A submersible camera and a method of installing and removing the same

Abstract

A system for installing an instrument (e.g. submersible camera 76) in a wall 100 (e.g. hull) of a vessel (e.g. ship or reaction vessel) comprises a housing 12 to be mounted in the wall, a valve (e.g.

Description

[001] The present disclosure concerns a submersible camera and a method for installing and removing the submersible camera. BACKGROUND

[002] Vessels, such as ships and boats, are typically fitted with a wide variety of camerasforvariousapplications. Forexample, through-hull camerasare a camera system that can be used in a variety of marine applications, including navigation assistance, underwater surveys and inspections, fishing, and recreational activities. In addition, through-hull cameras may provide real-time visuals of below the waterline. In some cases, the captured video or image can be integrated with navigation systems on the vessel or with augmented reality platforms to enhance the user experience. Vessels can be fitted with through-hull cameras on the side and / or the bottom of the hull, allowing for underwater surveillance, or monitoring, by capturing video or images from beneath the vessel. Through-hull cameras are typically housed in a protective casing that seals it securely, preventing water from entering the hull.

[003] Conventional through-hull cameras are often limited in design, features, and performance. Most available options are either permanently fixed to the hull, making removal difficult, or employ a spring-loaded flap design. In the spring-loaded flap designs, the user may remove the camera element, housed in a separate enclosure which inserts through a permanently installed hull fitting, or a skin fitting, for cleaning or maintenance. Pressure from the water keeps the spring-loaded flap closed, thereby restricting the inward flow of water into the vessel. However, the flap's reliance on water pressure for closure is insufficient to guarantee complete water ingress prevention. While this existing design may temporarily stem the flow of water, the spring-loaded flap mechanism frequently fails due to saltwater corrosion, flimsy materials and substandard design.

[004] Additionally, existing through-hull cameras models, due to their reliance on outdated camera module technology, are typically limited in size. While other through-hull cameras designs incorporate lens window glass within the skin fitting and a removable camera module, these designs are inherently flawed. Damage to the glass can compromise the vessel's watertight integrity, necessitating significant repair measures such as boat lifting and hull cutting. Furthermore, cleaning the window requires specialised diving or lifting equipment. SUMMARY OF THE INVENTION

[005] Accordingly, the present application seeks to address the limitations and drawbacks of conventional through-hull cameras.

[006] According to a first aspect of the present invention, there is provided a submersible camera as defined in claim 1 hereinafter. The submersible camera for installation in a hull of a vessel, the submersible camera comprising: a housing comprising a bore; a ball valve within the bore of the housing, the ball valve comprising a spherical body and a conduit through the spherical body; and a camera cassette comprising a camera, the camera cassette configured to be inserted through the conduit and into the bore of the housing.

[007] In this way, a submersible camera with a housing and with a ball valve and a removable camera cassette provides several key advantages for marine vessels. The ball valve ensures a watertight seal during installation and removal of the camera cassette, allowing maintenance and repairs to be performed while the vessel remains in the water, thereby reducing downtime and costs. The modular submersible camera simplifies the maintenance, enabling quick replacements and upgrades of the camera cassette without disrupting the housing or compromising underwater seals. Moreover, the submersible camera enhances safety by preventing water ingress. The submersible camera simplifies the installation and removal process ensuring long-term durability and reliability in harsh marine environments.

[008] In embodiments, the ball valve comprises a rotational means for adjusting the orientation of the conduit of the ball valve. In embodiments, the rotational means comprises a slot formed in the spherical body and a keyway configured to be positioned within the slot. In this way, the orientation of the conduit of the ball valve can be precisely controlled to prevent water ingress.

[009] In embodiments, the keyway comprises a tool engagement means configured to receive a driving tool for rotating the keyway. In embodiments, the housing comprises a keyway aperture. In this way, the keyway can be rotated by conventional tools, thereby allowing easier removal and installation of the camera cassette.

[0010] In embodiments, the tool engagement means is received within a keyway aperture in the housing to enable rotation of the tool engagement means about the keyway aperture. In this way, the keyway and, as a result, the spherical body of the ball valve, can be fixed in position relative to the housing.

[0011] In embodiments, the tool engagement means is configured to rotate the spherical body of the ball valve between an open position and a closed position, wherein, in the open position, the conduit of the ball valve is aligned with the bore of the housing, and, in the closed position, the conduit of the ball valve is substantially perpendicular to the bore of the housing. In this way, when the conduit is in a closed position, water ingress is prevented into the hull of a vessel during removal of the camera cassette. Moreover, when the conduit is in an open position, the camera cassette can be inserted into the housing during installation.

