April 1983 - Maritime Reporter and Engineering News

SNAME Los Angeles Section Hears Paper On Arctic Air Cushion Vehicles

A paper entitled "Air Cushion Vehicles for the Arctic" was presented recently to the Los Angeles Section of The Society of Naval Architects and Marine Engineers by Raymond A. Bennett, vice president for commercial development at Global Marine Development, Inc.

The paper described the experiences of Global Marine during the mobilization and use of a 100- ton-cargo-capacity hoverbarge called the ACT-100. The purpose of the mobilization, which was accomplished at Prudhoe Bay, Alaska, during April 1981 through 1982, was to demonstrate and test the ACT-100 and gain insight to the payload requirements to be considered while developing new and larger air cushion supported craft.

The interest in vehicles such as the ACT-100 was revived by the recent decision to allow offshore drilling 10 months out of the year on Alaskan federal leases and on a case-by-case basis on state leases. According to the author, the ACT-100 meets the criteria for operation in the expanded drilling year: • It is an all-terrain, heavy load, transport vehicular system for the offshore as well as for environmentally sensitive, i.e., wilderness, onshore drill sites.

• It operates equally well in open water; thin fall ice; thick, potentially snow-covered, hard winter ice; and in water, which includes snow-covered, lesionmarked, spring breakup ice.

Global Marine, through its Arctic Systems Ltd. (Canadian) subsidiary, designed and built the 75-foot by 40-foot cargo deck area hoverbarge after obtaining a license from British Hovercraft for the skirt portion of the system.

The craft's basic marine structural configuration uses steel to simplify maintenance welding at remote areas of operation and to ensure durability and the capability to handle uneven or highly concentrated loads.

The craft, which has a lightweight of 185 tons and a deadweight (including ballast and fuel) of 192 tons, exerts a ground pressure of 0.93 pounds/square inches at its loaded capacity. It requires a draw-bar pull of 4,000 to 15,000 pounds at 8 mph under level conditions. A maximum air rate of 190,000 cfm is provided for lift via two centrifugal, diesel driven, horizontal fans. The ACT- 100 can hover fully loaded on one engine.

Mr. Bennett concluded his presentation with a film, made during the mobilization, that showed the ACT-100 being towed by a helicopter; a pair of "Rolligons"; and an Archimedes Screw Tractor. The film also showed the ACT-100's icebreaking capabilities while being pushed by the Canadian Coast Guard vessel Alexander Henry.

Other stories from April 1983 issue


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