Vessel insert

Abstract

A hydrodynamic insert for a vessel hull, comprising: an insert body for engaging an insert housing in a vessel hull; and a fluid guide for exchanging fluid between the exterior and the interior of the vessel hull.

Description

VESSEL INSERTTECHNICAL FIELD

[0001] The present disclosure relates to a fluid transfer unit for a vessel hull. In particular, the present disclosure relates to apparatus and methods for transferring fluids into or out of vessel hulls for interfacing vessel systems with ambient water.BACKGROUND

[0002] Maritime transport of goods via maritime vessels is an essential facet of modern logistics, enabling energy efficient transport of heavy goods and equipment over bodies of water such as oceans, canals or the like.

[0003] Such maritime vessels often rely on water collected from the surroundings of the vessel to service ballast systems for maintaining draught and trim of the vessel, cool onboard equipment, or to process to provide potable water onboard the vessel. Water is typically collected through devices known as ‘sea chests’, arranged at or in the surface of a maritime vessel hull to collect water.

[0004] Furthermore, energy-efficient modes of transport are being sought in an effort to reduce the environmental impact and use of fossil fuels in long distance transport.

[0005] Improvements in energy-efficiency of maritime vessels have been achieved using a technique known as air lubrication, whereby air is released at the vessel hull to form a layer of bubbles to lubricate the vessel hull and reduce resistance to movement of the vessel hull through the water.

[0006] In each of the instances above, fluids are transferred from the vessel to the surrounding environment, or from the surrounding environment into the vessel. Units for performing this function are typically provided at or below the waterline of a maritime vessel hull and are formed within the vessel hull.

[0007] Historically such units have therefore needed to be designed to accommodate the complexity of both structural requirements and hydrodynamic concerns. Aspects and features of the present disclosure have been devised with the foregoing in mind.SUMMARY

[0008] In a first aspect, a hydrodynamic insert such as an insert module for a vessel hull is provided. The hydrodynamic insert comprises: an insert body for engaging an insert housing such as a cavity box in a vessel hull; and a fluid guide such as a fluid conduit for exchanging fluid between the exterior and the interior of the vessel hull.

[0009] Such a hydrodynamic insert can be rapidly exchanged in a modular fashion within an insert housing to provide a fluid transfer unit, whilst still providing the same benefits of a traditional non-modular approach. The modular approach of the present disclosure separates the structural requirements of the hull from the hydrodynamic requirements of the fluid exchange unit. Examples of the hydrodynamic insert include hydrodynamic inserts configured for fluid egress, such as air exiting the vessel hull, and fluid ingress, such as water entering the vessel hull.

[0010] The insert body may be for removably engaging an insert housing in a vessel hull.

[0011] The insert body may be configured to be bolted to an insert housing in a vessel hull.

[0012] The insert body may be configured to be bonded to an insert housing in a vessel hull.

[0013] The insert body may be configured to be friction fitted to an insert housing in a vessel hull.

[0014] The hydrodynamic insert can thereby be partially or fully secured into an insert housing in a hull of a vessel.

[0015] The insert body may be positively buoyant in water.

[0016] The hydrodynamic insert may thereby be further secured in an insert housing in a vessel hull in use by its buoyancy urging the insert into the insert housing.

[0017] The hydrodynamic insert may further comprise at least one deflector element for shielding the fluid guide.

[0018] A deflector element such as a deflector plate provides mechanical protection for a fluid guide of the hydrodynamic insert by preventing large waves or solid objects from impacting the fluid guide. In some examples, the deflector element such as a deflector plate provides a wall to define a cavity within the fluid guide in which adesired fluid pressure can be maintained. In some examples, the deflector element such as a deflector plate reduces drag on the hull by at least partially occluding the fluid guide.

[0019] The at least one deflector element may be removable.

