WO2021096368A1

WO2021096368A1 - Floating construction with mooring system and mooring method

Info

Publication number: WO2021096368A1
Application number: PCT/NO2020/050277
Authority: WO
Inventors: Harald Vartdal
Original assignee: Footprint Mooring As
Priority date: 2019-11-15
Filing date: 2020-11-11
Publication date: 2021-05-20
Also published as: NO346197B1; NO20191360A1; WO2021096368A4

Abstract

Floating construction (10) with a mooring system, the mooring system comprising at least two anchors (20) peripherally arranged on the floating construction (10) and configured to be submerged to the seabed soil. The anchors (20) are provided with one or more anchor-lines (40) extending towards an opposite peripheral part of the floating construction (10) and connected to a fastening point (41) on the floating construction (10). Each anchor-line (40), when moored, comprises a catenary configuration substantially lying within the footprint of the floating construction (10). It is also described a mooring method for a floating construction (10).

Description

Title: Floating construction with mooring system and mooring method Field of the invention

The present invention relates to a floating construction with a mooring system, the mooring system comprising at least two anchors peripherally arranged on the floating construction and configured to be submerged to rest on the seabed soil. The invention also relates to a mooring method for a floating construction.

Background of the invention

Conventional mooring is typically performed by the aid of a tugboat or a tender vessel that hauls out the anchors with the mooring line to position the anchors at a distance away from the vessel. The process is repeated to position and lower all of the anchors to be used to moor the vessel or floating construction. The anchors are spread out from the floating construction, in order to obtain a free hanging catenary anchor line at an angle down towards the seabed, where the anchor is submerged into the seabed soil. This is a cumbersome and costly operation, requiring planning and preparations, and dependent on availability of one or more tugboats. Moreover, the anchor-lines extend a certain distance out from the floating construction, i.e. the total footprint of the floating construction including mooring system when moored, is much larger than the vessel itself. This represents restrictions as to where ships may berth, or restrictions to other marine operations and activities close to the moored floating construction. It also may set restrictions as to how close to shore a floating construction may be moored. In some areas, such as narrow or constricted bays, it is especially advantageous or even crucial to minimize the total footprint of a vessel or a floating construction and also to eliminate dependency of or required assistance from tug boats or the like, which would also be space-requiring. In such areas, traditional mooring may not be an option due to the space required, and the vessel may need to maintain its position by using the engine and thrusters, if the stay is short, for example loading/unloading situations.

In remote waters, such as the Arctic waters, there is little or no areas for establishing a permanent harbor plant, without having to make heavy impact on the coastline, both due to the permafrost, but also due to lack of sheltered waters. There may also be environmental restrictions for establishing such harbor plants. There is therefore a need for a floating construction that can provide for a harbor plant close to already established infrastructure, such as roads or built-up areas, and a method for establishing a harbor plant without having to make detrimental environmental impact on the shore or coastal line or the sea bed. Such floating construction may also serve as a floating base for hotels, production plants, storage or base for other type of activities.

Summary of the invention

The present invention is based on the principle of a self-supported mooring system for establishing a moored structure at shore, not depending on assistance from other floating structures or any need of preparatory seabed work for establishing a moored unit at shore, including towing a complete plant with a self- supported mooring system for establishing a moored facility or plant.

It is an object of the invention to provide a floating construction with a mooring system, wherein the footprint of the floating construction does not impose restrictions for other activities in the close vicinity of a moored plant due to the design of the mooring system when the floating construction or mooring spread is moored.

It is also an object of the invention to provide a floating construction with a mooring system that is independent of the assistance of another vessel(s) to perform mooring operation of the floating construction.

Another object of the invention is to provide a safe and secure mooring system with sufficient inherent contingency, able to resist any storm, extreme wind and storm surge, possibly combined with any maximum anticipated wave heights.

Further, it is an object to provide a mooring system that may be used for mooring a structure close to a shore or a coastal line, without having to depend on detrimental and/or excessive construction work for establishing a storage plant or a quay for vessels to moor along or a floating hotel along a shoreline.

Another object of the present invention is to provide a foundation for buildings or plants, such as for example hotels, living quarters, industrial plants, or other types of building in remote areas or regions where heavy and/or irreparable impact on the nature has to be avoided, and where the nature to a largest extent may be brought back to or reset to its original state upon the end of the activity in question. Yet another object of the invention is to provide a floating structure, suitable to function as a harbor plant, or a base for one or more buildings to be added or installed in respect to existing infrastructure.

Yet another object is to provide a system with a complete building construction, such as a hotel, which may be constructed on a barge deck at a shipyard or the like, and upon completion towed to a remote area where the barge with its payload is moored closed to the shoreline or at the shoreline.

Yet another object is to provide a floating structure that may be moored in a removable manner and that is self-mooring, i.e. can be moored or removed without being dependent on separate use of heavy machinery, preparation of the seabed or use of anchor handling vessels and with as little impact to the shore or seabed as possible.

Yet another object is to provide a floating vessel and a mooring system that is sustainable from an environmental perspective.

The objects of the invention are achieved by a floating construction and a method as defined by the independent claims.

Preferred alternatives, variants and embodiments are defined by the dependent claims.

Thus, in a first aspect the present invention relates to a floating construction with a mooring system, the mooring system comprising at least two anchors peripherally arranged on the floating construction as an integrated part of the barge and configured to be submerged to the seabed soil. The anchors are provided with one or more anchor-lines extending towards an opposite peripheral part of the floating construction and connected to a fastening point on the floating construction. The fastening point may for example be a winch arrangement or a chain stopper arranged at this opposite peripheral part of the construction.

At least a section of the length of each anchor-line, when the floating construction is in its moored configuration, will therefore pass under at least a part of the body of the floating construction. This will be the case also in the unmoored configuration. In an embodiment, the entire length of each of the anchor-lines is located directly underneath the body of the floating construction. Each anchor-line, when moored, comprises a catenary configuration substantially lying within the footprint of the floating construction.

It is a key element of the invention that the anchor-lines lie within the footprint of the floating construction, or at least substantially within the footprint, thus eliminating any detrimental restrictions to the mooring of other vessels to the floating construction using a separate mooring system.

Another key element of the invention is that the total mooring system including anchors and the anchor lines are transported as an integrated part of the floating construction, pre-installed and ready for mooring at a mooring site and that the anchor-lines fixed at one end to respective anchors, are configured to be in a predefined position beneath the floatable construction and/or possibly also partly along the sides of the floating construction, ready to be lowered vertically for establishing the predefined configuration upon arrival at the destined mooring site.

In some embodiments, for example where the invention is used on an already existing barge or similar, the anchors and/or anchor-lines may in moored state have a small portion extending sidewise out of the footprint (viewed from above), however the mooring system is in substance lying within the footprint, compared to conventional mooring systems, where the anchor is submerged at a distance sideways away from the vessel and the anchor-line accordingly extending in a direction outwards and downwards from the vessel. In the present invention however, the anchors are submerged more or less vertically down to seabed underneath the floating construction at the corner of the floating construction or at any point along the periphery of the floating construction and the anchor-lines extend preferably from the floating construction towards the seabed in a direction going towards an opposite peripheral part of the floating construction. This has the advantage that it allows for flexible marine operations. Conventionally spread mooring systems require a large area restricted of marine activities, while with this invention, restrictions are minimal, and all sides of the floating construction can be used as quay area. The possibility of interference for mooring of berthed vessels is eliminated or at least substantially reduced. Even more, the floating construction does not need assistance from tugs for the mooring operation. The floating construction may comprise wells or vacant voids arranged in the hull of the floating construction configured to accommodate the anchors when the floating construction is in transfer or transit mode, i.e. unmoored. The anchors are contained inside the wells for example during transport of the floating construction, or during other activities and operations where the floating construction is unmoored.

