US 3299640 A
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Description (OCR text may contain errors)
Jan. 24, 1967 I s NlELSEN 3,299,640
MEANS FOR INFLUENCING THE SUBMARINE MIGRATION OF MATERIAL Filed Dec. 31, 1963 2 Sheets-Sheet 1 INVENTOR fl jr 60mm N/c/sc n Mm; vhmlu/ ATTORNEYS Jan. 24, 1967 P. s. NIELSEN 3,299,640
MEANS FOR INFLUENCING THE SUB-MARINE MIGRATION OF MATERIAL Filed Dec. 31, 1965 2 Sheets-Sheet 2 INVENTOR N MP 71% ATTORNEYS United States Patent Ofiice 3,299,645 Patented Jan. 24, 1967 Denmark Filed Dec. 31, 1963, Ser. No. 334,738
Claimspriority, applicationsDenmark, Jan. 14, 1963, 16
19 Claims. (Cl. 61-3) The invention relates to a means for controlling or influencing the migration of material along coasts or shores of seas, lakes, rivers and the like waters. Such means are used for protecting coastlines and sub-marine structures against erosion, for counter-acting or preventing fairways from sanding up and for reclaiming new land off a coast.
For these purposes it is known to use different means such as breakwaters consisting of solid constructions of different types, e.g., rows of rammed-down poles, between which natural stone or artificially produced blocks, e.g., concrete blocks, are laid out. In shallow waters, e.g., in the North Sea Flat, sub-marine fascines are also used as silt collecting means, and it is moreover known to cover the floor of a waterway with laid-out foils kept in place e.g., by'the subsequent dropping of stone. These known protective means are all relatively expensive in manufacture and laying, and the placing thereof often requires heavy and expensive machinery. The result of the said known measures have in many cases proved unsatisfactory as compared with the costs involved.
.It is an object of the invention to provide a protective means which excels by being cheap and capable of being laid out in a simple manner with low expenses. With a view hereto, the means according to the invention is characterised in that it consists of synthetic, non-waterabsorbent threads, tapes or the like having a specific gravityof below -1 gramme pr. cubic cm., said threads or tapes being secured to anchoring means which are placed at the bottom of the fairway.
Such threads or tapes will, when placed at the bottom of the fairway, have a subduing effect on the water velocities produced by waves and/or currents just above the bottom and thereby provide the desired control of the migration of material. As the specific gravity of the threads is less than 1.0 they will tend to keep upright in the water whereby it is to be expected that deposits may be collected in a substantial thickness without the threads being covered by the material deposited. As the means according to the invention operates as a resistance to the motion of the water at the bottom of the fairway thereby bringing about a collection of material, it is possible to obtain an influence on the motion of the water also at higher levels. In addition to the aimed-at raising of the bottom, a reduction is then obtained as well in the motion of the water by dissipating energy in breakers where this might be desirable.
According to a feature of the invention the means may comprise solid mono or multi-filaments of polyethylene or polypropylene. The threads or tapes may, however, also consist of hollow cells, e.g., monofilaments, which are closed at their ends, Such end-closed hollow cells or monofilaments may, if so desired, be gasfilled. If so, one is not bound to use materials whose own specific gravity is below 1.0, such as polyethylene and polypropylene, but by a suitable choice of the-cross-sectional dimensions of .the filaments or the tapes it is also possible to use heavier materials, if otherwise they are suitable for the purpose, and likewise it is possible to produce threads or tapes of widely diiferent effective buoyancy in water. As examples of such other synthetic materials as may come into consideration, reference could be made to polyamides, polyesters and acrylics.
The anchoring means may according to a feature of the invention be formed as relatively short elements placed in extension of each other whereby the manufacture as well as the transport and the laying-out are facilitated. The individual elements may according to a further feature of the invention be interconnected by means of flexible members such as chains, cables or rope. The anchoring means may also as such be constituted of chains, cables or rope, to which sinkers are secured at intervals. If cordage is used the threads or the tapes may be woven into or lashed to the cordage. The shape of the anchoring means, or the sinkers, may be varied dependent on conditions but it will often be expedient to form the said elements as dishes, in that the dish shape offers the least resistance, at the same time giving the elements a tendency to dig themselves into the bottom.