[0012] In embodiments, the housing comprises a first flange configured to abut an external surface around the hole in the hull of the vessel. In this way, the housing can be inserted into the hole in the hull of the vessel and the flange creates a watertight seal around the hole.

[0013] In embodiments, the housing comprises a first shoulder within the bore, the spherical body of the ball valve configured to abut the first shoulder. In this way, the housing can be inserted into the hole in the hull of the vessel and the flange creates a watertight seal around the hole.

[0014] In embodiments, the housing comprises a first threaded portion at a first end of the housing and a second threaded portion at a second end of the housing. In embodiments, the submersible camera further comprises a locking ring comprising a first aperture, the first aperture comprising a third threaded portion configured to engage with the first threaded portion to secure the housing to the hole in the hull of the vessel. In this way, the housing can be fastened within the hole in the hull of a vessel and thereby allowing for the installation and removal of the camera cassette.

[0015] In embodiments, the locking ring comprises one or more grooves around an outer circumference of the locking ring. In this way, the locking ring can be fastened onto the housing more easily.

[0016] In embodiments, the submersible camera further comprises a first anti-friction ring between the spherical body of the ball valve and the first shoulder within the bore. In this way, friction is reduced as the spherical body of the ball valve is rotated.

[0017] In embodiments, the submersible camera further comprises a housing end cap comprising a fourth threaded portion configured to engage the third threaded portion of the housing. In embodiments, the housing end cap comprises a second flange configured to abut against the second end of the housing. In embodiments, the housing end cap comprises a second shoulder configured to abut the spherical body of the ball valve opposite to the first shoulder. In this way, the ball valve can be secured in position within the housing to ensure correct alignment.

[0018] In embodiments, the submersible camera further comprises a second antifriction ring between the spherical body of the ball valve and the second shoulder of the housing end cap. In this way, friction is reduced as the spherical body of the ball valve is rotated.

[0019] In embodiments, the housing end cap comprises a second aperture and a fifth threaded portion within the second aperture.

[0020] In embodiments, the submersible camera further comprises an open ring cap, the open cap ring comprising a sixth threaded portion configured to engage the fifth threaded portion of the housing end cap.

[0021] In embodiments, the submersible camera further comprises a closed back cap, the closed back cap comprising a seventh threaded portion configured to engage the fifth threaded portion of the housing end cap.

[0022] According to a second aspect of the present invention, there is provided a method of installing a camera cassette into a submersible camera as defined as described above. In this way, a watertight seal can be created by the ball valve to ensure that water does not ingress into the hull of the vessel.

[0023] According to a third aspect of the present invention, there is provided a method of removing a camera cassette into a submersible camera a submersible camera as defined as described above. In this way, a watertight seal can be created by the ball valve to ensure that water does not ingress into the hull of the vessel as the camera cassette is removed from within the housing. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Illustrative embodiments of the present invention will now be described byway of example only with reference to the accompanying drawings in which:

[0025] Figure 1 shows an exploded view of a submersible camera system;

[0026] Figure 2 shows a cross-section view of the submersible camera system shown in Figure 1 installed in a hull of a vessel;

[0027] Figure 3 shows a cross-section view of the submersible camera system shown in Figure 1 with an open back ring removed;

[0028] Figure 4 shows a cross-section view of the submersible camera system shown in Figure 1 with a camera cassette partially withdrawn;

[0029] Figure 5 shows a cross-section view of the submersible camera system shown in Figure 1 with a ball valve in a closed position;

[0030] Figure 6 shows a cross-section view of the submersible camera system shown in Figure 1 with a closed back cap fastened;

[0031] Figure 7 shows a cross-section view of the submersible camera system shown in Figure 1 with a camera cassette partially inserted;

[0032] Figure 8 shows a cross-section view of the submersible camera system shown in Figure 1 with the ball valve in an open position; and

[0033] Figure 9 shows a cross-section view of the submersible camera system shown in Figure 1 installed in a hull of a vessel, corresponding to Figure 2. DETAILED DESCRIPTION

[0034] Figure 1 shows a submersible camera system 10, or a through-hull camera, of a first illustrative embodiment. The submersible camera system 10 comprises a skin fitting housing 12 configured to be inserted into a hole in a hull 100 of a vessel. The skin fitting housing 12 may comprise a first flange 14 at a first end 16 of the skin fitting housing 12. The first flange 14 may have a larger diameter than a diameter of the skin fitting housing 12 and a diameter of the hole in the hull 100 of the vessel to prevent the skin fitting housing 12 from passing through the hole in the vessel.

