WO2018002570A1

WO2018002570A1 - Vessel anchor assembly

Info

Publication number: WO2018002570A1
Application number: PCT/GB2017/000097
Authority: WO
Inventors: Benjamin Smedley COLLETT
Original assignee: Quintessence Yachts Bv
Priority date: 2016-06-30
Filing date: 2017-06-30
Publication date: 2018-01-04
Also published as: GB201611597D0; EP3478564A1; GB2551847A; GB2551847B

Abstract

A vessel anchor assembly (10) comprises an anchor arm (11) pivotable in use about a pivot axis (12) between an operative setting for lowering and raising an anchor and an inoperative setting for stowage of the anchor and an anchor (13) connected with one end of a flexible anchor line (16) which is movably guided in the length direction of the arm along a length section thereof. The line (16) is connectible at its other end to a windlass for unreeling and reeling up the line and for maintaining tension in the line (16) to keep the anchor (13) in abutment with the arm at a free end thereof. In order to counteract generation of slack in the line (16) during pivotation of the arm (11) from the operative to the inoperative setting the assembly includes guide means (19) guiding the line substantially through the zone of the pivot axis (12) thereby to maintain a substantially constant length of the line (16) between the pivot axis (12) and the connection of the line with the anchor (13) in and during pivotation of the arm between the operative and inoperative settings. As a result, line tension keeping the anchor (13) in abutment with the free end of the arm (11) is substantially maintained without compensatory movement of the line (16).

Description

VESSEL ANCHOR ASSEMBLY

The present invention relates to a vessel anchor assembly.

Anchors as used on watercraft of all kinds are conventionally retained by an anchor line in the form of a rope, cable, chain or other suitable flexible elongate coupling (in which sense the term "line" is to be understood in context of the present specification) which is let out and hauled in by way of a windlass, or other suitable rotary drum or spool functioning as a winch, to lower and raise the anchor. Although larger vessels traditionally store raised anchors against the hull, inboard stowage of anchors in anchor lockers has been the general practice for smaller vessels. This has led to the use of motor-driven swing arms designed to move anchors between an inboard stowed position and an outboard position at which the anchor can be lowered. Pivotation of the arm between the two anchor positions typically involves travel through a range of more than 90, but less than 180 degrees. The anchor in the outboard position is suspended at a free end of the arm by the attached anchor line leading to the windlass, the arm thus serving as a jib.

A problem with existing anchor assemblies having swing arms of such a kind is that the heavy and usually pronged anchor is held, except when it is lowered, against the arm by the tension in the line attached to the anchor and spooled at the windlass. This applies when the arm is pivoted in direction from the outboard anchor position at which the anchor can be lowered and raised and the inboard anchor position at which the anchor can be stowed. The arm pivotation in this direction creates slack in the line which would necessitate running the windlass to remove the slack and restore or maintain tension, failing which the anchor would drop under its own weight away from the arm. The complication involved in running the windlass in synchronism with the separately actuated arm pivotation and the risk represented by an unsecured and possibly flailing anchor, which could cause significant damage or even injury, has led to the practice of securing the anchor to the arm by a manually insertable and removable locking pin. This manual action has to be undertaken on every occasion the anchor is lifted up to the arm and equally on every occasion the anchor is readied for lowering. Apart from the laborious nature of this task, the risk of forgetting to insert the pin and lock the anchor could have the undesirable consequence of the anchor being able to come away from the arm during pivotation unless the line tension is constantly adjusted.

An example of a prior art anchor assembly employing a pivotable anchor arm and with a spring-assisted line tensioner to counteract line slack induced by arm pivotation is disclosed in GB 2339181 A. Other designs of pivotable anchor arms are disclosed in, inter alia, EP 1 852 345 B1 , US 2975748 A, US 4526123 A, US 3974793 A, US 4057025 A, US 3074370 A, US 3865065 A, US 2931331 A and WO 2010/08772 A.

It is therefore the primary object of the present invention to address this issue and improve an anchor assembly, of the kind structured on the described principle of an anchor carried and moved by a swing arm, in the respect of eliminating the risk of uncontrolled anchor drop without resort to a locking pin, a spring tensioner or other extraneous measure.