According to a feature of the invention, a plurality of anchorings means or rows of anchoring means with threads or ta-pes secured thereto, may be placed substantially interparallel. If so it is possible, dependent on the local conditions, to build-up broader or narrower zones of threads or tapes. According to a feature of the invention it is also possible to secure a plurality of rows of interparallel threads or tapes to a common anchoring element, whereby this element, which e.g., may be designed as a small concrete caisson, may secure the mutual placing of the thread or tape rows.
The length of the threads or the tapes may be varied in conformity with the purpose concerned in the specific case, and if other considerations so require, e.g., navigation, ice and similar conditions. One could e.g., imagine a coast protection comprising a zone extending along the coast, wherein the means is used with increasing height towards the coast so that the height farthest away from the coast is e.g., about 1 m., while the height closest to the coast corresponds to mean level of the Sea or above, whereby the effect of the breakers proper is reduced.
The invention will be explained in detail in the following with reference to the accompanying diagrammatical drawings, wherein FIG. 1 is a vertical longitudinal section through a coast protective means according to the invention,
FIG. 2 is a plan view of two groups of means like those shown in FIG. 1,
FIG. 3 is a plan view of two corresponding groups of protective means placed at the entrance to a port,
FIG. 4 is a vertical longitudinal section through a coast protective means like the one shown in FIGS. l-3,
FIG. 5 is a picture corresponding to FIG. 1, where the threads or tapes forming part of the protective means are combined in interspaced groups,
FIG. 6 is a picture corresponding to FIG. 2, where a group of protective means according to the invention are placed substantially parallel to a coast line, and
FIG. 7 is a vertical section through a modified embodiment of the means according to the invention.
In FIG. 1 a sea level is designated 1 whilst 2 is a beach which continues into the seabottom 3. From the coastline 4, see FIG. 2, protective means according to the in- Vcntion are laid out in the form of rows 5 of synthetic filaments secured to anchoring means, which in FIG. 1 must be considered immersed in the seabottom and which, therefore, are not shown.
The said rows are collected in groups each of five rows, and FIG. 2 shows two such groups 6 extending substantially at right angles to the coastline 4.
FIG. 4 shows quite diagrammatically a section through a single row 5, which in this case consists of mono or multifilaments 7 having a plurality of individual filaments, e.g. up to 200 or more. The filaments are produced of a synthetic material, the specific gravity of which is below 1 gramme per cubic crn., e.g. polyethylene or polypropylene, and which does not absorb water. Also other materials complying with the above requirements and being sufficiently flexible in having practically unlimited lifetime at the bending stresses here occurring, may be used. Materials having a specific gravity above 1 may be used in the form of hollow, closed and, if so desired, gas-filled threads or tapes, provided that the specific gravity of the hollow thread or tape is less than that of water. As a consequence of this latter condition, the filaments will tend to stand upright in the water and take up a fan-shape configuration as shown in FIG. 4, when at bottom they are secured to an anchoring member 8. The threads 7 may be collected into tufts which are secured closely to each other.
I The anchoring means 8 is in FIG. 4 shown quite diagrammatically as having a circular cylindrical shape butmay have any suitable form. As material for the anchoring means concrete maybe chosen which excels by being comparatively cheap but also other materials, such as lead or steel, may beused. The anchoring means may also be shaped as a dish or simply an anchor. The securing of the threads 7 to the anchoring member may be effected in different ways, e.g. the anchoring member may have cast-in eyes or bows, in which tufts of threads are lashed. The anchoring members 8 may expediently be performed in sections having a length of e.g. about 0.5 m., and the individual elements may be interconnected by means of chains or rope. Hereby, the length of the individual rows of thread 5, see FIGS. 1 and 2, may easily be adapted to the local conditions, and likewise the height of the thread 7 in the individual sections or elements may be adapted according to the varying depth of the seabottom 3.
In FIG. 4, the anchoring member 8 is shown resting upon the seabottom 3, i.e. immediately after the laying of the protective means, and after a comparatively short time the member will by wholly or substantially sinking into the bottom dependent on the weight of the member and the softness of the bottom, and by accumulation of deposited material around the member, function as an effective anchoring of the threads secured to the member at the seabottom.
FIG. 3 shows a plan view of a coastline 11, having a port basin 12 framed by two piers or quays 13. At a distance off the piers or quays 13 there are at the seabottom placed two groups 14 each consisting of five rows 15 of synthetic mono or multifilament threads like those described above.
