GB2433973A

GB2433973A - A device for fending off the stem of a vessel at a mooring

Info

Publication number: GB2433973A
Application number: GB0614602A
Authority: GB
Inventors: Donald Foster
Original assignee: Individual
Current assignee: Individual
Priority date: 2006-01-05
Filing date: 2006-07-24
Publication date: 2007-07-11
Anticipated expiration: 2026-07-24
Also published as: GB2433973B; GB0600150D0; GB0614602D0

Abstract

A device 2 for fending off the stem 4 of a vessel 6 at a mooring 8. The device 2 comprises: a mounting 12, 32, 36, 38 for attaching the device 2 to a part of the mooring 8; a load spreading member 10 pivotable with respect to the mounting about a longitudinal axis 44 between a first position and a second position and presenting a contact portion 14, 16 outwardly, and a resilient biasing means 12 which can act to resist pivoting of the load spreading member 10 from the first position to the second position. The device presents a larger contact area of the contact portion 14, 16 to the stem 4 of the vessel 6 in the second position than in the first position.

Description

Marine Device The present invention relates to a marine device, and

more particularly to a device to assist in mooring a vessel to help prevent or reduce damage to the vessel.

When a vessel is moored, there can be the risk of vessel being damaged by parts of the hull of the vessel hitting parts of any structure to which the vessel is to be moored with significant force. For example, vessels are often provided with feiiders which are positioned around the side of the vessel to provide protection against parts of moorings such as pontoons, docks, mariners or other structures to which the vessel can be moored.

However, there is also the need to provide protection to the stern of the vessel which can be unprotected. This is particularly the case for vessels which are difficult to control or where there are insufficient crew to be able to easily control rnanoeuvring of the vessel during mooring.

Therefore, it would be desirable to provide a device which reduces the risk of damage to the stem of a vessel during mooring of the vessel.

According to a first aspect of the invention there is provided a device for fending off the stem of a vessel at a mooring. The device can comprise a mounting for attaching the device to a part of the mooring. The device can include a load spreading member pivotable with respect to the mounting about a longitudinal axis between a first position and a second position. The load spreading member can present a contact portion outwardly. The device can also include a resilient biassing means which can act to resist pivoting of the load spreading member from the first position to the second position. The device can present a larger contact area of the contact portion to the stem of the vessel in the second position than in the first position.

When the stem of the vessel engages with the contact portion of the device, the load spreading member spreads the load over a larger area of the device than just the area of contact between the stem and device. Further, the load spreading member pivots to increase the area of contact between the contact portion and the stem thereby further spreading the load and reducing pressure applied by the stem to the device Furthermore, the resilient biassing means helps to absorb some of the force of the stem on the device as the load spreading member pivots against the action of the resilient biassing means. Accordingly, the device provides a buffer which interacts with the shape of the stem of a vessel to help reduce or prevent damage to the stem that may otherwise occur by impact with a part of a mooring. The device also helps reduce or prevent damage to the mooring.

Preferably, the contact portion includes at least a first formation and a second formation which can provide separate points of contact for the stem of the vessel. The provision of a plurality of forniations can help to spread the force between the device and the stem over a large area. Preferably, the first formation is to one side of the longitudinal axis and the second formation is to the opposite side of the longitudinal axis. As the first and second formations are on either side of the longitudinal axis, the moments about the longitudinal axis caused by forces on the first and second formations will counteract each other, and therefore reduce the net moment about the longitudinal axis. Accordingly, the resilient biassing member need not be as resilient, so as to counteract the net moment, as would be required if the first and second formations are on only one side of the longitudinal axis.

Preferably, the formations are configured so that, when the stem of the vessel contacts the formations in use, substantially the same load is applied to each formation by the stem. Preferably, the points of contact provided by the formations for contact with the stem of the boat have substantially same area. This helps to avoid an imbalance in the pressure being exerted on the stem at one contact point and at another contact point.

Therefore, this helps to reduce the risk of damage to the stem.

Preferably, the contact portion is configured so that, when the formations are in contact with the stem of the vessel in use, there is substantially no net moment about the longitudinal axis. This ensures that in use, the device does not act to lift the vessel out of the water due to an imbalance in the moment about the longitudinal axis.

Preferably, the contact portion comprises at least one resiliently compressible member.