Other objects and advantages of the invention will be apparent from the following description.

According to the present invention there is provided a vessel anchor assembly comprising an anchor arm pivotable in use about a pivot axis between an operative setting for lowering and raising an anchor and an inoperative setting for stowage of the anchor, an anchor connected with one end of a flexible anchor line which is movably guided in the length direction of the arm and which is connectible at the other end with means for paying out and hauling in the line and for maintaining tension in the line to keep the anchor in abutment with the arm, and guide means guiding the line substantially through the zone of the pivot axis thereby to maintain a substantially constant length of the line between the pivot axis and the connection of the line with the anchor in and during pivotation of the arm between the operative and inoperative settings so that line tension keeping the anchor in abutment with the arm is substantially maintained without compensatory movement of the line.

Such an anchor assembly dispenses with the need for a locking pin or similar securing device to fix the anchor to the arm during pivotation of the arm, thereby eliminating an inconvenient manual intervention in the process of movement - which can be automated such as by motor-driven pivotation of the arm - of the anchor between outboard and inboard stations respectively associated with the operative and inoperative settings of the arm. Also eliminated is the associated risk of inadvertent omission to fit the securing device. Accordingly, the vessel and occupants are safeguarded from uncontrolled movement of an anchor following unintended separation from the free end of the arm. Retention of the anchor in position at this end of the arm is instead achieved by a specific disposition of the line to run in the length direction of the arm and then through the zone of the pivot axis of the arm, in particular to cross or nearly cross that axis, as a result of which a substantially constant length of the line along the arm is maintained during pivotation. Consequently, for a given line tension holding the anchor against the free end of the arm the anchor is unable to depart or depart to a significant extent from this position due to line slack arising during pivotation of the arm from the operative setting to the inoperative setting. Conversely, in the case of pivotation in the opposite sense there is no undue tautening or significant tautening of the line. No adjustment or movement of the line to accommodate induced slack or tautening, in particular adjustment by driving a windlass or other winch equipment responsible for setting and maintaining line tension, is necessary in order to ensure that the anchor does not depart or significantly depart from its position against the arm when the arm is pivoted. The disposition of the line to intersect or closely pass by the pivot axis of the arm is achieved simply by appropriate line guidance along a prescribed path.

In a preferred embodiment of the anchor assembly the guide means produces bending of the line during pivotation of the arm between the operative and inoperative settings and the anchor is pivotable about a fulcrum at the arm during the pivotation of the arm so as to substantially absorb any change in line length which might occur due to bending and unbending of the line. This is relevant to, especially, an anchor in which the line is connected therewith at a spacing from the abutment of the anchor with the arm so as to create a lever arm in the anchor between the point of abutment and point of connection, in which case the fulcrum can conveniently be provided by the point of abutment. Thus, if the guide means produces reverse bending of the arm the anchor may undergo an oscillatory pivot movement or rocking during pivotation of the arm, which may enable absorption of any line length change by slight motion of the anchor without risk of departure from the arm.

If the guide means guides the line so that the longitudinal axis thereof precisely intersects the pivot axis of the arm and if the line undergoes bending deflection in the vicinity of that axis - such bending depends on, especially, the line orientation downstream of the assembly and whether that orientation is variable or invariable - the length of the line between the stated reference points of arm pivot axis and point of connection of the line with the anchor may undergo a small fluctuation during the pivotation, thus departure from a strictly constant length. Such a departure from strict constancy of the line length between these reference points may be tolerable if it is small in amount and it may in any case be absorbed by the above-mentioned possibility of pivotation of the anchor. For preference, however, if the guide means produces bending of the line during pivotation of the arm between the operative and inoperative settings then the line in that case can be guided in the zone of the pivot axis so that the longitudinal axis of the line passes through a point offset relative to the pivot axis substantially in a direction away from a free end of the arm in a setting of the arm intermediate the operative and inoperative settings so as to counteract the change in the line length due to bending and unbending of the line. It may thus be possible to eliminate or minimise departure of the line length from strict constancy. The amount of the offset is preferably dependent on the radius and arc length of bending of the line and can be determined by reference to, in particular, given geometric parameters of the guide means and also the line. In a typical arrangement of the guide means appropriate to an anchor line of suitable diameter (maximum diameter if the line is a chain composed of links) and thus strength for carrying a vessel anchor and also appropriate to guidance of the line with a radius of bending avoiding creation of undue bending stress, the offset can be approximately equal to at most the radius of bending of the line.

