PROTECTING OFFSHORE STRUCTURES FROM ICE

• US 3,766,737 A
• Filed: 04/13/1972
• Issued: 10/23/1973
• Est. Priority Date: 04/13/1972
• Status: Expired due to Term

• Current Assignee: George C. Howard
• Original Assignee: George C. Howard
• Inventors: Howard, George C.
• Primary Examiner(s): Shapiro, Jacob
• Application Number:
  US05/243,719
• Time in Patent Office: 558 Days
• Field of Search: 61/1,46.5,46,36A,63 114/40,41,42
• US Class Current: 405/61
• CPC Class Codes: E02B 17/0021 against ice-loads

Abstract

This invention relates to a method of protecting a structure such as a vessel or platform located in water covered with sheet ice. In a preferred embodiment, an ice trenching machine is suspended from a boom supported at the top of the structure. The ice trenching machine removes ice in a circular path at a rate approximately equal to the rate of movement of the sheet ice toward the protected structure. Means are provided so that the boom can be moved entirely around the top of the structure so that a trench can be cut in the ice in any direction from the structure or to completely surround it.

Claims

1. A method of protecting a structure in water supporting an ice sheet which has limited movement, which comprises:

removing ice with an ice trenching machine by cutting a trench through the ice sheet in a path located a substantial distance from said structure and at least partially surrounding said structure on the side thereof toward the movement of said ice sheet toward said structure, maintaining said trench in an open condition by removing ice at a rate approximately equal to the rate of movement of sheet ice toward said structure so that said trench is never closed by incoming ice.

2. A method as defined in claim 1 including the step of supporting said ice trenching machine from said structure only by non-rigid support means.

3. A method as defined in claim 1 including the step of supportiNg a boom at the top of said structure and supporting said ice trenching machine with a cable supported from said boom, there being no other connection between said trenching machine and said structure.

4. A method as defined in claim 2 in which said trench is cut at a distance of at least 50 feet from said structure.