[0020] A removable deflector element facilitates inspection of the fluid guide of the hydrodynamic insert or insert module, maintenance of the hydrodynamic insert and in some examples blanking of the hydrodynamic insert. Further, a removable deflector element allows replacement of the elements of the hydrodynamic insert which are most susceptible to mechanical damage, and allows selection of different materials for different elements of a fluid transfer unit comprising the hydrodynamic insert.

[0021] The at least one deflector element may be reversibly engageable with a housing in a vessel hull for retaining the hydrodynamic insert.

[0022] The deflector element may thereby be configured to attach to the hull to secure, or aid in securing, the hydrodynamic insert in a insert housing in a vessel hull.

[0023] The at least one deflector element may comprise a composite material.

[0024] Material selection of the deflector element enables examples where the deflector element maybe configured to be light but strong for some applications.

[0025] The at least one deflector element may comprise steel.

[0026] The deflector element may thereby be configured to be mechanically robust for some applications.

[0027] The hydrodynamic insert may be for an air release unit and the fluid guide maybe for guiding air from an interior to an exterior of a vessel hull when the vessel hull is in water.

[0028] The hydrodynamic insert can thereby be formed as an air release unit, to guide compressed air into the water surrounding a vessel to generate microbubbles at an air-water interface, reducing the resistance to movement of the vessel through the water and increasing efficiency of the vessel.

[0029] The fluid guide may comprise an outwardly-facing opening arranged towards a trailing end of the insert body when the hydrodynamic insert is driven through water, wherein the fluid guide is configured to guide air to mix with the water at the opening to form a lubricating bubble layer trailing the hydrodynamic insert.

[0030] The insert body may thereby include a fluid guide with an outwardly- facing opening arranged to encourage mixing of air and water and create a bubble layer to lubricate passage of a vessel through water. In some examples, the fluid guide is configured to maintain a desired pressure within a cavity formed by the fluid guide and a deflector element, thereby providing a stable air-water interface to induce fluid shearing.

[0031] The fluid guide may be configured to promote mixing of air and water at the outwardly-facing opening of the fluid guide; and / or the fluid guide may comprise a cross-sectional volume that decreases towards the trailing end of the insert body.

[0032] A section of the fluid guide may thereby have a profile which narrows towards the trailing end of the insert, thus distributing air flow more uniformly across the fluid guide towards the opening. A uniform distribution of air within the fluid guide, and especially towards the opening of the fluid guide promotes fluid shearing between the air within the fluid guide and the water surrounding the fluid transfer unit.

[0033] The hydrodynamic insert may be for a sea chest and the fluid guide may be for guiding water from an exterior to an interior of a vessel hull when the vessel hull is in water.

[0034] The insert can be formed as a sea chest, to guide water into a vessel port in a vessel hull for intake by the vessel for ballasting, cooling and / or other purposes.

[0035] The insert body may comprise a phenolic resin.

[0036] Phenolic resins are resistant to abrasion and to thermal cycling as required for an air release unit which needs to tolerate temperatures up to 235C whilst immersed in sea water at ambient temperatures.

[0037] The phenolic resin may be a novolak.

[0038] Novolaks are particularly thermally resistant and durable materials, suitable for forming the insert body.

[0039] The insert body may comprise light steel.

[0040] The hydrodynamic insert may be formed from steel and therefore provide an insert that is very mechanically and thermally robust for some applications.

[0041] In a second aspect, a fluid transfer unit for a vessel hull is provided. The fluid transfer unit comprises: a hydrodynamic insert for exchanging fluid between the exterior and the interior of the vessel; and an insert housing formed by the vessel hull for retaining the hydrodynamic insert.

[0042] A fluid transfer unit with a replaceable hydrodynamic insert can be reconfigured with different hydrodynamic inserts for different purposes or conditions. Examples of the hydrodynamic insert include hydrodynamic inserts configured for fluid egress, such as air exiting the vessel hull, and fluid ingress, such as water entering the vessel hull.

[0043] The hydrodynamic insert of the fluid transfer unit may be a hydrodynamic insert as described above.

