JP2021514892A - Variable density and diameter cables for cables used in cable propulsion vessels and / or submarine cable control by the use of external forces - Google Patents

Abstract

Cables for propelling and / or guiding cable ferry are disclosed, which allows their use on longer ferry routes. One embodiment provides the use of a cable for propelling and / or guiding a cable ferry in which the unit weight, density, specific gravity and / or diameter of the cable is variable over the length of the cable. According to one embodiment, a heavier or denser cable is used adjacent to the terminal and a lighter or less dense cable is used for the central section. If the section has positive buoyancy, the cable may be connected to one or more anchors. If the section has negative buoyancy, the cable may be connected to one or more floats.

Description

The present invention is a cable ferry, cable tugboat, cable that uses a cable for guidance and / or propulsion, whether propelled primarily using cables or primarily propeller or jet driven and cable guided. Regarding the field of cargo ships, cable ships, or other ships.

Cable ferries, also known as chain ferries, have long been used to transport vehicles and people over relatively short distances across water bodies. Such ferries are guided by cables, ropes or chains, all of which are referred to herein as cables. Currently, the cables used for cable ferry are generally 6 or 8 to form cables with a diameter of 1 "or more, typically 1-1 / 2" to 1-3 / 4 ". Made of stranded steel wire rope with the main strand of the wire wrapped around an independent wire rope core.

Cable ferry is becoming more and more used in seawater and long-distance ferry applications. This is primarily more energy efficient for vessels that use cables to propel themselves than for propellers, jets, or the same vessel that uses any other method to achieve motion and guidance. Is good. Therefore, cable ferries use some of the energy compared to comparable conventional vessels, resulting in reduced greenhouse gas emissions. They are cheap to build, have a small crew, and have the advantage of docking. Also, cable-driven vessels are much quieter when in motion than propeller-driven vessels. Low noise means a healthy experience for passengers and crew and less interference for marine mammals. Despite the essential advantages of cable ferry, given the current distance constraints and obstacles to other marine traffic, it is possible to make cable ferry popular and to use submarine cables for propulsion. It is worthwhile to create new technologies that enable the emergence of other sexual ferries.

A recent example of cable ferry application is the recently introduced cable ferry service operated by BC Ferries (“Denman Island Ferry”) that crosses Baines Sound from Vancouver Island, British Columbia, Canada to Denman Island. This cable ferry route is currently considered to be the longest cable ferry in the world with a length of about 2000 m. A knowledgeable ferry operator will assist the ferry in properly guiding and propelling the ferry with sufficient strength to withstand the additional forces acting on the ferry from wind and flow while still having a factor of safety. We believe this is approaching the maximum cable ferry length due to the tensile force that must be applied to tension the steel cable to pull it. The problems imposed on the crew to handle the axial and vertical forces of the terminal anchors and the heavy weight associated with the maintenance of the cable system are to have long distances between the ferry terminals and to place the cables on the seabed. It is not feasible to consider using a cable ferry that uses steel wire rope for drive and induction cables on routes where the water is too deep. On the Denman Island ferry, the cables are placed at the bottom of the body of water so that most of their length crosses to reduce the tension required for the cables. In a fully extended cable system with a typical 1 1/2 inch cable, the cable tension for clear spans over 1 km is very high. Obtaining greater tensile strength using a larger diameter cable also increases the weight of the cable, which exacerbates the problem.

Contact of the cable with the seabed causes wear of the cable and causes environmental damage due to wear of the cable at the bottom. The bottom material must be constantly removed from the cable to prevent wear of the moving parts and the cable itself. At some parts of the Denman ferry route, the cable is very deep, resulting in an excessively steep approach angle of the cable to the ferry, resulting in inefficiency. The steep approach angle at one end of the route increases the weight and friction of the cable, while reducing the magnitude of the horizontal vector that provides the movement of the ferry. The high tensile forces give rise to the corresponding high tightening forces applied to the bullwheels of the ferry, which may require them to be specially designed, against them as the tension of the cables increases with the length of the route. Increases wear. Another problem is caused by cables that come into contact with the bottom when the ferry route has rocky, irregular or steep bottom terrain. The problem here is the more extreme wear of the cable from the abrasive bottom, or the catching of the cable.

Due to the physical weight and friction of commonly used uniform steel cables, there is a challenge in controlling the long length of the cable. As the ferry passes through the route, the catenary of the cable rises from the bottom very rapidly, resulting in a dramatic increase in cable tension as well. This effect becomes more pronounced as the droop rate required to limit the overall cable tension when the ferry route is long and deep and the cable is not supported at the bottom.

Therefore, it is common to provide improved cable structures that alleviate the aforementioned problems and, in particular, allow cable ferry and other vessels to be deployed on longer crossings than are currently possible. There is a need.

The above-mentioned examples of related techniques and related limitations are exemplary and not exclusive. Other limitations of the relevant art will be apparent to those skilled in the art by reading the specification and studying the drawings.

The following embodiments and embodiments are not limited in scope and are described and illustrated in connection with systems, tools, and methods intended to be exemplary and descriptive. In various embodiments, one or more of the problems mentioned above are alleviated or eliminated, while other embodiments are directed to other improvements.

