GB2599685A

GB2599685A - Marine fenders

Info

Publication number: GB2599685A
Application number: GB2015987.7A
Authority: GB
Inventors: Mallorie Paul; Forrester Stuart
Original assignee: Gtechs Consulting Ltd
Current assignee: Gtechs Consulting Ltd
Priority date: 2020-10-08
Filing date: 2020-10-08
Publication date: 2022-04-13
Also published as: GB202015987D0

Abstract

A method of constructing a marine fender 301 comprising an energy-absorptive core 302 and a protective cover 303, 304 is disclosed. The method comprises obtaining an energy-absorptive core, obtaining a protective cover shaped to conform around the energy-absorptive core, and locating the protective cover around the energy-absorptive core to cover the energy-absorptive core. A marine fender comprising an energy-absorptive core and a protective cover formed from first and second parts covering the energy-absorptive core is disclosed. A kit of parts formed from an energy-absorptive core and a protective cover that is manipulable to cover the energy-absorptive core is also disclosed.

Description

MARINE FENDERS

Field of the Disclosure

The present disclosure relates to marine fenders. Background of the Disclosure Marine fenders are bumpers deployed for cushioning between a vessel and a berthing structure, such as a quay wall or another vessel, to thereby protect both the vessel and the berthing structure from damage. In particular, marine fenders are useful for absorbing kinetic energy during berthing of the vessel against the structure. For this purpose, marine fenders are required to exhibit high energy absorption and low reaction force characteristics, whilst also being durable. Marine fenders may be attached either to the vessel or to the berthing structure.

Summary of the Disclosure

A first aspect of the present disclosure provides a method of constructing a marine fender comprising an energy-absorptive core and a protective cover, the method comprising: obtaining an energy-absorptive core; obtaining a protective cover shaped to conform around the energy-absorptive core; and locating the protective cover around the energy-absorptive core to cover the energy-absorptive core.

in other words, the method relates to constructing a marine fender in which an energy-absorptive core and a protective cover for the core are formed separately, i.e. where the protective cover is formed ex-situ of the core, before the pre-formed protective cover is subsequently located over the pre-formed core.

The disclosure is thus useful in relation to a marine fender comprising an inner core and a structurally distinct protective outer cover. Such a construction of a marine fender may be desirable, for example, where it is desired to use for the core a material that may be relatively susceptible to damage in use, but which has other desirable characteristics, e.g. foam which has desirable energy-absorption characteristics, but which may be relatively susceptible to damage in use if left uncovered. The protective cover may thus protect the energy-absorptive core from damage in use. An example of a marine fender for which such a construction is desirable is a floating fender, which requires a low-density/low-reaction force core for absorbing energy and providing positive buoyancy, and a mechanically and chemically durable cover to protect the core from mechanical and/or chemical damage in use.

The disclosed method has a number of practical advantages. Firstly, because the energy-absorptive core and the protective cover are formed separately, rather than, for example, forming the protective cover in-situ on the energy-absorptive core, the energy-absorptive core and the protective cover may each be pre-formed, potentially at different forming sites, and the final step of locating the pre-formed protective cover around the pre-formed energy-absorptive core may be relatively quick and simple. This may confer manufacturing efficiencies.

Further, because the protective cover is formed ex-situ of the energy-absorptive core, the method allows, optionally, for moulding of the protective cover in a mould. An advantage of moulding the protective cover is that moulding as an operation tends to be relatively material-efficient, which is to say that very little wastage of the constituent material with which the mould is charged occurs. in comparison, other possible methods of forming the protective cover, for example, forming the protective cover by wet-spraying material directly onto the energy-absorptive core, tends to result in significant wastage of the constituent material due to over spraying. Such over IS spray also undesirably results in contamination of the local environment.

The protective cover could, for example, be formed and located around the energy-absorptive module as a single part. Alternatively, the protective cover could be formed in plural parts, for location separately around the energy-absorptive core.

In an implementation, the protective cover is formed of plastic material, and the locating the protective cover around the energy-absorptive core comprises locating the protective cover around the energy-absorptive core whilst the protective cover has an average temperature of at least 50 degrees Celsius.

An advantage of forming the protective cover from plastic, such as thermoplastic, e.g. polyethylene, and locating the protective cover around the energy-absorptive core whilst the protective cover is relatively warm, is that, in a warm state the plastic of the protective cover will tend to be more flexible and pliable than when the plastic is filly cooled. This enhanced flexibility/pliability of the protective cover may advantageously result in easier manipulation of the protective cover around the energy-absorptive core. For example, the protective cover may be more easily deformed by an operative to fit around the energy-absorptive core. A further advantage to locating the protective cover over the energy-absorptive core whilst the protective cover is warm is that, the plastic, e.g. thermoplastic such as polyethylene, of the protective cover will tend to be thermally expansive, with the result that as the protective cover cools in-situ on the energy-absorptive core, the cover will tend to shrink, to thereby conform more closely around the energy-absorptive core. This shrinkage of the protective cover about the energy-absorptive core advantageously ensures a close final fit between the protective cover and the energy-absorptive core, thereby reducing the risk of misalignment/displacement of the protective cover during use of the fender.

An average temperature of the protective cover of at least 50 degrees Celsius has been found, in the case of certain plastic materials, such as polyethylene, to result in a particularly desirable balance of structural strength with flexibility/pliability/shrinkage of the moulded part. Indeed, it has been found that temperatures higher than 50 degrees Celsius may even more desirably enhance the flexibility/pliability/shrinkage of the moulded part. Thus, in examples, the locating the protective cover around the energy-absorptive core comprises locating the protective cover around the energy-absorptive core whilst the protective cover has an average temperature of at least 60 degrees Celsius, or at least 70 degrees Celsius, or at least 80 degrees Celsius.

IS

In an implementation, the obtaining a protective cover comprises forming the protective cover by heating plastic material to soften the plastic material and shaping the plastic material to conform around the energy-absorptive core, and the locating the protective cover around the energy-absorptive core comprises locating the protective cover around the energy-absorptive core at a time when the protective cover retains residual heat from the forming the protective cover.

As noted above, it may be desirable to locate the protective cover around the energy-absorptive core whilst die protective cover is relatively warm. Utilising the residual heat of the forming process, i.e. heat energy remaining from the forming, e.g. moulding, process, to achieve the warm protective cover, may advantageously be a relatively energy, and so cost, efficient way of achieving heating of the protective cover. Further, utilising the residual heat from the forming process, rather than re-heating the protective cover after forming, may advantageously avoid fatiguing the protective cover through heat-cycling the protective cover.

In an implementation, the protective cover is adapted to shrink as a temperature of the protective cover reduces, and the method further comprises allowing the temperature of the protective cover to reduce following the locating the protective cover around the energy-absorptive core to cause the protective cover to shrink around the energy-absorptive core An advantage of the protective cover shrinking around the energy-absorptive core following fitting is that a closer fit may be achieved between the core and the cover, thereby reducing the risk of misalignment/displacement of the protective cover during use of the fender. Consequently, the energy-absorptive core may be better protected by the cover in use.

In an implementation, the protective cover is formed of thermoplastic material. Thermoplastic material may advantageously be relatively easily formed, e.g. by moulding. Additionally, many thermoplastic materials may tend to be relatively mechanically and chemically durable when fonned. In examples, the protective cover is formed of polyethylene and/or polyurethane.

Polyethylene and polyurethane are each advantageously relatively easily moulded, flexible, and mechanically and chemically durable. An advantage of using polyethylene for forming the protective cover, instead of polyurethane, is that polyethylene is more easily recyclable at an end of life of the fender.

in an implementation, the obtaining a protective cover comprises moulding the protective cover from plastic material. As noted, an advantage of moulding the protective cover is that moulding as an operation tends to be relatively material-efficient, and which is to say that very little wastage of the constituent material with which the mould is charged occurs. In comparison, other possible methods of forming the protective cover, for example, forming the protective cover by wet-spraying material directly onto the energy-absorptive core, tends to result in significant wastage of the constituent material due to over spraying. Such over spray also results in contamination of the local environment.