[0044] The hydrodynamic insert of the fluid transfer unit is further provided with an insert body and a fluid guide, improving the flow properties of implementations configured for fluid egress, such as air exiting the vessel hull, and fluid ingress, such as water entering the vessel hull.

[0045] The hydrodynamic insert may be configured to fit into the insert housing such that a periphery of an outer face of the transfer unit lies flush with an outer surface of a vessel hull.

[0046] Thereby the external surface of the fluid transfer unit is arranged to lie flush with the surface of the vessel and provide reduced hydrodynamic resistance of a vessel hull comprising the insert compared to non-flush examples which may disrupt fluid flow.

[0047] In a third aspect, a vessel hull comprising an insert housing for retaining a hydrodynamic insert as described above is provided.

[0048] Costs and difficulty in providing a vessel hull suitable for fitting with a fluid transfer unit are reduced by using the same materials as the rest of the vessel hull. Furthermore, compliance with regulatory requirements is encouraged by used of the same materials.

[0049] The insert housing may be formed between longitudinal and transverse supports of the vessel hull. In some examples, the insert housing maybe formed between, intersecting and / or spanning longitudinal and transverse supports.

[0050] The vessel hull structure and strength is uncompromised by addition of the insert housings for receiving the inserts. Insert housings compensate structurally for the discontinuity associated with the hull opening created.

[0051] In a fourth aspect, a method of providing a vessel hull with a fluid transfer unit is provided. The method comprises: forming an insert housing in the vessel hull;and fitting a hydrodynamic insert as described above into the insert housing of the vessel hull.

[0052] In a fifth aspect, a method of forming a fluid transfer unit in a vessel hull is provided. The method comprises: fitting a hydrodynamic insert as described above into an insert housing of the vessel hull.

[0053] A vessel provided with insert housings and inserts of various types can thereby be rapidly repaired or reconfigured with no structural alterations and without sacrificing any structural performance of the vessel. Thus a vessel can be rapidly safely reconfigured whilst in keeping with regulatory requirements.BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Embodiments of the present disclosure will now be described, by way of example only, with reference to the accompanying drawings, in which:Fig. 1 shows an example of a fluid transfer unit;Fig. 2a shows a view of an example of a hydrodynamic insert from above;Fig. 2b shows a view of an example of a hydrodynamic insert from below;Fig. 3a shows a view of an example of an insert housing from inside a vessel hull;Fig 3b shows a view of an example of an insert housing from beneath a vessel hull; andFig. 4 shows a cross-sectional view of an example of a fluid transfer unit.DETAILED DESCRIPTION

[0055] Fig. 1. shows an example of a fluid transfer unit 100 installed in a vessel hull, showing a hydrodynamic insert 102, a deflector element 104, here a deflector plate, and a vessel hull 106. The hydrodynamic insert is placed within an insert housing 108. The hydrodynamic insert 102 of the fluid transfer unit 100 comprises a leading end 110 and a trailing end 112. Herein the term ‘leading end’ refers to the ‘front’ of the fluid transfer unit or component parts in the direction of travel through a medium such as water and / or sea water of the fluid transfer unit when in use. The term ‘trailing end’ refers to the ‘rear’ of the fluid transfer unit or component parts in the direction of travel through a medium such as water and / or sea water of the fluid transfer unit when in use.

[0056] As shown in Fig. 1, the hydrodynamic insert 102 comprises features and formations which are designed to improve hydrodynamic properties of the insert when exposed to flowing water, and / or to improve flow within the hydrodynamic insert to facilitate fluid ingress (such as water intake) or fluid egress (such as air output).

[0057] The hydrodynamic insert 102 is placed within an insert housing 108 formed in the vessel hull 106 which is capable of providing structural continuity to the vessel hull 106 independently of the hydrodynamic insert 102. The insert housing 108 provides the structural support whilst the hydrodynamic insert 102 provides hydrodynamic features to provide the desired improvements in transfer of fluids between the interior and exterior of the vessel hull.