This is advantageous because the resiliently compressible member can absorb some of the force of the stem acting on the device, and thereby reduce the pressure exerted on the stem. Preferably, each formation is a resiliently compressible member.

Preferably, the resilient compressible members are hollow tubes. Preferably, the tubes are open at at least one end. This is advantageous because it allows for the insertion of resiliently compressible reinforcing members into the resilient compressible members.

Preferably, the device further comprises at least one resilient compressible reinforcing 1 5 member removably located in the hollow tube. The provision of at least one removable resilient compressible reinforcing member can allow the user to select the amount by which the resilient compressible members compress to absorb the force of the stem. Preferably, the at least one resilient compressible reinforcing member is a hollow tube which is open at at least one end. This is advantageous because it allows for the insertion of further resiliently compressible reinforcing members into the resilient compressible members.

When first and second hollow tubes are and located respectively below and above the longitudinal axis preferably, the ratio of a) the distance of the point at which the first hollow tube is fixed to the load spreading member to the longitudinal axis to b) the distance between the point at which the second hollow tube is fixed to the load spreading member and the longitudinal axis, is at least 1.005. Preferably the ratio of a) to b) is not more than 1.02. For example, preferably, the ratio of a) to b) is approximately 1.01. This helps to ensure that when the hollow tubes deform under the force of the vessel, the longitudinal axis is located approximately midway between the first and second hollow tubes.

Preferably, the mounting is provided by a part of the resilient biassing means. By fastening the resilient biassing means directly to the mooring, it is not necessary to use an intermediate connecting portion. This can reduce the complexity and cost of the device.

Preferably, the mounting includes a plurality of apertures for receiving fastenings to secure the device to a part of a mooring. It can be preferable to provide for the use of a plurality of fastenings so that the force between the resilient biassing means and the part of the mooring is spread over a plurality of points. Preferably, the apertures are distributed evenly along the length of the resilient biassing means.

Preferably, the resilient biassing means comprises a strip of resiliently deformable material which can bend about the longitudinal axis. Preferably, the resiliently deformable matenal has a first portion on a first side of the longitudinal axis and a second portion on a second side of the longitudinal axis opposite to the first side. The first and second portions can pivot relative to each other about the longitudinal axis.

Preferably, the load spreading member is fastened to the first portion of the resiliently deformable material Preferably, the mounting is provided by the second portion of the resiliently defonnable material. Preferably, the strip of resiliently deformable material is a strip of elastomeric material. Preferably, the strip of resiliently deformable material is a strip of rubber material. The use of a resiliently deformable material has been found to be advantageous over the use of other types of resilient biassing means, such as a coil spring, because the strip of resiliently deformable material can absorb some of force of the stem on the device and also provides the pivot mechanism for the load spreading member. The line along which the strip of resiliently deformable material can bend defines the longitudinal axis about which the load spreading member pivots.

Such a configuration provides a simpler device having a continuous pivot.

It is also possible to use other devices to provide the pivot, for example mechanical pivots can be provided, such as hinges and similar. Alternatively, the pivot mechanism can be an integral part of the resilient biassing means. For example, the resilient biassing means can be provided by a foam, or similar, which is adapted or other wise configured to pivot with respect to a mounting because of its shape and/or configuration.

The load spreading member can be provided by a single rigid member or a plurality of rigid members. The load spreading member can extend along the longitudinal axis of the device and preferably extends along the entire length of the device. The load spreading member can be provided by a single rigid board, which can be of wood, plastics, metal or any other similar sufficiently strong material.

Embodiments of the present invention will now be described by way of example only with referenced to the accompanying drawings in which: Figure 1 shows a schematic cross-sectional side view of a device according to the present invention, attached to a part of a mooring; Figure 2 shows a schematic cross-sectional side view of the device shown in 1 5 Figure 1, with a stem of a boat contacting the device, Figure 3 shows a cross-sectional plan iew of the device shown in Figure 1 along line A-A; and Figure 4 show a schematic cross-sectional side view of the device shown in Figure 1 with an additional load spreading member attached between the device and the mooring.

Referring to the drawings, Figures 1 to 4 show a device 2 for fending off the stem 4 of a vessel 6. References herein to stem should be understood to mean the leading edge of the hull at the bow end of the vessel. Accordingly, in wooden hulled boats, this means the wooden stem post protruding from the bow end of the hull of the boat and to which the wooden boards forming the sides of the hull are attached. In non-wooden hulled boats, the stem means the edge at which the sides of the hull at the bow end meet.