In an implementation, the moulding the protective cover comprises moulding the protective cover from polyethylene. For the marine fender application, polyethylene has been found to be suitably tough, durable and flexible as to perform well as a cover to protect the energy-absorbing core, whilst also being relatively easily fonned into the desired shape, and being sufficiently flexible, in particular when warm, to allow convenient location of the protective cover over the energy-absorptive core. As an example alternative, the protective cover could be moulded from polyurethane.

in an implementation, the moulding the protective cover comprises rotational moulding the protective cover. For example, the protective cover could be rotationally moulded from polyethylene.

In an implementation, the obtaining a protective cover comprises, obtaining a first cover part shaped to conform around a portion of the energy-absorptive core, and obtaining a second cover part, separate to the first cover part, shaped to conform around a portion of the energy-absorptive core; and the locating the protective cover around the energy-absorptive core comprises locating the first cover part around a portion of the enemy-absorptive core and locating the second cover part, separately to the first cover part, around a portion of the energy-absorptive core.

Forming the protective cover in two parts may advantageously allow for relatively easier location of the protective cover around the energy-absorptive core than if the protective cover were a single part. This is particularly advantageous where the energy-absorptive core is large or irregularly shaped.

In an implementation, the second cover part is shaped to overlap the first cover part when the first cover part and the second cover part are located around the energy-absorptive core, the locating IS the second cover part around a portion of the energy-absorptive core comprises the locating the second cover part around a portion of the energy-absorptive core such that the second cover part overlaps the first cover part.

An advantage of this configuration is that a double thickness of cover material is provided where the second cover part overlaps the first cover part. The energy-absorptive core may thus be better protected from damage caused by impact energy, and in particular the double thickness of cover material may better protect the energy-absorptive core from penetration by sharp objects. In an example, the second cover part could overlap the first cover part along substantially the full length of the energy-absorptive core, to thereby best protect the energy-absorptive core in use.

In an implementation, the method further comprises joining the first cover part to the second cover part after the locating the first cover part arid the second cover part around the energy-absorptive core.

Joining, i.e. mechanically attaching, the first and second cover parts advantageously reduces the risk of the cover parts becoming misaligned or even detached from the energy-absorptive core during use of the fender. Consequently, protection of the energy-absorptive core may be improved.

In an implementation, the first cover part and the second cover part are formed of plastic material, and the joining the first cover part to the second cover part comprises welding the first cover part to the second cover part.

The join between the cover parts should be sufficiently mechanically strong as to resist tearing under the sort of, relatively high, repeated, loads to which the fender will typically be subjected in use, to thereby ensure that the cover parts remain correctly located over the energy-absorptive core during use, and are not misaligned or even torn off the energy-absorptive core by incident load. Furthermore, it is generally desirable that the join between the two cover parts is substantially water-proof, to prevent water ingress through the cover into the energy-absorptive core. Where the first and second cover parts are each fonned of plastic, a weld may be expected to provide a convenient and durable mechanical coupling between the two cover parts. in comparison, adhesive will typically provide a relatively weak bond between many plastic materials, such as polyethylene. In an example, the weld join may be configured to form a IS continuous, water-proof, seam between the cover parts, to thereby prevent water ingress into the energy-absorptive core. In other examples, in particular where the first and second cover parts are formed of materials other than plastics, other joining teclmiques, such as bonding or penetrative fasteners, such as stitches, could be employed in substitute for, or in addition to, a weld.

in an implementation, the welding the first cover part to the second cover part comprises lap welding the first cover part to the second cover part.

A lap-weld joint between the first and second cover parts may advantageously provide a relatively stronger mechanical join than a butt weld, thereby reducing the risk of failure of the join in use. 25 In an implementation, the obtaining a first cover part comprises forming the first cover part by heating plastic material to soften the plastic material and shaping the plastic material to conform around a portion of the energy-absorptive core; the locating the first cover part around a first portion of the energy-absorptive core comprises locating the protective cover around a portion of the energy-absorptive core at a time when the first cover part retains residual heat from the forming the first cover part, the obtaining a second cover part comprises forming the second cover part, subsequent to the locating the first cover part around a portion of the energy-absorptive core, by heating plastic material to soften the plastic material and shaping the plastic material to conform around a portion of the energy-absorptive core: and the locating the second cover part around a portion of the energy-absorptive core comprises locating the protective cover around a portion of the energy-absorptive core at a time when the second cover part retains residual heat from the forming the second cover part.

In other words, the first and second cover parts could be formed sequentially, rather than simultaneously. An advantage of this method is that a single mould may be used for moulding both of the cover parts, which may confer manufacturing cost efficiencies. A further advantage is that each cover part may be more easily located about the energy-absorptive core, by a single operative, whilst warm, i.e. whilst each of the cover parts retains residual heat from the forming process. In comparison, if the cover parts were formed simultaneously, as a first of the cover parts were being fitted warm to the energy-absorptive core by an operative, the other cover part would be cooling, which may mean that by the time the operative comes to fitting the other cover part, the other cover part is undesirably cool, and may thus be undesirably less flexible/pliable.

A second aspect of the present disclosure provides a marine fender constructed by the method of

ally one of the preceding statements

A third aspect of the present disclosure provides a marine fender comprising: an energy-absorptive core; and a protective cover covering the energy-absorptive core; wherein the protective cover comprises a first cover part located around a portion of the energy-absorptive core, and a second cover part, separate to the first cover part, located around a portion of the energy-absorptive core.

In other words, the protective cover may be fonned by two distinct parts. Forming the protective cover from two parts has a number of practical advantages, as discussed above. In particular, thrilling the protective cover by two parts advantageously allows for the protective cover to be pre-formed, ex-situ of the energy-absorptive core, e.g. by moulding the protective cover. The two parts of the protective cover also allow for easier location of the protective cover around the energy-absorptive core during construction of the marine fender. Additionally, the two cover parts may be easier to handle during construction of the marine fender than a single, relatively larger, cover part. Additionally, the two cover parts may desirably facilitate easier repair of the marine fender in the instance that only one of the cover parts is damaged in use, as only the damaged cover part requires replacement, whilst the undamaged cover part may be reused.

In an implementation, the second cover part overlaps the first cover part. An advantage of this configuration is that a double thickness of cover material is provided where the second cover part overlaps the first cover part. The energy-absorptive core may thus be better protected from damage caused by impact energy, and in particular the double thickness of cover material may better protect the energy-absorptive core from penetration by sharp objects. in an example, the second cover part could overlap the first cover part along substantially the full length of the energy-absorptive core, to thereby best protect the energy-absorptive core in use.

In an implementation, the first cover part is joined to the second cover part. Joining the first cover part to the second cover part advantageously reduces the risk of the cover parts becoming misaligned or even detached from the energy-absorptive core in use of the fender. Consequently, protection of the energy-absorptive core by the protective cover may be improved.

In an implementation, the first cover part is joined to the second cover part at a join extending circumferentially around the energy absorptive core. Where the marine fender is deployed for IS absorbing impact loads incident on the fender in a direction perpendicular to the length of the energy absorptive core, this arrangement of the join may advantageously reduce the risk of the cover parts becoming detached from the energy-absorptive core under load. In particular, this arrangement may result in the least load being imparted on the join, thereby reducing the risk of failure of the join.

In an implementation, the first cover part and the second cover part are formed from plastic material, and the first cover part is joined by a weld to the second cover part. A weld is a convenient mid durable method of joining the cover parts. In particular, a weld tends to provide good joining strength, thereby reducing the risk of breaking of the join during use of the fender.

In an implementation, the first cover part and the second cover part are formed of moulded thermoplastic, In an implementation, the first cover part and the second cover part are formed of polyethylene.

In an implementation, the energy-absorptive core is formed of closed-cell foam. Closed cell foam has advantageous energy-absorption characteristics, and furthermore is less susceptible to collection or absorption of water than many other types of foam.

In an implementation, the marine fender is configured as a floating fender.

A fourth aspect of the present disclosure provides a kit of parts for constructing a marine fender, the kit of parts comprising: an energy-absorptive core; and a protective cover, separate to the energy-absorptive core, shaped to conform around the energy-absorptive core, wherein the protective cover is manipulable to cover the energy-absorptive core.