The anchors may be arranged with anchor-lines attached, ready for being submerged to the seabed.

In an embodiment, the wells are configured as recesses in the floating construction at least partly enclosing and thus shielding the anchor and the corresponding anchor-lines from an outer side part of the floating construction to be used for quay area of other vessels.

In another embodiment, the wells are configured as vertical holes through the hull of the floating construction, with at least a part of the body of the hull surrounding all sides of the anchors, except the top and bottom of the anchor.

The anchor-lines may be arranged such that they pass through a well arranged on an opposite peripheral part of the floating construction relative to the anchor location, or relative to the lowering means for the anchor in question. The opposite peripheral part will generally refer to a region of the body of the floating construction that is furthest away from the anchor location in a direction along one of the sides of the vessel, but may also refer to a region of the body of the floating construction that is furthest away from the anchor location in a direction diagonally across the hull. For a circular construction, the opposite peripheral part will refer to a region that is as far away from the anchor location as possible (i.e. in a direction passing through the center of the construction). At this opposite peripheral part of the construction, they can be attached to a fastening point arranged on the deck of the floating construction, for example a winch arrangement for manual or automatic operation. The anchor-lines may run along the bottom of or a side part of the hull of the floating construction when the anchors are contained in the wells.

The wells may comprise one or more guideways, preferably inclined and/or curved, for positioning and guiding the anchor-lines through the well and towards the anchor located on an opposite peripheral part of the floating construction. The guideways are preferably arranged with an offset relative to the guideways in an opposite well, in order to prevent interference between adjacent anchor-lines both during transit, installation and use of the mooring system.

The fastening point on the barge may be a winch arrangement for controlling the length and tension of the anchor-line. Various types of winch arrangements are suitable, manual and/or automatic variants. The main purpose of the winch arrangement is to provide a fastening point for the anchor line, where the free length, i.e. the length of the anchor-line running from the fastening point to the anchor, can be adjusted, and wherein the winch arrangement is capable of keeping the anchor line tensioned and being able to handle the resulting anchoring loads.

In an embodiment, each anchor is provided with anchor-lines extending in two different directions towards a well on an opposite peripheral part of the floating construction.

In an embodiment, the floating construction comprises four wells and four corresponding anchors, each anchor being provided with two anchor-lines, one of said two anchor-lines extending towards an opposite well in one direction, the other of said two anchor-lines extending towards an opposite well in another direction.

In one embodiment, the floating construction comprises four wells and four corresponding anchors, each anchor being provided with two pairs of anchor-lines, i.e. four anchor-lines. Two of said four anchor-lines extend in parallel towards an opposite well in one direction, the other two of said four anchor-lines extend in parallel in a preferably orthogonal direction towards a well on an opposite side of the floating construction. With this mooring configuration system, the floating construction obtains a high degree of directional stability and is able to cope with high mooring loads.

The floating construction may in one embodiment comprise a rectangular or square shape wherein the wells are located near the corners of the floating construction, the anchor-lines extending substantially in the transverse or longitudinal direction of the floating construction. The mooring system arrangement thus exploits the floating constructions shape to obtain maximum distance from the fastening point on the floating construction to the anchoring point on the seabed, obtaining a mooring system that can handle high mooring loads. The mooring system may, in addition to peripherally arranged anchors, comprise a centrally arranged anchor well and anchor, the centrally arranged anchor being provided with anchor-lines extending towards at least two peripherally, preferably diametrically arranged anchor wells. Accordingly, the corner anchors may have anchor-lines extending towards the central well. The centrally arranged anchor may have additional functions such as serving as an anchoring point when the floating construction may need to temporarily change its heading for example during anchor-line inspection, service or mooring line change-out. The center anchor can be submerged to the seabed while the other anchors are hoisted or contained inside the wells, and the floating construction can be rotated to another orientation while maintaining its position in the water.

The hull shape of the floating construction may comprise an upwards inclined bottom surface towards an end part of the floating construction intended to face the shore, such that the depth of the floating construction in the water at said part is reduced. This allows less water depth below the barge at the shore end and allowing the barge to be installed even closer to the shore.

The anchors may comprise various shapes, for example square, rectangular, octagonal, or circular shape. The anchor design is primarily a result of seabed conditions and expected mooring loads.

In an embodiment, one or more of the anchor-lines are provided with a shock absorber, also called dampening device, in order to reduce anchor-line peak loads and/or the effect of snap loads in the anchor lines. The shock absorber is in an embodiment connected to the fastening point of the anchor line on the barge or the shock absorber itself is the fastening point. The term shock absorber means a device that reduces or dampens the tension loads and especially shock loads in the anchor lines. The shock-absorber may for example be a hydraulic or gas cylinder and/or a spring-type shock absorber. The shock absorber may comprise a combination of hydraulic cylinder, gas cylinder, springs and/or cushions.

In another embodiment, the shock absorber is a counter-weight arranged within a well on an opposite side of the floating construction relative to the anchor and the anchor-line is arranged through one or more pulleys in the well such that the counter-weight can be suspended from the anchor-line and be at least partly submerged into the sea water in the well.

In an embodiment, the counter-weight is configured for arranging in the water line region, such that it can be completely immersed in water, or partly immersed and with an upper part above the water line, or even completely above water, depending on the tension in the anchor-line 40. The counter-weight should be arranged so that it can be pulled upwards at least partly out of the water in order to reduce the buoyancy force acting on it.

In an embodiment, one or more anchor-lines are provided with a damping device, such as a clump weight. This damping device may be disposed on the catenary profile of the anchor-line when the floating construction is in the moored configuration.

In an embodiment, one or more of the anchor-lines comprises a combination of a damping device located on one or more or the anchor-lines so that it is disposed on the catenary profile on the one or more anchor-lines in a moored configuration, and a shock absorber at the fastening point coupling the anchor line to the floating construction.

In a second aspect, the invention relates to a method for mooring a floating construction according to any of the preceding paragraphs, the floating construction being located in position for mooring, comprising:

- lowering each of the peripherally arranged anchors by use of a lowering means from a position within a well to the seabed, allowing the anchor-lines attached to said anchors to be released in order to allow the anchor to be at least partly submerged in the seabed preferably more or less vertically below the floating construction, wherein the anchors may be submerged one by one or simultaneously,

- disconnecting the lowering means from the anchors,

- tightening the anchor-lines and adjusting the tension in the anchor-lines, such that the anchor-lines obtain a catenary configuration substantially lying within the footprint of the floating construction.

