FR2776982A1 - NON-DESTRUCTIVE ANCHOR AND ANCHORING SYSTEM FOR THE SEA-BASE COMPRISING A LIVING HERBARIUM OF AQUATIC PLANTS - Google Patents

Abstract

The invention relates to an anchor and a non-destructive anchoring system for a seabed covered with a living herbarium (40) of aquatic plants, comprising at least one helical-shaped coil (10) implanted or intended to be implanted by screwing in. said herbarium (40).

Description

NON-DESTRUCTIVE ANCHOR AND ANCHOR SYSTEM FOR BACKGROUND

  SAILOR WITH A LIVING HERBARIUM OF AQUATIC PLANTS

  The present invention relates to an anchor and a non-destructive anchoring system for the seabed covered with a living herbarium of aquatic plants,

  forming a network of rhizomes and roots.

  The most beautiful coastal or island sites, especially in the Mediterranean regions, represent a real pole of attraction for boaters in all seasons. The large concentration of boats on these places of wild anchorage constitutes however a serious threat for the local ecosystem, which includes various forms of life fixed on the seabed, animal or vegetable, in particular seagrass of aquatic plants like Posidonia seagrass. Given the ravages caused by such seagrass beds by the anchoring of anchors and their skidding under the effect of swell and wind, measures to protect certain natural sites have been taken, in particular by decree, aimed at limiting wild anchorage by providing fixed anchor points at predetermined locations. Figure 1 shows, by way of example, a fixed anchor point comprising a concrete block 1 placed on the bottom, a chain 2 and a

mooring buoy 3.

  However, this form of organized mooring, although preferable to wild mooring, is not entirely satisfactory from an ecological point of view because the permanent surface occupied by the concrete blocks, associated with the repeated sweeping of the chains on the herbaria,

  sterilizes a large area of soil.

2 2776982

  Document FR 81 07194 also discloses an anchor formed by a rod comprising a helical projecting part, intended to be screwed into an underwater bottom. Such an anchor proves to be very destructive for a living herbarium and moreover totally ineffective, in that it grinds and chops the herbarium in depth, thus cutting out a cylinder of material detaching from the

least effort.

  Thus, the objective of the present invention is to provide an anchor and an anchoring system which are non-destructive for a living herbarium of aquatic plants,

while being effective.

  This objective is achieved by providing an anchor comprising a helical winding, constituted for example by a steel wire, implanted or intended to be implanted by screwing in an aquatic herbarium. According to one embodiment, the winding

  has at one of its ends a close turn.

  According to one embodiment, the winding comprises a flange fixed to the close turn. Such a flange makes it possible, for example, to apply a screwing torque to the anchor, to hook a mooring line to the anchor, etc. According to one embodiment, the winding has a length of the order of 1 to 2.5 meters, a diameter of the order of a few tens of centimeters, and a helical pitch of the order of ten to a few

tens of centimeters.

  The present invention also relates to a non-destructive anchoring system comprising at least one anchor according to the invention implanted in a living herbarium of aquatic plants, and a mooring line, for example a polyamide rope, having an end integral with the anchor and another end hooked to

a floating object.

  Advantageously, the length of the mooring line is determined as a function of the depth of the water so that the traction angle of the mooring line is of the order of 30 to 45 relative to the bottom. Advantageously, the mooring line comprises two sections delimited by a submerged float, the length of the first section between the anchor and the submerged float being such that the second section between the submerged float and the floating object does not rub

  not on the herbarium when it is relaxed.

  According to one embodiment, the anchoring system according to the invention comprises a plurality of anchors

  coupled to a link bar.

  These objects, characteristics and advantages of the present invention will be explained in more detail in the

  following description of an exemplary embodiment of

  the invention, made without implied limitation with reference to the attached figures among which: - Figure 1 previously described represents a conventional anchoring system, - Figure 2 represents an anchor according to the invention, - Figures 3A and 3B respectively represent a sectional view and a top view of a flange fixed to the anchor of Figure 2, - Figure 4 shows an anchoring system according to the invention, and Figure 5 shows an anchoring system

  comprising several anchors according to the invention.

  FIG. 2 represents an anchor according to the invention, comprising a helical winding 10 formed by a wire 11 of steel or any other known material offering a

  sufficient strength for the needs of the application.

  The anchor 10 as shown is located in a

  living herbarium 40, for example a posidonia herbarium.

