US 3407775 A
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Oct. 29, 1968 T. T. LUNDE METHOD AND APPARATUS FOR PULLING ANCHORS Filed Feb. 13, 19,67
INVENTOR. MOM/J5 I UA/@f M45 www Md ATTORNEYS x II Il United States Patent O 3,407,775 METHOD AND APPARATUS FOR PULLING ANCHORS Thomas T. Lunde, 6 Locksley Ave., San Francisco, Calif. 94122 Filed Feb. 13, 1967, Ser. No. 615,503 Claims. (Cl. 114-206) ABSTRACT OF THE DISCLOSURE A method and apparatus for breaking out a ships anchor using the momentum of a small vessel to apply an adequate but controlled force to an anchor at the pivotal juncture between the anchor shank and lukes. One end of a breakout line is connected to the pivotal juncture of an anehors shank and lukes; the other end of the line is connected to a braking device mounted upon a small vessel, which is then moved in a direction opposite that used in setting the anchor. The breakout line is payed out until the vessel develops sucient momentum to break the anchor loose, and then a controlled braking force is applied to the line.
This invention generally relates to the art of anchoring ships, and more particularly to a method and apparatus rfor breaking out anchors of large ships.
It is common practice for ships to break anchor by `using brute force alone. The breakout forces required are largely attributable to the weight of material above the anchor and to the shear forces required for breaking up materials in which the anchor is imbedded. Conventional methods of breaking anchor require the use of large Winches capable of applying tremendous line tension. The initial cost of such equipment is high and the cost of operation is expensive. Even so, conventional methods and apparatus cannot be used if the floatation left in a loaded vessel is insutlicient to resist the line pull required to free the anchor. In many instances the size of the supply vessel, and/or its ability to trim, requires that an auxiliary vessel or tug be used to break out and lift the anchor. Auxiliary vessels themselves, of course, must have sufficient oatation and pulling capacity to exert the necessary line pull.
In brief, the present invention involves the use of the momentum of a relatively small vessel or tug to break out the anchor of larger vessels. The method contemplates rst securing an anchor line to the small vessel, then moving the vessel to gain speed while simultaneously paying out line, and linally applying a controlled tension to the line suicient to break out the anchor. It is further contemplated that the tug should be moved away from the anchor in a direction opposite that used in setting the anchor. In this manner a minimum force will be required to break out the `anchor when and as the line of pull is directly opposite to the anchor llukes.
One object of the present invention is to provide methods and apparatus for pulling and breaking out anchors of very large vessels by means of relatively light equipment and a small vessel.
Another object is to provide methods and apparatus for breaking out an anchor by applying a controlled tension to an anchor line and utilizing the momentum of a small vessel to pull the anchor.
A still further object of the invention is to provide relatively inexpensive apparatus for breaking loose and pulling anchors of large vessels.
Other objects of this invention will 'become apparent in view of the following detailed description.
In the drawings forming a part of this application,
FIG. 1 is an elevation view and a schematic drawing ICC showing a preferred method of the invention in pulling a ships anchor;
FIG. 2 is a perspective view of a conventional anchor for large vessels; and
FIG. 3 is a schematic drawing of a control circuit including apparatus for applying a controlled tension to an anchor line.
Referring to FIGS. 1 and 2, there is shown a portion of a vessel 10 held at anchor `bya line 11 connected to an anchor 12. The anchor is of conventional construction comprised of a shank 13 having flukes 14 pivotally connected thereto on an axis 15 extending transverse to the shank. One end of a second line 16, to be used in 'breaking out anchor 12, is connected 'to the anchor on axis 15, a retrieving buoy 17 being attached to the other end of line 16.
A small vessel or tug 18 having a winch 19 with means for retrieving and paying out line 16, and a connecting spool line 20, is used for breaking out and raising anchor 12. Winch 19 may be hydraulically powered and need be of sutlicient power to lift only the anchor, its line and fittings and an adhering mudload. Details of the winch and operating equipment associated therewith are shown schematically in FIG. 3.
With reference to FIG. 3 there is shown a preferred form of apparatus for retrieving and/or applying a controlled tension to payout line 16 and spool line 20. Winch 19 generally comprises a drum 21, a pair of reversible hydraulic motors 22 and a clutching device 23 for selectively connecting the drum to the motors. The pressure of a lluid pressure source 24 may be app-lied to drive motors 22 through a connection including a control valve 25., a clutch operating cylinder 26 having a spring release 27, and one of two directional control valves 28 or 29. The construction of cylinder 26 and its connection to motors 22 requires that clutch 23 be engaged before iluid pressure is transmitted on to motors 22. Thus, the various hydraulic apparatus and connections provide a control means for sequentially actuating clutch 23 before communicating hydraulic pressure to either hydraulic motor.