The method may include the following variant steps of a floating construction comprising four anchors and wherein two of said four anchors are peripherally arranged and spaced apart at a first end part of the construction and the other two of said four anchors are peripherally arranged and spaced apart at a second end part of the floating construction being opposite the first end part, the steps being performed in sequence so as to increase the spread of the anchors at the second end part of the construction, the floating construction being positioned in an initial position at 0°, for example with the stern facing the shore line in a more or less parallel state:

- lowering a first of the anchors located at the first end part of the floating construction, i.e. for example with the starboard aft corner anchor of the floating construction as a starting point, installed on the seabed as described above, said first anchor serving as a pivot point, and preferably having a hoisting rope fastened to said first anchor,

- rotating the floating construction to approximately 0° to 25° in counter-clockwise direction from the initial position, using the installed anchor as a pivot such that the other three peripheral anchors on the floating construction are shifted sideways,

- lowering a second anchor, said second anchor being located at the second end part of the floating construction and being in front of the rotation, i.e. in the embodiment with the stern facing the shore-line and the pivot point being at the stern starboard side, the second anchor to be submerged after a counter-clockwise direction would be the port side anchor at the bow of the floating construction,

- detaching the hoisting rope from said second submerged anchor,

- rotating the floating construction in the opposite direction about the pivot point i.e. in a clockwise direction, to approximately 0° to 25° relative to the initial 0-position,

- submerging the other one of the anchors located at the second end part of the floating construction, i.e. from the embodiment above, the starboard anchor at the bow, and detaching the corresponding hoisting rope from said anchor,

- rotating the floating construction back to approximately its initial 0-position, and preferably at this stage, tightening the anchor-lines connected to the submerged anchors at the second end part of the floating construction,

- submerging the last of the four anchors, i.e. from the embodiment above, the port side anchor at the stern, detaching the remaining hoisting ropes (22) from the submerged anchors,

- tightening the remaining anchor-lines, wherein the sequence may be performed vice versa, i.e. first rotating the floating construction in the clockwise direction.

According to a third aspect of the present invention, there is provided a floating construction with a mooring system, the mooring system comprising at least one anchor arranged on the floating construction and configured to be lowered to the seabed soil by a lowering means, the at least one anchor being connected to a first end of an anchor-line, wherein the second end of the anchor-line is connected to a fastening point on the floating construction via a shock absorber.

In an embodiment, the mooring system comprises at least two anchors peripherally arranged on the floating construction.

In an embodiment, the fastening points for the at least two anchors are located on an opposite peripheral part of the floating construction to the lowering means and the corresponding anchor when the vessel is unmoored.

In an embodiment, the shock absorber is a spring or piston.

In an embodiment, the floating construction further comprises wells arranged in a hull of the floating construction configured to accommodate the anchors.

In an embodiment, the shock absorber for an anchor comprises a spring or piston arranged within or above an opposite well to the well configured to accommodate the anchor.

In an embodiment, the shock absorber comprises a counter-weight arranged within an opposite well to the well configured to accommodate the anchor and the anchor-line is arranged such that it passes over a pulley and is coupled to the counterweight at the second end.

In an embodiment, the counterweight is arranged such that it is at least partially submerged in water in use.

In an embodiment, the mooring system comprises one or more clump weights coupled to each of the one or more anchor-lines and disposed either in one location or distributed along a segment of the anchor-line in a section above seabed.

In a fourth aspect of the present invention, there is provided a method for mooring a floating construction, the method comprising: lowering each of one or more anchors arranged on the floating construction and attached to a first end of at least one anchor-line by use of a lowering means to the seabed, attaching a second end of the at least one anchor-line via a shock absorber to a fastening point on the floating construction, disconnecting the lowering means from the anchor, and tightening the anchor-line and adjusting the tension in the anchor-line such that the anchor-line obtains a catenary configuration substantially lying within the footprint of the floating construction.

In an embodiment, the floating construction comprises at least two anchors and the anchor-lines are configured such that they extend towards and are coupled to a fastening point on an opposite peripheral part of the floating construction, wherein the method comprises lowering the anchors one by one or simultaneously.

According to a fifth aspect of the present invention, there is provided a floating construction with a mooring system, the mooring system comprising at least two anchors peripherally arranged on the floating construction and configured to be submerged to the seabed soil, wherein the anchors are provided with one or more anchor-lines extending towards an opposite peripheral part of the floating construction, and connected to a fastening point on the floating construction, and wherein each anchor-line, when moored, comprises a catenary configuration substantially lying within the footprint of the floating construction.

In embodiments, the floating construction comprises wells arranged in the hull of the floating construction configured to accommodate the anchors when the floating construction is unmoored.

In embodiments, the anchor-lines are arranged such that they pass through a well arranged on an opposite peripheral part of the floating construction relative to the anchor location, and is attached to a fastening point arranged on the deck of the floating construction, the anchor-lines running along the bottom of or a side part of the floating construction when the anchors are contained in the wells.

In embodiments, said wells comprise one or more guideways preferably inclined and/or curved, for positioning and guiding the anchor-line(s) through the well and towards the anchor located on an opposite peripheral part of the floating construction, the guideways being arranged with an offset relative to the guideways in an opposite well.

In embodiments, the fastening point is a winch arrangement for controlling the length and tension of the anchor-line. In embodiments, the floating construction comprises four wells and four corresponding anchors, each anchor being provided with four anchor-lines, two of said four anchor-lines extending in parallel towards an opposite well in one direction, the other two of said four anchor-lines extending in parallel towards an opposite well in another direction.

In embodiments, the floating construction comprises a rectangular or square shape wherein the wells are located near the corners of the floating construction, the anchor-lines extending substantially in the transverse or longitudinal direction of the floating construction.

In embodiments, the mooring system comprises a centrally arranged anchor, the centrally arranged anchor provided with anchor-lines extending towards at least two peripherally arranged anchors.

In embodiments, the hull shape of the floating construction comprises an upwards inclined end towards an end part of the construction intended to face the shore, such that the depth of the floating construction in the water at said part is reduced.

In embodiments, the anchors comprise a square, rectangular, octagonal, or circular shape.

According to a sixth aspect of the present invention, there is provided a method for mooring a floating construction of the fifth aspect, the floating construction being located in position for mooring, comprising: submerging each of the anchors by use of a hoisting rope to the seabed, allowing the anchor-lines attached to said anchors to be released in order to allow the anchor to be submerged to the seabed , wherein the anchors may be submerged one by one or simultaneously, disconnecting the hoisting ropes, tightening the anchor-lines and adjusting the tension in the anchor-lines, such that the anchor-lines obtain a catenary configuration substantially lying within the footprint of the floating construction.

In embodiments, the floating construction comprises four anchors and wherein two of said four anchors are peripherally arranged and spaced apart at a first end part of the construction and the other two anchors are peripherally arranged and spaced apart at a second end part of the floating construction being opposite the first end part, and wherein the following steps are performed in sequence so as to increase the spread of the anchors at the second end part of the floating construction, the floating construction being positioned in an initial position at 0°: submerging a first of the anchors located at the first end part of the floating construction, said first anchor serving as a pivot point, and preferably keeping the hoisting rope fastened to said first anchor, rotating the floating construction to approximately 0° to 25° in counter-clockwise direction about said pivot point such that the other three peripheral anchors are shifted sideways, submerging a second anchor and detaching the corresponding hoisting rope, said second anchor being located at the second end part of the floating construction and being in front of the rotation, rotating the floating construction in the opposite direction about the pivot point to approximately 0° to 25° relative to the initial position, submerging the other one of the anchors located at the second end part of the floating construction and detaching the corresponding hoisting rope, rotating the floating construction back to approximately its initial position and preferably at this stage, tightening the anchor lines connected to the anchors submerged from the second end part, submerging the last of the four anchors and detaching the remaining hoisting ropes, tightening the remaining anchor-lines, wherein the rotation may also be performed first in a clockwise direction.