In that connection, the guide means preferably comprises two curved guide surfaces arranged to guide the line therebetween, the curvature of the guide surfaces providing bending deflection of the line in the zone of the pivot axis of the arm. For preference the guide surfaces are so arranged that the line runs therebetween substantially at a right angle relative to the line direction along the arm when the arm is in the operative setting thereof. Such a guide surface configuration referred to the arm operative setting imposes a change in direction on the line run, which, depending on the coefficient of friction between guide surface and line and the extent of the change in direction may contribute to maintenance of tension in the line. Any friction contributing to tension should not, however, be such as to impede movement of the line over the guide surfaces under operation of a windlass or other form of winch employed to move the line. Depending on the guide surface radius and line orientation downstream of the guide means, thus between anchor assembly and an associated windlass, the line when passing through the guide means may primarily or exclusively engage just one of the guide surfaces or may engage both surfaces in succession. The line looping angle of that one guide surface or of both guide surfaces, i.e. angle of wrap, will similarly depend on, inter alia, the geometry of the guide surfaces (radius of curvature of the guide surfaces, spacing of the guide surfaces, etc.) and on the downstream line orientation.

The guide means can be provided in various forms, particularly rotary guide means rather than purely sliding guide means, although the latter is possible provided the line has a free- running capability. However, for preference the curved guide surfaces are formed by circumferential surfaces of two rotary guide elements. The elements can thus rotate to minimise friction in relation to the line. The guide elements are preferably pulleys which, if flanged rollers, are particularly suitable for guidance of a line in the form of, for example, a chain and which can be arranged in juxtaposition to define a relatively narrow passage, such as a passage with a maximum cross-sectional dimension not significantly greater than the line diameter or, in the case of a chain, maximum diameter. In a preferred embodiment the arm is pivotable relative to the guide means, the latter thus being separate from the arm and, in particular, disposed in a fixed position relative to a mount - which ultimately represents a static part of a vessel - for the pivot arm. This ensures that the guide means can be more readily positioned to minimise undesired influence on the line, especially slight change in line length, arising from change in angle of wrap around a guide pulley or guide pulleys. In that case, with advantage the arm defines a slot at an end thereof remote from a free end of the arm, the guide means being received at least partly in the slot. This not only protects the guide means, but facilitates alignment of the guide means with the path of the line along the arm. It is then convenient if the arm comprises two mutually spaced-apart and fixedly interconnected elongate side members, the slot being defined by a space between the members. Such an arm is thus of fabricated construction, but it is equally possible for the arm to be of integral construction.

For preference, the pivot axis is defined by two coaxial axles each connected with a respective one of the side members, whereby the space forming the slot for reception of the guide means is free from intrusion by an axle. One of the axles is preferably connected with drive means for pivoting the arm, so that pivotation of the arm is mechanised and the torque required for that purpose is introducible directly into the axle arrangement. The drive means can conveniently comprise a pinion connected with said one of the axles and a rack drivingly coupled to the pinion, preferably a hydraulically operated rack-and-pinion system, but other forms of drive are equally possible.

The arm preferably includes a plurality of spaced-apart rotatably mounted pulleys to guide the line along the arm when the anchor is lowered from and raised back to the arm. In that case at least one of the pulleys can act to guide and support the line when the anchor is in abutment with the arm. For preference, the pulleys mounted on the arm define a guide path for the line substantially along a longitudinal axis of the arm, so that the line can effectively be enclosed in the arm and shielded in at least some directions from the possibility of contact with foreign objects.

