US 2135337 A
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Nov. 1, 1938. T. R. HERBEST, JR 2,135,337
MESH JETTY Fiied Feb. 14, 1936 2 Sheets-Sheet 1 Nov. 1, 1938. -r. R. HERBEST, JR
MESH JETTY Filed Feb. 14, 1936 2 Sheets-Sheet 2 INVENTOR Patented Nov. 1, 1938.
UNITED STATES PATENT OFFICE 6 Claims.
This invention relates to jetties and more particularly to mesh or reticulated jetties for use in preventing beach erosion as well as for the building up or reclaiming of eroded beaches.
At many places on the seacoast and on the shore of the larger inland lakes and especially where violent storms occur, the sand beaches are subject to serious erosion occasioned by action of the waves. In many places, destructive erosion takes place only during storms which occur at certain seasons of the year.
I find that large numbers of particles of sand are constantly in suspension in active sea water adjacent the shore and sand bars, and the amount of sand is greatest during times of greatest activity of the water as during the winter months and more particularly during, and immediately following, a storm. I find that the movement of sand takes place mostly in water that is less than four feet in depth and that most of the sand particles in suspension seldom rise more than twelve inches above the bottom.
A ledge of rock or projecting point of land may be in the path of the directional movement of sand. This movement is intermittent and nor mally slow. In such cases, the sand accumulates and fills all pockets and natural traps until these are over-run and, when this point is reached, the oncoming sand particles creep out until they pass the end of the barrier. Eventually the sand that is not definitely trapped or pocketed continues on its directional course. A sand bar is, as 'a rule, merely a deposit of particles of sand which, due to change in average velocity and activity of sand carrying waters, have been temporarily deposited in their course of natural travel. Sand bars sometimes collect sand on one side and erode on the other, denoting merely a delay in the travel of the sand.
I find that there is a well-defined directional drift of suspended sand in each locality. The drift tendency of sand so carried, terminates or builds up at one point with the sand which has been eroded at another point. The distance between the point of well-defined erosion and welldefined settlement may be many miles apart.
An object of this invention is to produce a mesh or reticulated jetty for use in the preservation and restoration of sand beaches and which is adapted to rest upon such beach and to be unconnected therewith except at points adjacent the ends of the jetty.
Another object of this invention is to produce a mesh or reticulated jetty or mat which is adapted to loosely rest upon a sand beach and to be unconnected therewith except above high water mark and below low water mark.
Another object is to produce a reticulated or mesh structure for use in the preservation and restoration of sand beaches and which is made up of easily handled individual units connected together into an articulated whole adapted to rest upon a beach and be unattached thereto except at points adjacent and beyond its ends.
A further object of this invention is to produce a reticulated tubular element for use in the makeup of jetties or beach protection mats.
A still further object of this invention is to produce a jetty or mat made up of interconnected reticulated elements which are relatively light in weight and which are'adapted to be rolled to a greater or less extent by the action of the Waves thus freeing themselves from embedment in the sand deposited because of their action.
A still further object is to produce a jetty adapted to rest upon a beach and to be unconnected therewith except by anchoring means secured to its ends whereby its direction may be readily shifted by merely shifting the location if its end anchors. V
These, as well as other objects, I accomplish by the several forms of jetty and the component parts thereof described in the specification and illustrated in the drawings accompanying and forming part of this application.
In the drawings- Figure 1 is a more or less schematic view in perspective of a beach with several jetties and a mat embodying this invention shown in position thereon;
Fig. Zis a transverse section through the beach of Fig. 1 and shows a jetty or mat in side elevation resting upon such beach;
Fig. 3 is a perspective view of one form of reticulated tubular element which may be used in the make-up of jetties and mats such as shown in Figs. 1 and 2. In this view, the jetty or mat element is shown as circular in section;
Fig. 4 is a- View similar to- Fig. 3, but in this figure, the jetty or mat element is hexagonal in section; and
' Fig. 5 is a fragmentary top plan view of four interconnected reticulated tubular elements and illustrates one form of connecting such elements into a beach mat or lattice-like structure such as shown at the left-hand portion of Fig. 1.