The device 2 is shown in use, attached to an edge of a part 8, e.g. a pontoon, of mooring 8. The device 2 comprises a wooden board 10 which acts as a load spreading member, a strip of rubber 12 which acts as a resilient biassing means, and first 14 and second 16 hollow plastic tubes which provide contact areas of the contact portion of the device, i.e the parts of the device which face outwardly toward the stem of a vessel in use. The device 2 is shown in a first position in Figure 1 in the absence of a vessel, and in a second position in Figure 2 in which the stem 4 of the vessel 6 is acting on the device 2.

The load spreading member 10 is a single rigid board which extends along the length of the device. In the embodiment shown, the board lOis made of resin bonded plywood and is approximately 1220mm in length, 200mm in height and 19mm in depth. As will be understood, the material and dimensions of the load spreading member can be varied to suit the particular application, for example, the size or type of vessel and or the size, type or part of the mooring for which the device is intended to be used.

The resilient biassing means 1 2 can be made from any suitable material which resists stretching, allows bending and has a degree of resilience. As indicated above in the illustrated embodiment of strip laminated reinforced rubber is used. It has been found that a strip of material commonly used as conveyor belting is particularly suitable.

Such materials are available from, for example, Sempertrans France Belting Technology SAS under the trade mark MULTITRANS. The length and height of the rubber strip 12 are similar to those of the load spreading member. The depth of the rubber strip 12 is dependent on the properties of the laminated rubber material and the biassing requirements. The properties of the resilient biassing means 12 should be such that the load spreading member 10 is biassed to the position shown in Figure 1 in the absence of a vessel acting on the device 2 while having sufficient strength to prevent the rubber strip from being damaged by shear forces when the stem of the boat engages the device, as illustrated in Figure 2.

The first 14 and second 16 hollow tubes can be made of any resilient, flexible material.

In the embodiment described, the first 14 and second 16 hollow tubes are made from a resilient, flexible plastic material. When made of plastic, the hollow tubes are preferably reinforced against shearing forces. For example, the plastic hollow tubes can be reinforced with a plastic monofilament. As will be understood, the hollow tubes need not be made of plastic. For example, the hollow tubes could be made from a resilient, flexible rubber material. In the embodiment described, the first 14 and second 16 hollow tubes are approximately 1220mm in length, have an outer diameter of approximately 45mm, and a wall thickness of approximately 4mm.

First 40 and second 42 resiliently compressible reinforcing members can be located in the first 14 and second 16 hollow tubes to increase the resilience of the first 14 and second 16 hollow tubes. In the embodiment shown, the first 40 and second 42 resiliently compressible reinforcing members are closed cell rubber cylinders. As will be understood, the first 40 and second 42 resiliently compressible reinforcing members can be have any suitable shape and structure and can be made of any suitable material so as to increase the resilience and impact absorbing properties of the first 14 and second 16 hollow tubes. For example, the first 40 and second 42 resiliently 1 5 compressible reinforcing members can be hollow tubes, into which further resiliently compressible reinforcing members (not shown) can be inserted. In this way the properties of the device can be tailored to match the requirements of the vessel with which the device is to be used.

The second hollow tube 16, the load spreading member 10 and the resilient biassing means 12, are attached by a first plurality of set of nuts 20 and bolts 18 that extend through respective apertures in the second hollow tube 16, load spreading member 10 and the resilient biassing means 12. The first plurality of nuts 20 and bolts 18 are spaced along the length of the device 2 as shown in Figure 3, with substantially equal spacing between adjacent bolts.

First 22 and second 24 support strips are located between the head 26 of the bolt 18 and the inside of the second hollow tube 16 and also between the nut 20 and the surface of the resilient biassing member 12 respectively. The first 22 and second 24 support strips distribute the forces of the bolt 18 and nut 20 across a large surface area of the second hollow tube 16 and the resilient biassing member 12 to help prevent the tube from being stripped from the board 10 and also the board 10 being ripped from rubberstrip 12.

The first hollow tube 14 is attached to the load spreading member 10 by a second plurality of nuts 28 and bolts 30 that extend through respective apertures in the first hollow tube 14 and the load spreading member 10. The second set of nuts 28 and bolts are spaced along the length of the device 2 as shown in Figure 3. A third support strip 32 is located between the head 34 of the bolt 30 and the inside of the first hollow tube 14 to help prevent the tube 14 from being stripped from the board in use..