Cables for propulsion and / or guidance of cable ferry have been disclosed, which allows their use on longer ferry routes. One embodiment provides the use of a cable for propelling and / or guiding a cable ferry in which the unit weight, specific density, density and / or diameter of the cable is variable over the length of the cable. According to one embodiment, a heavier or denser cable is used adjacent to the terminal and a lighter or less dense cable is used for the central section. If the section has positive buoyancy, the cable may be tethered to one or more anchors. If the section has negative buoyancy, the cable can be connected to one or more floats. In this method, the positioning of the cable and the control of its dynamic qualities are achieved. Cable control, i.e. positioning of the cable and its mechanical properties, is achieved by the physical properties of the cable itself, using variable density and / or diameter (“VSGD”) cables. In another aspect, cable control is achieved by applying an external force to the cable, which may or may not include a VSGD cable section. According to this aspect, cable control is achieved by applying an external force to the cable through a weight, float, or attachment to the bottom of the body of water.

In addition to the exemplary embodiments and embodiments described above, additional embodiments and embodiments will become apparent by reference to the drawings and reviewing the following detailed description.

An exemplary embodiment will be described with reference to the accompanying drawings. The embodiments and figures disclosed herein are intended to be considered exemplary rather than limiting.

It is a side sectional view of the conventional cable ferry which shows the undersea profile of the cable with the ferry in the dock. FIG. 5 is a side sectional view of a prior art cable ferry showing a submarine profile of a cable in which the ferry is moving. FIG. 5 is a side sectional view of a cable ferry using a VSGD cable according to an embodiment of the present invention, showing the seafloor profile of the cable with the ferry in the dock. FIG. 5 is a side sectional view of a cable ferry using a cable according to an embodiment of the present invention, showing the seabed profile of the cable in which the ferry is moving. FIG. 5 is a side sectional view of a cable ferry using a cable according to a second embodiment of the present invention, showing the seabed profile of the cable in which the ferry is moving. FIG. 5 is a top view of a cable ferry using a cable according to a third embodiment of the present invention, partially by perspective to show the submarine profile of the cable at which the ferry is moored. It is a partial side sectional view of the cable ferry shown in FIG. It is a partial side sectional view of the cable ferry cable according to the 4th Embodiment of this invention. It is a partial side sectional view of the cable ferry shown in FIG. 8 while the ferry is moving. FIG. 5 is a side sectional view of a cable ferry using a cable according to a fifth embodiment of the present invention in which the ferry is moored. FIG. 5 is a side sectional view of a cable ferry using a cable according to a sixth embodiment of the present invention in which the ferry is anchored. It is a plot of the catenary curve formed by the cable according to the first embodiment in which the ferry is moored and the ferry is moving. It is a plot of the catenary curve formed by the cable according to the first embodiment in which the ferry is moored and the ferry is moving. It is a plot of the catenary curve formed by the cable according to the first embodiment in which the ferry is moored and the ferry is moving. It is a plot of the catenary curve formed by the cable according to the first embodiment in which the ferry is moored and the ferry is moving. FIG. 5 is a side sectional view of a cable ferry using a cable according to an embodiment of the invention used to protect sensitive underwater habitats. It is a top view of the embodiment of the cable ferry shown in FIG. FIG. 5 is a side sectional view of a cable ferry using a cable according to an embodiment of the present invention to avoid underwater infrastructure. FIG. 5 is a side sectional view of a cable ferry using a cable according to an embodiment of the present invention to avoid underwater features that can cause wear or damage to the cable. FIG. 5 is a side sectional view of a cable ferry using a cable according to an embodiment of the present invention that allows a large ship to pass over the cable. FIG. 3 is a top view of a cable ferry that uses a cable according to an embodiment of the present invention in a strong flow compared to the use of a standard cable. FIG. 5 is a top view of a cable ferry using a cable according to an embodiment of the present invention, showing a moving cable ferry in which two floating cables are connected to an anchor and extend the cable upwards and inward towards the cable ferry. FIG. 5 is a side sectional view of a cable ferry using a standard cable to show the occurrence of friction points when the cable contacts the bottom to support its weight.

Specific details are provided through the description below to provide a complete understanding by those skilled in the art. However, well-known elements may not be shown or explained in detail to avoid unnecessarily obscuring the disclosure. Therefore, the specification and drawings should be considered as exemplary rather than limiting.

The term "cable ferry" means a ferry, vessel, barge, tugboat or other that is guided or used by cables, ropes, chains, or other types of lines (s) for guidance and / or propulsion. Means a ship of.
"Cable shipping" means ferries, vessels, barges, tugs that are guided or used by cables, ropes, chains or other types of lines (s) for guidance and / or propulsion. Or other vessel.
"Cable control" means positioning a cable and controlling its mechanical properties.
"Specific weight" (also referred to as unit weight) is the weight per unit volume of a substance. The density of a material is the mass per unit volume, while the specific gravity or unit weight is the gravity of the material with respect to the unit mass.
"Specific gravity" means the density of the reference material, that is, the ratio of the density of the substance to the density of water at 4 ° C. of the specific gravity 1, and means the ratio of the mass of the substance to the mass of the reference substance of the same volume.
"Tether" means a line with one end attached to the cable and the other end attached to or fixed to the bottom, weight or float.
"VSGD" is an acronym for Variable Specific Gravity and Diameter, meaning that the unit weight, density, density and / or diameter of a cable is variable over the entire length of the cable.
In the drawings, thick black lines are used to show VSGD cable sections that vary in unit weight, specific gravity, density, and / or diameter from the rest of the cable.