In other words, the protective cover, despite being shaped to conform around the energy-absorptive core, should be able to be manipulated around die energy-absorptive core after forming of the protective cover, e.g. by including an opening through which the energy-absorptive core may pass. For example, the protective cover may desirably be flexible to allow deformation of the protective cover to allow fitting of the cover around the core. The protective cover could be located around the energy-absorptive core as a single part, or could alternatively comprise plural parts.

In an implementation, the protective cover comprises a first cover part shaped to conform around a first portion of the energy-absorptive core, and a second cover part, separate to the first cover part, shaped to conform around a second portion of the energy-absorptive core.

Forming the protective cover from two parts has a number of practical advantages, as discussed above. In particular, forming the protective cover by two parts advantageously allows for the protective cover to be pre-formed, ex-situ of the energy-absorptive core, e.g. by moulding the protective cover. The two parts of the protective cover may also allow for easier location of the protective cover around the energy-absorptive core during construction of the marine fender, in particular where die energy-absorptive core is large or irregularly shaped. Additionally, the two cover parts may be easier to handle during construction of the marine fender than a single, relatively larger, cover part. Additionally, the two cover parts may desirably facilitate easier repair of the marine fender in the instance that only one of the cover parts is damaged in use, as only the damaged cover part requires replacement, whilst the undamaged cover part may be reused.

In an implementation, the first cover part and the second cover part are flexible plastic. Flexible plastic may desirably allow for easy manipulation of the pre-formed protective cover over the pre-formed energy-absorptive core.

In an implementation, the marine fender, may comprise a shaft on which and the energy-absorptive module formed by the energy-absorptive core and the protective cover may be located on the shaft such that the shaft extends through die energy-absorptive module; and the marine fender may further comprise a collar releasably attached to the shaft for releasably retaining the energy-absorptive module on the shaft.

In other words, the marine fender may have a modular construction, whereby the energy- ) absorptive module may be releasably retained on the shaft by the releasable collar. The energy-absorptive module may absorb kinetic energy during use of the marine fender. The shaft may impart axial rigidity to the marine fender and provide a structure for attachment of the marine fender to a berthing structure. An advantage of the releasable collar is that the collar may be removed from the shaft to allow location of the energy-absorptive module on the shaft, or to allow removal of the energy-absorptive module from the shaft. An advantage of this modular configuration is that it may desirably allow for the energy-absorptive module to be removed from the shaft if the energy-absorptive module is damaged during use, whilst the shaft may be reused.

The collar should be 'releasable' from the shaft, i.e. the mode of attachment of the collar to the shaft should permit non-destructive detachment of the collar from the shaft, i.e. detachment of the collar from the shaft without destruction of the collar and/or the shaft. This advantageously permits convenient detachment of the collar from the shaft by an operator, potentially as a field repair, for example, to allow removal/replacement of the energy-absorptive fender. In contrast, a non-releasable attachment of the collar to the shaft, for example, a weld, would undesirably require destructive work to detach the collar, e.g. by grinding away the weld, and would potentially require re-welding of the collar to the shaft to reattach the collar to the shaft.

The releasable attachment of die collar to the shaft should however be sufficiently mechanically strong to allow the collar to function to retain the energy-absorptive module on the shaft in use. 25 In an implementation, the shaft extends loosely through the energy-absorptive module such that the energy-absorptive module is movable relative to the shaft. This configuration advantageously allows for the energy-absorptive module to be easily located on and/or removed from the shaft. Further, this configuration may advantageously allow for the energy-absorptive module(s) to rotate relative to the shaft in use. This rotation may advantageously reduce the stress imparted on the energy-absorptive module by an impact from a berthing vessel, as the module may rotate to accommodate both the initial impact and the subsequent rise, fall and roll of the berthed vessel.

In an implementation, the energy-absorptive module comprises energy-absorptive material and a rigid tube extending through the energy-absorptive material. This rigid tube may desirably impart axial rigidity to the energy-absorptive module. Further, the rigid tube may desirably define a bore through which the shaft can be located, such that the rigid tube may protect energy-absorptive material of the energy-absorptive module from damage caused by the shaft in use. Further, where the rigid tube defines a bore through which the shaft is located, the rigid tube may permit convenient insertion of the shaft through the energy-absorptive module. Further, the rigid tube may advantageously be arranged to engage the collar, such that retaining force applied on the energy-absorptive module by the collar is applied onto the rigid tube rather than on to energy-absorptive material of the energy-absorptive module, and so does not axially crush such energy-absorptive material.

In an implementation, the collar is configurable when releasably attached to the shaft to bear against the rigid tube to exert a retaining force on the rigid tube to thereby releasably retain the energy-absorptive module on the shaft. By bearing against the rigid tube, the collar will be less likely to axially crush energy-absorptive material of the energy-absorptive module. Thereby, the energy-absorbing characteristics of such energy-absorptive material may be preserved.

In an implementation, a screw thread is formed on the collar, and a cooperating screw thread is formed on the shaft, and the collar is releasably attachable to the shaft by engagement of the screw thread formed on the collar with the cooperating screw thread formed on the shaft. A screw thread may advantageously provide a relatively simple, convenient and secure releasable connection between the collar and the shaft. Further, the screw thread may allow convenient tightening of the collar against the energy-absorptive module, to thereby securely retain the energy-absorptive module in a desired position on the shaft in use.

In an implementation, the marine fender is configured such that rotation of the collar relative to the shaft, when the screw thread formed on the collar is engaged with the cooperating screw thread fonned on the shaft, causes the collar to move towards the energy-absorptive module to exert a retaining force on the energy-absorptive module. This arrangement may allow convenient tightening of the collar against the energy-absorptive module, to thereby securely retain the energy-absorptive module in a desired position on the shaft in use.

In an implementation, the marine fender further comprises a stop for retaining the energy-absorptive module on the shaft, wherein the stop is located on an opposite side of the energy-absorptive module to the collar, wherein the stop is permanently attached to the shaft. The energy-absorptive module may thereby be sandwiched between the stop and die collar. Permanently attaching the stop to the shaft, for example, by welding of the stop to the shaft, or by forming the stop integrally with the shaft, may desirably reduce the risk of the stop becoming detached from the shaft in use, thereby reducing the risk of the energy-absorptive module detaching from the shaft in use.

In an implementation, the marine fender further comprises a further energy-absorptive module, separate to the energy absorptive module, located on the shaft such that the shaft extends sequentially through the energy-absorptive module and the further energy-absorptive module, wherein the collar releasably retains the energy-absorptive module and the further energy-absorptive module on the shaft. In other words, the marine fender may comprise a plurality of the energy-absorptive modules retained on the shaft by the releasably attachable collar. The dimension of the marine fender may thus be easily adapted to suit a range of applications using multiples of the universal energy-absorptive module.

This modular configuration of the marine fender, whereby energy absorption is provided by a plurality of energy-absorption modules instead of a single module, may advantageously reduce the cumulative stress imparted on the energy-absorptive modules by impacts from a berthing vessel on a subset of the modules, as the stress from the impact may be confined to that subset of modules, instead of stressing the entirety of a single energy-absorptive module on each impact.

in an implementation, the shaft extends loosely through the further energy-absorptive module such that the further energy-absorptive module is movable relative to the shaft.

A particular advantage of the energy-absorptive modules being rotatably movable relative to the shaft is encountered in the case of a fender comprising plural energy-absorptive modules, inasmuch that the energy-absorptive modules may rotate relative to one another. This relative rotation of the energy-absorptive modules may advantageously reduce the stress imparted on the energy-absorptive modules by an impact from a berthing vessel, as the modules may rotate by mutually different amounts, or in different directions, depending, for example, on the angle of the impact on each module, or the rise, fall and roll of the vessel against each module, both of which factors may vary between the plural modules. This may reduce stress on the modules, and thereby reduce the risk of damage occurring to the modules, and accordingly may advantageously increase the service life of the modules.

In an implementation, the further energy-absorptive module comprises further energy-absorptive material and a further rigid tube extending through the further energy-absorptive material.