The resilient biassing means 12 is attached to the edge of the part 8 of the mooring by a plurality of screws 32 that extend through respective apertures in the resilient biassing means 12 into the mooring 8. The set of screws 32 are spaced along the length of the resilient biassing means 12. The plurality of apertures in the biassing means provides a mounting by which the device can be mounted at the corner of the part of the mooring in use. A fourth support strIp 36 is located between the heads 38 of the screws 32 and the surface of the resilient biassing means 12.

As best shown in Figure 3, the support strips 22, 24, 32, 36 are in the form of strips of trellis and are made of galvanised steel. The nuts 20, 28, bolts 18, 30 and the screws 32 are also made of galvanised steel.

The mounting of the resilient biassing means 12 and the load spreading member 10 allow the device 2 to be attached to the part 8 of the mooring as shown in Figures 1 and 2, so that the corner edge 44 of the mooring 8 defines a longitudinal axis of the device about which the load spreading member 10 can pivot. Further, in the embodiment described the first 14 and second 16 hollow tubes are spaced at approximately equal distances either side of the longitudinal pivot axis.

As described below, in use the stem can tend to ride up the first 14 and second 16 hollow tubes, causing them, and the resilient biassing means 12 to shear. The shearing of the resilient biassing means 12 can cause an offset in the longitudinal axis about which the load spreading member 10 pivots. The sheanng of the first 14 and second 16 hollow tubes can change the point at which the force by the stem on the hollow tubes is imparted on the load spreading member I 0. For example, as the stem rides up the first 14 and second 16 hollow tubes, the tubes can stretch upwards causing the points at which the force of the stem is imparted onto the load spreading member to rise.

This shearing can disrupt the balance of the moments about the longitudinal axis caused by forces on the first 14 and second 16 hollow tubes, and result in an undesirable net moment about the longitudinal axis. This can be overcome by locating the first hollow tube 14 at slightly greater distance from the longitudinal pivot axis than the second hollow tube 16 so that when in use, when the first 14 and second 16 hollow tubes shear, they are located approximately equally from the longitudinal axis, so that the moments about the longitudinal axis caused by forces on the first 1 4 and second 16 hollow tubes counteract each other, and therefore reduce the net moment about the longitudinal axis.

The difference in the distances between the longitudinal axis and the first 14 and second 16 hollow tubes depends on many factors including the size of the load spreading member 10, hollow tubes 14, 16, as well as the size and mass of the vessel with which the device 2 is to be used. In the embodiment shown, the first hollow tube 14 is located approximately 6mm further away from the longitudinal axis than the second hollow tube 16.

In an alternate embodiment, a single resiliently compressible member can be provided instead of the first 14 and second 16 hollow tubes. The single resiliently compressible member can take the form of a block of closed cell rubber 52 located on the outwardly facing side of the load spreading member 10, as illustrated by the phantom lines in Figure 4. The block of closed cell rubber 52 can be fastened to the load spreading member 10 by an adhesive, or by fastenings extending though apertures in the block of closed cell rubber 52 and the load spreading member 10. The block of closed cell rubber 52 can be coated with a coating to reduce friction between the block of closed cell rubber 52 and the stem 4 of the vessel 6 during use. For example, the block of closed cell rubber 52 can be coated with an acrylic material (not shown). This also helps to prevent damage to the block of closed cell rubber 52 caused by Ultraviolet (UV) radiation.

Also as shown in Figure 4, when the device 2 is to be attached to a mooring part 46 having a sharp edge 48, a curved formation 50 can also be provided, fastened between the resilient biassing means 12 and the mooring 46. The curved formation 50, which can be made of a strip of metal with a half circular head, presents a rounded surface which the resilient biassing means 12 contacts when the load spreading member 10 pivots, and therefore prevents the resilient biassing means being damaged by the sharp edge 48 of the mooring 46.

To protect the materials of the device 2 against damage and detenoration caused by UV radiation, parts of the device 2 can be covered with an acrylic material (not shown), or other UV tolerant coverings. For example, the first 14 and second 16 hollow tubes could each individually be covered with an acrylic material. Optionally, a sheet of acrylic material could be provided that covers both of the first 14 and second 16 hollow tubes.