Brief Description of the Figures

Embodiments of the present invention will now be described, by way of example only, with reference to the following figures wherein:

Figure 1 shows schematically in perspective an embodiment of a moored floating construction according to the invention, comprising four anchors and four corresponding wells arranged at each corner of the floating construction, wherein the figure is a sectional view having the cutting plane through two of the anchor wells, i.e. a part of the floating construction is cut-away;

Figure 2 shows schematically a sectional view of an anchor well of a floating construction according to an embodiment of the invention, where the anchor is contained inside the well; Figure 3 shows a schematic bottom perspective view of an embodiment of a well with indication of possible positions for the vertical guides or duct for the anchor chains;

Figure 4a-d shows schematically a sectional view of a possible installation sequence seen from two sides of the floating construction, where Figure 4a shows the floating construction in a position ready for the mooring operation; Figure 4b shows schematically one anchor submerged, but still connected to a crane onboard the floating construction; Figure 4c shows schematically, from the opposite side of the construction, the second pair of anchors submerged; and Figure 4d shows all anchors installed on the seabed and the anchor line in tensioned state;

Figure 5 shows schematically a top view of an embodiment of the floating construction and its mooring system, also showing a fifth, central anchor with corresponding anchor lines;

Figure 6 shows schematically a top view of an embodiment of the floating construction having a circular shape and an anchor system according to the invention;

Figure 7 shows schematically a sectional side view of another embodiment of the invention, configured to be moored close to the shoreline;

Figure 8 shows schematically a perspective view of an embodiment of the invention having a mooring system implemented on an existing barge, the wells being arranged on an outside of the floating construction;

Figure 9 illustrates schematically an embodiment of shock absorbers/damping devices for the anchor lines;

Figure 10 shows schematically a more detailed view of the shock absorbers/damping devices of fig. 9, and

Figure 11 illustrates schematically an embodiment of a shock absorber in the form of a counterweight.

Detailed description of embodiments of the invention

The following description of the exemplary embodiments refers to the accompanying drawings. The same reference numbers in different drawings identify the same or similar elements. The following detailed description does not limit the invention. Instead, the scope of the invention is defined by the appended claims. Reference throughout the specification to “one embodiment” or “an embodiment” means that a particular feature, structure or characteristic described in connection with an embodiment is included in at least one embodiment of the subject matter disclosed. Thus, the appearance of the phrases “in one embodiment” or “in an embodiment” in various places throughout the specification is not necessarily referring to the same embodiment. Further particular features, structures or characteristics may be combined in any suitable manner or in one or more embodiments.

Although features or elements may be disclosed in connection with one specific embodiment, it should be appreciated that such elements or features may be combined with any other disclosed embodiment, unless otherwise specifically disclaimed or specified to the contrary.

Figure 1 shows schematically a perspective view of an embodiment of a moored floating construction 10 according to the invention, comprising four anchors 20 and four corresponding wells 30 arranged at or close to the corners of the floating construction, and wherein the figure is a sectional view with the cutting plane going through two of the anchor wells 30, i.e. the front part of the floating construction is cut away to show the inside of the wells 30. The floating construction of this embodiment is symmetrical, so that the cut-away front part is identical to the rear part of the floating construction. The wells 30 in this example extend through the hull of the floating construction 10, such that the anchors 20 are completely surrounded by inner walls 35 of the hull of the floating construction 10 when unmoored. The anchors 20 may be handled from topside and submerged down to seabed 100 from the well 30. The floating construction 10 can be a barge functioning as a base for various applications, such as a floating hotel, a shipyard, a production plant etc. A key principle of the invention is that the mooring system and its configuration is such that when moored (and when unmoored), the mooring system lies within the footprint of the floating construction 10, i.e., the anchors 20 and anchor-lines 40 do not extend outwards and downwards in sideways direction away from the floating construction 10, but comprise a catenary profile from the floating construction 10 towards the seabed 100, extending from one side of the floating construction 10 towards an opposite side of the floating construction 10, when moored.

In the embodiment of Figure 1, each anchor 20 is provided with four anchor lines 40 arranged in pairs, of which one pair of anchor-lines 40 extends in parallel along one side of the floating construction 10, while the other pair of anchor-lines 40 extends in parallel along another side of the floating construction 10. Preferably, and especially if the floating construction comprises a rectangular shape, if an anchor 20 is provided with two pairs of anchor-lines 40 intended to extend in two different directions, the angle between these two directions is close to or equal to 90°. In another embodiment, the anchors 20 are provided with two anchor-lines extending towards two different opposite peripheral parts of the floating construction. This can be similar to the embodiment shown in Fig. 1 , but instead of having two parallel anchor-lines 40 in each direction, only one single anchor-line 40 is provided for each direction. The double parallel anchor-lines 40 may be used for additional capacity and/or for redundancy in case of breakage of an anchor-line 40. In yet an embodiment, a combination of single and double anchor-lines 40 may be used, depending on the environmental conditions, the barge and/or mooring design. Each anchor may also be coupled to only one anchor-line extending towards an opposite side of the floating construction, however at least two anchor-lines for each anchor will provide better stability. The anchor-lines 40 are fastened to the anchors 20 by a fastening device 21 , such as eye-bolts or similar on the anchor 20, however the fastening method is optional. It is desirable that the distance between the anchor’s 20 submerged position and the well 30 through which the attached anchor-lines 40 passes through the hull is as large as possible, in order to obtain a shallow angle of the mooring line in moored state, thus capable of handling higher mooring loads. In order to obtain a stable and more or less stationary position of the floating construction, the anchors should be spread such that if the mooring system comprises two anchors 20, the anchors 20 are preferably arranged at opposite peripheral parts of the floating construction (for example at the fore and aft of the floating construction 10), and if the mooring system comprises four anchors 20, the anchors are preferably arranged in a quadrilateral pattern wherein the anchors 20 represent the corners of the quadrilateral and are peripherally arranged on the floating construction 10.

The anchors may be of various types and holding power may be achieved for example by heavy weight anchors of metal, concrete or other heavy material (such as olivine), by forcing the anchor pile into seabed, or by suction anchors. The fastening device 21 is preferably arranged on the side face of the anchor, more or less at mid-height (as can be seen in Fig. 2), minimizing the lever arm of the pulling forces from the anchor-lines 40 on the anchor 20. When the anchor is submerged and installed, the fastening device is preferably at seabed level. The anchor-lines 40 extend from the anchor 20, towards a well 30 in another part of the floating construction 10, where the anchor-line 40 is connected to a fastening point 41 (see Figure 2), optionally guided via a fairlead or similar. The fastening point 41 may for example be a winch arrangement or a chain stopper on deck. The fastening point 41 may for example comprise a simple manual fastening and adjustment arrangement, or a more complex automatic winch arrangement. The fastening point 41 should comprise means allowing the anchor-line to be fastened at various lengths of the anchor-line, for adjusting the free length of the anchor-line 40. It must also be capable of handling the anchoring loads and the weight of the anchor-lines 40.