1 and 2 show side views of a typical prior art cable ferry configuration. Cable ferry 10 crosses body of water 12 between docks 14 and 16. The ferry 10 is guided by a cable 18 secured at either end of the dock or coastline and is used for propulsion. The cable 18 may be a single cable or a plurality of parallel cables. Cable 18 has 6 or 8 main strands wound around a separate wire rope core, eg, with a synthetic plastic coating or wrapping, and has a diameter of 1-1 / 2 "to 1-3 / 4". It can be made of steel wire rope, which is a range. Typically, one end of the cable 18 is attached to the embedded deadman anchor and the other end is attached to the tension winch. For part of the crossing, the cable is above the seabed and is pulled to one end of the ferry 10 deck through a friction-driven bullwheel (s) or idler (s) and the other end of the ferry 10 deck. Will be returned to the outboard.

FIG. 1 shows the ferry 10 anchored at the dock 14. Thus, the cable 18 forms a catenary curve when not mounted on the seabed, in which a suspended flexible wire or chain is supported at its ends and is acted upon by uniform gravity. It is a curve assumed in the case. In FIG. 2, the ferry 10 is passing between the docks 14 and 16. Cable 18 forms two catenary curves 22, 24, the relative size of which is that the ferry 10 crosses the water surface 20 until a single catenary curve is formed again when the ferry 10 reaches the dock 16. It changes as you move. For the reasons mentioned above, the use of cables for longer ferry routes is impractical, so cables have traditionally been used only for ferries traveling short distances from land to land. Also, the direction of the cable ferry has not been changed. Changing the direction of the cable ferry is desirable for a number of reasons, including allowing more routes and additional terminal locations to be considered for such ferries.

3 and 4 show a cable section 26 in which the cables 18 have varying specific densities and / or diameters (VSGD), spliced, tied, or connected to each other along the length of the cable 18. , 28, 30 are shown in the side view of the first embodiment. Also, cables can be specifically manufactured, so that the density or diameter can be varied without splicing, knotting or other attachments. Sections 26 and 30 can be heavier standard wire rope cables, while the central section is of lower neutral buoyancy specific gravity or density, such as synthetic rope cables. For example, sections 26, 30 may be formed of wire rope with a diameter of 1.5 ", while central section 28 may be formed of a synthetic rope cable with a diameter of 1.5". This allows for the ability to guide the ferry without approaching the rupture point and reduce the tensile force required to provide the desired tension to propel. A lighter cable, typically towards the center of the span, allows the tensile strength to deviate from being devoted to maintaining its own weight, and instead provides an appropriate factor of safety. While providing, it withstands the forces applied to the cable by ferry or to the cable itself by flow. By using a material with varying specific densities, the depth of the cable across the cable span is closer to the terminal by using a heavier cable near the terminal, while using more buoyancy material in the center of the span. It can be designed to have the desired characteristics of cable weight and depth.

Nowadays, modern synthetic ropes with breaking loads equal to or greater than steel wire ropes of the same diameter are readily available. Rope manufacturers such as Samson Rope's and Cortland Rope's have made cables of several different fibers to provide a complete cable with the strength, weight, wear resistance and repetitive bending fatigue properties required for the intended application. provide. Cables can be custom made in almost any length and in varying diameters, either as continuous ropes or using twisted joints. For cable ferry applications, it has variable buoyancy of either neutral, positive or negative buoyancy and can also undergo repeated periodic bending as the cable passes over the drive bullwheel and deck guide sheave. There are advantages disclosed herein that result from having a cable.

The buoyancy of the cable section 28 can be obtained by incorporating a large mass of low density material such as cellular rubber or closed cell expanded polyethylene into the cable, as disclosed in US Pat. Nos. 2,403,693 and 2,818,905, or by incorporating a floating wire. In connection with, it can be increased by incorporating a filament braided buoyant member as disclosed in US Pat. No. 3,155,768. U.S. Pat. No. 3,806,568 provides a method for producing continuous cables with uniform diameters and different strength and weight sections in seawater without twisting different cable sections. Other VSGD cables can be made from synthetic rope or steel incorporating the desired properties.

Example A supposed cable ferry route with a length of 7600 feet was studied in very deep water. As for the assumed ferry route, it was envisaged to allow up to 35 feet of deep sea vessels to navigate by cable, except when the ferry is in transit. Therefore, when the ferry is not navigating, the portion of the cable within the area of the aisle of the vessel should not be about 80 feet shallow from the surface of the water. In such a configuration, considering the end force on the cable, a conventional wire rope cable with a 2 "diameter would have a root of its length and depth when a factor of safety of 5 was applied to the breaking force of the cable. The nominal breaking load of the 2 "wire rope is 360,000 pounds, which gives a maximum allowable load of 79000 pounds when the factor of safety 5 is applied. The end force is generated by the physical weight of the cable, the initial tension of the cable induced by the tensioning winch, and the resistance of water on the ferry's hull as it pulls itself along the cable. Hull resistance is proportional to the ferry load (number of vehicles) and water speed. When handling long cables, the axial and vertical forces of the terminal anchors, as well as the problems imposed on ferry crews and equipment handling heavy weights, are the steel wire ropes for the proposed route drive and induction cables. It is not difficult to conclude that it is unrealistic to consider.