Jetties or beach protection mats embodying this invention have a definite influence on the sand movement, and are practical for use inwater ing the force of the moving water. When used in the vicinity ofthe point of natural deposit of sand, the jetty is adapted to accelerate the deposit at any point that may be desired. When used within the region between the points of natural erosion and natural deposit, that is, the section of shoal water along which the sand naturally travels, the jetties and mats of this invention may be used at any point in this region to create a deposit of sand. Traveling sand thus trapped or caused to be deposited creates a sand beach of the best possible quality.
Mucherosion, on certain sand beaches, is caused by' the wind. The movement of sand by the wind over the beach takes place very close a to the surface of the beach. Fully 80% of average beach sand which is moved by the wind never rises more than twelve inches above the beach line. Oftentimes the growth of beach grass is undertaken to obstruct the movement of sand and prevent its being lifted by the wind. Many places where beach grass or similar natural beach protection does not occur, my type of mesh jetty will serve the purpose.
That part of the jetty that is exposed above the surface of the water and rests upon the beach serves to reduce the amount of sand that is lifted by the wind from that particular section of the beach and also serves to collect much of the moving sand blown from elsewhere that would otherwise be blown across the beach and into the water.
My mesh jetty is adapted for use in preventing movement of sand or dust on land which is not low water mark with all of the elements or members including the end members, resting loosely upon the beach to be protected or reclaimed.
The reticulated tubular elements or members can either be made from suitable coarse mesh, relatively heavy wire netting or from suitable expanded metal. At the present time, I prefer to form the body of such members fromwhat is known as chain link fabric. This is suitably bent to form with the-abutting edges of the mesh fabric either welded or stitched together in the manner well known in the art. The tubular members are preferably stiffened internally either by spaced stiffeners which are secured to the inner surface of thebody material; or by a springlike coil of heavy. wire rod of coarse pitch which expands into contact with the inner'surfaces of the body material.
The mesh material'is preferably galvanized and each of the completed elements before being used is preferably dipped in a bath of hot liquid hydrocarbon substance which at normal tempera;- ture is solid. After being coated with such substance and while the same-is still soft or plastic, the elementsare preferably -rolled in dry sand untila complete coating-of sand is obtained.
This sand covering not only gives added protection against the abrasive action of the sand in suspension in the water, but renders the appearance of the jetty less objectionable on a sand beach;
In'Figs. 3, 4 and 5 of the drawings, I show tubular members of different transverse section. In Fig. 3, the element is circular in transverse section and comprises a reticulated body portion ID of tubular form, annular end members H and a stiffening member l2 formed from' suitable wire rod bent into a helix of coarse pitch.
- The ends of this helix are preferablyconnected to the end members H as by welding and lying in contact with the inner surface of the body portion, tends to hold said body in shape. 'This forms'a structure that is adapted to conform to the profile of the beach. The ends are preferably provided with spokes l3 which connect with a central ring-like member l4. 7
In Fig. 4, the tubular member is hexagonalin transverse section, and is provided with hexagonal end members I! and one or more internal braces l8.
In some instances, it is preferable to make the tubular member buoyant and I accomplish this by suitably positioning within the mesh or re-. ticulated body portion NJ the desired number of floats as shown at l9-l9 of Fig. 4. These floats can be air-tight metal containers. or cork bodies.
Either type will preferably be shaped so as to conform to the shape of the tubular member and will preferably be of such dimensions as to render more buoyant and consequently more active by the effect of the waveaction, the member of which they form a part.
The tubular member shown in Fig. 4 also has each end provided with a centrally located ringlike member [4 and with spokes or braces l3 as shown in the drawings for supporting these ring-like members in place and for stiffening the end member. 7 V
In some cases, thetubular members are connected end to end as shown in the three jetties illustrated in the right-hand portion of Fig. '1. The means connecting the adjacent ends of the members are such as'toallow a limited amount of independent movement between the different members of the series forming a complete jetty and inorder to assure such movement, I employ flexible connecting means such as short lengths of chain as shown at inFigs. 3'and 4. The ends of the chain sections are preferably provided with detachable hook-like members 21, which'are'adapted to be hooked into eyes 22 securedwithin ring-like members of the end members.
