25, ''PCF-12'' received a single rocket from seaward at a low trajectory. The rocket passed a couple of feet over the main cabin and exploded in the water ten feet from the boat. ''PCF-12'' came about, increased speed and moved away from the kill zone while bringing its .50-caliber guns to bear against an aerial target hovering at {{convert|1,000|ft}} with lights blinking. The aircraft decreased altitude and turned off its lights. After a short time, ''PCF-12'' stopped to observe the scene and saw two aircraft appeared off its beams again with lights on. The boat commander contacted the marine observer and inquired about their status. The marines told him that they could not identify the aircraft because they did not have their identification, friend or foe (IFF) transponders turned on. At 02:35, the aircraft near the beach fired 40–50 rounds of .50-caliber tracer fire at the PCF. All rounds landed astern. ''PCF-12'' responded with machine-gun and mortar fire.<ref name=Sherwood/>{{rp|241}}

At 02:40, ''Point Dume'', now back on the scene was attacked by a fixed-wing aircraft, which made two attack runs against the vessel. Both the commanding officer of ''Point Dume'' and the commander of ''PCF-12'' positively identified the aircraft as a "jet." The crews of ''Point Dume'' and ''PCF-12'' then observed numerous lighted aircraft that appeared to be helicopters in the northern part of the area. These aircraft approached the U.S. vessels and made firing runs with their lights off. ''Point Dume'' received heavy caliber automatic weapons fire from these aircraft and returned fire. ''PCF-12'' also returned fire intermittently for approximately 75 minutes. Neither vessel was damaged in the engagement; there were no personnel injured.<ref name=Sherwood/>{{rp|241}}

On the afternoon of 16 June, Task Unit 77.1.0 ordered {{USS|Edson|DD-946|6}}, {{USS|Theodore E. Chandler|DD-717|6}} and the [[Royal Australian Navy]] guided-missile destroyer Hobart {{HMAS|Hobart|D 39|6}} to conduct a surveillance mission in the vicinity of Tiger Island in attempt to flush out any enemy helicopters or waterborne craft operating from there. At 01:18 on the 17th, ''Boston'', which was engaged in a naval gunfire support mission in the same general area, came under attack from an unidentified jet aircraft. The jet fired two missiles at the ship: one exploded {{convert|200|yd}} off the port beam; and the other close aboard to port, showering the ship with fragments. No sailors were injured, and the missiles caused only minor structural damage to the ship. At 03:09, while ''Hobart'' was searching a 5-mile radius area between the coast and Tiger Island with its radar, it detected a single aircraft tracking east. The aircraft was not squawking IFF. An attempt was made to identify the aircraft by visual gun direction personnel on the bridge. Five minutes later a missile slammed into the chief petty officers' mess and nearby spaces, killing one sailor and wounding two others. The ship took evasive action but temporarily lost radar contact with the aircraft. At 03:16, two more missiles hit the ship, destroying the gunners' store and damaging other spaces, including the engineers' workshop, the seamen's mess, the missile director room, the [[RIM-24 Tartar]] checkout room, and the chiefs' mess (again). This second attack killed an officer and wounded other sailors. As the aircraft turned to make a third pass, one of the ship's gun turrets fired five rounds and the aircraft turned and retreated. Fourteen minutes later ''Edson'', now at general quarters due to reports from ''Hobart'' about hostile aircraft in the area, came under attack by an unidentified aircraft. Lookouts and sonar confirmed a near miss astern by a missile.<ref name=Sherwood/>{{rp|242}}

The next day Vice Admiral [[William F. Bringle]], Commander Seventh Fleet, appointed Rear Admiral S. H. Moore, Commander Task Group 77.1/70.8, to conduct an informal investigation into the various firing incidents occurring between 15 and 17 June. The board determined that Air Force [[McDonnell Douglas F-4 Phantom II|F-4s]] launched two [[AIM-7 Sparrow|AIM-7E Sparrow]] missiles on 17 June at 01:15 and one at 03:15 that same day. Fragments of Sparrow missiles complete with serial numbers found on ''Boston'' and ''Hobart'' confirmed these findings. The case was therefore quite clear with regard to these two attacks on 17 June — ''Hobart'' and ''Boston'' had been the victims of friendly fire. The board also investigated the 16 June attacks on ''Boston'' and ''PCF-19'' and the attack on ''Edson'' on the 17th. From the positions of American vessels and attacking aircraft, the board concluded that Air Force aircraft attacked ''Boston'' and ''PCF-19'' on the 16th and that American aircraft also attacked ''Edson'' on the 17th. Unlike the ''Boston'' and ''Hobart'' attacks on the 17th, however, no physical evidence supported these findings. Later research of the incident with surviving veterans and a review of salvage reports from {{USS|Acme|MSO-508|6}}, the ship that recovered the bodies and codebooks from ''PCF-19'' shortly after the attack, found that the rocket entry holes in the hull of ''PCF-19'' were 76.2mm in size—the size of a standard helicopter rocket carried by a [[Soviet Union|Soviet]]-manufactured [[Mil Mi-4|Mi-4 Hound]] helicopter and not Sparrow or [[AIM-9 Sidewinder|Sidewinder]] holes, which would have been larger.<ref name=Sherwood/>{{rp|242}}<ref>{{citation|last = Steffes|first = James|title = Swift Boat Down: The real story of the sinking of ''PCF-19''|year = 2005|isbn = 1-59926-612-1|publisher = [[Xlibris]]}}</ref>

===Vietnam People's Navy service===
The [[Vietnam People's Navy]] managed to capture 107 of [[Republic of Vietnam Navy]] PCFs after the [[Fall of Saigon]] in 1975. The PCFs were quickly used in VPN operations at [[Thổ Chu]] and other islands to repel the invasion of the [[Khmer Rouge]].<ref>{{cite web | url=https://infonet.vietnamnet.vn/hai-chien-voi-pol-pot-tren-dao-tho-chu-chuyen-bay-gio-moi-ke-146990.html | title=Chuyên trang Infonet Báo VietnamNet }}</ref> The Swift Boats are still active in the Vietnam People's Navy.<ref name = "soha">{{cite web|archive-url=https://web.archive.org/web/20140620100829/http://soha.vn/quan-su/kham-pha-vu-khi-moi-tren-tau-pcf-vn-sau-nang-cap-20140617211242499.htm |archive-date=2014-06-20 |date=2014-06-18|url=http://soha.vn/quan-su/kham-pha-vu-khi-moi-tren-tau-pcf-vn-sau-nang-cap-20140617211242499.htm|title=Khám phá vũ khí mới trên tàu PCF VN sau nâng cấp|language=Vietnamese|publisher=Soha |url-status=live}}</ref><ref>{{cite web | url=https://soha.vn/quan-su/gia-sung-da-nang-tren-tau-pcf-20151106203248191.htm | title=Giá súng đa năng trên tàu PCF | date=6 November 2015 }}</ref>

The M2 machine gun was replaced by a domestically produced 12.7&nbsp;mm NSV gun, which had fewer jamming problems and was easier for the crews to maintain.<ref name = "soha"/> The electronic and communication systems were also overhauled.<ref name = "soha"/> Some PCFs captured have a DsHK HMG and an AGS-17 AGL mounted on top.<ref name="Soha2"/>