Therefore, although the cross section is constant over the entire length, it was considered to use a synthetic rope cable for the central section of the cable. Synthetic cables can also be manufactured along their length with varying densities and diameters without the need for more seams. A cable catenary shape with an end of the same unit weight as a 2 "diameter steel wire rope (7.4 lbs / ft) and a long central section of a 2" diameter synthetic rope with a unit weight of less than 1 lb / ft. Calculations were made to determine. A 2 "diameter cable drains a volume of water weighing more than 1 lb, so the central section of the cable is arched upward towards the surface of the water and is constrained only by heavy ends. 690 ft in length. The cable balances with the lighter central section when the lower end of the heavy section is submerged at 190 ft and the top of the upward arc of the synthetic central section is 85 ft below the surface of the water, using a 2 ”steel wire rope. I found. This shows the case where the ferry is moored on the same exaggerated vertical scale in FIGS. 12 and 13. This is shown in FIGS. 14 and 15 with the same exaggerated vertical scale when the ferry is in motion. Preferably, a combination of a heavier (more dense) end section of the synthetic rope cable and a central section of the lighter synthetic rope that is balanced 80 to 100 feet below the surface can also be used. 690 feet was considered for the length of the heavy end section, but different lengths, 500 feet or other lengths, apply, depending on the ferry route considered.

Therefore, in waters close to each terminal, drive and guide the ferry by using the denser and denser parts of the cable and then the lighter cable to connect the ends of the heavier cables. It was considered to provide a continuous set of cables. Since the drive cable must be in physical contact with the friction drive bullwheel and idler, the transition between the heavier end section and the lighter center section of the cable must be smooth and symmetrical. The transition may take the form of a splice with a more appropriate adjustment to the allowable safe load of the cable. The techniques surrounding synthetic ropes are currently well developed and applicable safety factor multiplicands are available or will soon be computable and suitable splices can be manufactured and tested. A preferred option is a continuous synthetic rope cable with heavier ends and a less dense central section.

This design has a very beneficial effect on the reaction force at the terminal anchor and the depth of the catenary loop. Some synthetic fibers have a unit weight whose volume is less than the weight of drained water, and they generate upward buoyancy. In conclusion, it is feasible to use a lighter central section for the cable, and consider a cable ferry route with a much larger distance between the ferry terminals without making the cable too heavy and unrealizable. It is possible.

Some modern synthetic ropes have the same mechanical strength properties as steel wire ropes of the same diameter, but are considerably lighter. A synthetic rope with a diameter of Samson, Amstile Blue Dynaema 2-1 / 8 "has a breaking load of 396,000 pounds. Applying a safety factor of 5, the safe load of this synthetic rope is 79,000 pounds and a diameter of 2". It is the same value as the steel wire rope of. The elastic elongation at 20% of the breaking load of the Dyneema synthetic rope is less than 1%, which is comparable to the elasticity of steel wire rope. There is a big difference in the unit weight of the two cables. Steel cables weigh 7.3 lbs / ft, and synthetic cables weigh only 0.91 lbs / ft. The volume of water drained by each 2 "diameter linear foot with a cross-sectional area of 3.142 square inches is 37.7 cubic inches per linear foot. The synthetic cable under consideration has a buoyancy of 1.39 pounds. Occurs and the cable floats. When the geometric force at two cable end anchors with a lighter synthetic cable is calculated using the same safety factor of 5 as the 7600 ft spacing between cable terminal anchors, the buoyancy is calculated. The droop before consideration was the same as the steel wire, but the force acting on each anchor was found to be reduced to 8,600 lbs. Taking into account the buoyancy of the cable, the cable floats on the surface of the water, of the anchor. The force is much smaller.

With reference to FIG. 5, the use of the disclosed VSGD cable is the front of the ferry and when the ferry brings the cable to the surface of the water as it propels itself along the route and when approaching the terminal. It is also possible to change the design of the approach angle and escape angles B and A of the rear cable. Thick cables with large diameters have greater frictional forces that resist being pulled to the surface of the water. By changing the diameter of the cable, the mechanical interaction of the ferry with the cable can be changed. Larger diameters work in harmony with the specific gravity of the cable, so that the approach angle of the cable can be maximized. The escape angle A of the cable from the ferry (FIG. 5) is smaller than the approach angle B of the cable to the ferry. This is because the cable exits the vessel under less tension than the cable that enters the vessel being pulled by the vessel. The cable diameter can be increased to increase the approach angle B of the cable entering the ferry. The steeper approach angle B increases the likelihood that the cable will avoid contact with other marine traffic that may cross the route while the ferry is moving. Alternatively, reducing the diameter of the cable can be used in the section of the route where there is a strong flow to reduce the effect of the flow on the cable.

FIG. 5 shows a modified side view of the first embodiment of FIGS. 3 and 4 using a cable having a larger diameter such as 3 ". Again, the cable 18 is along the length of the cable 18. It is formed from cable sections 26, 28, 30 with varying specific gravities and / or diameters (VSGD) that are spliced, tied, or tied together, with larger diameters, as shown in FIG. In the cable, there is a steeper approach angle B to the moving ferry compared to the 1.5 "cable shown at angle C due to the increased friction of the 3" cable by water as it is pulled.

6 and 7 show top and side views of a third embodiment in which a combination of floats and anchors connected to the cable is used with the VSGD cable, respectively. The anchor or weight 32 is on the seabed 36 and is attached to the cable 18 by a tether 38. Similarly, the float or buoy 34 floats above the water surface 20 and is attached to the cable 18 by the tether 38. The positions where the floats, anchors and weights 32, 34 are connected to the cable 18 are selected to achieve the desired cable profile. For example, in FIGS. 6 and 7, section 40 of the cable 18 may be buoyant, section 42 may be subducted, and section 44 may be of variable density.