In an implementation, the thither rigid tube of the thither energy-absorptive module bears against the rigid tube of the energy-absorptive fender, such that a retaining force exerted on the rigid tube by the collar is transferred by the rigid tube to the further rigid tube, to thereby releasably retain each of the energy absorptive module and the further energy-absorptive module on the shaft.

A sixth aspect of the present disclosure provides a kit of parts for constructing a marine fender, the kit of parts comprising: a shaft; an energy-absorptive module locatable on the shaft such that the shaft extends through the energy-absorptive module; and a collar releasably attachable to the shaft for releasably retaining the energy-absorptive module on the shaft.

In an implementation, the shaft is a loose fit for the energy-absorptive module such that the energy-absorptive module may slide freely along the shaft in an implementation, the energy-absorptive module comprises energy-absorptive material and a rigid tube extending through the energy-absorptive material.

In an implementation, the collar is configurable, when releasably attached to the shaft, to bear against the rigid tube to exert a retaining force on the rigid tube to thereby releasably retain the energy-absorptive module on the shaft.

In an implementation, a screw thread is formed on the collar, and a cooperating screw thread is formed on the shaft, and the collar is releasably attachable to the shaft by engagement of the screw thread formed on the collar with the cooperating screw thread formed on the shaft.

In an implementation, the kit further comprises a further energy-absorptive module, separate to the energy absorptive module, locatable on the shaft such that the shaft extends also through the further energy-absorptive module.

A seventh aspect of the present disclosure provides a method of constructing a marine fender, the method comprising: locating an energy-absorptive module on a shaft such that the shaft extends through the energy-absorptive module; and releasably attaching a collar to the shaft to releasably retain the energy-absorptive module on the shaft.

In an implementation, the collar is releasably attached to the shaft by engagement of a screw thread formed on the collar with a cooperating screw thread formed on the shaft, and the method comprises engaging the screw thread fonned on the collar with the cooperating screw thread formed on the shaft, and rotating the collar relative to the shaft to cause the collar to move along the shaft towards the energy-absorptive module to exert a retaining force on the energy-absorptive module.

These and other aspects of the invention win be apparent from the embodiment(s) described below,

Brief Description of the Drawings

In order that the present invention may be more readily understood, embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 shows schematically an example of a marine fender, embodying an aspect of the present disclosure, deployed for cushioning between a vessel and a berthing structure, Figures 2a and 2b show the marine fender previously identified with reference to Figure 1 in schematic side and end elevation views respectively, Figures 3a, 3b and 3c show an example of an energy-absorptive module of the marine fender,in schematic side-sectional exploded, side-sectional, and end-sectional views respectively, Figures 4a, 4b and 4c show the marine fender in schematic side-sectional views in mutually different states of assembly, Figure 5 shows a second example of a marine fender embodying an aspect of the present disclosure, in a schematic side sectional view.

Figures 6a and 6b show the second example of the marine fender, previously identified with reference to Figure 5, in schematic side sectional views in mutually different states of assembly, Figures 7a and 7b shows a second example of an energy-absorptive module of the marine fender, in schematic side-sectional exploded and side-sectional view respectively, Figure 8 shows processes of an example method, embodying an aspect of the present disclosure, for constructing the first and second examples of the marine fenders previously identified with reference to Figure 1 to 7b, which includes a process of constnicting an energy-absorptive module, Figure 9 shows processes involved in constructing an energy-absorptive module according to the first or second example, which includes processes of obtaining an energy-absorptive core, obtaining protective cover parts, arid locating the protective cover parts around the energy-absorptive core, Figure 10 shows processes involved in obtaining the energy-absorptive core, Figure 11 shows processes involved in obtaining protective cover parts and locating the protective cover parts around the energy-absorptive core, Figure 12 shows processes involved in an example method of obtaining protective cover parts and locating the protective cover parts around the energy-absorptive core, and Figure 13 shows processes involved in constructing a marine fender from energy-absorptive modules of the type previously identified with reference to Figure 8,

Detailed Description of the Disclosure

Referring firstly to Figure 1, a marine fender 101 embodying an example of an aspect of the present disclosure is being used for cushioning between a vessel 102, floating on body of water 103, and a berthing structure 104, which in the example is a quay wall. Marine fender 101 is chained to the quay wall 104, to hold the fender in place on the quay wall.

Marine fender 101 is configured to space the vessel 102 away from the quay wall 104, to protect the vessel from abrasion by the quay wall, and to absorb kinetic energy resulting from impact between the vessel and the quay wall, to thereby protect the vessel and the quay wall from mechanical damage. The marine fender 101 is particularly useful in absorbing impact energy generated during berthing of the vessel 102 against the quay wall 104. In the example, marine fender 101 is a floating fender, so called because it is configured to float on the surface of the water 103 to accommodate a change in height of the water, e.g. tidal range.

Whilst the disclosure is described in detail herein with reference to a floating fender, it should be appreciated that the utility of the disclosure is not limited to floating fenders. Rather, aspects of the disclosure have utility in relation to other types of marine fenders, and in particular, though not exclusively, to quayside fenders. For example, aspects of the disclosure may alternatively usefully be deployed as donut fenders and/or submarine fenders.

Referring next to Figures 2a and 2b collectively, marine fender 101 comprises a main body 201 and chains 202, 203.

Main body 201 is generally cylindrical in shape, and has a length dimension 1' that is approximately twice the diameter dimension 'D'. in use, the main body 201 is deployed to extend in length along the quay wall. As will be described, main body 201 comprises an energy-absorptive material, and is resiliently compressible in the diametric dimension, to dissipate mechanical force exerted on the main body 201 by a vessel, and thereby cushion between the vessel and the quay wall. Chains 202 and 203 are fixed to opposing lengthwise ends of the main body 201, to permit securing of the marine fender 101 to the quay wall 104.

Marine fenders are deployed in many different applications, for cushioning of vessels of many different sizes. Marine fenders embodying the present disclosure are thus anticipated to be provided in various different sizes, for example, ranging from fenders having length and/or diameter dimensions of one metre or less, to large fenders having length and/or diameter dimensions of more than one metre, for example length dimensions in excess of five metres and diameter dimensions of well over one metre. In the specific example described in detail herein, the marine fender 101 has a length of approximately two metres and a diameter of approximately one metre.

Referring next to Figures 3a to 3c, the main body 201 of the marine fender 101 comprises an energy-absorptive module, a first example of which is depicted at 301, which comprises an energy-absorptive core 302, a protective cover 303, 304, for covering the energy absorptive core 302 to thereby encapsulate the energy-absorptive core 302, and a tube 305 arranged to extend through the energy-absorptive core.

The energy-absorptive core 302 is resiliently compressible in the diametric dimension of the main body, exhibiting a low reaction force to compression in the diametric dimension, and is provided for absorbing impact energy to function as a cushion between the vessel 102 and the quay wall 104, in the example, the energy-absorptive core 302 is formed of closed-cell foam, specifically, closed-cell polyethylene foam. The closed-cell foam has a particular advantage in the example floating fender application, inasmuch that the closed cell foam will retain air even if immersed in water, thereby providing desirable buoyancy characteristics. In the example application therefore, the purpose of the energy-absorptive core 302 is two-fold; firstly, to absorb kinetic energy by compression of the energy-absorptive core, and secondly to exhibit positive buoyancy, to cause the main body 201 to float on the surface of water in which it is immersed. Polyethylene is desirably relatively elastic and durable. As will be described in more detail with particular reference to Figure 9, in an example, the energy-absorptive core 302 is formed from a wound sheet of closed-cell foam.

In alternative applications, the energy-absorptive core could be formed of materials other than a closed-cell foam and/or other than polyethylene. As noted, the primary function of the energy-absorptive core for a marine fender generally is to absorb kinetic energy to thereby function as a cushion, and many other materials will be known to the skilled person which serve this purpose.

For the specific application of a floating fender, the energy-absorptive core should further provide positive buoyancy. As an example, alternative, the energy-absorptive core 302 could instead be formed of open-cell foam, e.g. foamed plastic, or could comprise a solid particulate filling suitable for absorbing impact energy, or could comprise a working fluid and damping for the working fluid to dissipate kinetic energy. In the example, the energy-absorptive core is generally cylindrical in shape, having flat ends, and a central bore 306, which extends lengthwise through the full length of the energy-absorptive core to define a through-bore.