  As shown in more detail in FIGS. 3A and 3B, the last turn of the winding 10, preferably lying close to the surface of the herbarium, is a close turn 12, that is to say a turn of substantially flat shape having a helical pitch tending towards zero. Optionally, the coil 12 receives a flange 13, for example of steel, having for example the shape of a disc. Here, the flange 13 comprises at its periphery folded tabs 14 forming flanges, tightened by bolts 15 around the wire 11, as well as a ring 16 allowing for example to attach a mooring line. Furthermore, the flange 13 is provided with holes 17 allowing the anchor 10 to be screwed by means of a conventional hydraulic key (not shown) comprising a rod at the end of which are

  pins coming to cooperate with the holes 17.

  The anchor 10 according to the invention has the advantage of being harmless to the herbarium, into which it penetrates without cutting or grinding the very dense web of rhizomes and roots. In addition, it offers great resistance to tearing. Thus, an anchor according to the invention with a length of 1.5 m and a diameter of cm, constituted by a steel wire with a diameter of 3 cm, having a helical pitch of 20 cm, can resist at an effort of 21 kN or 2.14 tonnes. To fix the ideas, this resistance corresponds to that offered by a 4-ton concrete block with a side length of 1.9 meters and a height of 50 cm. Still for information, a 15m x 5.2m sailboat subjected to a headwind of 130 km / h and the associated sea current generates a

horizontal force of 17.3 kN.

  FIG. 4 represents an anchoring system 20 according to the invention comprising the anchor 10 to which a mooring line 21 has been attached, for example a rope

polyamide.

  According to the invention, the mooring line 21 comprises a first section 22 connected to a submerged float 23, the section 22 being permanently stretched by the float 23, and a second section 24 connecting the float 23 to a floating object such as a buoy 25, a beacon, a pontoon, a floating platform, etc. The length of each section 22, 24 is determined so that the second section 24 cannot drag

  on the surface of herbarium 40 when it is relaxed.

  Moreover. the length of the mooring line 21 is calculated as a function of the depth of the water so that the mooring line preferably has an angle of 45 when it is stretched. This angle, or traction angle, allows an equal distribution in the horizontal plane and in the vertical plane of the force exerted on the herbarium. It also results from this that the surface turning radius is equal to the depth of the water. More generally, the traction angle will preferably be chosen within a range of 30 to 45 per

  relative to the bottom in order to limit the vertical effort.

  The present invention is of course susceptible of various variants and embodiments. For example, as illustrated in FIG. 5, an anchoring system 30 capable of withstanding high tensile forces can comprise several anchors 10-1, 10-2, 10-3 according to the invention, arranged in line or in star, coupled to a connecting rod 31, for example by bolts

  housed in the flanges of the anchors. Here, the mooring line 21 is hooked to the connecting bar 31.

6 2776982

Claims (10)

  1. Non-destructive anchor for the seabed covered with a living herbarium (40) of aquatic plants, characterized in that it comprises at least one helical winding (10) implanted or intended to be implanted by screwing in said herbarium. 2. Anchor according to claim 1, characterized in that the winding (10) comprises at one of its   ends a close turn (12).   3. Anchor according to claim 2, characterized in that the winding (10) comprises a flange (13) fixed to the close turn (12).   4. Anchor according to one of the claims   previous, characterized in that the winding (10)   consists of a steel wire (11).   5. Anchor according to one of the claims   above, characterized in that the winding (10) has a length of the order of 1 to 2.5 meters, a diameter of the order of a few tens of centimeters, and a helical pitch of the order of one ten to a few tens of centimeters.   6. Non-destructive anchoring system (20, 30) for the seabed covered with a living herbarium (40) of aquatic plants, characterized in that it comprises at least one anchor (10, 10-1, 10-2 , 10- 3) according to one of   previous claims implanted in said herbarium,   and a mooring line (21) having one end secured to the anchor (10) and another end   attached to a floating object (25).   7. Anchoring system according to claim 6, characterized in that the length of the mooring line (21) is determined as a function of the depth of the water so that the traction angle of 7 2776982   the mooring line is around 30 to 45 per report to the merits.   8. Anchoring system according to one of claims   6 and 7, characterized in that the mooring line (21) comprises two sections (22, 24) delimited by a submerged float (23), the length of the first section (22) between the anchor and the submerged float such that the second section (24) between the submerged float and said floating object (25) does not rub on the herbarium when she’s relaxed.   9. Anchoring system according to one of claims   6 to 8, in which the mooring line (21) is a polyamide rope.   10. Anchoring system (30) according to one of   Claims 6 to 9, comprising a plurality of anchors   (10-1, 10-2, 10-3) coupled to a link bar (31).