Buoy Anchoring System

This invention relates to buoy anchoring systems, and more particularly to improvements in such systems of the type wherein a mooring line is payed out as the anchoring device descends and is automatically secured at the proper length when the anchor device comes to rest on the bottom.

The advantages and uses of systems of this type are well known and include primarily the ability to establish a marker buoy having a reasonably small watch circle even though anchored in relatively deep water, and without having to have prior knowledge of the actual depth of the water in order to predetermine the length of mooring line.

A variety of anchoring systems of the mentioned typed have been devised in the past and have employed a brake or jamming means to snub or arrest the payout of mooring line from a reel or a coiled supply carried by the anchor device. Those systems have typically used reel locks, brakes, line jamming jaw means, or line snubbing shafts around which line from a fixed coil is caused to take a plurality of turns so as to frictionally resist further payout.

Of the foregoing, those devices that rely on the friction of a plurality of turns of line about a shaft or core to halt line payout from a fixed coil that is coaxial with the shaft are considered to be the least likely to cause line breakage or damage. U.S. Pat. Nos. 3,336,892 to G. J. Barry et al and 3,351,158 to P. E. Kite disclose line payout arresting mechanisms using that principle. In the Barry et al device, as the line pays off the fixed coil, it passes through an aperture in a rotary member mounted on the end of the shaft. A solenoid or spring driven pin is provided to halt rotation of the rotary member, thereby causing the line to wrap the shaft and terminate payout. It is evident that any hockle in the line or binding of the rotary member will result in premature termination of the line payout. The required interactions of a plurality of mechanical and/or electrical parts during actuation to terminate payout increases likelihood of failure of the device to function properly at the required time. The Kite disclosure reveals a similarly complex device wherein actuation of a number of coacting mechanical elements, including pivoting of an arm at the end of the shaft by a spring, are required to result in proper operation of the device. Of course, the complexity of each of these devices renders them expensive to fabricate and maintain. Maintenance prior to use, is of course, an important factor in buoy anchoring systems of the type concerned which may remain stored for substantial periods under conditions in which rust, corrosion, and dampness tend to attack various, mechanical, electrical and pyrotechnic components, rendering them liable to failure.

With the foregoing in mind, it is a principal object of this invention to provide an improved buoy anchoring system having automatic termincation of line payout.

Another object of this invention is the provision of a buoy anchoring device having an unusually high degree of reliability.

Still another object is to provide an improved anchoring and automatic mooring line securing device that does not subject the line to the pinching, jamming, or chaffing common to some prior art anchoring devices, and avoids the shortcomings attendant the unnecessarily complicated structure of other such devices.

As another object, the invention aims to provide an anchoring apparatus that is noteably more economical to manufacture than its predecessors, and which can be stored for great lengths of time under severe conditions of temperature and humidity without degrading the reliability thereof.

Other objects and many of the attendant advantages will be readily appreciated as the subject invention becomes better understood by reference to the following detailed description, when considered in conjunction with the accompanying drawings.

FIG. 1 is a perspective view of a buoy anchoring system including a line payout and anchoring device embodying the invention;

FIG. 2 is a vertical sectional view of the anchoring device of FIG. 1; and

FIG. 3 is a view similar to that of FIG. 2 but with parts in different operative positions.

Referring first to FIG. 1, a buoy 10 illustrated in the process of being anchored in a body of water of indeterminate depth. The buoy 10 floats at the surface S of the water as an anchoring device 12, connected to the buoy by a mooring cable or line 14, plummets toward the floor or bottom 16, paying out mooring line as it falls.

Referring additionally now to FIG. 2, the anchoring device 12 comprises a body in the form of a cylindrical cannister 20. Fixed in the lower end of the cannister 20 is a lead weight 22 having a projecting portion presenting a rounded or curved surface 22a. The weight 22, is further provided with a central bore 24 that is coaxial with the cylindrical cannister 20.

Housed within the cannister 20, and spaced from the upper surface of the weight 24 by an annular spacer or ring 26, is a stationary coil or bale 28 of the mooring line 14.

