Ice-breaking trials using an air cushion vehicle are to be carried out this winter on the St. Lawrence River because of the success of earlier icebreaking efforts with the amphibious craft. In tests undertaken in February 1974 by the Canadian Coast Guard at Parry Sound, an air cushion craft was used to break ice 15 in. thick. Because the 15 in. ice was the thickest that could be found in the Parry Sound area, the vehicle could not be tested there to its fullest potential. However, it is considered that ice 20 in. thick could have been broken, according to D.O. Dutfield of the Air Cushion Vehicle Division of the Ministry of Transport. The craft used was the Voyageur ACV built by Bell Aerospace Canada, a division of Textron Canada Ltd of Grand Bend. The craft has a payload of 25 tons and a gross weight of 90,000 lb. The success of the ACV as an icebreaker has led to optimistic speculation on its use where conventional icebreakers cannot be employed. Consideration has been given to fitting air cushions to the bows of conventional ships to break ice and to building ACVs that could be easily transported to where icebreaking is needed. Because of an ACV's mobility on ice and its speed of operation, the Voyageur programme will continue on the St. Lawrence River this winter. Icebreaking by air cushion operations is a new application of the ACV technology, which was discovered almost by accident in ACVs in the North. It was found that in operations over previous winter testing of ice the vehicle was breaking the surface behind it because the air cushion formed a cavity under the ice into which it would break off under its own weight. It was found in the Parry Sound tests that the Voyageur vehicle consistently broke 9 in. of clear ice with the air cavity effect, while travelling at 4 mph. But at 12 mph, 15 in. of ice was broken by an entirely different process. At this speed the air cushion would create a 3 to 4 ft wave under the ice behind the craft and deflect it upward.

  • Corporate Authors:

    Reed (Thomas) Industrial Press Limited

    36/37 Cock Lane, Saracen's Head Building
    London EC1A 9BY,   England 
  • Publication Date: 1974-12

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Filing Info

  • Accession Number: 00084633
  • Record Type: Publication
  • Source Agency: Reed (Thomas) Industrial Press Limited
  • Files: TRIS
  • Created Date: May 7 1975 12:00AM