Icebreaking vessel
AssigneeMaersk Supply Service A/S
InventorNiels Peter Elmbo
Life of this patent
Estimating the term…
Abstract
A vessel and method for breaking ice drifting in a predominant direction relative to an offshore installation such as a drilling vessel. The vessel is used to deploy an anchor in a position at a distance from the offshore installation and in a direction which, seen from the offshore installation, is substantially in parallel with the direction of movement of the ice. By means of the machinery of the vessel, the direction of the anchor line is adjusted and so is the orientation of the vessel relative to the anchor line to the effect that the propellers can be used to crush and dispose of the ice without using motive energy to hold the vessel against the pressure of the ice.
Claims57
An icebreaking vessel for use in proximity to an offshore installation in an area containing drifting ice, said vessel comprising:
- motive power means for moving the vessel while it is anchored, said motive power means including at least one propeller shaft;
- at least one hull portion having a lower wall being positioned deeper than said at least one propeller shaft, said lower wall including at least one underwater opening;
- and
- a first anchor connected to said vessel via a first anchor line, said anchor line extending through said at least one underwater opening;
- wherein said vessel is capable of performing icebreaking tasks while anchored.
A configuration of vessels positioned over an area of water, said area including large pieces of floating ice, said configuration comprising:
- an offshore installation anchored in said water;
- and
- at least one service vessel anchored in said water a first distance from said master vessel and in proximity to large pieces of floating ice;
- wherein each of said at least one service vessel includes at least one anchor secured to an anchor line extending from an opening positioned below the water line on the bottom portion of said hull of each of said vessels, and wherein each of said at least one vessels includes a motive power drive for positioning the vessel and a power winch for winding and unwinding said at least one anchor.
A method of breaking large pieces of floating ice drifting generally in a float direction towards an offshore installation, said method comprising the steps of:
- positioning a plurality of vessels at a distance from said offshore installation to encounter said large pieces of floating ice before said pieces contact said offshore installation;
- anchoring each of said plurality of vessels utilizing at least one anchor on each vessel, each of said anchors being secured to its respective vessel via at least one anchor line, said anchor line transferring a holding force to its respective vessel via said at least one anchor line;
- and
- utilizing a motive drive means on each of said plurality of vessels to orient said vessel relative to its respective anchor;
- wherein each of said plurality of vessels breaks large pieces of floating ice into smaller pieces of floating ice as said large pieces of floating ice contact said anchored vessels, thereby preventing said large pieces of floating ice from contacting said offshore installation.
An icebreaking vessel for breaking large pieces of ice in a surface area of water in proximity of an offshore installation, said vessel comprising:
- an anchor which can be deployed in an anchor line at a distance from the vessel;
- an anchor handling winch capable of winding or unwinding an anchor line through an opening in the vessel;
- and
- motive power means for moving the vessel while it is anchored;
- wherein said vessel is capable of performing icebreaking tasks while it is anchored, and said vessel is movable across a surface area of the water which has a significantly larger expanse than the expanse of the vessel by means of the motive power means or the anchor handling winch.
A method for breaking ice comprising the steps of:
- arranging a plurality of vessels at a distance from an offshore installation and in a direction which, as seen from the offshore installation, is substantially in parallel with the direction of movement of the ice to the effect that the vessels are capable of breaking ice drifting in the direction towards the offshore installation;
- deploying at least one connected to an anchor line from each vessel so that the vessels are positioned such that the holding force of the anchors can be transferred from the anchors to the vessels via anchor lines and one or more anchor handling winches.
An icebreaking vessel for use in proximity to an offshore installation in an area containing drifting ice, said vessel comprising:
- a hull extending at least partially under water and having a water line;
- at least one propeller extending out of said hull under the water line;
- at least one hull portion having a lower wall being positioned deeper than said at least one propeller, said lower wall including at least one underwater opening;
- and
- a first anchor connected to said vessel via a first anchor line, said anchor line extending through said at least one underwater opening;
- wherein said vessel is capable of performing icebreaking tasks while anchored.
A vessel having an icebreaking hull to break ice in a surface area of water in proximity of an offshore installation, said vessel comprising:
- an anchor which can be deployed in an anchor line at a distance from the vessel;
- an anchor handling winch capable of winding or unwinding an anchor line through an opening in the vessel;
- and
- motive power means for moving the vessel while it is anchored;
- wherein said vessel is capable of performing icebreaking tasks while it is anchored and said vessel being movable across a surface area of the water which has a significantly larger expanse than the expanse of the vessel.
The vessel of 46 wherein said opening is arranged as far towards the stern in the bottom of the vessel as possible without the opening rising higher than the level of the horizontal plane of the vessel bottom.
Dependencies are inferred from the claim text.