The wells 30 are intended to accommodate the anchors when unmoored, for example during transport of the floating construction 10 and may in one embodiment completely surround the anchor, i.e. having an inner wall or walls 35 covering all sides of the anchor 20, or may in another embodiment only partly surround the anchor 20, for example having two inner walls 35 covering the anchor 20. The shape of the well 30 (and the anchor 20) can also vary. The embodiments shown illustrate a square well, however the well 30 in some examples may be circular, semi-circular, hexagonal, and so on. Where the anchor 20 is only partly surrounded in an unmoored configuration, the well 30 may include at least one part extending outward of the hull of the vessel 10 at least as far as the outermost edge of the anchor 20 itself. This part may comprise a wall similar to extending walls 11 shown in figure 8, which can protect both the anchor 20 and the anchor-lines 40 (in the moored and unmoored configuration) from adjacent structures, such as crafts which are moored directly alongside the vessel 10. Whilst a well 30 may be closed along its back and one side only, and may be open outwards at its front and in the other sideways direction, it may be preferable for a well 30 to surround the anchor 20 on at least three sides to provide the optimum protection to both the anchor 20 and anchor-lines 40 in an unmoored configuration and to at least an upper part of the anchor-lines 40 in a moored configuration. In Figure 1, the anchors 20 have been lowered towards and sunken into the seabed 100 by a means for lowering and hoisting, such as a hoisting rope 22 or chain arranged on a winch, and the anchor-lines 40 have been tensioned in order to obtain a stable and stationary floating construction 10 with minimal movements.

The steepness of the catenary profile of the anchor-lines 40 is a result of the water depth and the distance between the anchor wells 30. The mooring system configuration is thus and amongst others, a result of analyses for a specific area. More specifically, the mooring system and size are a result of geotechnical information of seafloor composition and characteristics as well as wind and water model testing, or calculations, of wind, water, waves or ice incurred loads on the barge with its topside structure. These combined tests and data will determine the mooring loads. The mooring loads may also be determined by computational fluid dynamics calculations. By positioning the anchors 20, and thus the wells 30, close to or at the periphery of the floating construction 10, the horizontal distance from the anchor 20 to the fastening point on the floating construction 10 is maximized, thus obtaining a more shallow anchor-line 40 angle providing a mooring system capable of coping with higher mooring loads. Accordingly, the barge size may be determined based on the mooring loads such that in the direction where the mooring loads are largest and a larger damping effect is needed, the horizontal distance of the anchor line 40 is longest, for obtaining a favorable anchor-line angle. Typically, favorable anchor-line angles lie within the range 0-20° relative to the seabed 100.

Exemplary sizes for a rectangular barge for obtaining a suitable catenary profile and anchor-line angle are; 20 m x 20 m at 5-10 m water depth, 80 m x 160 m at 50 m water depth. However, the configuration must be adjusted according to the estimated mooring loads, depending on the factors as described above. Also, as the mooring loads may be significantly larger in open sea as compared to inside a sheltered bay area, the water depth for various barge sizes and mooring system configurations may vary, however it is especially an advantage of the invention that it may be utilized in shallow waters close to the shoreline.

Figure 2 shows schematically a side sectional view of the internal of an anchor well 30 of a floating construction 10 according to an embodiment of the invention, where the anchor 20 is inside the well 30. The anchor 20 is completely contained inside the well 30 and is held in position during transit or during installation. A lowering device can be used to hold the anchor 20 and/or to lower it down for installation on the seabed. This may also be used for later hoisting it back up to the well 30. The lowering or hoisting device may be detachable from and re- attachable to the anchor 20. This lowering device can comprise a hoisting rope or wire 22, which may be further connected to a hoisting arrangement (for example in the form of winches and the like), for lowering and potentially lifting of the anchor 20 in a controlled manner. The lowering device may comprise a crane, or other suitable standard lifting equipment with the necessary capacity. Where a hoisting rope or wire 22 is used, this may be guided from the deck and out to the center of the well 30 by a lever arm, wherein the rope or wire 22 may comprise shock-reducing or absorbing means such as a snubber of elastic rubber or other standard mooring line snubber device, and/or the lever arm may also comprise shock-absorbing means. The lever arm may for example be allowed to pivot slightly in a manner which is limited by a spring or a compressible material. The anchor 20 comprises several fastening devices 21 , such as for example eye bolts, for attaching the hoisting rope 22 and/or anchor-lines 40, and/or other equipment. For convenience, the anchor 20 is here provided with three fastening devices 21 on its top side, allowing the hoisting rope to be attached to a center point, or to an offset point on the anchor 20. The anchor 20 further comprises fastening devices 21 on the side faces, for attaching anchor-lines 40. If the mooring system configuration is as illustrated in Figure 1, each anchor must at least have two such fastening devices 21 arranged on two side faces of the anchor 20. Preferably, fastening devices 21 arranged on the same side face of the anchor 20 are spaced apart in order to avoid interference of two adjacent anchor lines 40, as illustrated on Figure 1.

Figure 2 also illustrates schematically guideways 31 , 32, for positioning and guiding the anchor-lines exiting (guideways 31) or entering (guideways 32) a well 30. Preferably, the guideways comprise a curved transition out from/into the well 30 for not tearing on the anchor-line 40. The guideways 31 may preferably extend along the entire height of the wells 30, while the guideways 32 may be arranged at the lower end of the well 30. The guideways 31,32 may preferably be configured and dimensioned in such way that the anchor lines 40 do not come in conflict with the anchors 20 during transit or installation of the anchors 40. Figure 2 also discloses a storage cell in the interior of the floating construction 10 for storage of the anchor line 40. As shown from the referenced storage cell, the anchor-line 40 runs over a winch serving as a fastening point 41 on the floating construction 10 and also serving as a means for lowering or hoisting the anchor line 40 and the anchor 20. At the edge of the well 30 guides or fairleads may be installed to reduce friction and wear or damage to the hull and/or the anchor line 40.

Figure 3 shows a schematic bottom perspective view of a well 30, comprising slots as guideways 31, 32. The well 30 of Fig. 3 is configured to envelop or surround the anchor 20 completely. The guideways 31, 32 are preferably slots along the inner wall of the well 30, for having the anchor-lines 40 protected and out of the way for the anchor 20, when the anchor 20 is inside the well 30. However, the guideways 31 , 32 could also be eye-bolts, hooks, wheels or similar arranged in a line, extending out from the inside wall of the well 30. In one embodiment, the guideways 31 for guiding the anchor-lines exiting a well 30 and extending towards an anchor 20 in an opposite well 30, comprise slots extending through the entire well 30, from top to bottom. In one embodiment, the guideways 32 for guiding the anchor-lines 40 entering the well 30 and being attached to the anchor 20 in that well 30, comprises slots extending mainly around the bottom transition between the inside wall of the well 30 and the bottom of the hull of the floating construction 10. The guideways 31, 32 should be arranged with an offset relative to the guideways 31, 32 on an opposite well 30, in order to prevent interference between adjacent anchor-lines 40. In one embodiment, the floating construction 10 may also have guideways arranged on the outside of the hull for holding the anchor-line 40 when the floating construction is unmoored, i.e. when the anchors 20 are contained inside the wells 30.

Figure 4a-d show schematically an embodiment of an installation sequence seen from a side view, the figures showing a section through two wells in order to show the internal of said wells. Figures 4a and 4b shows one side of the floating construction, while figures 4c and 4d shows the opposite side of the floating construction. In Figure 4a, the anchors 20 are contained inside the wells 30, the anchor-lines 40 being arranged from one well 30 towards an opposite well 30 and an opposite end or side of the floating construction 10 and fastened to an anchor 20.