However, the requirement for the energy-absorptive core 302 to provide desirable energy-absorption, and optionally also positive buoyancy characteristics, typically correspondingly requires that the energy-absorptive core is formed of a low density, easily compressible, material, such as foam. Consequently, the energy-absorptive core may tend to be relatively susceptible to damage in use, by mechanical abrasion, or protrusion by sharp objects. Accordingly, the main body 201 further comprises a protective cover, in the example, formed in two parts 303, 304, for covering the energy-absorptive core 302, to thereby protect the energy-absorptive core from damage in use, e.g. by mechanical abrasion or penetration by sharp objects.

Protective cover is formed in two parts; first cover part 303 and second cover part 304. First cover part 303 and second cover part 304 are substantially identical, each being generally bucket-shaped, having a cylindrical side wall, one open end, and one closed end. The dosed end of each of the first and second cover parts 303, 304 comprises a central aperture.

The first cover part 303 has a generally cylindrical inner form, and is shaped to conform closely around a first longitudinal half of the energy absorptive core 302, to thereby substantially cover the side and end wall of that half of the energy-absorptive core. The second cover part 304, similarly, has a generally cylindrical inner form, and is shaped to conform closely around a second longitudinal half of the energy-absorptive core 302, to thereby substantially cover the side and end wall of that half of the energy-absorptive core. When the first and second cover parts 303, 304 are located around their respective halves of the energy-absorptive core, they together cover the energy-absorptive core to substantially encapsulate the energy-absorptive core, and thereby protect the energy-absorptive core.

In the example, each of the first and second cover parts 303, 304 are formed of moulded thermoplastic material, specifically, moulded polyethylene. The method of moulding first and IS second cover parts will be described in further detail with particular reference to Figures 10 and 11.

An important function of the protective cover is to protect the energy-absorptive core from damage caused, for example, by mechanical abrasion and/or penetration by sharp objects, in use.

A further function is for the protective cover to protect the energy-absorptive core 302 from chemical damage in use. However, it is also desirable that the protective cover 303, 304 does not excessively interfere with the energy-absorbing characteristics of the energy-absorptive core 302. For this reason, the protective cover should be formed of a durable and mechanically strong, but also flexible, material. Rigid materials such as, for example, thick metal sheet, would likely provide adequate mechanical protection to the energy-absorptive core 302, but would undesirably resist transmission of incident force onto the energy-absorptive core, and in most applications would therefore be an unsuitable material choice from which to form the protective cover. Flexible yet durable plastics, such as polyethylene and/or polyurethane, are thus anticipated to represent the best material choice for forming, e.g. moulding, the protective cover 303, 304. it is further desirable that the protective cover is waterproof, to thereby prevent water-ingress into the energy-absorptive core, thus, water-proof materials, such as flexible plastics, are advantageous in many applications. The skilled person will be aware of many other flexible and durable materials from which the protective cover may be formed.

In the example, the first and second cover parts 303, 304 are sized such that the rims of their respective open ends abut or overlap slightly approximately halfway along the length of the energy-absorptive core 302. The first and second cover parts 303, 304 are mechanically joined where they meet, by a mechanical join 307 extending circumferentially around the full circumference of the energy absorptive cover. In the example, the first and second cover parts are joined by welding.

The technique for joining the first and second cover parts is primarily dictated by the material(s) from which the first and second cover parts is formed. The join should be sufficiently mechanically strong as to resist tearing under the sort of, relatively high, repeated, loads to which the fender will typically be subjected in use, to thereby ensure that the cover parts 303, 304 remain correctly located over the energy-absorptive core 302 during use, and are not misaligned or even torn off the energy-absorptive core by incident load. Furthermore, it is generally desirable that the join between the two cover parts 303, 304 is substantially water-proof, to prevent water ingress through the protective cover into the energy-absorptive core. As described, in the example, the first and second cover parts 303, 304 are each formed of thermoplastic, and a weld may be expected to provide a convenient and durable mechanical coupling between the two cover parts. An example welding process for welding the first and second cover parts comprises heating the surface to be welded of each of the first and second cover parts, to pre-plasticize the cover parts, and subsequently injecting a molten plastic filler material into the heated weld area to fuse the first and second cover parts together.

In comparison, adhesive will typically provide a relatively weak bond between many thermoplastic materials, such as polyethylene. In the example, the weld join is configured to form a continuous, water-proof, seam between the cover parts, to thereby prevent water ingress into the energy-absorptive core. In other examples, in particular where the first and second cover parts are formed of materials other than thermoplastics, other joining techniques, such as bonding or penetrative fasteners, such as stitches, are employed in substitute for, or in addition to, a weld.

The tube 305 forms a tubular liner to the inner diameter of the energy-absorptive core 302, to thereby define a wall of the bore 306 through the energy-absorptive core 302.

A fiinction of the tube 305 is to resist bending of the energy-absorptive core about its long axis, to optimise the absorption of impact energy by the energy-absorptive core. A further function of the tube 305, as will be described in more detail with particular reference to Figures 4a to 4c, is for providing an incompressible load path in the length direction of the energy-absorptive core. For these purposes, the tube 305 should be rigid, so as to be inflexible about its length, and incompressible in its length dimension. In the example, the tube 305 is a rigid metal tube, such as a steel tube, but could instead be formed of an alternative rigid and durable material, such as carbon fibre reinforced polymer.

Referring next to Figures 4a to 4e, the marine fender 101 further comprises a shaft 401, for insertion through the bore 306 of the energy-absorptive module 301, and a collar 402 that is releasably attachable to the shaft 401 to releasably retain the energy-absorptive module 301 on the shaft 401.

Referring in particular to Figure 4c, in use, the shaft 401 is inserted through the energy-absorptive module 301, through the bore of the tube 305. The shaft 401 is sized to have an outer diameter that is marginally smaller than an inner diameter of the tube 305, such that the energy-absorptive module 301 is loosely fitted over the shaft, and may move relatively freely, rotationally and axially, relative to the shaft.

The shaft 401 comprises a stop 403, in the form of a flange extending radially out from the shaft, for abutting against an end of the tube 305 of the energy-absorptive module 301. The stop 403 thus acts to retain the energy-absorptive module 301 on the shaft. The energy-absorptive module may thus be located on the shaft 401, such that the shaft passes through the bore 306, and leftward movement of the energy-absorptive module 301 is restrained by the stop 403. In the example, the stop 403 is permanently fixed to the shaft 401, for example, by welding or bonding of the stop to the shaft, but could alternatively be releasably attached to the shaft.

A function of the shaft 401 is to stiffen the energy-absorptive module 301, to resist bending of the module 301 along its length. A further function of the shaft 401 is to carry fittings for attachment of the chains 202, 203 and to provide a load path for tensile stress between the chains 202, 203 separate to the energy-absorptive module 301, to thereby permit secure attachment of the marine fender 101 to the quayside. The shaft 401 should thus be rigid and resistant to tensile stress along its length. In the example, the shaft is formed of metal bar, for example, steel bar, but could instead be formed of an alternative rigid and strong material, such as carbon fibre reinforced polymer.

Releasable collar 402 is releasably attachable to the shaft 401. The releasable collar 402 comprises an annular wall. The releasable collar 402 is employed for releasably retaining the energy-absorptive module 301 on the shaft 401, by restraining rightward movement of the energy-absorptive module 301 on the shaft 401. In the attached state depicted in Figure 4c, the energy-absorptive module 30 I may thus be retained on the shaft 401, sandwiched between the stop 403 and the releasable collar 402. Referring however to Figure 4a, detachment of the releasable collar 402 from the shaft 401 allows removal of the energy-absorptive module 301 from the shaft 401.