In the embodiments shown in FIGS. 8 to 11, cable control is achieved by applying an external force to a uniform cable that is not a VSGD cable. By incorporating a VSGD cable, cable control, i.e. positioning of the cable and its mechanical properties, is achieved by the physical properties of the cable itself, but in this embodiment the cable control is to a weight, float, or bottom. Achieved by utilizing external force through the installation of. In FIG. 8, the side view shows that when the ferry is anchored, the entire cable 18 is buoyant and can be held below the water surface 20 by an elastic stretchable tether 38 at a depth selected. FIG. 9 shows another side view of the configuration of FIG. 8 when the ferry 10 is in motion.

The cable tethering method described above makes it possible to select both the depth profile and orientation of the cable, as shown in FIGS. 6 and 7. This method can typically be used by a cable ferry with a drive sheave mounted overboard the ferry on either side. By using a system of fairleads, idlers or guards, the tether 38 between the cable and the anchor or weight 32, for example, by using the method used on longline commercial fishing vessels, etc. It can be oriented and kept away from passing through the drive sheave. A similar technique can be used to orient the tether 38 of the float 34 attached to the cable away from the drive sheave. The notch can be machined into the outer sheave to which the tether is oriented shortly before approaching the sheave. Alternatively, fittings similar to those used by ski chair lifts on cables can be used to prevent the tether for the attached weights from following the main line through the drive sheave.

As shown in FIG. 11, the weight 32 can be used to pull the cable 18 near the bottom without touching the bottom. When the weight 32 comes into contact with the bottom 36, the cable 18 cannot be pulled down any further. The float 34 (shown in FIG. 7) can be used to mark the location of the navigation route across the cable or to establish the depth of the cable. The buoy can be used as a float 34 for both acting on the cable for navigation or other purposes and serving to mark the cable.

The float 34 is preferred in shallow water where the bottom tether 38 to the anchor 32 is not suitable due to the limitation that shallow water is placed with a limit corresponding to the elasticity of the tether to the length of the tether to the anchor. It can be. See also FIG.

As shown in FIG. 7, the system of anchors 32 and buoys 34 thus controls the cable 18 in the longitudinal and vertical directions (xy) and is located laterally separated from the main cable line. The anchor 32 is oriented on the horizontal plane (z). This system allows for various routes of other maritime traffic across the cable line, where the cable is well below the surface of the water and can cross miles of water, as shown in Figure 6. , Designed and placed to take the desired profile on the xyz axis, and then tensioned. If the ferry is in motion, it brings the main cable 18 to the surface of the water, which is allowed by the elasticity of the tether 38 fixed to the bottom. The cable is then subducted or pulled down to the desired depth by the tether 38 as the cable ferry passes.

The bottom attachment can be made by connecting an elastic tether 38 between the cable 18 and the correspondingly disposed anchor 32 set on the bottom, as shown in FIGS. 8 and 9. In this case, the cable 18 itself is made of a floating material. The cable resembles the reverse of a suspension bridge. The elasticity of the tether is shown in FIGS. 9 and 22 by the different lengths of the solid dashed lines representing the tether 38. In the tow winch, the main cable 18 is pulled by a sheave, while the tether 38 uses a guide, idler, or a fixture such as a fairleader used in commercial longline gear hauling by some means. Can be modified to move away from the sheave. One cable can be used with the proper configuration of the winch, but depending on the application, two outer cables may provide redundancy and provide more directional control. In fact, on a ferry with winches on both sides, a certain amount of steering can be achieved using two cable systems by varying the winch speed. Thus, by reducing cable tension, the anchor 32 and tether 38 may allow redirection to bypass obstacles such as islands and coral reefs that were not possible before the cable ferry. This allows the cable ferry route to be designed to allow the terminal of the cable ferry route to be in protected waters to provide a safe port for the ferry. The ferry 10 can be designed as a catamaran or other multi-hull vessel, and one cable system with a winch-mounted intermediate vessel between the catamaran hulls can be used.

Routine navigation of long cable routes across intercontinental vessel routes through barges or other towing operations, ferry vessels, and certain maritime traffic lanes by orienting cables under control in the xyz plane. Can be made to assist the vessel of the cable ferry and can provide the benefits of efficiency and other benefits of cable ferry. Examples of regular transportation lanes that use barge traffic are barges, chips to pulp mills, or freight to the island community, sending raw log booms, and supplying supplies along tourist routes. If there is.

By using the VSGD cable described above, the cable profile can be designed to meet the requirements of each ferry route. This can be applied to cable ferry routes where it is desirable for the cable to be fully suspended from land to land. VSGD cables can be used on long cable ferry routes that do not necessarily require bottom contact to limit tension on the cable, but bottom contact may and may be desirable. The specific gravity of the cable can be reduced, typically near the central section of the route, thereby reducing the overall tension applied to the cable, which results in a longer cable span, Therefore, longer cable ferry routes are possible. The notable advantages of hanging the cable away from the bottom include a much longer life of the cable and less wear on the mechanical parts. Cable ferry will be able to be used on longer routes than previously possible using steel wire rope cables that are uniform, typically wrapped in plastic.