J The land end of each jetty is preferably connected by a length of chain 23 to a post 24 which is anchored to the land at a point above high water mark. The'o'pposite end is preferably con nected by means of a section of chain 25 to a suitable anchor 26 which may either rest on the The form of tubular member preferred by me is that having a circular transverse section such as shown in Fig. 3. When such members are flexibly connected end to end to form an articulated series the individual members or elements resting loosely upon a beach may be readily rolled to a limited extent by the action of the waves and because of this rolling action, will free themselves from the sand. Instead of becoming embedded in the sand deposited from the waves, such members roll under the action of the waves, and thus free themselves since they have a tendency to move up onto the sand as it accumulates.
I prefer to make the tubular jetty sections of from about 8 to 16 feet in length and about 12 inches in diameter. The individual jetty members are readily handled and transported from place to place and readily assembled into a complete jetty'or beach mat structure.
During the summer months when storms are not prevalent, the jetties or mats may be readily disconnected and moved to some convenient place ready to be reassembled in position when storm warnings are received.
In those localities where heavy ice is apt to accumulate on the beach during the winter months, jetties and mats can be readily removed, dismantled and stored away until the ice disappears.
From time to time, the hydrocarbon coating which is utilized to protect the metal parts from the action of sea water and salt spray has to be renewed and since the individual jetty members are relatively light and relatively small, the worn or cracked coating may be easily renewed by the application of suflicient heat and the jetty members redipped in hot coating material.
Mesh or reticulated material made from one of the alloys which resists the action of sea water is an ideal material from which to construct these tubular jetty members, exceptfor the present cost of such alloys. Mesh o-r reticulated material made from an alloy of the so-called 188 type (which is a chrome nickel steel containing about 18% chromium and about 8% nickel, with the balance low carbon steel) is particularly adapted for the making of these members since this material is highly resistant to the action of sea water.
A jetty embodying my invention may be readily shifted from one position to another until the most effective position is obtained.
Under certain conditions, it may be desirable to anchor the end member of the jetty or the mat as the case may be to the beach by weighting such end members with stones or other weights inserted within such members, and of course when this means of anchoring is resorted to, anchoring means such as described above may be omitted.
Having thus described my invention what I claim as new and desire to secure by Letters Patent is:
1. In combination with a beach, a jetty comprising a series of tubular reticulated members resting upon the beach and extending from a point above high water mark to a point below low water mark and anchoring means for the end members only for substantially maintaining the relative position of said members on the beach while permitting limited movement of the same with respect to the beach.
2. An articulated jetty comprising a number of reticulated tubular members arranged and con-' nected end to end and adapted to rest on a beach and means for anchoring the end members only of the jetty to the beach above high water mark and below low water mark.
3. A jetty including a series of reticulated tubular members connected together in the form of quadrilaterals arranged to produce a lattice-like structure.
4. In combination witha beach, a jetty extending from a point above high water mark on said beach to a point below low water mark on said beach, and means for securing the jetty to the beach only at its ends, the intermediate portions of the jetty being made up of a plurality of separate but flexibly interconnected tubular members capable of limited movement with respect to the beach in response to wave movements and unconnected to said beach.
5. In combination with a beach, a series of reticulated tubular members flexibly connected to form an articulated mat-like jetty, means for securing one end of the jetty to the beach above high water mark and the other end of the jetty to the beach below low water mark, the jetty being otherwise free and the tubular members thereof being capable of limited rolling movement with respect to the beach in response to wave and current movements.
6. A jetty adapted to rest on a beach and to extend from a point above high water mark to a point below low water mark, means for securing the ends only of said jetty to said beach above high water mark and below low water mark, the intermediate portions of the jetty being made up of a plurality of tubular members connected to form quadrilaterals and unsecured to the beach but loosely connected to each other and capable of limited movement with respect to the beach. THOMAS R. HERB'EST, JR.