In a further aspect, there is provided a vessel equipped with an anchor assembly according to the invention. For preference, the assembly is mounted in a below-deck locker of the vessel in the bow thereof so that the assembly can be safely positioned and out-of-sight when the arm is in its inoperative setting. The line can be guided in the locker by at least one pulley arranged below the anchor assembly, so that the line can depart from the guide means of the assembly in a predetermined desired direction. A preferred embodiment of the present invention will now be more particularly described by way of example with reference to the accompanying drawings, in which:

Fig. 1 is a schematic side view of an anchor assembly embodying the invention, showing a pivotable anchor arm of the assembly in one of two end settings, in particular a setting associated with an outboard position for an anchor carried by the arm;

Fig. 2 is a view similar to Fig. 1 , but simplified and showing the anchor arm in a setting intermediate the two end settings;

Fig. 1 is a view similar to Fig. 1 , but again simplified and here showing the anchor arm in the other one of the two end settings, in particular a setting associated with an inboard position for an anchor carried by the arm; and

Fig. 4 is a schematic plan view, to an enlarged scale, of the lefthand part of the assembly of Fig. 1.

Referring now to the drawings there is shown an anchor assembly 10 intended for use primarily, but not exclusively, with smaller and medium-size watercraft such as yachts, launches and other such vessels. The assembly comprises an anchor arm 11 pivotable at one end thereof about a pivot axis 12, in particular through a range of up to about 180 degrees between an operative setting shown in Fig. 1 and an inoperative setting shown in Fig. 3. The arm 11 carries an anchor 13, which bears against the other or free end of the arm and which consists of a bed-engaging fluke part and a lever part fixed to the fluke and extending back along the arm. When the anchor assembly 10 is installed in a vessel (not shown) the operative setting of the arm corresponds with an anchor outboard setting in which the anchor 13 can be lowered and raised and the inoperative setting of the arm corresponds with an anchor inboard setting in which the anchor 13 can be stowed safely and out of sight. In the operative setting, the arm 11 will rest on a supporting part of the vessel, such as by way of a support yoke (not shown) attached to the arm. The assembly is intended for mounting in the bow of a vessel so that the anchor 13 can be raised and lowered directly in front of the prow. Mounting of the assembly is in a below-deck anchor locker in which the anchor 13 is stowed in the inboard setting, the locker being covered by openable and closable hatches.

The anchor arm 11 can be an integral machined component, but here is a fabricated construction from stainless steel. In the illustrated embodiment the arm 11 is composed of two spaced-apart and rigidly interconnected elongate side members 11a and 1 b bounding a space which receives the lever part of the anchor 13. At the pivoted end of the arm 11 the space between the side members 1 1 a, 1 1 b defines a slot having a purpose which is indicated further below. As shown in Fig. 4, the side members 11 a, 11 b are outwardly stepped in the region of the slot so that the width of the slot is sufficient to accommodate standard-size components of the same dimensions as those able to be accommodated in the space between the side members 11 a, 1 1 b along the rest of the arm 11.

The pivot axis 12 is defined by two mutually spaced coaxial axles 12a and 12b each rigidly connected, such as by way of screws, to a respective one of the side members 11 a and 1 1 b of the arm 11 via a circular flange. Each axle 12a, 12b is rotatably journalled, such as by a plain bearing, in a respective one of two spaced-apart mounting plates 14a and 14b, only part of each of which is shown in Fig. 4. The mounting plates 14a, 14b are fixed relative to one another and fixable to a part of a vessel in which the anchor assembly is fitted, in particular in the afore-mentioned anchor locker of the vessel. The righthand axle 12b in Fig. 4 is of two-part construction and comprises a sleeve fixed to the side member 11 b of the arm 1 by way of the associated circular flange and an axle shaft engaged in the bore of the sleeve and keyed to the sleeve, the axle shaft being journalled in the mounting plate 14b. The shaft is drivingly connected with a pivot drive 15 in the form of a pinion 15a fixed to the free end of the shaft and a rack 15b meshing with the pinion 15a and mounted on, for example, a bracket (not shown) secured to the adjoining mounting plate 14b. The rack is displaceable by hydraulic pressure to pivot the arm 11 together with the anchor 13 between the end settings of Figs. 1 and 3 and intermediate settings such as that of Fig. 2. Such drives are available as proprietary actuators for various purposes, but other forms of drive - including electrical and pneumatic - are equally possible provided the drive has sufficient power to cope with the combined weights of the moving parts of the assembly.

The described parts included in the pivotation arrangement for the arm 11 are preferably all constructed from stainless steel or other appropriate corrosion-resistant material.