The pressure of source 24 may also be applied through a valve 30 to a pair of hydraulic actuated braking cylinders 31 having spring reelases 32. The amount of pressure applied to each cylinder 31 is controlled by adjusting the size of opening through a throttling valve 33. The instantaneous braking pressure applied to cylinders 31 is shown on a pressure indicator 34 that is preferably scaled to show the tension in lines 16 and 20.
Hydraulic motors 22, clutch operating cylinder 26 and braking cylinders 31 are each provided. with return line connections to an exhaust tank 35 located above the high point of this system. Directional control valves 28 and 29 alternately connect hydraulic motors 22 to tank 35 depending on the direction in which the motors are to be driven.
In operation, and for purposes of pulling anchor 12, buoy 17 is iirst retrieved and removed, and the end of line 16 is connected with spool line 20. A torque is then applied to drum 21, taking up slack in line 16, as shown in FIG. 1 by the solid line position of vessel 18. This operation is accomplished by connecting pressure source 24 with the clutch operating cylinder 26 to engage clutch 23, and then opening directional control valve 28 t0 pressure source 24 and valve 29 to tank 35. During this operation, valve 30 is closed and valve 33 is open as to bleed braking cylinders 31 to tank 35.
After line 16 has been retrieved, control valve 25 is operated to connect cylinder 26 with tank 35, thereby declutching drum 21 from hydraulic motors 22. Also, valve 30 is opened to apply pressure to the braking cylinders 31. Valve 33 is initially open to prevent a buildup of pressure in the cylinders, but as the tug gains the necessary speed for breaking out the anchor, valve 33 is closed, building up pressure in braking cylinders 21 as required. During this time line 20 is payed out under a controlled tension which can be observed by reference to pressure indicator 34. If the tension begins to approach the elastic limit of lines 16 4or 20, the load may be diminished by opening throttling valve 33 to tank.
By the time vessel 18 reaches the broken line position shown furthest on right in FIG. l, where line 16 is directionally opposite to flukes 14 of anchor 12, the anchor should be pulled free from the material in which imbedded. After the anchor has been broken free, lines 16 and 20 are retrieved. For this purpose, valve 30 is closed, valve 33 is opened to tank, valve 25 is operated to transmit pressure from pressure source 24 to clutch operating cylinder 26 and to hydraulic motors 22 through directional control valve 29, valve 28 being opened to tank 35.
It is to be understood that the size of vessel 18 as well as the tensile strength of lines 16 and 20 are matters of engineering design based on well-known formula. In general, it is believed that small vessels, equipped with only small capacity hydraulic motors, can be used to break out the largest of anchors.
Having thus described my invention, what I claim and desire to secure by Letters Patent is:
1. A method for breaking out a ships anchor secured to a line, comprising the steps: securing a tug to the line, moving the tug to gain speed while simultaneously paying out line, then applying a variable but controlled tension to said line and utilizing the momentum of the tug to pull the anchor.
2. The method of claim 1 wherein said tug is moved away from the anchor in the direction opposite to that used in setting the anchor.
3. Apparatus for breaking out a ships anchor comprising: an auxiliary anchor-pulling line, one end of said line being secured to a ships anchor; a power-driven tug; means mounted on said tug for retrieving and paying out said auxiliary anchor-pulling line, said means comprising a reversible tluid motor, a source of uid pressure vfor driving said motor, a rotatably mounted drum, means for selectively clutching said drum to said motor, and control means for sequentially actuating said clutching means to connect said drum to said motor and then communicating said source of uid pressure to said uid motor; and means for applying a variable but controlled tension to said line as said line is being payed out; whereby said tug may be moved initially relative to said anchor to gain momentum and the momentum applied with a variable but controlled force in a direction opposed to the setting of said anchor.
4. The apparatus of claim 3 wherein said ships anchor comprises a shank having ukes pivotally connected thereto on an axis transverse to said shank, said line being connected to said anchor on said axis.
5. The apparatus of claim 3 wherein said means for applying a controlled tension comprises a fluid operated braking device, a source of uid operating pressure, :means `for selectively applying said source of pressure to said braking device to increase the tension in said line, and means for indicating the fluid pressure applied to said braking device.
References Cited UNITED STATES PATENTS 2,354,666 8/1944 Danforth 114-208 2,789,526 4/ 1957 Gollner 114-208 3,128,861 4/1964 Trondsen 192-17 3,132,622 5/ 1964 Hackenberger 114-235 3,106,180 10/1963 Rice 114-210 3,248,883 5/1966 Bowlsby 18S-152 X MILTON BUCHLER, Primary Examiner.
TRYGVE M. BLIX, Assistant Examiner.