jeffquitney
patreon
SK-5 Hovercraft (ACV): Air Cushion Vehicle Tests 1971 US Coast Guard
🕑 Added 2020-06-24 20:29:51 +0000 UTCmore at http://quickfound.net/
Originally a public domain film from the US Coast Guard, slightly cropped to remove uneven edges, with the aspect ratio corrected, and one-pass brightness-contrast-color correction & mild video noise reduction applied.
The soundtrack was also processed with volume normalization, noise reduction, clipping reduction, and/or equalization (the resulting sound, though not perfect, is far less noisy than the original).
USCG Air Cushion Vehicle Evaluation .pdf:
https://archive.org/details/DTIC_AD0755409
https://en.wikipedia.org/wiki/Patrol_Air_Cushion_Vehicle
Wikipedia license: http://creativecommons.org/licenses/by-sa/3.0/
The Patrol Air Cushion Vehicle (PACV), also known as the Air Cushion Vehicle (ACV) in Army and Coast Guard service, was a United States Navy and Army hovercraft used as a patrol boat in marshy and riverine areas during the Vietnam War between 1966 and 1970. Six hovercraft were built, three for the Army and three for the Navy.
The military developed the PACV because its lack of draft meant that it could operate unimpeded in the shallow and reed-choked waters widespread in South Vietnam, most notably in the Mekong Delta and Plain of Reeds. The PACV was also found to be valuable because of its unusually high speed of 60 knots (110 km/h; 69 mph), faster than other watercraft in the conflict. However, it faced major drawbacks, including its high cost of $1 million (equivalent to 13 Patrol Boat, Rivers) and unreliability. During the conflict, two of the Army hovercraft were destroyed by the Viet Cong. The PACVs in Vietnam were considered "unsuccessful" in evaluations and were withdrawn in 1970. Following their service in Vietnam, the Navy PACVs returned to the United States where they were used by the Coast Guard, where another sank in an accident...
Development
The PACV was based on the Bell Aerosystems Bell SK-5 hovercraft; a licensed version of the British Saunders-Roe (later, British Hovercraft Corporation) SR.N5 hovercraft. The SK-5 was adapted for American military use in 1965. Three were purchased by the US Navy for operations in the emerging Vietnam War. Training of PACV crews was performed in the waters off Coronado, California near San Diego. Design of the Army ACVs began in 1966 and was completed
Design
Two different designs were made: one for the Navy and one for the Army. The Navy's hovercraft, called Patrol Air Cushion Vehicles, more closely resembled the civilian SK-5s that they were based off while the Army crafts had more extensive modifications. Each hovercraft was 38 ft 10 in (11.84 m) long, with a beam of 23 ft 9 in (7.24 m) and a height of 16 ft 6 in (5.03 m) when floating on its air cushion. It weighed 15,660 pounds (7.10 tonnes) fully loaded. Army and Navy PACVs had a crew of 4—driver, radar operator, and gunners—and could carry up to 12 troops, many of whom rode on the outside of the vehicle...
Both designs were powered by a General Electric 7LM100-PJ102 gas turbine engine. The engine, its 304-gallon (1,150 litre) fuel tank, an auxiliary power unit, and the Westland transmission were located amidships. The engine powered both the three-blade variable-pitch propeller for thrust and the 7-foot (2.1 m) diameter centrifugal fan for lift... The PACV/ACV was very fast compared to contemporary watercraft, being capable of speeds up to 60 knots (110 km/h; 69 mph). It had a range of 165 nautical miles (306 km; 190 mi) and endurance of seven hours...
Following their withdrawal in 1970, the Navy PACVs were transferred to the U.S. Coast Guard for evaluation. The Coast Guard used PACVs, which they called Air Cushion Vehicles (ACVs), through 1975, when they cancelled the ACV program due to budget constraints. Two were stationed at Fort Point, San Francisco and the third was used for Arctic Trials in Point Barrow, Alaska, though they were also tested in the Great Lakes and Chesapeake Bay. The Coast Guard PACVs were modified to meet their requirements... Coast Guard PACVs were crewed by 3—operator, radar operator and navigator, and search-and-rescue crewman—and could carry 6 passengers and half a ton of cargo. Because it was lighter than the military version, the Coast Guard ACV could go up to 70 knots (81 mph; 130 km/h) and had a range of 300 nautical miles (350 mi; 560 km).
The ACVs in Coast Guard service were used primarily for search-and-rescue missions because of their speed and range...
In the final Coast Guard evaluation, Commander Thomas Lutton wrote that "The ACV has dramatically and repeatedly demonstrated its capability to effectively perform a wide range of Coast Guard missions." However, the Coast Guard was in the middle of a large upgrade of its other boats and cutters at the time and so did not have the money to acquire ACVs...
