Patrol Craft Fast (PCF), also known as Swift Boats, were all-aluminum, long, shallow-draft vessels operated by the United States Navy, initially to patrol the coastal areas and later for work in the interior waterways as part of the brown-water navy to interdict Vietcong movement of arms and munitions, transport South Vietnamese forces and insert SEAL teams for counterinsurgency (COIN) operations during the Vietnam War. Development Conception The Swift Boat was conceived in a Naval Advisory Group, Military Assistance Command, Vietnam (NAVADGRP MACV) staff study titled "Naval Craft Requirements in a Counter Insurgency Environment," published 1 February 1965. It noted that "counterinsurgency water operations are difficult, demanding, and unique. A prevalent belief has been that COIN craft can readily be obtained from existing commercial and naval sources when needed. Unfortunately, no concerted effort has been made to develop COIN craft specifically suited to perform the many missions needed to combat insurgent activities." The study went on to list characteristics of the ideal patrol craft: Reliable and sturdy Non-wooden hull, with screw and rudder protection against groundings Self-sufficient for 400 to 500 mile (600 to 800 km) patrol Speed of 20 to 25 knots (37 to 46 km/h) Small high-resolution radar range 4 to 6 miles (7 to 11 km) Reliable long-range communications equipment, compatible with Army and Air Force Quiet Armament for limited offense Sparse berthing, no messing Depth meter, accurate from 0 to 50 feet (15 m) Small, powerful searchlight The study was positively received, and the Navy began to search for sources. Sewart Seacraft of Berwick, Louisiana (Swiftships' predecessor), built water taxis for companies operating oil rigs in the Gulf of Mexico, which appeared nearly ideal. The Navy bought their plans, and asked Sewart Seacraft to prepare modified drawings that included a gun tub, ammo lockers, bunks, and a small galley. The Navy used those enhanced plans to request bids from other boat builders. Sewart Seacraft was chosen to build the boats. Mark I The Swift Boats had welded aluminum hulls about long with beam, and draft of about five feet (1.5 m). They were powered by a pair of General Motors 12V71"N" Detroit marine diesel engines rated at each, with a design range from at to about at . The normal complement for a Swift Boat was six: an officer in charge (skipper), a boatswains mate, a radar/radioman (radarman), an engineer (engineman), and two gunners (quartermaster and gunner's