[0035] The submersible camera system 10 further comprises a ball valve 18 provided within a bore 20 of the skin fitting housing 12. The ball valve 18 comprises a spherical body 22 (or other ball) comprising a conduit 24 passing through the centre point of the spherical body 22. The ball valve 18 may comprise a rotational means 26 for adjusting the orientation of the conduit 24 between an open position and a closed position. In the open position, the conduit 24 is substantially aligned with the bore 20 of the skin fitting housing 12. Preferably, the conduit 24 and the bore 20 have the same diameter to that when the ball valve 24 is open, they form a substantially continuous surface. In the closed position, the conduit 24 is substantially perpendicular to the bore 20 of the skin fitting housing 12.

[0036] The skin fitting housing 12 may comprise a first threaded portion 28 on an outer surface 30 of the skin fitting housing 12 at the first end 16 and a second threaded portion 32 on an inner surface 34 of the skin fitting housing 12 at a second end 36 of the skin fitting housing 12. The first end 16 of the skin fitting housing 12 is opposite to the second end 36.

[0037] The submersible camera system 10 may further comprise a locking ring 38 comprising a third threaded portion 40. The third threaded portion 40 enables the locking ring 38 to be screwed, or tightened, onto the first threaded portion 28 of the skin fitting housing 12, such that the skin fitting housing 12 can be secured to the hull 100 of a vessel within the hole. In addition, the locking ring 38 may comprise one or more grooves 42, or knurling, to prove a better grip for tightening the locking ring 38 onto the first threaded portion 28 of the skin fitting housing 12, for example with a spanner or socket wrench.

[0038] To install the skin fitting housing 12 within the hole in the hull 100 of the vessel, the skin fitting housing 12 is inserted into the hole from outside the hull 100 of the vessel until the first flange 14 of the skin fitting housing 12 abuts against the outer surface of the hull 100. The locking ring 38 is then tightened onto the first threaded portion 28 of the skin fitting housing 12 which compresses the first flange 14 against the outer surface of the hull 100. As the locking ring 38 is tightened, the locking ring 38 compresses against the inner surface of the hull 100, such that a watertight seal is created between the first flange 14 and the locking ring 38 due to the compression of the first flange 14 and locking ring 38 against the outer and inner surface of the hull 100, respectively. It will be appreciated that any suitable sealing material (not shown), such as an O-ring seal, washer and / or a resin or grease may be provided between the flange 14 and the hull 100 and / or between the locking ring 38 and the hull, or around the inside or outside of the joint.

[0039] The rotational means 26 of the ball valve 18 may comprise a slot 44 formed on the spherical body 22 and a keyway 46 configured to be inserted into the slot 44. The slot 44 may be formed on a side of the spherical body 22 that is perpendicular to the axis of the conduit 24. The slot 44 has a substantially rectangular surface 45 into which the keyway 46 is received. Preferably, the keyway 46 is shaped to substantially match the curvature of the spherical body 22 so that the keyway 46 is flush with the spherical body 22 when inserted into the slot 44. When the keyway 46 is inserted into the slot 44, the spherical body 22 is rotationally locked with the keyway 46, such that rotation of the keyway 46 changes the orientation of the spherical body 22. That is, rotation of the keyway 46 rotates the spherical body 22 and the conduit 24.

[0040] The keyway 46 may further comprise a tool engagement means 48 for engaging with a tool to rotate the keyway 46 and the spherical body 22. The tool engagement means 48 is shaped to engage a driving element of a tool. For example, the tool engagement means may comprise a tool slot 50 for receiving the driving element, such as a slot for a slotted screwdriver, a cross-shaped slot for a Phillips head screwdriver, a hexagon-shaped opening for an Allen wrench, a star-shaped slot for a Torx screwdriver, or any other slot suitable for receiving a conventional driving bit. In addition, the tool engagement means 48 may protrude out from the surface of the keyway 46. As such, the tool engagement means 48 may be inserted into a keyway aperture 52 provided in the skin fitting housing 12. In this way, the keyway 46 can be fixed in position relative to the skin fitting housing 12 and enables the keyway 46, and consequently the spherical body 22 and conduit 24, to be rotated about the keyway aperture 52. It will be appreciated that rather than providing a separate keyway 46, the tool engagement means 48, 50 may be provided directly on or integrally with the ball 22.

[0041] The submersible camera system 10 further comprises a skin fitting end cap 54 (so termed because it is the end cap of the skin fitting housing 12). The skin fitting end cap 54 is configured to be threaded into the second threaded portion 32 of the skin fitting housing 12. That is, the skin fitting end cap 54 comprises a fourth threaded section 56 that can be threaded into the second threaded section 32 of the skin fitting housing 12. In addition, the skin fitting end cap 54 may comprise a second flange 58 that corresponds to the diameter of the skin fitting housing 12. As such, when the skin fitting end cap 54 is threaded into the skin fitting housing 12, the second flange 58 of the skin fitting end cap 54 surrounds the second end 36 of the skin fitting housing 12, thereby ensuring a watertight seal between the skin fitting housing 12 and the skin fitting end cap 54.