[0058] The fluid transfer unit too is provided on a surface of the vessel hull 106 which is in contact with water when the vessel is in use. As shown in Fig. 1, the surface is a lower surface or bottom surface of the vessel hull, or surface of the hull typically submerged in use.

[0059] In some examples, the fluid transfer unit too is provided on a flat surface of the vessel hull 106. In some examples, the fluid transfer unit too is provided on a side of the vessel hull 106. Such an arrangement provides improvements in availability of water for intake through the fluid transfer unit when placed on a leading portion of the vessel hull.

[0060] In some examples, one or more fluid transfer units too are provided on the vessel hull 106. In some examples, one or more fluid transfer units are provided in a formation on the vessel hull 106 to provide uniform fluid transfer over an area of the vessel hull 106.

[0061] As shown in the example of Fig. 1, the periphery of the outer face of the fluid transfer unit (i.e. the face facing away from the vessel) is arranged to lie substantially in-plane or flush with the adjacent vessel hull 106 surface. That is to say, when installed, a face of the hydrodynamic insert 102 of the fluid transfer unit too is arranged such that it does not protrude substantially from the vessel hull, nor does it form a recess within the vessel hull when installed. This allows a fluid transfer unit to be provided that does not unnecessarily disrupt the flow of water past the vessel hull 106 and thus increase flow resistance of the vessel hull.

[0062] In some examples, the periphery of the fluid transfer unit is arranged to lie (i.e. protrude or lie beneath) within 5mm of the surface of the vessel hull. In someexamples, the face of the hydrodynamic insert that faces away from the vessel is configured to lie within 5mm of the periphery of the hydrodynamic insert across its width and breadth.

[0063] Fig. 2a shows an example of a hydrodynamic insert 102 as viewed from above. The hydrodynamic insert 102 comprises an insert body 200, an inner face 204, a lateral face 206 and a fluid guide 202.

[0064] The insert body 200 is configured to engage the insert housing 108 such that the insert housing 108 retains the hydrodynamic insert 102. As shown in Fig. 2a, the insert body 200 is configured to cooperatively engage the insert housing 108 such that the insert body 200 is constrained to a desired orientation once inserted.

[0065] The inner face 204 of the insert body 200 is arranged to abut the insert housing 108 and provide support for the hydrodynamic insert 102 to maintain alignment of the hydrodynamic insert 102 with the vessel hull 106. The lateral face 206 of the insert body 200 is configured to engage with the insert housing 108 to align the hydrodynamic insert 102 as desired in the vessel hull 106. In use, the inner face 204 faces away from the body of water in which the vessel hull 106 is placed.

[0066] In some examples, the lateral face 206 may engage with the insert housing 108 to prevent rotation of the insert body 200. In some examples, the lateral face 206 of the insert body 200 may engage with the insert housing 108 to retain the hydrodynamic insert 102 within the insert housing 108.

[0067] In some examples, the lateral face 206 and / or the inner face 204 is configured to be bonded to an insert housing 108 of a vessel hull 106 to retain the hydrodynamic insert 102 in the insert housing 108. In some examples, the lateral face 206 and / or the inner face 204 is configured to be bolted to an insert housing 108 of a vessel hull 106 to retain the hydrodynamic insert 102 in the insert housing 108. In some examples, the lateral face 206 is configured to be friction fit into an insert housing 108 of the vessel hull to retain the hydrodynamic insert 102 in the insert housing 108. In some examples, retention of the hydrodynamic insert 102 is achieved by combination of any of the above configurations of the lateral face 206 and / or the inner face 204. Arrangement of the connector on the lateral face 206 has benefits in the provision of sea chests.

[0068] In some examples, the insert body 200 is positively buoyant in water and / or sea water. Advantageously, the buoyancy of the insert body 200 urges the insert body 200 into the insert housing 108 to further secure the insert body 200 to the vesselhull 106. In some examples, the insert body 200 is positively buoyant in addition to having a lateral face 206 and / or inner face 204 configured as described above for engagement with the insert housing 108. Such an example provides a hydrodynamic insert 102 which is further secured to the vessel hull 106.