By varying both the specific gravity and diameter of the cable, and in some cases by using tethers to floats and anchors, route length, flow, environmental sensitivity, ferry traffic, and, if not limited, Specific challenges of cable ferry routes, including ferry propulsion efficiency, can be overcome. Additional applications for VSGD cables are shown below.

As shown in side views in Figures 16 and 17, VSGD is used to prevent sensitive cable scouring near terminals, such as habitats for risky species and other abundant low tide areas. Can be used. The buoyancy section 50 of the cable can be used in area 52 where sensitive habitats are present. The sinking cable 54 can be used where there is greater water depth. By increasing the weight, the tension of the cable can be adjusted and other traffic can traverse the cable. The result is an asymmetric side profile of the cable. As shown in FIG. 17, the navigation marker 56 can be used to alert traffic where the cable is always too shallow to traverse. VSGD cables can also be used to avoid contact with transmission lines, such as pipelines, which are typically found at the narrowest crossing distances where cable ferry can also be located, as shown in the side view in FIG.

The steep or irregular bottom structure 60 (FIG. 19) can interfere with the cable and wear it in one place. Boulders and ledges 60 can cause cable snagging. As shown in the side view in FIG. 19, the VSGD cable 54/50/54 with a denser specific gravity end section 54 and a neutral, negative or positive buoyancy central section 50 is a hazards. This problem can be addressed by being hung above the 60. The side profile of FIG. 23 of a standard cable 18 shows some chafing points 61 that can cause damage to the cable.

Other ship traffic across the route can be a design consideration for some possible cable ferry routes. The large vessel 62 can pass over the cable through the marked navigation channel, as shown in the side view in FIG. The increased cable density and / or diameter allows the section 54 of the cable to be deeper. A lighter material 55 is used in the vicinity of terminals 14, 16 which allows the overall tension to be reduced. Vessel 62 can cross the cable even when the cable ferry is in motion. This allows the cable ferry to be used on routes where it is not feasible to stop the passage of all vessels while in motion. Therefore, VSGD cables can be used with navigation markers to allow passage of vessels.

Also, varying cable diameters can be used to minimize the side forces caused by the flow acting on the cable. The diameter and density of the cable can be varied by modern materials. Changing the diameter and density of the cables is useful when there is a cross-current caused by tidal currents, rivers or other conditions, as shown in plan view in FIG. The diameter of the cable is reduced at the neutral buoyancy central section 57, while the density and diameter are increased at the end section 54. Compared to the standard uniform cable 18, a smaller lateral force generated by the flow acts on the cable 54/57/54. The advantages are: i) keep the cable ferry more accurately in the bow direction and within its route, ii) keep the cable deeper to avoid other traffic across the route, iii) cable ferry is its route Includes minimizing the work required to get through.

Floats and anchors can be used for cable ferry featuring tow winches attached to both sides of the ferry. In plan view, FIG. 22 shows a moving cable ferry 10 extending cables upward and inward towards the cable ferry. Here, as described above with respect to FIG. 9, two floating cables 50 are attached to the anchor 32 by the tether 38. Tensile forces act on vertical and horizontal planes. Greater extension of the tether 38 caused by the passage of the ferry is allowed without lifting the anchor 32. This is useful in shallow water. Moving the cables outside the route keeps the ferry 10 course more central.

Although some exemplary embodiments and embodiments have been discussed above, those of ordinary skill in the art will appreciate their particular variants, substitutions, additions, and partial coupling forms. For illustration purposes, only one cable is shown for cable ferry. The same concept applies to cable ferries that use multiple drive and / or inductive cables. There are two vessels shown, but usually only one works for the system. Thus, the appended claims and the claims introduced thereafter include all such modifications, substitutions, additions and subcombinations that are consistent with the broadest interpretation of the specification as a whole. It is intended to be interpreted as including.

Cable ferries, also known as chain ferries, have long been used to transport vehicles and people over relatively short distances across water bodies. Such ferries are guided by cables, ropes or chains, all of which are referred to herein as cables. Currently, the cables used for cable ferry generally form cables with a diameter of 1 "or more, typically 1-1 / 2" to 1-3 / 4 " (3.81 cm to 4.45 cm). It is made of stranded steel wire rope with 6 or 8 main strands wrapped around an independent wire rope core.

A recent example of cable ferry application is the recently introduced cable ferry service operated by BC Ferries (“Denman Island Ferry”) that crosses Baines Sound from Vancouver Island, British Columbia, Canada to Denman Island. This cable ferry route is currently considered to be the longest cable ferry in the world with a length of about 2000 m. A knowledgeable ferry operator will assist the ferry in properly guiding and propelling the ferry with sufficient strength to withstand the additional forces acting on the ferry from wind and flow while still having a factor of safety. We believe this is approaching the maximum cable ferry length due to the tensile force that must be applied to tension the steel cable to pull it. The problems imposed on the crew to handle the axial and vertical forces of the terminal anchors, as well as the heavy weight associated with the maintenance of the cable system, are to have long distances between the ferry terminals and to place the cables on the seabed. It is not feasible to consider using a cable ferry that uses steel wire rope for drive and induction cables on routes where the water is too deep. On the Denman Island ferry, the cables are placed at the bottom of the body of water so that most of their length crosses to reduce the tension required for the cables. In a fully extended cable system with a typical 1 1/2 inch (3.81 cm) cable, the cable tension for clear spans greater than 1 km is very high. Obtaining greater tensile strength using a larger diameter cable also increases the weight of the cable, which exacerbates the problem.