In the example the releasable collar 402 is releasably attachable to the shaft 401 by engagement of a screw thread 404 formed on an inner diameter of the annular wall of the collar 402 with a cooperating screw thread 405 formed on an outer diameter of the shaft 401. Referring in particular to Figure 4b, this threaded engagement of the releasable collar 402 with the shaft 401 has the effect that rotation of the collar 402 relative to the shaft 401 causes the collar 402 to move towards and tighten onto the energy absorptive module 301. Because the energy-absorptive module 301 is loosely fitted on the shaft 401, tightening of the releasable collar 402 against the energy-absorptive module 301, urges the energy-absorptive module 301 leftward against the stop 403.

Rotation of the collar 402 thus allows convenient sandwiching of the energy-absorptive module 301 between the stop 403 and the collar 402, to thereby prevent movement of the energy-absorptive module 301 along the shaft 401 during use of the marine fender 101.

Referring in particular to Figure 4e. the tube 305 of the energy-absorptive module 301 protrudes marginally outwards of the ends of the energy-absorptive core 302, and the stop 403 and the collar 402 are configured to contact the ends of the tube 305. In this way, the stop 403 and the collar 402 thus act on the tube 305, rather than on the energy absorptive core 302. The tube is substantially incompressible along its length, and may thus resist relatively high retaining forces exerted on it by the stop 403 and the collar 402. In comparison, if the stop 403 and the collar 402 were to act on the energy-absorptive core 302, the energy-absorptive core would tend to compress when subjected even to relatively low retaining forces, which may undesirably allow movement of the energy-absorptive module 301 along the shaft 401 during use, even when the collar 402 is tightened against the energy-absorptive module 301.

The releasable attachment of the collar 402 to the shaft 401 should be sufficiently mechanically strong to allow the collar 402 to function as a stop, to restrain rightward movement of the energy-absorptive module 301 on the shaft 401 in use, whilst still permitting convenient detachment of the collar by an operative when desired, for example, to allow removal of the energy-absorptive module 301 from the shaft 401. In this regard, although a threaded connection between the releasable collar 402 and the shaft 401 is described herein in detail, alternative modes of releasable attachment could instead be used. For example, in an alternative example, the collar 402 could be relcasably attached to the shaft 401 by a set screw, carried by the collar 402, for tightening onto the shaft 401 to mechanically, releasably, lock the collar to the shaft. In a further alternative example, the collar could be releasably attached to the shaft by bolts, rivets or by clips, etc. A fundamental requirement of the releasable attachment of the collar to the shaft is that the attachment should be 'releasable', i.e. that it should permit non-destructive detachment of the collar 402 from the shaft 401, i.e. detachment of the collar from the shaft without destruction of the collar 402 and/or the shaft 401 and/or the energy-absorptive module 301. This advantageously permits convenient detachment of the collar from the shaft by an operator, potentially as a field repair, for example, to allow removal/replacement of the energy-absorptive module 301. In contrast, anon-releasable attachment of the collar 402 to the shaft 40 I, for example, a weld, would undesirably require destructive work to detach the collar, e.g. by grinding away the weld, and would potentially require re-welding to reattach the collar to the shaft.

IS Configuring the fender to allow convenient, non-destructive, removal of the energy-absorptive module 301 from the shaft 401 results in the marine fender having a modular rather than a unitary structure, which has a number of practical advantages.

Firstly, this configuration may desirably result in easier-handling of the marine fender, both during manufacture of the marine fender, and during transport/installation of the marine fender, as the shaft 401 and the energy-absorptive module(s) 301 may be handled separately prior to final assembly of the complete fender, which may be easier then handling of the shaft 401 and energy-absorptive module(s) 301 combined, which combined structure may be inconveniently bulky/heavy.

A further advantage of this configuration is that, in the event that the energy-absorptive module 301 is irreparably damaged in use, for example, by penetration of the protective cover 303, 304 by a sharp object, the energy-absorptive module 301 alone may be conveniently be replaced, potentially as a field repair, whilst the shaft 401 may be reused. This may advantageously reduce repair costs/repair time. In comparison, if the energy-absorptive module 301 were retained on the shaft 401 by a permanent fixing, or a fixing requiring destruction of the shaft 401 and/or the fixing to permit removal of the energy-absorptive module, irreparable damage to the energy-absorptive module 301 would likely, undesirably, require replacement of the marine fender 101 complete, including replacement of the shaft 401.

A further advantage of this configuration, where the energy-absorptive module 301 may be conveniently attached to and detached from the shaft 401, is that the shaft 401 itself may be configured to be a (semi)universal part used for a range of differently specified marine fenders, wherein only the energy absorptive module 301 is required to be adapted to suit the particular fender application, i.e. to adapt the size of the fender complete depending on the intended application. This may confer manufacturing and stock-holding efficiencies.

Referring next to Figures. marine fender 501 is similar to marine fender 101 previously described with reference to Figures 1 to 4c, and like reference numerals will be used to denote like features. 10 Marine fender 501 differs from marine fender 101 inasmuch that it comprises a plurality of the energy-absorptive modules 301, in the example, three energy-absorptive modules 301a to 301c, located on the shaft 401. Similarly to marine fender 101, in marine fender 501, the energy-absorptive modules 301a to 301c are releasably retained on the shaft 401 by stop 403 and releasably attachable collar 402.

Marine fender 501 illustrates a further advantage of the releasable attachment of the collar 402 to the shaft 401 for retaining the energy-absorptive modules 301a to 301c, inasmuch that the energy-absorptive modules 301 may be (semi)universal parts used for a range of differently specified marine fenders, wherein only the shaft 401 is required to be adapted to suit the particular application, i.e. by selecting an appropriately sized shaft to hold a required number of energy-absorptive modules 301. This may confer manufacturing and/or stock-holding efficiencies.

Referring still to Figure 5, it can be seen that the tubes 305 of each of the energy-absorptive modules 301a to 301c abut when the modules are located on the shaft 401 retained between stop 403 and releasable collar 402, to thereby transfer retaining force from the collar 402.

Referring next to Figures 6a and 6b collectively, a particular advantage of the releasably attachable collar 402 permitting convenient removal of the energy-absorptive modules 301 arises in relation to the marine fender 501, comprising a plurality of the energy-absorptive modules 301a to 301c.

Referring in particular to Figure 6a, in this configuration, in the event that only a subset of the energy-absorptive modules 301, such as energy-absorptive module 301c, are irreparably damaged in use, for example, by penetration of the protective cover 301, 303 of the energy-absorptive module 301c by a sharp object, the one or more damaged energy-absorptive modules, e.g. module 301e. may conveniently be replaced, with a new energy-absorptive module, e.g. module 301d, potentially as a field repair, whilst the undamaged modules 301a, 30 lb, and the shaft 401 may be reused. In comparison, if the energy-absorptive modules 301a to 301c were substituted by a large unitary energy-absorptive module, irreparable damage to one of the energy-absorptive modules would necessitate replacement of the unitary module complete, mid indeed if the unitary energy-absorptive module were retained on the shaft 401 by a permanent fixing, or a fixing requiring destruction of the shaft 301 and/or the fixing to permit removal of the energy-absorptive module 301, irreparable damage to any one of the energy-absorptive module(s) 301 would likely require replacement of the marine fender assembly 101 complete, including replacement of the shaft 401.

Referring next to Figures 7a and 7b, a second example energy-absorptive module 701 is substantially similar to energy-absorptive module 301 described previously with reference to Figures 1 to 6, save as will be described, and like reference numerals are used to denote like IS features.

Energy-absorptive module 701, like energy-absorptive module 301, comprises an energy-absorptive core 302, a protective cover 303, 304, for covering the energy absorptive core 302 to thereby encapsulate the energy-absorptive core 302, and a tube 305 arranged to extend through the energy-absorptive core.

Energy-absorptive module 701 differs from energy-absorptive module 301, inasmuch that the first and second cover parts 303', 304' are larger than cover parts 303, 304. Referring in particular to Figure 7b. each of cover parts 303', 304' is shaped to cover one end of energy-absorptive core 302 and substantially the full length L' of energy-absorptive core 302. Thus, second cover part 304' is shaped to overlap first cover part 303' along substantially the full length of the energy-absorptive core 302, when in the assembled condition shown in Figure 7b. First and second cover parts 303', 304' are joined by weld 307 in a lap-weld configuration, i.e. in which the portion of second cover part 304' that is welded to first cover part 303' overlaps the first cover part 303'.

