Southwest Research Institute® (SwRI®) News

SUB-ICE Icebreaking Engine

SAN ANTONIO, Texas -- Sept. 20, 1972 -- A new method of icebreaking known as SUB-ICE (Submerged Ice Cracking Engine), developed by Southwest Research Institute® (SwRI®), has been honored as one of the 100 most significant new technical products of the year.

Selection of SUB-ICE as an award winner in the 1972 "I.R 100" competition was announced in Chicago by Neil P. Ruzic, president of Industrial Research, Inc., publisher of Industrial Research magazine.

SUB-ICE, differing radically from conventional means of clearing channels for winter navigation, fractures ice by the release of high-pressure combustion gases underneath the ice surface. Its operation is not dependent upon the application of ship propulsive power.

Employed as a temporary bow attachment, this method would permit a low-powered vessel of conventional design to be seasonally assigned to icebreaking duties for which it would normally be under-powered, the developers of the SUB-ICE system said.

Key elements in the new system are a combustion chamber in which a mixture of hydrocarbon fuel and compressed air is ignited by a spark plug, and a large, fast-acting exhaust valve leading to ports positioned under the ice. The released combustion gases form a bubble which exerts strong upward force, breaking the ice.

The system is designed for repeated firings, at rates up to about two shots per second.

SUB-ICE, its developers said, can be a useful aid in extending the winter navigation season on the Great Lakes and along river shipping routes, and could be used to support offshore oil activities in the Arctic.

The concept can be adapted to particular needs, whether for a multiple-chamber plow-type unit designed for use as a vessel bow attachment, or for a stationary unit positioned to protect fixed structures from ice encroachment.

Under U.S. Coast Guard sponsorship, feasibility of the concept was demonstrated last winter in a series of tests conducted with an experimental device on Muskegon Lake, Michigan. The experimental device, equipped with a five-cubic-foot combustion chamber, successfully broke sheet ice up to 14 inches thick with results indicating ice two feet thick could be broken without difficulty. In areas of thicker ice, channels could be cleared either by repeated passages or by use of units having larger combustion chambers.

Developers of SUB-ICE, all members of the Southwest Research Institute Department of Automotive Research, are: Charles D. Wood, manager for energy conversion; John M. Clark, Jr., technical vice president for automotive research; John W. Colburn, Jr., research engineer; and, Allan R. Nye, senior research engineer.

Development of the patented SUB-ICE concept was performed by the Institute with the cooperation and support of H.B. Zachry Co., an international construction firm headquartered in San Antonio, and of the U.S. Army as well as the U.S. Coast Guard. SUB-ICE is based on the tractor-mounted earthmoving system known as REDSOD (Repetitive Explosive Device for Soil Displacement), developed by the Institute for the U.S. Army Mobility Equipment Research and Development Center, Fort Belvoir, Virginia.

For more information about the Sub-Ice Icebreaking Engine, contact Joe Fohn, Communications Department, Southwest Research Institute, P.O. Drawer 28510, San Antonio, Texas, 78228-0510, Phone (210) 522-4630, Fax (210) 522-3547.

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