GB2091188A - Single fluke anchor - Google Patents

Abstract

A single fluke anchor for ships, structures floating on or in the water, buoys, fishing nets and the like comprising a fluke 2 formed integral to a shank 1, a stabiliser 3 located behind the fluke and formed integral with the fluke and perpendicular to the shank, and triggers 6 arranged integral to the both sides of the curved portion of the shank, whereby big holding power can be provided together with operation easiness. <IMAGE>

Description

SPECIFICATION Single fluke anchor This invention relates to anchors, Stock anchors are of the type having flukes arranged on both sides of the base of a shank and a long stock arranged at the foremost end portion of the shank and perpendicular to the shank.

Different from the stock anchors, those having a single fluke are called single fluke anchors. The conventional single fluke anchor seems like large letter "J" or fishhook and has a long big stock arranged atthe upper end of the shank and perpendicular to the shank so as to gain stably holding power for holding and mooring an object floating on or in the water, said holding power representing the force with which the anchor moors the object.

The conventional single fluke anchors like this are good in stability and have good holding power, but with the drawback that the fluke cannot be readily forced into the sand on the sea bottom when the anchor lies on its side or back and the "setting" of the anchor is more difficult. Furthermore the weighing of the anchor is also troublesome.

A single fluke anchor having good holding power and which is stable and easy to lay is desirable for the mooring structures floating on or in the water such as small boats and oil rigs, buoys and fixed fishing nets.

According to the present invention, there is provided an anchor comprising a shank having a curved portion disposed in a plane a fluke formed integral with said shank at an extremity thereof a stabiliser formed integral with said fluke and extending substantially perpendicular to the plane of said shank, and trigger portions disposed substantially perpendicular to the plane of said shank whereby the trigger portions cause or allow the anchor to lie on the sea bed so that when a pull is exerted on the shank, the fluke will dig in to set the anchor.

An object of the present invention is therefore to provide a single fluke anchor excellent in its holding power and stable at the time of mooring.

Another object of the present invention is to provide a single fluke anchor capable of being always returned to its normal position even when anchored in wrong position.

A further object of the present invention is to provide a single fluke anchor easy to anchor and to further draw after anchored.

A still further object of the present invention is to provide a single fluke anchor useful for vessels, particularly small ones.

A still further object of the present invention is to provide a single fluke anchor useful for structures built on the sea bottom or floating on or in the water, buoys, fishing nets, fixed fishing nets and the like.

A still further object of the present invention is to provide a single fluke anchor excellent in strength.

Following is a description by way of example only and with reference to the accompanying drawings of methods of carrying the invention into effect.

In the drawings; Figure lisa plane view showing a single fluke anchor of the present invention.

Figure 2 is a side view of the anchor shown in Figure 1 and showing the anchor embedded in the sand particularly on the sea bed.

Figure 3 is a view taken from the bottom of the anchor shown in Figure 1 Figure 4 is a front view of the anchor shown in Figure 1 and showing the anchor embedded in the sand on the sea bed similarly as in Figure 2.

Figure 5 is a view showing how the single fluke anchor of the present invention is operated.

Figure 6 is a plane view showing another single fluke anchor of the present invention.

Figure 7 is a side view of the anchor shown in Figure 6.

Figures 1 through 4 show the whole of a single fluke anchor A of the present invention, respectively, and the anchor includes a "J" or fishhook-shaped shank 1 when viewed from the side thereof, and a fluke 2 formed integral to the lower end of the shank 1, said fluke having a tip portion 2a terminating in a point and an edged rim (2b) extending rearwardly therefrom. Formed integral to the base of the fluke 2 is a stabiliser 3 having substantially the same area as the surface area of the fluke 2 and extending perpendicular to the shank 1; the angle defined by the plane containing the rim 2(b) of the fluke 2 and stabiliser 3 (see Figure 2) (angle a) is preferably about 140".

The anchor of the present invention has such arrangement that the J-shaped shank 1 is formed integral to the centre of the fluke 2. As shown in Figure 2, the angle P of the fluke 2 relative to the horizontal line h of the anchor A is about 25 degrees.

The end of the shank 1 has a through bore to receive the pin 5 of shackle 4 for the attachment of an anchor chain or rope.

The curved portion R of the shank 1 carries a pair of laterally extending triggers 6 and 6' together having an area about half the surface area of the stabiliser 3. Triggers 6 and 6' are formed integral with said shank 1 and are preferably inclined to the horizontal line h of the anchor A at an angle of 60 degrees (angle"). The two-dotted wave line shown in Figures 2,4 and 5 represents the sand surface Eon the sea bed and the anchor A embedded in the sand as shown in Figures 2 and 4 serves to moor an object.