[0069] In some examples, the deflector element 104 is configured to retain the hydrodynamic insert 102 in the insert housing 108 by engaging the vessel hull 106 and / or the insert housing 108, thereby clamping the hydrodynamic insert 102 between the deflector element 104 and the insert housing 108.

[0070] The fluid guide 202 is confined or defined by a boundary formed by the insert body 200, defining a connector 208. The connector 208 is configured to interface with a complementary vessel port (not shown in Fig. 1 or 2) to enable fluid to pass between the hydrodynamic insert 102 and the interior of the vessel hull 106. In some examples, the connector 208 is arranged on the lateral face 206 of the insert body 200 and / or the inner face 204 of the insert body 200, such as at a leading end 110 or a trailing end 112 of the insert body 200.

[0071] In some implementations, the connector 208 is arranged towards the leading end 110 of the hydrodynamic insert 102. In some examples, the connector 208 is arranged towards the centre of the hydrodynamic insert 102. In some examples, the connector 208 is arranged towards the trailing end of the hydrodynamic insert.

[0072] As shown in Fig. 2a, the insert body 200 has an approximately rectangular profile. In some examples, the insert body has a non-rectangular profile, such as a triangular, circular or elliptical profile. Different profiles of the insert body 200 may improve cooperation of the insert housing 108 with the vessel hull 106, and assist in providing structural benefits depending on the type of hull used.

[0073] Fig. 2b shows the hydrodynamic insert of Fig. 2a when viewed from below. The fluid guide 202 is shown as comprising a cavity 210 arranged on an outer face 214 of the insert body 200, terminating at an opening 212. The outer face 214 of the insert body 200 is arranged to interface with the body of water and / or sea water in which the vessel hull 106 is placed.

[0074] The cavity 204 of the fluid guide 202 as shown in the example of Fig 2b is configured to have a reducing cross-sectional area towards the trailing end of the hydrodynamic insert 102. The profile of the cavity 210 as shown provides improved uniformity of air pressure across the opening 212 of the fluid guide 202 to promote fluidshearing between the air in the fluid guide 202 and the surrounding water. This is achieved by distribution of the air to fill the cavity 210 as uniformly as is possible, creating a stable air-water interface that supports fluid shearing by leveraging Kelvin- Helmholtz instability. The action of fluid shearing is guided by the opening 212 from the leading end 110 to the trailing end 112 of the hydrodynamic insert 102.

[0075] In some examples, the hydrodynamic insert 102 comprises materials impervious to water absorption and / or water pressure. In some examples, the hydrodynamic insert 102 comprises materials that are resilient to thermal cycling and high thermal gradients. In implementations where the fluid transfer unit is configured as an air release unit (ARU), compressed air may enter the hydrodynamic insert 102 at temperatures as high as 235°C whilst the outer face 214 of the hydrodynamic insert is well thermalised to the ambient water, usually between -2°C and 2i°C. The hydrodynamic insert 102 must therefore be resilient to large temperature gradients and thermal cycling when the air release unit is not in use.

[0076] In some examples, the insert body 200 comprises one or more plastics. In some examples, the insert body 200 comprises one or more of: phenolics, polytetrafluoroethylene (PTFE), polyetheretherketone (PEEK), polyetherimide (PEI), polybenzimidazole (PBI) and / or nylon. In some examples, the insert body 200 comprises a metal. In some examples, the insert body 200 comprises thin gauge steel. In some examples, the insert body 200 comprises wood, optionally as a solid wooden element or as a filling material in resin casting. In some examples, the insert body 200 comprises a single material / is formed from a single material. In some examples, the insert body 200 comprises composite materials. In some examples, the insert body 200 comprises a combination of materials to accommodate different requirements. In some examples, the insert body may comprise any combination of the above described materials.

[0077] In some examples, the insert body 200 may be formed from a number of sub-elements which combine to form an insert body 200. Each of the sub-elements may comprise any of the materials as described above.