An advantage of this configuration is that a double thickness of cover material is provided over substantially the full length of the energy-absorptive core 302. The energy-absorptive core 302 may thus be better protected from damage caused by impact energy, and in particular the double thickness of cover material may better protect the energy-absorptive core 302 from penetration by sharp objections. Further, the lap-weld joint between the first and second cover parts 303', 304' may advantageously provide a relatively stronger mechanical join that the butt weld of energy-absorptive module 301, thereby reducing the risk of failure of the join in use. Further, locating the join, e.g. the weld 307, proximal to a longitudinal end of the energy-absorptive module 701, rather than at a centre of the energy-absorptive module, may advantageously reduce the stress exerted on the join by impact energy applied close to a centre of the length of the energy-absorptive module, and thereby further reduce the risk of failure of the join in use.

Either of marine fenders 101 or 501 could be constructed using energy-absorptive module 701 in substitute for energy-absorptive module 301.

Referring next to Figure 8, an example method of constructing the marine fenders 101, 501 described previously with reference to Figures Ito 7 comprises two stages.

At stage 801, the energy-absorptive modules 301/701 are constructed. In the case of marine fender 101, a single energy-absorptive module 301/701 is constructed, in the case of marine fender 501, three energy-absorptive modules, such as energy-absorptive modules 301a to 301c, are constructed.

At stage 802, the energy-absorptive module(s) 301/701 constructed at stage 801 are assembled with the shaft 401 and the releasably attachable collar 402 to create the marine fender 101. 501.

Referring next to Figure 9, an example of the method of stage 801 for constructing the energy-absorptive modules 301/701 comprises four stages.

At stage 901, the energy-absorptive core 302 is obtained.

At stage 902, the first and second cover parts 303, 304 of the protective cover are obtained.

At stage 903, the first and second cover parts 303, 304 obtained at stage 902 are located around the energy-absorptive core 302 obtained at stage 901.

At stage 904, the first and second cover parts 303, 304 are joined to encapsulate the energy-absorptive core 302 in the protective cover. As described previously with reference to Figure 3b, in as example, the first and second cover parts 303, 304 are joined by welding, but in alternative examples, depending on the material from which the cover parts 303. 304 are formed, the cover parts 303, 304 could instead be joined by alternative joining means, for example, bonding or penetrative fasteners.

Referring next to Figure 10, an example of the method of stage 901 for obtaining the energy- :, absorptive core 302 comprises three stages.

In the example, described previously with reference to previous Figures, the energy-absorptive core 302 is formed of foam. The example method described herein thus relates to forming the energy-absorptive core 302 from foam, specifically, from closed-cell foam.

At stage 1001, a roll of closed-cell foam sheet is wound repeatedly around a spindle until a desired thickness of foam around the spindle is obtained. in the example, the dosed-cell foam sheet has a thickness of approximately one centimetre, and, as previously described, the energy-absorptive core 302 is desired to have a diameter of approximately one metre. In the example therefore, this stage comprises winding the closed-cell foam sheet around the spindle many times to achieve the desired thickness of foam. The free end of the closed-cell foam sheet may then be joined to the underlying layer of foam sheet, e.g. by thenno-lamination, to retain the foam sheet in the wound configuration. Indeed, in an example, the foam sheet may be joined to its underlying layer at multiple points along the wound length, or may even be continuously joined to the underlying layer, for example, by thenno-lamination. The energy-absorptive core could, in other examples, be formed by alternative forming techniques, for example, moulding, or from other materials.

At stage 1002, once a sufficient amount of the closed-cell foam sheet has been wound around the spindle at stage 1001, the spindle is removed, leaving the central bore 306.

At stage 1003, the rigid tube 305 is inserted through the central bore 306.

Referring next to Figure 11, an example of the method of stages 892 and 903 for obtaining the protective cover parts 303, 304 and locating the protective cover parts around the energy-absorptive core 302 comprises three stages.

At stage 1101, the protective cover parts 303, 304 are formed, in the example, the protective cover parts are formed of thermoplastic, specifically polyethylene, by a rotational moulding technique. In the example to be described in detail herein, the protective cover parts 303, 304 are formed separately at stage 1001. Thus, as previously described with reference to Figure 3a, in the example method, each of the protective cover parts 303, 304 is generally bucket-shaped. to thereby conform closely around a respective longitudinal half of the energy-absorptive core 302. As an example alternative, the protective cover parts 303, 304 could be formed, e.g. moulded, as a single part, and subsequently cut into two parts. The protective cover parts 303, 304 could, in other examples, be formed by an alternative forming teclunque, for example, injection moulding.

In the example method, raw polyethylene powder is introduced into a hollow mould, heated in the mould to soften the powder and a least partially liquify the powder, and then the mould is rotated to coat the walls of the mould with the polyethylene. At some point during rotation of the mould, the heating is stopped, and the charge is allowed to cool whilst the mould continues to rotate. As the heated polyethylene cools, it solidifies on the mould wall to form the respective cover part. As discussed above, in the example, this moulding process is performed separately for each of the cover parts 303, 304, IS At stage 1102, following cooling and solidification of the moulded cover part at stage 1101, the cover parts are removed from the mould. In an example, the moulded cover parts 303, 304 are each extracted from the mould before they are completely cooled, i.e. before they reach ambient temperature of the surroundings of the mould, whilst they retain residual heat from the moulding process at stage 1101. An advantage of removing the parts 'warm' from the mould is that, where the cover parts are formed of plastic, e.g. thermoplastics such as polyethylene, or other thermally weakened materials, in a warm state the cover parts will tend to be more flexible and pliable than when they are fully cooled. This enhanced flexibility/pliability of the moulded parts means that they may more easily be located around a respective half of the energy-absorptive core 302, at later stage 1103. A further advantage to removing the parts from the mould warm, for subsequent location around the energy-absorptive core 302 is that, where the cover parts are formed of plastic, e.g. thermoplastics such as polyethylene, or other thermally-expansive materials, as the cover parts 303, 304 cool in-situ on the energy-absorptive core 302, they will tend to shrink, to thereby conform more closely around the energy-absorptive core 302. This advantageously ensures a close fit between the cover parts 303, 304 and the core 302, thereby reducing the risk of misalignment/displacement of the protective cover parts from the core during use of the fender.

A particular advantage of locating the cover parts of the energy-absorptive core whilst the cover parts are warm may be observed in relation to energy-absorptive module 701, wherein the second cover part 304' may be more easily manipulated over the pre-installed first cover part 303'.

ideally, the moulded cover parts 303. 304 are removed from the mould, at stage 1102, whilst the respective moulded cover part has an average temperature of at least 50 degrees Celsius, or even at least 60 degrees Celsius, at least 70 degrees Celsius, or at least 80 degrees Celsius, which temperatures have been found, in the case of moulded plastic cover parts, e.g. moulded polyethylene or polyurethane parts, to result in a particularly desirable balance of structural strength with flexibility/pliability/stretch of the moulded part.

An advantage of moulding the cover parts 303, 304 is that moulding as an operation tends to be relatively material-efficient, which is to say that very little of the constituent material is wasted during the moulding. In comparison, other possible methods of forming the cover parts, for example, wet-spraying of a thermosetting plastic about a male mould, or about the energy-absorptive core 302 directly, would likely result in significant wastage of the raw material and environmental contamination caused by over spraying.

At stage 1103, as previously alluded to, the warm cover parts 303, 304, extracted from the mould at stage 1002, are located about the corresponding half of the energy absorptive core 302, and are allowed to cool to ambient temperature around the energy-absorptive core 302. As described previously, during cooling, the cover parts 303, 304 will tend to shrink to conform more closely around the energy-absorptive core 302. The cover parts may then be joined by the joining process of stage 804. as described previously with reference to Figure 9.

Referring next to Figure 12, in an example representing a refinement to the method described previously with reference to Figure 10, the method of stages 902 and 903 for obtaining the protective cover parts 303, 304 and locating the protective cover parts around the energy-absorptive core 302 comprises four stages.