The anchor 13 is pivotably connected at the free end of its lever part with one end of a flexible anchor line 16 movably guided along a length section of the arm 11 , in particular a length section including the pivot end of the arm, and downwardly away from the assembly at the pivot end of the arm as described further below. The line 16 has a longitudinal axis 16a and for the sake of clarity is represented in Figs. 2 and 3 simply by this axis. The line is guided approximately along or close to the longitudinal axis of the relevant length section of the arm 16 so that this axis can be coincident, at least to some degree, with the axis 16a of the line. The line 16 can be, for example, a cable, rope or chain; here it is a chain, as indicated by links 16b in Fig. 4. In Fig. 4, the plan area occupied by the line 16 is denoted by dashed lines.

For guidance of the line 16, particularly when the anchor is raised and lowered, the arm 1 1 includes a plurality - here five - of pulleys 17 rotatably mounted between and at intervals along the side members 11a and 11 b of the arm. In that case, the pulleys 17 can be rotatably mounted on axle spindles which also serve to rigidly connect the side members 11 a and 11 b together. Each pulley 17, which is preferably an injection-moulded body of wear-resistant plastics material, consists of a centre cylinder and two outlying chamfered end flanges, but other constructions are equally possible. Equally possible is the use of rollers in place of pulleys or even simply slide surfaces. A combination of different forms of line guide elements, such as rotary elements and slide elements, is also feasible, but flanged pulleys are preferred from the aspects of low-friction guidance of the line and confinement of the line to a desired path. The pulleys are represented in Fig. 1 simply by the centre cylinders and in Figs. 2 and 3 merely by the axes of rotation of the pulleys. A complete pulley 17, which is preferably a proprietary component of selected standard dimensions, is shown at the top in Fig. 4.

Apart from line guidance during raising and lowering the anchor the pulley 17 closest to the pivot end of the side members 11 a, 11 b provides substantially constant guidance of the line 16, i.e. even when the anchor 16 is raised and bearing against the free end of the arm 11. The pulley 7 furthest from the pivot end of the side members, thus the pulley at the free end of the arm, protrudes slightly from the side members as shown in Fig. 1 and forms an abutment for the anchor 16, specifically the fluke part of the anchor, when the anchor bears against that free end. This abutment also represents a fulcrum about which the anchor 16 is capable of slight pivot movement, including rocking movement, as indicated further below. All or individual ones of the pulleys 17 apart from that closest to the pivot axis 12 also serve to support the lever part of the anchor in the operative setting of the arm (Fig. 1) and at least in settings before the arm swings over-centre towards the inoperative setting.

The line 16 is guided at the pivoted end of the arm 11 by guide means constructed as explained further below. The guided line departs from the assembly 10 to enter, in the installed state of the assembly as alluded to above, the anchor locker, where it is conducted to an electrically powered windlass or similar winch. The windlass is operable to pay out the line to drop the anchor 13, i.e. allow it to fall away from the free end of the arm 1 1 in the operative setting of the arm, and to haul in the line to raise the anchor and bring the anchor, specifically the fluke part of the anchor, into abutment with the free end of the arm as represented by the protruding part of the pulley 17 at that end, against which the anchor can be held simply by tension in the line. The tension is exerted by the windlass, which is locked against rotation of its drum. In the anchor locker, the line is guided in its route to the windlass by way of one or more pulleys 18, two of which are shown in Figs. 1 to 3 (represented in Figs. 2 and 3 simply by axes of rotation). These pulleys are, as evident from Figs. 1 to 3, disposed in fixed locations. However, they could mounted to be variable in position to influence line guidance downstream of the anchor assembly 19, thus in the anchor locker. The pulleys 18 are not part of the anchor assembly as such, but depending on their position can have an influence on the line guidance within the assembly inasmuch as they predetermine the direction of departure of the line from the assembly.