The anchors 20 are held inside the wells 30 by a hoisting rope 22 and a winch, connected to a hoisting arrangement. When the mooring process starts, the anchor lines 40 are released to allow enough free length of the anchor-lines 40 so that the anchor 20 can be lowered and sunken into the seabed 100. The anchors 20 are then lowered, as illustrated by Figure 4b and 4c. The anchors may be lowered one-by- one, or more anchors can be lowered simultaneously until they reach the seabed 100, utilizing the hoisting rope 22. The anchor-lines 40 are at this point hanging loosely in a catenary profile (Figure 4c) and are allowed to sink into the seabed by its own weight. The anchor-lines 40 can now be tightened, for example by utilizing a winch system on board, in order to pull the anchor 20 into the seabed 100, and to obtain a taut catenary anchor-line 40, as illustrated by Figure 4d, providing a stable and stationary floating construction 10. The hoisting rope 22 is at this point released from the anchor 20 and pulled back. If the anchor is a suction type, or other type of anchor that requires an additional installation process, this installation process must be included as a step in the installation sequence above according to the relevant anchor installation process.

The mooring system may have various numbers of anchors 20, anchor-lines 40 and various configurations. In order to avoid undesired wear or tear in the anchor lines 40, the anchor lines 40 in a pair should preferably be arranged in parallel and spaced apart.

Figure 5 shows schematically a top view of an embodiment of a floating construction 10 according to the invention and its mooring system, the mooring system comprising four peripherally arranged corner anchors 20, and one centrally arranged anchor 20. As such, the anchor and anchor line configuration of the four corner anchors 20 correspond in essence to the configuration disclosed in Figures 1 to 4. The corner anchors 20 are each connected to five anchor-lines 40, of which one pair of anchor lines extends in one direction towards an opposite well 30, and the other pair of anchor-lines 40 extends in a direction approximately 90° from the first pair towards another well 30, while the last of the five anchor-lines 40 extends towards a centrally arranged well accommodating the central anchor. The central anchor 20 has four anchor-lines 40 attached, extending in different directions towards the wells 30 intended to accommodate the four corner anchors 20. This results in that the corner wells 30 each have five outgoing anchor-lines 40 and five incoming anchor-lines 40, while the center well 30, has four outgoing anchor-lines 40 and four incoming anchor-lines. In an embodiment, the adjacent anchor-lines 40 are spaced apart by designing the origin point and end point of the anchor-lines and/or by providing guides at the exit points of the well, such that the horizontal distance between the adjacent anchor-lines is 0,5m-1m approximately. This is to avoid interference between the anchor-lines 40. As can be seen from Figure 5, the corner anchors 20 have a pentagonal shape, while the center anchor 20 has a circular shape. The wells 30 of any of the embodiments described herein may comprise shapes corresponding to the shape of the anchors 20 such that in the example shown in figure 5 the corner wells 30 comprise a pentagonal shape having five inner walls 35 while the center well 30 comprises a circular shape having a circular inner wall 35, however this is not a requirement. These anchor shapes are intended to allow the anchor-lines 40 to extend straight outwards from the anchor 20 towards the fastening point 41 on the floating construction 10. The anchors 20 may have various shapes depending on the mooring system design, seabed conditions, expected anchor loads, etc. The number of anchors, and correspondingly the number of wells, may also vary. Only two opposite corners of the craft may include wells in which anchors can be disposed, for example.

In another embodiment, the corner anchors 20 are each connected to three anchor-lines 40, of which a first anchor-line 40 extends in a first direction towards an opposite well 30, and a second anchor-line 40 extends in a second direction approximately 90° from the first anchor-line 40 towards another well 30, while the last of the three anchor-lines 40 extends towards a centrally arranged well 30 accommodating the central anchor 20. In yet another embodiment, the mooring system design may comprise four corner anchors 20, each having four anchor-lines 40, as shown in Figure 5, however without a center anchor 20. In yet another embodiment, the peripherally arranged anchors 20 have only two anchor-lines 40 attached, in which case both anchor-lines extend in parallel towards one other well 30, going through the well 30 and fastened to fastening points 41 arranged close to said well 30, or the two anchor-lines extend in different directions towards two other wells 30, going through the wells 30 and fastened to a fastening point arranged close to said wells 30. Thus, it is not required that the corner anchors 20 have anchor-lines 40 connected to fastening points at two different opposite ends of the floating construction. Furthermore, the invention is not limited to specific mooring designs or mooring configurations, as this should be evaluated according to the requirements and specifications of the floating construction, the environment, and expected loads in each case.

The floating construction 10 may for example have various shapes and sizes depending on the application of the construction, for example as shown in Figure 6, which illustrates in a schematic top view, a circular shaped floating construction 10, having four peripherally arranged wells 30 for accommodating four corresponding anchors 20, all located within the footprint of the floating construction 10. The wells 30, anchors 20 and anchor-lines 40 are arranged such that that the mooring system comprises a rectangular profile lying within the circular footprint of the floating construction, seen from a top view.

Figure 7 shows schematically a side view of another embodiment of the invention, configured to be moored close to the shoreline, i.e. with a smaller water depth. The end configuration of the floating construction, on the end intended to face the shore, has an upwards inclined bottom on the end facing the shore. The bottom of the hull extending in a skewed manner up through the water surface 90, forming a nose part arranged above the sea surface 90, allowing less water depth below the floating construction 10 and allowing it to be installed even closer to the shore, possibly with the front extending in over the shore or so close to shore that use access ramps 50 between shore and the floating construction 10 may be feasible. Thus, the hull of the floating construction 10 at this end does not extend as deep into the water column as the major part of the hull of the floating construction. Since the floating construction 10 according to this embodiment is close to shore, a gangway 50 may be installed between the shore and the adjacent end of the construction 10. The invention is suitable for new built floating constructions, but also for use on already existing constructions, for example already existing barges that may be used as a base for building a hotel or a harbor plant. In an embodiment where the invention is utilized on an already existing construction, the wells 30 may be arranged on an outside of the construction 10, as illustrated in Figure 8, however the mooring system may be set up as described in the previous embodiments, having anchor-lines 40 extending from one well 30 to another, such that the anchors 20 and anchor-lines 40 are lying substantially within the footprint of the floating construction 10. The hull or the wells 30 may in such case comprise outwards extensions 11 extending beyond the anchor 20 when unmoored, for protecting the anchor 20 and/or for providing a quay area on the construction 10 that does not risk interference with or damage to the anchors 20 or anchor-lines 40. The wells 30 should preferably be configured or arranged such that the anchor-lines 40 will be situated underneath the floating construction 10, not extending outside the vertical footprint of the construction 10, when the floating construction is in a moored configuration, at least in the upper part of the water column such that a vessel may come alongside at any side of the construction without risk of interference with the anchor-lines 40. This can be achieved if the walls 35 of the well 30 covers or extend outwards of the anchor 20 or at least the part of the anchor 20 where the anchor lines 40 extend towards an opposite part of the floating construction 10. For example, the outwards extensions 11 can be used to provide an additional wall 35 for the well 30, such that the two sides of the anchors 20 in Fig. 8 having anchor lines 40 extending out are covered by two walls 35. This ensures that the anchor lines 40 are situated underneath the floating construction 10 or at least underneath the outer most parts of the construction 10 that form the quay area of the construction 10. If this is the case, then when viewed from above the entirety of the upper end of each anchor-line (extending downwards from the fastening point in a moored configuration) will lie inward of the parts of the hull which extend the furthest outward from a center point of the vessel footprint. A craft moored alongside the floating construction 10 will contact this part of the hull, and this will prevent the craft from contacting the anchor-lines 40 even when the floating construction 10 is in a moored configuration. The upper part of the anchor-line 40 may refer to a region of the anchor-line closest to the fastening point and may refer to a region lying within the upper 50% of the water depth, preferably 80%, and most preferably 90%. Depending on the use and also on the actual water depth at the mooring site, the upper part or region may in another embodiment refer to a 0.5 to 20 meter length of the anchor-line extending from the fastening point, preferably a 1 to 10 meter length of the anchor-line extending from the fastening point, and most preferably a 5 meter length of the anchor-line extending from the fastening point.