In this example, the first and second cover parts 303, 304 are moulded sequentially, rather than simultaneously. An advantage of this method is that a single mould may be used for moulding both of the cover parts, which may confer manufacturing cost efficiencies. A further advantage is that each cover part may be more easily located about the energy-absorptive core 302, by a single operative, whilst warm. In comparison, if both of the cover parts 303, 304 were moulded and extracted from the moulds simultaneously, as a first of the cover parts were being fitted to the energy-absorptive core by an operative, the other cover part would be cooling, which may mean that by the time the operative comes to fitting the other cover part, the other cover part is undesirably cool. Thus, a particular advantage of moulding the cover parts 303, 304 in two parts, rather than moulding a single part which is subsequently cut into two parts, is that the parts may be formed, e.g. moulded, and extracted for fitting sequentially.

Thus, in this method, at stage 1201, the first cover part 303 is moulded, in substantially the same way as described previously with reference to Figure 11, i.e. by rotational moulding.

At stage 1202, the first cover part 303 is extracted from the mould whilst still warm, and located immediately around the corresponding half of the energy absorptive core obtained at stage 901. The first cover part 303 is then allowed to cool on the energy-absorptive core 302.

Then, at stage 1203, the second cover part 304 is moulded, in substantially the same way as the first cover part 303. The second cover part 304 may optionally be moulded in the same mould as the first cover part 303.

Next, at stage 1204, the second cover part 304 is extracted from the mould whilst still warm, and located immediately around the corresponding half of the energy absorptive core 302 obtained at stage 801. The first cover part 303 is then allowed to cool on the energy-absorptive core. Again, the first and second cover parts 303, 304 may then be joined by the method of stage 904.

Referring finally to Figure 13, in an example, the method of stage 802 for assembling the marine fender 101, 501 using the energy-absorptive module(s), 301/701, obtained at stage 901, comprises four stages.

At stage 1301 he shaft 305 is obtained, for example, by machining billet metal.

At stage 1302, one or more of the energy-absorptive modules 301, constructed at stage 801, is obtained At stage 1303, the one or more energy-absorptive fender modules 301/701 obtained at stage 1302 are located on the shaft 401, such that the shaft 401 passes through the bore 306 of the tube 305 of each energy-absorptive module 301/701. In the case of marine fender 101, only a single energy-absorptive module 301/701 is located on the shaft, in the case of marine fender 501, a plurality, e.g. three, of the energy-absorptive modules 301/701 is located on the shaft.

And, at stage 1304, the releasably attachable collar 402 is releasably attached to the shaft 401, c.g, by engaging the thread 404 of the collar 402 with the cooperating thread 405 of the shaft 401, to exert a retaining force on the energy-absorptive module(s) 301, to thereby releasably retain the energy-absorptive module(s) 301 securely on the shaft.

Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from die spirit and scope of the invention as defined by the appended claims.In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality.

Claims

Claims 1. A method of constructing a marine fender comprising an energy-absorptive core and a protective cover, the method comprising: obtaining an energy-absorptive core; obtaining a protective cover shaped to conform around the energy-absorptive core; and locating the protective cover around the energy-absorptive core to cover the energy-absorptive core.
2. The method of claim I. wherein the protective cover is formed of plastic material, and the locating the protective cover around the energy-absorptive core comprises bearing the protective cover around the energy-absorptive core whilst the protective cover has an average temperature of at least 50 degrees Celsius.
The method of claim 1 or claim 2, wherein the obtaining a protective cover comprises forming the protective cover by heating plastic material to soften the plastic material and shaping the plastic material to conform around the energy-absorptive core, and the locating the protective cover around the energy-absorptive core comprises locating the protective cover around the energy-absorptive core at a time when the protective cover retains residual heat from the forming the protective cover.
4. The method of claim 2 or claim 3, wherein the protective cover is adapted to shrink as a temperature of the protective cover reduces, and the method further comprises allowing the temperature of the protective cover to reduce following the locating the protective cover around the energy-absorptive core to cause the protective cover to shrink around the energy-absorptive core.
5. The method of any one of the preceding claims, wherein the protective cover is formed of thermoplastic material.
6. The method of any one of the preceding claims, wherein the obtaining a protective cover comprises moulding the protective cover from plastic material.
7. The method of claim 6, wherein the moulding the protective cover comprises moulding the protective cover from polyethylene.
8. The method of any one of claims 5 to 7, wherein the moulding the protective cover comprises rotational moulding the protective cover.
9 The method of any one of the preceding claims, wherein: the obtaining a protective cover comprises, obtaining a first cover part shaped to conform around a portion of the energy-absorptive core, and obtaining a second cover part, separate to the first cover part, shaped to conform around a portion of the energy-absorptive core; and the locating the protective cover around the energy-absorptive core comprises locating the first cover part around a portion of the energy-absorptive core and locating the second cover part, separately to the first cover part, around a portion of the energy-absorptive core.
10. The method of claim 9, wherein the second cover part is shaped to overlap the first cover part when the first cover part and the second cover part are located around the energy-absorptive 20 core.
I. The method of claim 8 or claim 9, further comprising joining the first cover part to the second cover part after the locating the first cover part and the second cover part around the energy-absorptive core.
12. The method of claim 11, wherein the first cover part and the second cover part are formed of plastic material, and the joining the first cover part to the second cover part comprises welding the first cover part to the second cover part.
13. The method of claim 12, wherein the welding the first cover part to the second cover part comprising lap-welding the first cover part to the second cover part.
14. The method of any one of claims 8 to 13 wherein: the obtaining a first cover part comprises forming the first cover part by heating plastic material to soften the plastic material and shaping the plastic material to conform around a portion of the energy-absorptive core; the locating the first cover part around a portion of the energy-absorptive core comprises locating the protective cover around a portion of the energy-absorptive core at a time when the first cover part retains residual heat from the forming the first cover part, the obtaining a second cover part comprises forming the second cover part, subsequent to the locating the first cover part around a portion of the energy-absorptive core, by heating plastic material to soften the plastic material and shaping the plastic material to conform around a portion of the energy-absorptive core; and the locating the second cover part around a portion of the energy-absorptive core comprises locating the protective cover around the portion of the energy-absorptive core at a time when the second cover part retains residual heat from the forming the second cover part.
15. A marine fender constructed by the method of any one of claims 1 to 14. 20
16. A marine fender, comprising: an energy-absorptive core; and a protective cover covering the energy-absorptive core; wherein the protective cover comprises a first cover part located around a portion of the energy-absorptive core, and a second cover part, separate to the first cover part. located around a-portion of the energy-absorptive core
17. The marine fender of claim 16. wherein the second cover part overlaps the first cover part.
18. The marine fender of claim 16 or claim 17, wherein the first cover part is joined to the second cover part.
19. The marine fender of claim 18, wherein the first cover part is joined to the second cover part at a join extending circumferentially around the energy absorptive core.
20. The marine fender of claim 18 or claim 19, wherein the first cover part and the second cover part are formed from plastic material, and the first cover part is joined by a weld to the second cover part.
21 The marine fender of claim 20, wherein the first cover part is lap-welded to the second cover part.
22. The marine fender of any one of claims 16 to 21, wherein the first cover part and the second cover part are formed of moulded thermoplastic
23. The marine fender of any one of claims 16 to 23, wherein the first cover part and the second cover part are formed of polyethylene.
24. The marine fender of any one of claims 16 to 23, wherein the energy-absorptive core is formed of closed-cell foam.
25. The marine fender of any one of claims 16 to 24, configured as a floating fender.
26. A kit of parts for constructing a marine fender, comprising: an energy-absorptive core; and a protective cover, separate to the energy-absorptive core, shaped to conform around the energy-absorptive core, wherein the protective cover is manipulable to cover the energy-absorptive core.
27. The kit of parts of claim 24, wherein the protective cover comprises a first cover part shaped to conform around a portion of the energy-absorptive core, and a second cover part, separate to the first cover part, shaped to conform around a portion of the energy-absorptive core.
28. The kit of parts of claim 26 or claim 27, wherein the first cover part and the second cover part are flexible plastic.