In order to ensure guidance of the line 16 in such a way as to avoid or substantially avoid creation of slack during pivotation of the arm 1 from, in particular, the operative setting to the inoperative setting the anchor assembly 10 includes guide means 19 for constrained guidance of the line 16 on a defined path in the region of the pivot end of the arm. The guide means 19 is provided separately from the arm and intended to be mounted in a stationary position in the vessel, here in the anchor locker. For this purpose the guide means 19 comprises two spaced-apart mounting cheeks 19a fixed relative to one another and extending in the slot defined in the region of the pivot end on the arm 11 by the spaced side members 1 a, 1 1 b. Two guide pulleys 19b, which are of the same or substantially the same size, shape and construction as the arm pulleys 17, are rotatably mounted between the cheeks 19a and bound a guide passage through which the line 16 passes prior to departure from the assembly 10 towards the pulleys 18 in the locker, as shown in Figs. 1 to 3.

As can be seen in Fig. 1 , in the installed state of the assembly including the guide means 19 the pulleys 19b are arranged at an angle to the horizontal on a path which, when the arm 1 1 is in in its operative setting, is approximately parallel to the longitudinal axis of the end section of the arm containing the pivot axis 12 of the arm. The pulleys 19b accordingly guide the anchor line 16 through the zone of the pivot axis 12. As a consequence, the length of the line 16 along the arm 1 1 remains substantially constant in all angular settings of the arm, thus the operative and inoperative settings and all intermediate settings. This constancy of length prevents creation of any slack or of slack to a meaningful degree in the line 16 during pivotation of the arm 1 from the operative to the inoperative setting, so that the fluke part of the anchor 13 remains in abutment with the free end of the arm 1 during this pivotation, in particular held in place solely by tension in the line 16. The tension is generated by pull on the cable exerted by the windlass in a static state, i.e. with the drum of the windlass locked in a rotational setting in which it holds the anchor 13 against the free end of the arm 1 .

The zone of the pivot axis 12 through which the line 16 is guided by the guide means 19 is a region including and lying adjacent to the axis, i.e. the line 16 passes through that axis or closely by the axis. If the line intersects the axis, but is bent by the guide means - as is the case here with the path of the line passing partly around the pulleys 19b on the way to the fixed-position locker pulleys 18 - the length of the arm can vary slightly as the arm pivots and the degree of bending of the line 16 changes, here from bending in one direction to bending in the reverse direction and inclusive of an intermediate state without bending as evident from comparison of Figs. 1 , 2 and 3. The slight change in the length of the line 16 in this area is represented by the difference in the line length in unbent state and maximum bent state as determined by the radius of the centre cylinder of either pulley 19b and angle of wrap around that cylinder. Depending on these parameters the change in line length may be insufficient to cause significant change in the line tension, so that the length of the line along the arm remains constant in the sense that the anchor 13 when held against the free end of the arm does not depart from this position. However, compensation for slight change in line length due to bending and unbending of the line under pivotation of the arm can be provided or provided to a substantial degree by guiding the line so that it passes not directly through the arm pivot axis 12, but through a point 20 offset slightly from the axis in a direction away from the free end of the arm in the setting intermediate the operative and inoperative settings, i.e. the intermediate setting shown in Fig. 2. The amount of offset can be calculated by reference to the maximum change in line length that can be produced by the given geometric parameters of line thickness, radius of the centre cylinder of either guide pulley 19b and maximum angle of wrap around that cylinder and typically is approximately a third to a half the cylinder diameter, in effect equal to at most the radius of the cylinder or, stated differently, the radius of bending of the line 16 around the curved circumferential surface of the cylinder.

In addition, to the extent that any change in length of the line 16 between the pivot axis 12 and the point of connection of the line with the anchor 13 might occur, i.e. any slight departure of this length from a strictly constant value, this change may be capable of absorption by pivot movement of the anchor about the fulcrum represented by the protruding pulley 17 at the free end of the arm 11. The pivot moment is initiated by gravitational force, i.e. the anchor weight, in conjunction with relaxation in line tension due to change in line length between the reference points of pivot axis and point of line connection with the anchor. Thus, in the example of movement of the arm 11 from the inoperative setting of Fig. 3 to the intermediate setting of Fig. 2 the line might be capable of lengthening as it unwraps from the lefthand pulley 19a, allowing the anchor to pivot in one rotational sense about the fulcrum at the end of the arm. When the arm moves from the intermediate setting of Fig. 2 to the operative setting of Fig. 1 the line might then shorten again as it wraps around the righthand pulley 19a, allowing the anchor to pivot in the opposite rotational sense about the fulcrum. This rocking or oscillatory pivot motion of the anchor may accommodate the slight relaxation and tautening of the line during transition from maximum bending deflection in one sense to maximum bending deflection in the other sense and with a progressively changing degree of deflection therebetween.

