Abstract: A drag embedment normal load anchor ("Denla") comprises a fluke with a shank pivotally attached thereto, the shank including an anchor cable attachment point and control or restraint mechanisms whereby the shank can be set such that the cable attachment point can lie selectively in first, second, and third directions relative to the fluke centroid, the directions providing three fluke centroid angles (.alpha., .beta., and .theta., respectively) with the fluke forward direction (F). The Denla is part of an anchoring apparatus including a rear drogue line serving to orientate the anchor correctly at the sea bed without the need for a separate pendant line. In operation, the Denla is embedded by pulling on an anchor cable with the first fluke centroid angle .alpha. present; when the desired horizontal anchor loading is achieved, the shank is moved to the second larger centroid angle .beta.

Abstract: A chain joining link (1) having an assemblage of disaassemblable parts enabling the link (1) to be fitted on two adjacent chain sections, the assemblage having U-shaped end members (2) to retain said chain sections, the U-shaped members (2) including recesses (7) receiving flanges (4) whereby the members (2) are joined for assembly of the link. Each recess (7) has a width greater than that of the corresponding flange (4), and the width difference (gap) is accommodated by a wedge (8). The wedge (8) is fitted into the gap so as to preload the link by a predetermined amount and to this end the wedge (8) is first placed in the gap to a first position with no force fitting, and thereafter the wedge (8) is forced a predetermined distance from said first position to a second position so causing a compressive preload in the flange (4) and a tensile preload in the material surrounding the recess (7). Assembly is completed by the fitting of a columnar stud (15).

Abstract: A filter for treating liquids comprises an elongate housing having a liquid inlet port, an outlet port for concentrated liquid and a permeate discharge port. Extending through the housing is a parallel array of filter tubes, each having a permeable wall so that permeate passes into a common chamber defined by the housing. Manifold members, located at each end of the housing, are provided with channel means which communicate with the ends of the tubes. In use, the channel means direct the liquid along at least three passes through the tubes, the volume of liquid being reduced between the first and final passes so as to maintain the desired flow velocity. Each pass comprises a group of tubes, and the liquid may pass through seven or eleven groups of tubes.

Abstract: This inductive power transfer system provides a capacitor (15) having a pickup coil (14) in series between the windings of the pickup coil and the electrical load (16, 17, 18). A power-factor compensating capacitor (19) may be used at the feed to a loop of one or a few turns of primary inductor cable (11,12), so that a reasonable supply-mains current can maintain the primary inductor current. The length of the cable, and hence the impedance, of primary cable may be varied in order to match the primary inductor to the voltage of the supply mains.

Abstract: The invention includes selective amplification methods for enriching target nucleic acid sequences that are present in a first source of nucleic acid but absent from a second source of nucleic acid. These methods involve using phenol to enhance the rate of the hybridization step, as well as modifications for reducing the amounts of reagents required for the reactions. Also included are methods for identifying sequences shared by two or more populations of nucleic acids.

Abstract: A discoidal dynamo-electric machine has a discoidal stator carrying a number of meandering copper windings imbedded in a substrate having a magnetic permeability of less than 20 relative to air, and a discoidal rotor mounted on a central shaft so that the rotor can be positioned close to and rotates in a plane parallel to that of the stator. The rotor has a circular array of permanent magnets mounted on a backing plate of mild steel, each of the magnets having a trapezoidal or a truncated sector of a circle shape, the magnets being closely spaced around the rotor to provide a series of closely apposed and alternating permanent magnetic poles.

Abstract: A marine anchor has an anhedral fluke with a shank attached thereto including an anchor line attachment point. A rear plate assembly behind the fluke is inclined at an obtuse angle .alpha. to the fluke and serves to provide a turning moment about the attachment point countering turning moments produced by friction effect on the fluke and the shank and by edge resistance during anchor burial to give improved anchor holding power while soil escapes the passage between the rear assembly and the fluke allows escape of sand and soft mud passing over the fluke. Peripheral edges of the rear assembly are shaped to cause rolling of the anchor to a burial position. An upturned toe portion at the front of the fluke encourages effective anchor operation in clay soils while also facilitating rock gripping by the anchor.

Abstract: A marine anchor comprising a fluke and a shank attached to the fluke is intended for drag embedment in a mooring bed by pulling the anchor substantially horizontally via the shank. Further, it is a particular feature of the anchor that two modes of operation are possible through use of the line extending between the anchor cable attachment point on the shank and the fluke centroid being variable to provide a first line present for drag embedment of the anchor, and a second line utilized when the anchor is embedded, wherein the pulling force on the anchor via the shank can now be essentially upwards, thereby providing an increased holding force due to the increased fluke area presented in the direction of the upwards force. The change in direction from the first line to the second line can be achieved by having the shank pivotal and by providing pivot control members permitting selective pivoting of the shank.

Abstract: There is provided a tensioning device for pretensioning mooring lines in accordance with the tension-in-a-bight principle. The tensioning device is located at the bight of the mooring lines and includes a link catching device comprising inclined land surfaces and a catching tooth at the lower end of the land surfaces, which catching device catches a link, the caught link, of link chain during heaving up on a riser chain section so enabling the pretensioning to be achieved in the mooring line. Slots are provided in the tensioning device adjacent the land surfaces such that the downline link threading the caught link and the following downline link each have a significant degree of pivotal freedom to preclude bending moment loading in these links during heaving up on the riser line during tensioning.