1 and 2 show side views of a typical prior art cable ferry configuration. Cable ferry 10 crosses body of water 12 between docks 14 and 16. The ferry 10 is guided by a cable 18 secured at either end of the dock or coastline and is used for propulsion. The cable 18 may be a single cable or a plurality of parallel cables. Cable 18 has 6 or 8 main strands wound around a separate wire rope core, eg, with a synthetic plastic coating or wrapping, and has a diameter of 1-1 / 2 "to 1-3 / 4" ( It can be made of steel wire rope, which ranges from 3.81 cm to 4.45 cm). Typically, one end of the cable 18 is attached to the embedded deadman anchor and the other end is attached to the tension winch. For part of the crossing, the cable is above the seabed and is pulled to one end of the ferry 10 deck through a friction-driven bullwheel (s) or idler (s) and the other end of the ferry 10 deck. Will be returned to the outboard.

3 and 4 show a cable section 26 in which the cables 18 have varying specific densities and / or diameters (VSGD), spliced, tied, or connected to each other along the length of the cable 18. , 28, 30 are shown in the side view of the first embodiment. Also, cables can be specifically manufactured, so that the density or diameter can be varied without splicing, knotting or other attachments. Sections 26 and 30 can be heavier standard wire rope cables, while the central section is of lower neutral buoyancy specific gravity or density, such as synthetic rope cables. For example, sections 26, 30 may be formed of wire rope 1.5 "(3.81 cm) in diameter, while central section 28 may be formed of synthetic rope cable 1.5" (3.81 cm) in diameter. Rope. This allows for the ability to guide the ferry without approaching the rupture point and reduce the tensile force required to provide the desired tension to propel. A lighter cable, typically towards the center of the span, allows the tensile strength to deviate from being devoted to maintaining its own weight, and instead provides an appropriate factor of safety. While providing, it withstands the forces applied to the cable by ferry or to the cable itself by flow. By using a material with varying specific densities, the depth of the cable across the cable span is closer to the terminal by using a heavier cable near the terminal, while using more buoyancy material in the center of the span. It can be designed to have the desired characteristics of cable weight and depth.

Example A hypothetical cable ferry route with a length of 7600 feet (2316.4 m) was studied in very deep water. As for the assumed ferry route, it was assumed that a deep sea vessel of up to 35 feet (10.7 m) could be navigated by cable, except when the ferry was sailing. Therefore, when the ferry is not navigating, the portion of the cable within the area of the aisle of the vessel should not be as shallow as about 80 feet (24.4 m) above the surface of the water. In such a configuration, considering the end force on the cable, a conventional wire rope cable with a diameter of 2 ”(5.08 cm) would have a length and depth when a factor of safety of 5 is applied to the breaking force of the cable. It is clear that it is not suitable for the route. The nominal breaking load of a 2 "(5.08 cm) wire rope is 360,000 pounds (163,293 kg) , which applies a factor of safety of 5. In this case, the maximum allowable load is 79000 lbs (35,834 kg) . The end force is generated by the physical weight of the cable, the initial tension of the cable induced by the tensioning winch, and the resistance of water on the ferry's hull as it pulls itself along the cable. Hull resistance is proportional to the ferry load (number of vehicles) and water speed. When handling long cables, the axial and vertical forces of the terminal anchors, as well as the problems imposed on ferry crews and equipment handling heavy weights, are the steel wire ropes for the proposed route drive and induction cables. It is not difficult to conclude that it is unrealistic to consider.

Therefore, although the cross section is constant over the entire length, it was considered to use a synthetic rope cable for the central section of the cable. Synthetic cables can also be manufactured along their length with varying densities and diameters without the need for more seams. 2 ” (5.08 cm) diameter steel wire rope (7.4 lbs / ft) (11.02 kg / m) with the same unit weight at the end and less than 1 lb / ft (1.49 kg / m). Calculations were made to determine the shape of the cable catenary with a long central section of synthetic rope with a diameter of 2 " (5.08 cm). A cable with a diameter of 2 " (5.08 cm) drains a volume of water weighing more than 1 lb (.454 kg), so the central section of the cable is arched upward towards the surface of the water and by a heavy end. only by using a steel wire rope 2 "(5.08 cm) length of .690ft (210.3m) to be bound, being immersed in the lower end of the heavy sections 190ft (57.9m), the central section of the synthesis The cable found a balance with the lighter central section when the top of the upward arc was 85 ft (25.9 m) below the surface of the water. This shows the case where the ferry is moored on the same exaggerated vertical scale in FIGS. 12 and 13. This is shown in FIGS. 14 and 15 with the same exaggerated vertical scale when the ferry is in motion. Preferably, a combination of the end section of a heavier (more dense) synthetic rope cable with the central section of a lighter synthetic rope that is balanced 80 to 100 feet (24.4 to 30.5 m) below the surface is also possible. It can also be used. 690 feet (210.3 m) was considered for the length of the heavy end section, but depending on the ferry route considered, 500 feet (152.4 m) or any other length. Different lengths apply.