[0042] The bore 20 of the skin fitting housing 12 may comprise a first internal shoulder 60 at the first end 16 of the skin fitting housing 12. The first internal shoulder 60 is configured to receive a first anti-friction ring 62. The first anti-friction ring 62 is configured to abut the first internal shoulder 60 and the spherical body 22 of the ball valve 18 to ensure that the spherical body 22 is correctly positioned within the bore 20, such that the tool engagement means 48 on the keyway 46 aligns with the keyway aperture 52. In addition, the skin fitting end cap 54 may comprise a second internal shoulder 64 that is configured to receive a second anti-friction ring 66. The second anti-friction ring 66 is configured to abut the second internal shoulder 64 and the spherical body 22 of the ball valve 18 as the skin fitting end cap 54 is fastened onto the skin fitting housing 12. Advantageously, the first anti-friction ring 62 and second anti-friction ring 66 reduce friction when the spherical body 22 of the ball valve 18 is rotated. The first and second anti-friction rings 62,66 may comprise Teflon, or any other suitable material with a low friction coefficient.

[0043] The skin fitting end cap 54 further comprises a first aperture 68 for receiving a camera cassette 70, or camera module, such that the camera cassette 70 can be inserted into the conduit 24 of the ball valve 18 and contained within the skin fitting housing 12. When the camera cassette 70 is, at least partially and / or fully, inserted into the bore 20 of the skin fitting housing 12, the camera cassette 70 forms a seal with the skin fitting housing 12 to prevent ingress of water into the hull 100 of the vessel. For example, the exterior diameter of the camera cassette 70 may be substantially the same as the diameter of the bore 20 of the skin fitting housing 12 to form the watertight seal. The camera cassette 70 comprises a camera cassette body 72 and a camera cassette end cap 74 and houses a camera 76 suitable for capturing photographs and / or video footage. In addition, a fifth threaded portion 78 is provided within the first aperture 68 of the skin fitting end cap 54.

[0044] The skin fitting housing 12 further comprises a camera aperture 80 at the first end 16, through which the camera 76 within the camera cassette 70 faces. The camera cassette 70 may comprise a lens window 82 that provides a sealed window for the camera 76. In this way, when submersible camera system 10 is secured within the hole in the hull 100 of the vessel, the camera 76 faces outwardly from the hull 100 in a direction substantially below the surface of the water and can capture images and video of the surrounding environment directly beneath and around the vessel. In addition, when the camera cassette 70 is fully inserted into the bore 20, the camera cassette 70 abuts the camera aperture 80 to form a watertight seal with the skin fitting housing 12 to prevent ingress of water into the hull 100 of the vessel. In arrangements, the camera aperture 80 may comprise a flange or shoulder that the camera cassette 70 abuts to form the watertight seal.

[0045] The camera cassette 70 may comprise a marker ring 84 provided on the camera cassette body 72 in a location corresponding to a distance between the second end 36 of the skin fitting housing 12 and a surface of the spherical body 22 of the ball valve closest to the second end 36. Advantageously, the marker ring 84 enables a user to determine when the camera cassette 70 has been sufficiently withdrawn during the removal or replacement of the camera cassette 70, which will be explained in more detail below. In embodiments, the marker ring 84 can be a painted ring or can be a machined groove on the camera cassette body 72. A suitable marker other than the marker ring 84 can be provided as well or instead.

[0046] To allow the camera cassette 70 to be inserted into the skin fitting housing 12, the conduit 24 within the spherical body 22 is aligned with the bore 20 of the skin fitting housing 12. That is, the conduit 24 is preferably concentrically aligned with the bore 20 of the skin fitting housing 12. In this way, the camera cassette 70 can be inserted into the conduit 24 of the ball valve 18 and fully inserted into the skin fitting housing 12. The orientation of the conduit 24 can be adjusted by rotation of the rotational means 26, as described above, to ensure correct alignment, such that the camera cassette 70 can be fully inserted into the skin fitting housing 12.

[0047] Once the camera cassette 70 has been fully inserted through the first aperture 68 of the skin fitting end cap 54 and through the conduit 24 of the ball valve 18, the camera cassette 70 is locked in place by an open back ring 86 having a second aperture 88. The second aperture 88 is sized to allow cables to pass through the second aperture 88 from within the camera cassette 70. The open back ring 86 comprises a sixth threaded portion 90 configured to engage with the fifth threaded portion 78 within the first aperture 68 of the skin fitting end cap 54. Fastening the open back ring 86 to the skin fitting end cap 54 locks the camera cassette 70 in place within the skin fitting housing 12.

