ICEBREAKING APPARATUS

摘要

In its most preferred embodiment the invention relates to a water navigable vessel, having ice-breaking means comprising an iceriding, forward portion, e.g. bow structure and ice-gripping, pulling or dragging means preferably rotatable screw means, attached to said iceriding portion of said vessel. Said ice-gripping means is in a cooperative relationship with the vessel's icebreaking bow structure whereby, when said vessel is positioned in an ice-covered body of water said ice-breaking means will break said ice in flexure when the ice-gripping means are activated (e.g. screw means are rotated), thereby permitting either retention of position of said vessel or movement of said vessel within the ice milieu. The screw means have ice-cutting flights (blades) and are journaled in a preselected generally parallel alignment with the exterior of said bow to allow the exterior edge of the helical blades of said screw means to pressingly contact the top of said ice. When the screw means are rotated, the blades form groves within the top of said ice layer thereby interacting with and gripping said ice layer thus translating the rotational energy of said screw means into a generally horizontal, (longitudinal) tractional force which pulls or drags the bow of said vessel forward and over said ice layer and, thereby, utilizes the mass of said bow to impart a downward gravitational force upon said layer of ice to cause it to fail flexurally. In effect the bow rides up over the ice due to the assistance of the screw means. The vessel can optionally be aided in its movement over the ice layer with additional propulsion means besides said pulling or dragging means. These means can be propulsion means located either intrinsically with the vessel, or extrinsically to the vessel or both. Other embodiments of the invention include use of ice-resistant structures having screw means mounted in a substantially vertical position on one or more substantially, vertical members to protect said member against damage by ice moving at an approximately 90.degree. angle to said member.