FIG. 5 shows a section corresponding to FIG. 1 where the sea level is designated by 21, the beach by 22 and the seabottom by 23. The protective means according to the invention consists here of individual groups 25 of synthetic threads or tapes like those mentioned above, which are secured in spaced relationship to anchoring means which should be imagined covered by the seabottom and which, therefore, are not shown.
FIG. 6 shows a picture corresponding to FIG. 2 where a group 26 consisting of six rows 27 of filament threads or tapes are placed substantially parallel to and at a distance from the coastline 28.
FIG. 7 shows diagrammatically a longitudinal section through an embodiment of anchoring member in a form of a rope 31 to which a group of tapes 32 produced of materials like those mentioned aboveare secured. The tapes 32 may e.g. be woven or braided into a rope 31 or in a suitable manner be lashed to this rope, FIG 7 shows only a single group of tapes but it is evident that such tapes may be secured to the rope in the entire length thereof in similarity to that shown in FIG. 1 or as shown in FIG. 5 there may be provided several groups of tapes spaced apart in the longitudinal direction of the rope. The rope 31 and the tapes secured thereto are kept down by means of loads or weights in the form of sinkers which in a suitable manner are secured to the rope 31. FIG. 7 shows two embodiments 33 and. 34, respectively, which both may be performed as faintly upwardly curved dishes. The difference between the two sinkers resides in that the sinker 33 is secured directly .to the rope 31, e.g. as shown by making the sinker integral with an eye or a bow to which the rope 31 is secured.- The sinker 34 is connected with the rope 31 by means of two short lengths of rope 35.
The embodiments shown and described only serve to illustrate the principles of the invention which may be realised in many other ways, particularly by other com-' binations of the details shown. Thus, the rope-shaped anchoring member shown in FIG. 7 may also be used for securing synthetic filament threads instead of tapes. The tapes may in a suitable manner be provided with edge reinforcements. The dish-shaped sinkers shown in FIG. 7 may be used directly as anchoring members for securing tapes or threads. By using anchoring members of relatively soft metal, e.g. lead, the threads or the tapes may be squeezed in slots in the anchoring member which are subsequently closed by compression.
1. A device for influencing the migration of material at the shore of a body of water, said device comprising anchoring means anchored in the bottom of said body of water and spaced from said shore; and a plurality of slender elongated members each having one end fixedly secured to said anchoring means; said members being flexible and buoyant along their entire length and consisting of synthetic nonwater absorbent material, each member extending generally upwardly and terminating in a freely floating end opposite to said fixed end, said members being grouped in a closely spaced unattached relationship along their length above said anchoring means.
2. The device of claim 1 wherein said members are assembled into a plurality of groups.
3. The device of claim 1 wherein said members are arranged into a plurality of interparallel rows.
4. The device of claim 1 wherein said anchoring means comprises an elongated flexible member and sinkers secured to said flexible member in spaced relationship lengthwise thereof.
5. The device of claim 1 wherein said members are in the form of threads.
6. The device of claim 5 wherein each of said threads 11. The device of claim 10 wherein said tapes are in the form of hollow mono-filaments closed at both ends.
12. The device of claim 11 in which said hollow mono;
filaments are gas-filled.
13. The device of claim 10 in which said tapes are A made of polyethylene.
14. The device of claim 10 in which said tapes are made of polypropylene.
15. The device of claim 1 wherein said anchoring References Cited by the Examiner means comprises a plurality of relatively short anchoring UNITED STATES PATENTS elements and means for interconnecting said elements.
1 6. The device of claim 15 in which said intercon- 2601015 6/1882 Ffanklm X necting means com-prises flexible members. 5 1,219,995 3/ 1917 P -l y 17. The device of claim 15 wherein said anchoring 2,655,790 10/1953 Daley 613 elements are rigid. 3,002,632 2/ 1962 Parks 6-15 18. The device of claim 1 wherein said anchoring 3,068,655 12/1962 Murray et al. 61-6 m an re p r llel. 3,098,262 7/1963 Wisotzky 264--74 19. The device of claim 18 wherein said anchoring 10 means are flexible. EARL J. W=IIMER, Primary Examiner.