|Green Bay Press-Gazette Sunday, Nov. 13, 1996 D-5|
|Sundew's New Shimmy
Will Help Break Ice
| STURGEON BAY (PG) - An experiment which may simplify the gigantic task
of icebreaking in the great Lakes has been launched here by the United
States coast guard.
Two new systems a vibrator system and a lubrication system, have been installed on the coast Guard's Sundew, a buoytender which also operates as an icebreaker during the winter and spring months. the installations have been made by the Sturgeon bay shipbuilding and dry Dock Co. at the request of the United states coast guard Yard, Curtis bay, Maryland, which developed them for Coast Guard use.
First of the experimental systems consists of a vibrator which is placed in the Sundew's forward hold. Two eccentric weights are placed on opposite sides of a motor. The device produces vibrations at the rate of 900 cycles per second, shaking the entire hull of the ship. coast Guard engineers believe the vibrations, which reduce the static friction, will help free the ship when the vessel's bow becomes stuck in the ice.
The other system consists of four 60-foot lengths of half-pipe which are installed around the ship's hull. The pipes, which have an inside diameter of 4 to 4½ inches, have regularly spaced orifices, through which water is forced by two pumps. The water, drawn from the lake, is pumped through the system by one pump at a rate of 2,800 gallons per minute, and by the other at the rate of 2,000 gallons per minute. The resultant film of water lubricates the hull., reducing the dynamic and static friction. In addition, it removes the snow on the ice, which makes it more difficult to break because of its friction with the ship's side.
Effectiveness of the two experimental systems will be monitored by instruments placed along the hull of the Sundew. Installation of the systems took approximately five weeks.
The Sundew, one of seven buoytenders of its type which travel on the Great Lakes, is primarily used to service marine aids to navigation. It is 180 feet long, and has a displacement of 1,000 tons.