Movement of marine structures in saline ice

Claim 2

Apparatus for facilitating relative motion between an ice sheet overlying a body of salt water and a structure disposed in the water and extending through the surface thereof comprising heat transfer means disposed along each discrete portion of the structure which is adapted to penetrate the water surface at the location on said portion of penetration and extending vertically along the structure for a selected distance above and below said location, and means for energizing the heat transfer means sufficiently to cause the heat transfer means to heat ice disposed proximately adjacent the heat transfer means to within about 2* C of its melting point.

Claim 3

Apparatus according to claim 1 wherein the structure is intended for support from the bottom of the body of water at a selected site in the body of water for a selected period, and the maximum thickness of ice to be encountered and the maximum tidal variation at the site during the period are known, and wherein the extent of the heat transfer means vertically along the structure is sufficient to locate the upper end of the heat transfer means at least adjacent the upper extent of a maximum thickness ice sheet at maximum high tide and to locate the lower end of the heat transfer means at least adjacent the lower extent of a maximum thickness ice sheet at maximum low tide.

Claim 4

Apparatus according to claim 1 wherein the structure is intended for use as a floating structure at a selected site in the body of water for a selected period and the maximum thickness of ice to be encountered at the site during the period is known, and wherein the extent of the heat transfer means vertically along the structure is sufficient to locate the upper end of the heat transfer means at least as far above the waterline of the structure as the height of a maximum thickness ice sheet above the water surface and to locate the lower end of the heat transfer means at least as far below the waterline as the depth of a maximum thickness ice sheet below the water surface.

Claim 5

Apparatus according to claim 1 wherein the extent of the heat transfer means vertically along the structure is at least equal to the thickness of a maximum thickness ice sheet expectable at a selected site of intended use of the structure during a selected period of use of the structure.

Claim 6

Apparatus according to claim 1 wherein each heat transfer mechanism is disposed to surround the adjacent discrete portion of the structure.

Claim 7

Apparatus according to claim 5 including means for energizing the heat transfer means about only a part of its extent around the adjacent portion of the structure.

Claim 8

Apparatus according to claim 1 including ice removing means movable along the structurE adjacent the heat transfer means and operable upon portions of an ice sheet adjacent the structure which are thermally influenced by operation of the heat transfer means to fragment and remove ice from engagement with the structure and from proximate juxtaposition to the structure.

Claim 9

Apparatus according to claim 8 wherein the ice removing means includes a rotatable ice cutting head and a plurality of teeth carried thereon operable in response to rotation of the head to comminute ice engaged thereby.

Claim 10

Apparatus according to claim 8 wherein the structure is a platform structure adapted for support above the water surface on at least one leg, the leg comprising said discrete portion of the structure, and wherein the ice cutting head is disposed substantially circumferentially of the leg in substantially coaxial alignment therewith and is of inverted truncated conical configuration, a support frame for the head, means cooperating between the frame and the leg for constraining the frame to movement only along the leg, and means cooperating between the frame and the head for rotating the head about the leg.

Claim 11

Apparatus according to claim 7 wherein the structure is a platform structure adapted for support above the water surface on at least one leg, the leg comprising said discrete portion of the structure, and wherein the ice removing means includes a plurality of externally toothed rotatable ice cutting heads disposed around the leg, the heads each having an inverted conical configuration, a support frame for mounting the heads for rotation about the cone axes thereof, and means for rotating the heads relative to the frame and arranged so that during operation thereof adjacent ones of the head rotate in opposite directions.

Claim 12

Apparatus for facilitating relative motion between an ice sheet overlying a body of salt water and a buoyant hull having a gunwale comprising heat transfer means disposed along the hull at and for a selected distance above and below the load waterline of the hull, means for energizing the heat transfer means sufficiently to cause the heat transfer means to melt ice disposed proximately adjacent the hull at least substantially to the melting point of the ice, ice removing means operable upon said proximately disposed ice to remove said ice from engagement with the hull and from proximate juxtaposition to the hull, and means cooperating between the hull and the ice removing means for supporting the ice removing means on the hull adjacent the gunwale and for movement of the ice removing means along at least a portion of the circumference of the hull.

Claim 13

Apparatus for facilitating relative motion between an ice sheet overlying a body of salt water and a buoyant hull having a gunwale comprising heat transfer means disposed along the hull at and for a selected distance above and below the load waterline of the hull, means for energizing the heat transfer means sufficiently to cause the heat transfer means to melt ice disposed proximately adjacent the hull at least substantially to the melting point of the ice, ice removing means operable upon said proximately disposed ice to remove said ice from engagement with the hull and from proximate juxtaposition to the hull, and means cooperating between the hull and the ice removing means for supporting the ice removing means on the hull adjacent the gunwale and for movement of the ice removing means along at least a portion of the circumference of the hull.

Claim 14

Apparatus according to claim 11, wherein the ice removing means is arranged for operative ice removing engagement with ice extending from above the hull waterline to adjacent the bilge of the hull.

Claim 17

The method according to claim 13 wherein the melting step is performed by applying heat to the ice from the portions of the structure which would be forcefully engaged by the ice in the absence of performance of the melting step.

Claim 18

The method according to claim 14 including controlling the rate of heat application to the ice in relation to the rate of movement of the ice toward the structure.

Claim 23

Apparatus for facilitating relative motion between an ice sheet overlying a body of salt water and a structure disposed in the water and extending through the surface thereof comprising heat transfer means disposed along each discrete portion of the structure which is adapted to penetrate the water surface at the location on said portion of penetration and extending vertically along the structure for a distance at least equal to the thickness of a maximum thickness ice sheet expectable at a selected site of intended use of the structure during a selected period of use of the structure, means for energizing the heat transfer means sufficiently to cause the heat transfer means to heat ice disposed proximately adjacent the heat transfer means at least substantially to the melting point of the ice, and means for moving the heat transfer means vertically along the structure.

Claim 24

Apparatus for facilitating relative motion between an ice sheet overlying a body of salt water and a structure disposed in the water and extending through the surface thereof comprising heat transfer means disposed along each discrete portion of the structure which is adapted to penetrate the water surface at the location on said portion of penetration and extending vertically along the structure for a distance at least equal to the thickness of a maximum thickness ice sheet expectable at a selected site of intended use of the structure during a selected period of use of the structure, means for energizing the heat transfer means sufficiently to cause the heat transfer means to heat ice disposed proximately adjacent the heat transfer means at least substantially to the melting point of the ice, and means for moving the heat transfer means vertically along the structure.