Some modern synthetic ropes have the same mechanical strength properties as steel wire ropes of the same diameter, but are considerably lighter. A synthetic rope with a diameter of Samson, Amstile Blue Dynaema 2-1 / 8 " (5.08 cm) has a breaking load of 396,000 pounds (179,623 kg) . Applying a factor of safety 5, the safe load of this synthetic rope. Is 79,000 pounds (35,834 kg) , which is the same value as a steel wire rope with a diameter of 2 " (5.08 cm). The elastic elongation at 20% of the breaking load of the Dyneema synthetic rope is less than 1%, which is comparable to the elasticity of steel wire rope. There is a big difference in the unit weight of the two cables. Steel cables weigh 7.3 lbs / foot (10.87 kg / m) and synthetic cables weigh only 0.91 lbs / foot (1.35 kg / m) . The volume of water drained by each 2 " (5.08 cm) diameter linear foot (.305 m) with a cross-sectional area of 3.142 square inches (20.27 square cm) is 37.7 cubic inches ( 37.7 cubic inches) per linear foot. 176.16 cubic cm / m) . The synthetic cable under consideration produces 1.39 lbs (0.63 kg) of buoyancy and the cable floats. Two cable end anchors with a lighter synthetic cable When the geometric force at is calculated using the same safety factor of 5 as the distance of 7600 feet (2,316.4 m) between the cable terminal anchors, the droop before considering the buoyancy is the same as the steel wire. It was found that the force acting on each anchor was reduced to 8,600 lbs (3,900.9 kg) . Taking into account the buoyancy of the cable, the cable floats to the surface of the water and the force of the anchor is considerably reduced.

FIG. 5 shows a modified side view of the first embodiment of FIGS. 3 and 4 using a cable with a larger diameter such as 3 ”(7.62 cm). Again, cable 18 is cable 18. It is formed from cable sections 26, 28, 30 with varying specific gravities and / or diameters (VSGD) that are spliced, tied, or linked along the length of the cable, as shown in FIG. For larger diameter cables, due to the increased friction of the 3 "(7.62 cm) cable with water as it is pulled, compared to the 1.5" (3.81 cm) cable shown at angle C. There is a steeper approach angle B to the moving ferry.

Claims (21)

Cable between terminals A cable for propulsion and / or guidance of propulsion vessels.
The unit weight, specific gravity, density and / or diameter of the cable is variable over the length of the cable.
cable. The unit weight, specific gravity, density and / or diameter of the cable is larger in the portion of the cable closer to the terminal than in the portion of the cable away from the terminal.
The cable according to claim 1. Any one or a combination of the unit weight, specific gravity, density or diameter of the cable varies over the length of the cable.
The cable according to claim 1. The unit weight of the cable varies over the length of the cable.
The cable according to claim 1. The specific gravity of the cable varies over the length of the cable.
The cable according to claim 1. The density of the cable varies over the length of the cable.
The cable according to claim 1. The diameter of the cable varies over the length of the cable.
The cable according to claim 1. The cable has a section of wire rope cable at both ends and a central section of synthetic rope.
The cable according to claim 1. The cable has a section of cable having negative buoyancy and a section of cable having positive buoyancy.
The cable according to claim 1. The section of the cable with positive buoyancy is connected to one or more anchors by a flexible connector.
The cable according to claim 1. The section of the cable with negative buoyancy is connected to one or more floats.
The cable according to claim 1. The flexible connector expands and contracts.
The cable according to claim 10. Cable propulsion between terminals A cable system for the propulsion and / or guidance of vessels:
i) With a cable, wherein the section of the cable has a cable section with positive buoyancy;
ii) With one or more anchors connected to the cable at positions separated by flexible connectors;
Have,
Cable system. The flexible connector expands and contracts.
The cable system according to claim 13. Cable propulsion between terminals A cable system for the propulsion and / or guidance of vessels:
i) With a cable, wherein the section of the cable has a cable section with negative buoyancy;
ii) With one or more levitation devices connected to the cable at positions separated by flexible connectors;
Have,
Cable system. The flexible connector expands and contracts.
The cable system according to claim 15. Cable propulsion between terminals A cable system for the propulsion and / or guidance of vessels:
i) With a cable, wherein the section of the cable has a section having positive buoyancy or negative buoyancy;
ii) With a cable, wherein the section of the cable has a section in which the unit weight, specific density, density or diameter of the cable is variable over the length of the cable;
iii) With one or more anchors or levitation devices connected to the cable at positions separated by flexible connectors;
Have,
Cable system. The flexible connector expands and contracts.
The cable system according to claim 17. A method of controlling the position or force of a cable used to propel or guide a cable propulsion or guidance vessel over the path of the vessel at sea across a body of water between two points on the path:
i) With the step of determining the selected route over the sea across the two points;
ii) The step of selecting the VSGD cable according to any one of claims 1 to 12 for propulsion and / or guidance to suit the desired properties of the transverse;
including,
Method. A method of controlling the position or force of a cable used to propel or guide a cable propulsion or guidance vessel over the path of the vessel at sea across a body of water between two points on the path:
i) With the step of determining the selected route over the sea across the two points;
ii) With the step of selecting the combination and position of the force-applying elements for connection with the cable at positions spaced along the length of the cable to suit the desired properties of the transverse;
including,
Method. The factors that give the force are:
i) With a levitation device connected to the cable at positions separated by elastic connecting elements;
ii) With an anchor device connected to the cable at a position separated by an elastic connecting element;
iii) With an elastic connecting device that connects the cable to the bottom of the body of water;
iv) With the combination of the above devices;
Selected from a group of
The method of claim 20.

Images