In yet an embodiment of the invention, in which case a larger spread of the submerged anchors 20 may be required, for example if the shape of the floating construction 10 is more narrow at one end part or there are physical restrictions on the hull of the floating construction resulting in a more narrow spread of the anchors 20, if mooring loads are especially challenging in one direction, or to increase capacity of the mooring system, the mooring sequence may include a small rotation of the floating construction 10 during installation of the anchors 20, in order to shift the location of one or more submerged anchors 20 in moored condition, relative to a location directly vertical from the anchor well 30 down to seabed. This method makes use of one of the integrated anchors 20, and preferably also the corresponding hoisting rope 22, as a pivot point for rotation.

An example of such an embodiment will be described by a trapezoidal shaped floating construction 10 having the longest side part towards shore and the shortest side part towards the sea, the construction 10 comprising four peripherally arranged corner anchors 20, two at the shore-side of the construction 10, and two at the sea side of the construction 10. Each of the anchors 20 are provided with two anchor lines 40 running towards an opposite well 30 in one direction, and two anchor-lines 40 running towards an opposite well 30 in another direction, similar to the embodiment shown in Figure 1 , however with a trapezoidal shape of the floating construction 10. Alternatively, single anchor-lines 40 may be used such that each anchor has two anchor-lines extending towards different opposite peripheral parts of the floating construction 10. In such case, it may be required to increase the distance between the sea-side anchors 20 such that it is larger than the actual distance between the corresponding wells 30 at the sea-side of the floating construction 10. First, one of the shore-side anchors 20 is submerged in the initial mooring position of the construction 10. The hoisting rope 22 is kept attached to the anchor 20 and utilized as a pivot point. Then, the floating construction 10 is rotated about this pivot point, for example to a -20° rotation counter-clockwise. At this position, the sea-side anchor being in front of the rotation, i.e. the left most anchor 20 (relative to a shore- side view) arranged on the sea-side of the floating construction 10, is submerged and the corresponding hosting rope 22 detached and collected on the barge. Keeping the corresponding anchor-lines 40 in a loose configuration, the floating construction 40 is then rotated, still using the first submerged anchor 20 with the hoisting rope 22 as a pivot point, in the opposite direction (clock-wise) past the initial 0-position and to +20°. At this position, the sea-side anchor being in front of this rotation, i.e. the right most anchor 20 (relative to a shore-side view) on the sea-side of the construction 10, is submerged and the corresponding hoisting rope 22 is detached and collected on the barge. Keeping the corresponding anchor-lines 40 in a loose configuration, the floating construction 10 is rotated back to its initial position (0°). At this point, the anchor-lines 40 of the two sea-side anchors are preferably tightened, however, this can wait until all the anchors 20 are submerged. Then, the last shore-side anchor 20 may be submerged. The two hoisting ropes 22 of the shore-side anchors 20 may be detached and collected, and the corresponding anchor-lines 40 may be tightened. The result of this mooring sequence is that the sea-side anchors 20 may be installed with an increased relative distance compared to the relative distance when accommodated in the wells 30, and may even be installed at a short distance outside the footprint of the floating construction 10, however, with the anchor-line 40 still lying substantially within the footprint of the floating construction 10 and with the anchor-line 40 comprising a catenary configuration from one peripheral part of the construction 10 towards, and possibly slightly beyond, an opposite peripheral part of the floating construction 10. Thus, the majority of or the entire catenary profile of the anchor-line 40 lies within the footprint of the floating construction 10, and only a small section, which will be lying on the seabed 100 or close to the seabed 100, will be outside the footprint of the floating construction 10. The part of the anchor-lines 40 being at the top section of the water column, which is where interference with other vessels is relevant, will in any case be inside of the vertical footprint of the floating construction. It will therefore not interfere with or set restrictions to the quay area of the floating construction 10, nor to other marine activities in relation to or proximate to the floating construction 10.

Especially if the floating construction is moored close to shore and where the inclination of the seabed is such that the water depth on the sea-side of the barge is significantly larger than on the shore-side of the barge, this method may be utilized to increase the spread between the sea-side anchors to achieve a greater mooring capacity, without coming into conflict with or set restrictions to marine activities and operations in the vicinity of the barge, or to the quay area of the barge, as the section of the anchor-lines 40 that extends outside the footprint of the barge will be at a water-depth that is not interfering with such activities, operations or other vessels.

The same mooring sequence may be applied to floating constructions of all shapes, including the embodiment of Figure 1, and to floating constructions comprising a different mooring system configuration, in order to increase the horizontal distance between a submerged anchor 20 and the fastening point of the anchor-lines 40 on the floating construction 10. The key element being to rotate the floating construction after having submerged one anchor 20 in order to shift the submerged position of an anchor 20 relative to a position directly vertically down from the corresponding well 30 on the construction 10 when moored. The distance that the anchor position is shifted using this method, depends on how much the floating construction is rotated, and also the distance between the pivot point and the location of the anchor on the floating construction. Thus, the method comprises a rotation of up to 25°, from the initial 0-position of the floating construction. Results from mooring analyses may be used for determining how much the floating construction should be rotated in order to obtain the desired catenary profile of each mooring line.

In an embodiment, as illustrated by Figures 9 and 10, one or more of the anchor-lines 40 may be provided with a shock absorber 60, also called a damping device. The shock absorber 60 reduces the peak loads experienced in the anchor lines 40, which is especially advantageous for a floating construction 10 according to the invention where the horizontal mooring distance is limited by the size of the floating construction 10. The effect of snap loads is also reduced. Any type of damping device/shock absorber 60 may in principal be used, having the required capacity for the relevant load scenarios. Each shock absorber 60 may be arranged on a deck of the floating construction 10, preferably at an upper edge of a well 30 and preferably above guideway 31 , as in Figure 9 and 10, for connection to an anchor-line 40 in that well 30. The anchor-line 40 may be attached to the shock- absorber 60 after the anchor 20 has been submerged to seabed 100. In order to attach the anchor-line 40 to the shock absorber 60, a temporary chain stopper on the floating construction 10, preferably within or in the vicinity of the well 30, may be used to secure that the anchor-line 40 is attached to the shock absorber 60 with correct tension. The attachment to the shock absorber 60 may be via a fastening device such as a clamp, hook, or ring arranged preferably at a bottom end of the shock absorber 60.