[0078] In some examples, the insert body 200 comprises materials which are resistant to fouling. In the present context, fouling refers to accumulation of undesired materials on marine surfaces, for example marine life such as mussels. It is a further benefit of the present disclosure that when selecting such anti-fouling materials structural requirements of the vessel hull 106 need not be considered.

[0079] A further benefit is presented when fouling of elements of the fluid transfer unit occurs, replacement of the hydrodynamic insert 102 can be achieved rapidly and without extensive delays thus restoring operation of the fluid transfer unit too. This is achieved without the delays necessary to clean the relatively complex interior surfaces of the hydrodynamic insert 102.

[0080] In some implementations, the insert body 200 and / or the deflector element 104 comprise recyclable plastics or other recyclable materials, thus reducing the environmental impact of production of fluid transfer units too.

[0081] Fig. 3a shows an example of an insert housing 108, such as a cavity box in a vessel hull 106 as viewed from above, or as viewed from within the vessel hull 106. The insert housing 108 is shown between transverse supports 306 and intersecting a longitudinal support 304 of the vessel hull 106.

[0082] The insert housing 108 is configured to meet the same structural requirements as the vessel hull 106. The insert housing 108 forms both an integral element of the vessel hull 106 watertight envelope and is subject to primary hull loading forces, as do all elements of the hull structure.

[0083] The insert housing 108 comprises a vessel port 300, configured to interface with a connector 202 of a hydrodynamic insert 102. The vessel port 300 is typically connected to one or more components within the vessel hull 106, configured for processing fluid as required. In some examples, the vessel port 300 is blanked off to prevent any fluid flow. In some examples, the vessel port 300 comprises a valve configured to prevent fluid flow in an undesired direction, such as forming a watertight boundary in the context of an emergency situation.

[0084] Fig. 3b shows the insert housing 108 of Fig. 3a from below, beneath or outside of the vessel hull 106. The insert housing 108 is shown comprising an internal surface 302. In some examples, the internal surface 302 is configured to cooperatively engage with a lateral face 206 and / or an inner face 204 of a vessel insert.

[0085] An advantage to the provision of an insert housing 108 and a hydrodynamic insert 102 is the separation of structural design considerations from fluid flow considerations, whether in design of a fluid transfer unit or construction and fitting of a fluid transfer unit. The shape of the insert housing 108 can be reduced in complexity, allowing its shape and hull integration to consider only primary functions which are to maintain hull watertight integrity whilst carrying both global and local hullloadings. Design or manufacture of the insert housing 108 therefore need not consider the internal functions of the hydrodynamic insert 102.

[0086] In some examples, such an insert housing 108 is subject to Classification Society Rules for the construction of ships and therefore some implementations of the insert housing 108 and its integration into a vessel hull 106 will be subject to regulatory approval.

[0087] In some examples the insert housing 108 is configured to inhibit transmission of hull stresses to the hydrodynamic insert 102. Advantageously, this prevents the hydrodynamic insert 102 from becoming deformed or displaced from the insert housing 108, thus ensuring the hydrodynamic insert 102 operates correctly.

[0088] In some examples engagement between the insert body 200 and the insert housing 108 further inhibits transmission of hull stresses to the hydrodynamic insert.

[0089] Shown in Fig. 4 is a cross-section of the fluid transfer unit too of Fig. 1, showing the vessel hull 106, insert housing 108, hydrodynamic insert 102, deflector element 104, fluid guide 202, cavity 210 of the fluid guide 202, connector 208, vessel port 300, and internal surface 302 of the insert housing 108.

[0090] As shown in Fig. 4, the connector 208 of the insert housing 102 is connected to the vessel port 300 such that fluid can pass between the hydrodynamic insert 102 and the interior of the vessel hull 106.

[0091] In some implementations, the vessel 300 and connector 208 must provide a robust connection capable of withstanding high pressures up to 300 kPa and high temperatures up to 24O°C.