The bale 28 is of cylindrical configuration so as to snugly fit into the cannister 20, and is wound so as to be open-cored or hollow as shown. The mooring cable or line 14, of which the bale is wound, may be formed of any suitable material and may include both electrical conductors and strength members for certain applications. If the cable used must have a synthetic fiber strength member for weight reduction, enough elongation capability with good fatigue life to accommodate surface wave action must be provided. In shallow water, polyester is a good choice. In deep water, however, aramid synthetic fiber appears to be the better choice. The high strength, excellent fatigue resistance, and small elongation under load provide the necessary properties for long tension members.

The cable or line 14 is pre-twisted during winding of the bale to prevent a helix from forming as the line is pulled from the center thereof during deployment. As the line wound to form the bale it is coated with a matrix material such as depolymerized rubber. This ensures a constant payout resistance force and avoids any advance payout that would cause snarling.

A lid or top 30 is fixed to the cannister 20 at the upper end thereof in confining relation to the bale 28 of mooring line. The top 30 is provided with a central opening 32 through which the mooring line 14 can be drawn from the innermost layer of the bale 28. The opening 32, of course, is provided with a smooth edge 34 to assure sliding of the mooring line thereover without damage.

Mounted in the central bore 24 of the lead weight 22 is a line locking shaft 40. At the upper end of this shaft is a radially extending, rigid arm means in the form of a cross-bar 42 that limits downward movement of the shaft 40, and also cooperates with the shaft in effecting a line securing function upon impact of the anchor device 30 with the bottom 16. The shaft 40 extends below the lead weight 22 for a distance l that is substantially equal to, or slightly less than the length of the bale 28. At the bottom end of the shaft 40 is provided an impact pad 44, conveniently in the form of a disc welded to the shaft, which serves to minimize penetration of the shaft 40 into the bottom, and also prevents rotation of the shaft after impact as will later be discussed.

The shaft 40 is normally held in an extended position by a shear pin 46 just below the lead weight 22. In that extended position the cross-bar 42 is located in the recess defined by the central opening of the spacer ring 26 so as to be below the bottom of the bale 28. It will be recognized that the recess could be defined in the upper surface of the lead weight 22, and the spacer ring 26 omitted.

Upon deployment of the anchor device 12, as by rolling over the side of a ship in the case of large units, the device plummets downwardly with the shaft 40 and pad 44 aimed toward the bottom. The mooring line 14, having its bitter end secured to a buoy 10, for example, is payed out smoothly from the bale 28 through opening 32 of the cannister lid. Because the bale 28 is stationary or fixed relative to the cannister, the point of departure of the line from the bale revolves around the central axis of the device.

When the pad 44 impacts upon the bottom 16, the momentum of the cannister 20 and the weight 22 cause the pin 46 to be sheared and the shaft 40 to be driven inwardly of the device 12 to the position illustrated in FIG. 3. That movement brings the cross-bar 42 into a position diametrically crossing the opening 32 in the cannister lid 30, thereby effectively preventing the standing portion of the line 14 from revolving about the shaft 40. Because of that condition and the fact that the bale 28 remains fixed relative to the shaft 40, the line 14 being pulled from the innermost layer of the bale will wrap about the shaft 40 until the turns 14a thereabout produce sufficient friction to prevent further pay-out. While rotation of the shaft 40 is generally precluded by the frictional engagement of the pad 44 with the weight 22, which engagement increases with increasing forces on line 14, the addition of one or more projections or tooth means 44a may be provided on the upper surface of the pad 44, or on the sides of the shaft 40, so as to bite into the lead weight and effect a more positive fixation of the shaft against rotation.

From the foregoing detailed description it will be recognized that the present invention has met the aforementioned objects and advantages, and in particular has provided a particularly reliable anchor device with a line pay-out arresting mechanism of the shaft wrapping type.

Obviously, other embodiments and modifications of the subject invention will readily come to the mind of one skilled in the art having the benefit of the teachings presented in the foregoing description and the drawing. It is, therefore, to be understood that this invention is not to be limited thereto and that said modifications and embodiments are intended to be included within the scope of the appended claims.