In an embodiment, as illustrated by Figure 11, the shock absorber 60 is a counter-weight 61 arranged within a well on an opposite side of the floating construction 10 relative to the anchor 20 and wherein the anchor-line 40 is arranged through one or more pulleys 62 in the well 30 such that the counter weight 61 can be suspended from the anchor-line 40 and be at least partly submerged into the sea water in the well 30. The counter weight 61 is allowed to move upwards or downwards within the water and at least partly out of the water, by the anchor-line 40 moving in the pulley 62, such that buoyancy is reduced when lifted out of water and increased when submerged further down into the water. This produces the effect of a shock absorber 60, since the anchor-line 40, when exposed to high tension, will pull the counter weight 61 upwards and at least partly out of the water, whereby the counter weight 61 will provide an increased pulling force the opposite way on the anchor-line 40. Since this embodiment of a shock absorber 60 may utilize a well 30 where an anchor 20 is accommodated when unmoored, the anchor-line 40 must then be attached to the counter weight 61 after the anchor accommodated in the well 30 has been submerged. In an embodiment, the counter-weight is a hollow waterfilled steel box, a solid metal clump weight or concrete clump weight. Any type of clump weight that has a larger weight than the weight of the displaced water, i.e. that sinks in water, may in principle be used. Reference numbers in the figures

Claims

1. Floating construction (10) with a mooring system, the mooring system comprising at least two anchors (20) peripherally arranged on the floating construction (10) and configured to be lowered to the seabed soil by a lowering means, the at least two anchors (20) are provided with one or more anchor-lines (40) extending towards an opposite peripheral part of the floating construction (10), and connected to a fastening point (41) on the floating construction (10), characterized in that the floating construction (10) further comprises wells (30) arranged in a hull of the floating construction (10) configured to accommodate the anchors (20) when the floating construction (10) is unmoored.

2. Floating construction (10) according to claim 1 , wherein the wells (30) are configured as recesses in the floating construction (10) configured to at least partially surround an anchor in an unmoored configuration and thus shield the anchor (20) and the corresponding anchor-lines (40) from contact with another vessel in an area adjacent the floating construction (10) to be used as a quay area.

3. Floating construction (10) according to claim 1 , wherein the wells (30) are configured as vertical holes through the hull of the floating construction (10), such that the well surrounds the anchor (20) on all sides when the anchor is within the well.

4. Floating construction (10) according to any of the preceding claims, wherein the anchor-lines (40) are arranged such that they pass through a well (30) arranged on an opposite peripheral part of the floating construction (10) relative to the anchor location, and is attached to a fastening point (41) arranged on the deck of the floating construction (10), the anchor-lines (40) running along the bottom of or a side part of the floating construction (10) when the anchors (20) are contained in the wells (30).

5. Floating construction (10) according to any of the preceding claims, wherein said wells (30) comprise one or more guideways (31) preferably inclined and/or curved, for positioning and guiding the anchor-line(s) through the well and towards the anchor located on an opposite peripheral part of the floating construction, the guideways (31) being arranged with an offset relative to the guideways (31) in an opposite well (30).

6. Floating construction (10) according to any of the preceding claims, wherein the fastening point (41) is a winch arrangement for controlling the length and tension of the anchor-line (40).

7. Floating construction (10) according to any of the preceding claims wherein each anchor (20) is provided with anchor-lines (40) extending in two different directions towards a well (30) on an opposite peripheral part of the floating construction (10).

8. Floating construction (10) according to any of the preceding claims, comprising four wells (30) and four corresponding anchors (20), each anchor (20) being provided with two anchor-lines (40), one of said two anchor-lines (40) extending towards an opposite well (30) in one direction, the other of said two anchor-lines (40) extending towards an opposite well (30) in another direction.

9. Floating construction (10) according to claim 8, each anchor (20) being provided with four anchor-lines (40), two of said four anchor-lines (40) extending in parallel towards an opposite well (30) in one direction, the other two of said four anchor-lines (40) extending in parallel towards an opposite well (30) in another direction.

10. Floating construction (10) according to claim 8 or 9, comprising a rectangular or square shape wherein the wells (30) are located near the corners of the floating construction (10), the anchor-lines (40) extending substantially in the transverse or longitudinal direction of the floating construction (10).

11. Floating construction (10) according to any of the preceding claims, wherein the mooring system comprises a centrally arranged anchor (20), the centrally arranged anchor (20) provided with anchor-lines (40) extending towards at least two peripherally arranged anchors (20).

12. Floating construction (10) according to any of the preceding claims wherein the hull shape of the floating construction (10) comprises an upwards inclined end towards an end part of the construction (10) intended to face the shore, such that the depth of the floating construction (10) in the water at said part is reduced.

13. Floating construction (10) according to any of the preceding claims, wherein one or more of the anchor-lines (40) are provided with a shock absorber (60) at the fastening point (41) of said one or more anchor-lines (40) on the floating construction (10).

14. Method for mooring a floating construction according to any of the claims 1-13, the floating construction (10) being located in position for mooring, comprising:

- lowering each of the peripherally arranged anchors (20) on the floating construction (10) by use of a lowering means from a position within a well (30) in the floating construction (10) to the seabed (100), wherein the anchors (20) may be lowered one by one or simultaneously, while

- allowing the anchor-lines (40) attached to said anchors (20) to be released in order to allow the anchor (20) to be at least partly submerged in the seabed (100), the anchor-lines (40) extending towards an opposite peripheral part of the floating construction (10), and being connected to a fastening point (41) on the floating construction,

- disconnecting the lowering means from the anchors (20),

- tightening the anchor-lines (40) and adjusting the tension in the anchor-lines (40), such that the anchor-lines (40) obtain a catenary configuration substantially lying within the footprint of the floating construction (10).

15. Method according to claim 14, wherein the floating construction (10) comprises four anchors (20) and wherein two of said four anchors (20) are peripherally arranged and spaced apart at a first end part of the construction (10) and the other two anchors (20) are peripherally arranged and spaced apart at a second end part of the floating construction (10) being opposite the first end part, and wherein the following steps are performed in sequence so as to increase the spread of the anchors (20) at the second end part of the floating construction (10), the floating construction being positioned in an initial position at 0°:

- submerging a first of the anchors (20) located at the first end part of the floating construction (10), said first anchor (20) serving as a pivot point, and preferably having a hoisting rope (22) fastened to said first anchor (20),

- rotating the floating construction (10) to approximately 0° to 25° in counter clockwise direction about said pivot point such that the other three peripheral anchors (20) are shifted sideways,

- submerging a second anchor (20) and detaching the corresponding hoisting rope (22), said second anchor (20) being located at the second end part of the floating construction (10) and being in front of the rotation,

- rotating the floating construction (10) in the opposite direction about the pivot point to approximately 0° to 25° relative to the initial position,

- submerging the other one of the anchors (20) located at the second end part of the floating construction (10) and detaching the corresponding hoisting rope (22),

- rotating the floating construction (10) back to approximately its initial position and preferably at this stage, tightening the anchor-lines (40) connected to the anchors (20) submerged from the second end part,

- submerging the last of the four anchors (20) and detaching the remaining hoisting ropes (22),

- tightening the remaining anchor-lines (40), wherein the rotation may also be performed first in a clockwise direction.