[0092] The deflector element in Fig. 4 is shown partially occluding an opening 212 of the fluid guide 202. This position of the deflector element 104 advantageously provides a back pressure to enable fluids (such as air) to fill the cavity 210 when the vessel hull 106 is in motion through water. A further benefit of the deflector element is masking the cavity 210 thus minimising hull flow resistance or drag.

[0093] In some examples, the deflector element 104 is integrally formed with the insert body 200.

[0094] As shown in Fig. 1, the deflector element maybe used to provide further retention of the hydrodynamic insert 102 by clamping the hydrodynamic insert 102 between the deflection plate 104 and the insert housing 108. In some implementations,the deflector element 104 is configured to be removably engaged with the vessel hull 106 and / or the insert housing 108.

[0095] In some examples, the deflector element 104 is configured to engage the vessel hull 106 by being bolted to the vessel hull surrounding the insert housing 104. In some examples, the deflector element 104 is configured to engage the insert housing 108 by being bolted to the insert housing 108.

[0096] In some examples, the deflector element 104 retains the hydrodynamic insert 102 by occluding the insert housing 108 to prevent the hydrodynamic insert 102 from leaving the insert housing 108.

[0097] In some examples, the hydrodynamic insert 102 is configured as a sea chest for collecting water, and the deflector element 104 comprises a grillage configured to prevent large debris entering the vessel port 300.

[0098] In some examples where fluid transfer is not desired, the hydrodynamic insert 102 is configured to simply fill the insert housing 108 and eliminate any flow resistance that would be otherwise incurred by the presence of the insert housing 108 or a fluid transfer unit too.

[0099] In such an implementation where the hydrodynamic insert 102 is configured to simply fill insert housing 108, the connector 208 of the hydrodynamic insert 102 maybe configured to connect to the vessel port 300 and operably ‘blank’ the vessel port 300 to prevent water from entering the vessel port 300.

[0100] Vessels may be provided with fluid transfer units via a number of methods. In some implementations, a vessel may not comprise any recesses in its hull to receive a hydrodynamic insert 102 as described in the foregoing.

[0101] In such implementations, a recess is installed in the vessel hull 106 by excising a portion of the vessel hull 106 and replacing that portion with an insert housing 108 as described above. Advantageously, the insert housing 108 maybe formed from the same materials used in the rest of the vessel hull 106, reducing complexity of the fitting of the insert.

[0102] In some implementations, an insert housing 108 maybe provided in a vessel hull 106 at the point of manufacture of the vessel hull 106 and provided with a hydrodynamic insert 102 configured to ‘blank’ the vessel port 300 as described above, for later retrofit of the vessel with air release units and / or sea chests as required.

[0103] In such implementations, the hydrodynamic insert 102 is removed and a new hydrodynamic insert 102 is fitted to the insert housing 108 as required by the needs of the vessel.

[0104] In some implementations, a vessel hull may already comprise a fluid transfer unit too which has become damaged or obsolete, requiring repair or replacement. In such implementations, the hydrodynamic insert 102 is removed and a new hydrodynamic insert 102 is fitted to the insert housing 108 as required by the needs of the vessel.

[0105] The term ‘hydrodynamic’ in the present disclosure should be understood as relating to fluids, including materials which behave as fluids or can be modelled upon fluids, such as liquids, gasses, or plasmas.

[0106] The term ‘vessel’ in the present disclosure refers to a maritime vessel, such as a vessel for traversing oceans or other waterways.

[0107] The term ‘fluid’ in the present disclosure refers to materials which behave as fluids or can be modelled upon fluids, such as liquids, gasses, or plasmas.Penultimate comments

[0108] It is to be understood that the above description is intended to be illustrative, and not restrictive. Many other examples will be apparent to those of skill in the art upon reading and understanding the above description. Although the present disclosure has been described with reference to specific examples, it will be recognized that the present disclosure is not limited to the examples described, but can be practiced with modification and alteration within the spirit and scope of the appended claims. Accordingly, the specification and drawings are to be regarded in an illustrative sense rather than a restrictive sense. The scope of the present disclosure should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.