In use, the resilient biassing means 12 biasses the load spreading member 10 to a first position as shown in Figure 1. When the stem 4 of a vessel 6 is impacts the device 2, the stem 4 will first contact only the second hollow tube 16. Therefore, initially there is only a small contact area between the stem and device. The force of the stem 4 acting on the second tube 16 will cause the load spreading member 10 to pivot about the longitudinal pivot axis and about the corner edge 44 of the mooring part 8. As the load spreading member 10 pivots, the resilient biassing means 12 will act against the force of the stem 4 and thereby absorb some of the force of the stem 4 on the device 2.

The resilient biassing means 12 also acts to dampen the pivoting of the load spreading member 10. The load spreading member 10 continues to pivot to a second position when the first hollow tube 14 also contacts the stem 4, as shown in Figure 2. This increases the amount of contact area between the stem and device.

In the second position, the load spreading member will stop pivoting as substantially equal and opposite moments are generated by the force of the stem on the first and second tubes. The first 14 and second 16 hollow tubes will compress and further absorb some of the impact of the stem 4 on the device 2. If the stem 4 is driven into the device 2 with sufficient force such that the first 14 and second 16 hollow tubes cannot absorb all of the force of the stem 4, then the stem 4 will tend to ride up the first 14 and second 16 hollow tubes until the weight of the vessel 6 draws the vessel 6 back down into the water again. Hence the device of the present invention acts as a buffer which acts on the stem of the vessel to allow the vessel to be gently stopped without causing damage to the stem.

It will be appreciated that the device of the present invention is particularly suitable for use with sailing boats which can be difficult to control when mooring. However, the invention is not limited to use with such vessels only.

Further, it will be apparent that various other embodiments of the invention can be provided. For example, instead of using a strip of rubber to provide the resilient biassing, other types of resilient biassing means can be used such as mechanical type means, such as various types of springs, or materials type means, such as foams or other types or rubbers. For example a segment of foam could be located behind the board 10, which is then compressed between the board and moonng part 8 in use. A spnng could be placed between the board and mooring part 8, to be compressed in use, or between the lower end of the board and the mooring part so as to be extended in use.

Also, other types of pivoting mechanisms can be used. For example, a mechanical pivot could be provided using a hinge or plurality of hinges located along the longitudinal axis.

Also, other embodiments in which the pivoting mechanism and biassing means are the same entity can be provided. For example, a load spreading means can be provided within, or on an outer surface, of a foam or rubber circular cylinder with a quarter segment removed. The cylinder would then be placed on the corner of the mooring part, with the inward radius providing a mounting for attaching to the mooring part and the downwardly pointing radius free, so that the load spreading means can pivot.

Claims

CLAIMS: 1. A device for fending off the stem of a vessel at a mooring,

comprising a mounting for attaching the device to a part of the mooring, a load spreading member pivotable with respect to the mounting about a longitudinal axis between a first position and a second position and presenting a contact portion outwardly, a resilient biassing means which can act to resist pivoting of the load spreading member from the first position to the second position and in which the device presents a larger contact area of the contact portion to the stem of the vessel in the second position than in the first position.

2. A device as claimed in claim I, in which the contact portion includes at least a first formation and a second formation which caii provide separate points of contact for the stem of the vessel, and in which the first firniation is to one side of the longitudinal axis and the second formation is to the opposite side of the longitudinal axis.

3. A device as claimed in claim 2, in which the formations are configured so that, when the stem of the vessel contacts the formations in use, substantially the same load is applied to each formation by the stern.

4. A device as claimed in claim 2 or 3, in which the formations are arranged on either side of the longitudinal axis so that, when the formations are all in contact with the stem of the vessel in use, there is substantially no net moment about the longitudinal axis.

5. A device as claimed in any preceding claim, in which the contact portion comprises at least one resiliently compressible member.

6. A device as claimed in claim 2 or 3, in which each formation is a resiliently compressible member.

7. A device as claimed in claim 5 or 6, in which the resilient compressible members are hollow tubes.

8. A device as claimed in claim 1, in which the mounting is provided by a part of the resilient biassing means.

9. A device as claimed in claim 8, in which the mounting includes a plurality of apertures for receiving fastenings to secure the device to a part of a mooring.

10. A device as claimed in claim 9, in which the resilient biassing means is provided by a strip of rubber material and the load spreading member is provided by a rigid board.

I I. A device for fending off a vessel substantially as hereinbefore described with reference to the accompanying drawings.