Abstract: An anchor orientating device (1) to ensure that an anchor (2) comes over a ship's stern roller (3) on its back i.e. fluke outermost comprises an elongate body (4) carrying a transverse cordioid shaped cam (5) inclined backwardly on the body (4), the front of the body (4) being adapted for attachment to an anchor cable (7) and the rear, in substantial non-rotational manner, to an anchor. Reaction of the cam (5) with the roller surface causes device (1) to rotate so as to pivot the anchor to a fluke outermost position and to bring a stabilizing cam land (16) into engagement with the surface. The device (1) additionally includes a secondary reaction surface (20) which reacts with a smaller diameter bolster bar (21) of an anchor rack to further rotate the anchor and so enable the anchor fluke (2A) to engage the bolster bar (21) for anchor store.

Abstract: A marine anchor comprises a fluke with a shank attached to the fluke to enable the anchor to be joined to an anchor cable. Additionally there is provided a soil barrier plate located aft of the rear of the fluke but above the level of the fluke, with a soil passage between the barrier plate and the fluke. The barrier plate is set an angle to the fluke, and the barrier plate and the associated soil passage are arranged so as to function in a manner enabling the anchor to operate effectively and without adjustment in cohesive soils such as mud even when the fluke is set (say at an attack angle 0.degree. of 30.degree.) for optimum operation in non-cohesive soils such as sand, without substantially detracting from the performance of the anchor in non-cohesive (sand) soils.

Abstract: A marine anchor including a main fluke with a shank attached to the fluke. To enable the anchor to orientate on the sea bed from an inverted position to an upright working position, auxiliary flukes are supported by respective lugs upstanding from the fluke on either side of the anchor's vertical plane of symmetry. The auxiliary flukes extend laterally from the lugs and are inclined at an acute angle to the main fluke. The anchor includes support means arranged such that when the anchor lies inverted on a firm seabed one of the auxiliary flukes is located in position for digging in when the anchor is pulled forwardly.

Abstract: A chain comprises interconnected links with each link comprising opposed C-shaped ends joined by joining limb portions. Each C-shaped end includes a central crown with shoulders on either side of the crown, and by the present invention the section modulus about an axis perpendicular to the plane of the link of a cross-section at a shoulder is greater than the corresponding section modulus of a cross-section at the crown, and preferably additionally said section modulus of the section at the shoulder is greater than a corresponding section modulus of a cross-section at the associated joining limb portion.

Abstract: A joining shackle or link is provided for joining link chain sections and comprises a link shaped assemblage of members including a detachable member or members enabling the joining link to be fitted on the chain sections. Opposed U-shaped parts (1,2) of the assemblage have abutting flanges (3) provided with wedge surfaces (4)and the assemblage is held together by couplers (5) which preload the wedge surfaces and the flanges. This preloading of the joining shackle enables the shackle to better withstand cyclic loading. Two separate U-members (1,2) are preferably present and provide opposed pairs of abutting flanges (3), and the couplers comprise half shells (6) fitting over mid-portions of the U-members and drawable together by screws (8) for preloading of the flanges.

Abstract: A shank is provided for an anchor, which is in the form of a longitudinally extending double-plate girder with a transverse element joining the double plates. In accordance with the present invention, the transverse element is substantially spaced from the cable attachment end of the shank and is orientated with a positive attack angle so that the element can contribute to the burial force developed by the anchor. The above double-plate girder shank on the one hand provides increased resistance to bending moments in vertical and sideways directions and on the other hand enables satisfactory soil penetration by the shank due to the open construction. A plurality of the above transverse elements are preferably provided and form with the double plates passages diverging aft. The double-plate shank can be removably attached to the fluke.

Abstract: A locking system for locking a nut on a threaded shaft comprises a transverse through aperture in the shaft alignable with through apertures in the nut, and a pin extending between the aligned through apertures to lock the nut against rotation relative to the shaft. According to the present invention displaceable wedge means are located in a recess of the shaft and engage the pin to lock the pin against axial displacement. These wedge means preferably comprise a plastics plug with a waisted through aperture, the pin including a complementary necked portion. The locking system can be advantageously used with the nut and bolt of a shackle.

Abstract: An anchor includes a fluke attached to a shank having a forwardly located cable attachment point. The fluke includes concave side surfaces, and these side surfaces can serve to orientate the anchor to an upright burial position by interaction with the sea bed and to stabilize the anchor when buried in the sea bed. The fluke side surfaces are also arranged, either by relative orientation thereof or by the inclusion of a flat fluke portion interconnecting the side surfaces, such that, when the anchor is pulled through the sea bed, the peak pressure focus zone produced by the sea bed soil on interaction of the fluke with the soil is located clear of the shank and clear of the forward path of burial movement of the shank.

Abstract: A link chain, particularly for use as an anchor chain, comprises a plurality of links joined together in sequence, each link including a closed member comprising a pair of facing U-shaped portions, the base of the U at each end of the member having a portion of its inside surface of part cylindrical form, the cylindrical axes of said portions being arranged substantially transversely with one convex and the other concave so that the part cylindrical convex surface of one end of one link mates with one part cylindrical concave surface at the other end of a preceding link when the chain is straight under tension, and enables the chain to withstand greater loads, the U-ends being shaped to permit relative pivoting of the links about an axis substantially transverse to the plane of the link.

Abstract: In the placement of an anchor in the sea bed for mooring of a vessel a chaser in the form of a loop or hook is attached to a service line and the chaser is positioned on the anchor to support the anchor. A service vessel with the service line secured thereto pulls the anchor and anchor chain from the parent vessel to be moored and simultaneously lowers the anchor to the sea bed via the service line. The anchor is subsequently set in the sea bed for mooring and the chaser can then be removed from the anchor chain or returned up the chain to the moored vessel.To retrieve the anchor, the chaser is run down the anchor chain until it engages the anchor, and the service vessel then pulls the anchor from the sea bed by means of the service line and takes the anchor aboard. The anchor is then returned to the parent vessel.