Claims

CLAIMS1. A hydrodynamic insert for a vessel hull, the insert comprising: an insert body for engaging an insert housing in a vessel hull; and a fluid guide for exchanging fluid between the exterior and the interior of the vessel hull.

2. The hydrodynamic insert according to any preceding claim, wherein the insert body is for removably engaging an insert housing in a vessel hull.

3. The hydrodynamic insert according to claim 2, wherein the insert body is configured to be bolted to an insert housing in a vessel hull.

4. The hydrodynamic insert according to claim 2 or claim 3, wherein the insert body is configured to be bonded to an insert housing in a vessel hull.

5. The hydrodynamic insert according to any of claim 2 to claim 4, wherein the insert body is configured to be friction fitted to an insert housing in a vessel hull.

6. The hydrodynamic insert according to any of claim 2 to claim 5, wherein the insert body is positively buoyant in water.

7. The hydrodynamic insert according to any preceding claim, further comprising at least one deflector element for shielding the fluid guide.

8. The hydrodynamic insert according to claim 7, wherein the at least one deflector element is removable.

9. The hydrodynamic insert according to claim 8, wherein the at least one deflector element is reversibly engageable with a housing in a vessel hull for retaining the hydrodynamic insert.

10. The hydrodynamic insert according to claim 8 or claim 9, wherein the at least one deflector element comprises a composite material.

11. The hydrodynamic insert according to claim 8 or claim 9, wherein the at least one deflector element comprises steel.

12. The hydrodynamic insert according to any preceding claim, wherein the hydrodynamic insert is for an air release unit and the fluid guide is for guiding air from an interior to an exterior of a vessel hull when the vessel hull is in water.

13. The hydrodynamic insert according to claim 12, wherein the fluid guide comprises an outwardly-facing opening arranged towards a trailing end of the insert body when the hydrodynamic insert is driven through water, wherein the fluid guide is configured to guide air to mix with the water at the opening to form a lubricating bubble layer trailing the hydrodynamic insert.

14. The hydrodynamic insert according to claim 13, wherein the fluid guide is configured to promote mixing of air and water at the outwardly-facing opening of the fluid guide; and / or wherein the fluid guide comprises a cross-sectional volume that decreases towards the trailing end of the insert body.

15. The hydrodynamic insert according to any of claims 1-11, wherein the hydrodynamic insert is for a sea chest and the fluid guide is for guiding water from an exterior to an interior of a vessel hull when the vessel hull is in water.

16. The hydrodynamic insert according to any preceding claim, wherein the insert body comprises a phenolic resin or composite material.

17. The hydrodynamic insert according to claim 16, wherein the phenolic resin is a novolak.

18. The hydrodynamic insert according to any of claim 1 to claim 15, wherein the insert body comprises light steel.

19. A fluid transfer unit for a vessel hull, the fluid transfer unit comprising: a hydrodynamic insert for exchanging fluid between the exterior and the interior of the vessel; and an insert housing formed by the vessel hull for retaining the hydrodynamic insert.

20. The fluid transfer unit of claim 19, wherein the hydrodynamic insert is a hydrodynamic insert according to any of claims 1 - 18.

21. The fluid transfer unit according to claim 19 or claim 20, wherein the hydrodynamic insert is configured to fit the insert housing such that a periphery of an outer face of the transfer unit lies flush with an outer surface of a vessel hull.

22. A vessel hull comprising an insert housing for retaining a hydrodynamic insert according to any of claims 1-18.

23. The vessel hull according to claim 22, wherein the insert housing is formed between, intersecting and / or spanning longitudinal and transverse supports.

24. A method of providing a vessel hull with a fluid transfer unit, the method comprising: forming an insert housing in the vessel hull; and fitting a hydrodynamic insert according to any of claims 1-18 into the insert housing of the vessel hull.

25. A method of forming a fluid transfer unit in a vessel hull, the method comprising: fitting a hydrodynamic insert according to any of claims 1-18 into an insert housing of the vessel hull.

Images