An anchor assembly embodying the present invention offers the significant advantage that through the simple expedient of defined guidance of the anchor line retaining the anchor the anchor can be held against the anchor arm by the line tension alone during pivotation of the arm without slack in the line leading to uncontrolled departure of the anchor from the arm. The need for a manually insertable locking pin to secure the anchor to the arm is removed and operation of the arm to move the anchor between inboard and outboard positions is thus made faster and, through elimination of manual intervention into an automated process, ultimately safer.

Claims

1. A vessel anchor assembly comprising an anchor arm pivotable in use about a pivot axis between an operative setting for lowering and raising an anchor and an inoperative setting for stowage of the anchor, an anchor connected with one end of a flexible anchor line which is movably guided in the length direction of the arm and which is connectible at the other end with means for paying out and hauling in the line and for maintaining tension in the line to keep the anchor in abutment with the arm, and guide means guiding the line substantially through the zone of the pivot axis thereby to maintain a substantially constant length of the line between the pivot axis and the connection of the line with the anchor in and during pivotation of the arm between the operative and inoperative settings so that line tension keeping the anchor in abutment with the arm is substantially maintained without compensatory movement of the line.

2. An assembly according to claim 1 , wherein the guide means produces bending of the line during pivotation of the arm between the operative and inoperative settings and the anchor is pivotable about a fulcrum at the arm during the pivotation of the arm so as to substantially absorb any change in line length which might occur due to bending and unbending of the line.

3. An assembly according to claim 2, wherein the guide means produces reverse bending of the arm and the anchor undergoes an oscillatory pivot movement during pivotation of the arm.

4. An assembly according to any one of the preceding claims, wherein the guide means produces bending of the line during pivotation of the arm between the operative and inoperative settings and guides the line in the zone of the pivot axis so that the longitudinal axis of the line passes through a point offset relative to the pivot axis substantially in a direction away from a free end of the arm in a setting of the arm intermediate the operative and inoperative settings so as to counteract change in said line length due to bending and unbending of the line.

5. An assembly according to claim 4, wherein the amount of the offset is dependent on the radius and extent of bending of the line.

6. An assembly according to any one the preceding claims, the guide means comprising two curved guide surfaces arranged to guide the line therebetween.

7. An assembly according to claim 6, wherein the guide surfaces are so arranged that the line runs therebetween substantially at a right angle relative to the line direction along the arm in the operative setting thereof.

8. An assembly according claim 7, wherein the guide surfaces are provided by circumferential surfaces of two rotary guide elements.

9. An assembly according to claim 8, wherein the guide elements are pulleys

10. An assembly according to any one of the preceding claims, wherein the arm is pivotable relative to the guide means and defines a slot at an end thereof remote from a free end of the arm, the guide means being received at least partly in the slot.

11 An assembly according to claim 10, wherein the arm comprises two mutually spaced- apart and fixedly interconnected elongate side members, the slot being defined by a space between the members.

12. An assembly according to claim 11 , wherein the pivot axis is defined by two coaxial axles each connected with a respective one of the side members.

13. An assembly according to claim 12, wherein one of the axles is connected with drive means for pivoting the arm.

14. An assembly according to claim 13, the drive means comprising a pinion connected with said one of the axles and a rack drivingly coupled to the pinion.

15. An assembly according to any one of the preceding claims, wherein the arm includes a plurality of spaced-apart rotatably mounted pulleys to guide the line along the arm when the anchor is lowered and raised.

16. An assembly according to claim 15, wherein the pulleys of the arm define a guide path for the line substantially along a longitudinal axis of the arm.

17. A vessel equipped with an anchor assembly according any one of the preceding claims.

18. A vessel according to claim 17, wherein the assembly is mounted in a below-deck locker of the vessel in the bow thereof.

19. A vessel according to claim 18, wherein the line is guided in the locker by at least one pulley arranged below the anchor assembly.