In whatever position it may be anchored and in whatever direction force may be directed to the shackle 4 attached to shank 1, the anchor A of the present invention allows its fluke 2 to be forced into the sand on the sea bed to hold and moor a vessel.

Since fluke 2 is spaced remote from the shank 1 and is large in its surface area, it is capable therefore of cutting deeply into the sand on the sea bed. Once in such a condition, the anchor A of the present invention is stabilised by the stabiliser 3 against any undesired big force applied to the anchor thus providing high stability and good holding power.

Even when anchored with its side or back on the sand or turfed to cause its side or back to be on the sand by a stepped portion on the sea bed at the time of being laid, the anchor A will instantly turn to its normal position to hold and moor the vessel because the force applied to the curved portion R of the shank 1 when the anchor is further pulled in the forward direction causes the whole of the anchorto be rotated to its normal position.

When axes x andy are plotted relative to the anchor A as shown in Figure 5 and an axis z is further imagined vertical to the drawing surface with the centre of the anchor ring 4 located on the axis z, the whole of the anchor A is always forced to return to its normal position by the arrangement of the anchor A in spite of the angle 0 of the anchor shifted from its normal position.

This is achieved particularly by the stabiliser 3 and triggers 6, 6'. When the anchor A is capsized as shown in Figure 5 the unstability angle 6, i.e. the angle through which the anchor must rotate to its normal position is made about 120 degrees. The application of a load on the shank 1 results in stabiliser 3 contacting with the sand surface E. When further pulled in the forward direction, the anchor A is rotated cutting into the sand because the stabiliser 3 if formed to have the angle a relative to the fluke 2.

When the anchor A is rotated to reduce angle H to about 90 degrees, the stabiliser 3 is made approximately parallel to the line F (see Figure 2) in which direction the anchor A is pulled, thus making smaller the force applied to the stabiliser 3 to cause the whole anchorAto difficultly return to its normal position. However, the triggers 6 and 6' having the angle y relative to the anchor A and arranged reverse to the stabiliser 3 cause the whole anchor A to generate resistance and prevent the stabiliser 3 from being made parallel to the line F of the anchor A to induce the action of the stabiliser 3, thus applying to the shank 1 a force for turning the whole anchor Ato its normal position and forcing the fluke 2 to cut deeply into the sand.The stabiliser 3 now serves to hold the whole anchor A in such a way that the anchor A can hold and moor a vessel with maximum holding power.

The anchor A of the present invention can cut reliably into any kind of soil on the sea bed such as sand, mud and clay and has high reliability since it always operates when anchored. It has been found that even when initially laid on its side or back on the sea bed, the anchor A rotates to allow its fluke 2 to be forced into the sand on the sea bed by pulling the anchor A a distance of about two times the length of the shank 1.

When anchoring, it is sufficient to throw the anchor A in the water without considering the throwing shape and direction thereof.

The length of the mooring rope connected to the shackle 4 of the anchor A can be substantially shorter being only 2.5 times the depth of water.

The action of the stabiliser 3 and triggers 6, 6' serves to prevent the anchor A from being too deeply set into the sand on the sea bed, thus making it easy to pull the anchor A over the water.

The anchorAofthe present invention can be made integral of iron, so that it is excellent in strength and easy to make.

Figures 6 and 7 show another anchor of the present invention in which one end following the curved portion R of the shank 1 is made broader in the side thereof and the stabiliser 3 is within the width of the broad side when viewed from the side of the anchor, thus making it easy to attach the stabiliser 3 to the shank 1.

Claims (8)

1. An anchor comprising a shank having a curved portion disposed in a plane a fluke formed integral with said shank at an extremity thereof a stabiliserformed integral with said fluke and extending substantially perpendicular to the plane of said shank and trigger portions disposed substantially per pendicularto the plane of said shank whereby the trigger portions cause or allow the anchor to lie on the sea bed so that when a pull is exerted on the shank, the fluke will dig in to set the anchor.

2. An anchor as claimed in claim 1 wherein the fluke is disposed in a plane substantially transverse to the longitudinal axis of the shank.

3. An anchor as claimed in claim 1 or claim 2 the stabiiisers are disposed atan angle to the plane containing the fluke.

4. An anchor as claimed in claim 3 wherein the stabilisers have a surface area substantially the same as that of the fluke.

5. An anchor as claimed in claim 4 wherein the angle is between 135" and 145".

6. An anchor as claimed in any preceding claim wherein trigger portions are inclined at an angle of 50" to 70" to the longitudinal axis of the shank.

7. An anchor as claimed in any preceding claim wherein each trigger portion has a surface area substantially 50% of that of each stabiliser.

8. An anchor as claimed in claim 1 and substantially as described with reference to and as illustrated in Figures 1 to 7 of the accompanying drawings.