[0048] In addition, a closed back cap 92 may be provided with a seventh threaded portion 94 for securing the closed back cap 92 into the first aperture 68 of the skin fitting end cap 54. In this way, the closed back cap 92 can be fastened onto the skin fitting end cap 54 to seal the skin fitting housing 12 from water when the camera cassette 70 is removed from the skin fitting housing 12. It is to be understood that when the camera cassette 70 is removed from the skin fitting housing 12, the open back ring 86 is preferably replaced with the closed back cap 92.

[0049] Sealing elements, such as O-rings, may be provided between components of the submersible camera system 10 to ensure that a watertight seal is created once the components are fastened together. For example, a sealing groove 96 may be provided on the skin fitting end cap 54 and on the camera cassette body 72 that are configured to receive the sealing element (not shown). In this way, watertight seals are created when the skin fitting end cap 54 and the camera cassette 70 are respectively inserted into the skin fitting housing 12, thereby preventing ingress of water into the hull 100 of the vessel when the submersible camera system 10 is in use. It will be appreciated that other methods of creating a seal between the camera cassette body 72 and the skin fitting housing 12 may be used, as well or instead.

[0050] Figures 2 to 6 show removal of the camera cassette 70 from within the submersible camera system 10. To remove the camera cassette 70 from the skin fitting housing 12, the open back ring 86 is removed from the first aperture 68 of the skin fitting end cap 54, as shown in Figure 3, and the camera cassette 70 is removed from within the skin fitting housing 12 until the marker ring 84 is visible on the camera cassette body 72, but no further, as shown in Figure 4. This ensures that a watertight seal is formed between the camera cassette body 72 and the inside of the skin fitting housing 12, at least when the camera cassette body has been withdrawn from (or inserted in) the skin fitting housing 12 to the predetermined extent. Once the marker ring 84 is visible, the keyway 46 is rotated by the tool engagement means 48 until the ball valve 18 is in a closed position, as shown in Figure 5, thereby creating a second watertight seal within the skin fitting housing 12. It will be appreciated that a stop means may be provided to ensure that the ball 22 can only rotate to the perpendicular position and not beyond, thereby ensuring that the ball 22 is positioned to close the ball valve 18. Only when the ball valve 18 is in the closed position can the camera cassette 70 be fully removed from within the skin fitting housing 12 to ensure that water does not ingress into the hull 100 of the vessel. As shown in Figure 6, the closed back cap 92 is then fastened into the first aperture 68 of the skin fitting end cap 54 to seal the second end 36 of the skin fitting housing 12 to prevent ingress of water into the hull 100 of the vessel in case the ball valve 18 weeps or is accidentally opened.

[0051] Figures 6 to 9 show installation of the camera cassette 70 into the submersible camera system 10. To facilitate installation of the camera cassette 70 into the skin fitting housing 12, the steps described above in regard to removal are carried out substantially in reverse. First, the user checks that the ball valve 18 is in the closed position and then the closed back cap 92 shown in Figure 6 is removed by unscrewing the closed back cap 92 from the skin fitting end cap 54. The camera cassette 70 is then inserted into the skin fitting housing 12 through the first aperture 68 of the skin fitting end cap 54, preferably until the camera cassette 70 abuts the spherical surface 34 of the ball valve 18, as shown in Figure 7, but at least as far as the marker ring 84 aligns with the end 36 of the skin fitting housing 12 in order to create a seal between the camera cassette 70 and the skin fitting housing 12. The keyway 46 is then rotated by the tool engagement means 48 until the ball valve 18 is in a open position, as shown in Figure 9, where the conduit 24 is concentrically aligned with the bore 20. It will be appreciated that a stop means may be provided to ensure that the ball 22 can only rotate to the open position and not beyond, thereby ensuring that the conduit 24 of the ball 22 is aligned with the bore 20. Opening the ball valve 18 allows the camera cassette 70 to be fully inserted into the skin fitting housing 12. Once the conduit 22 of the ball valve 18 has been rotated to the open position, the camera cassette 70 is inserted into the skin fitting housing 12 through the conduit 22 until it is fully located within the skin fitting housing 12 and the camera 76 is substantially within the camera aperture 80. The open back ring 86 is then fastened into the first aperture 68 of the skin fitting end cap 54 to secure the camera cassette 70 in place within the skin fitting housing 12.

[0052] Accordingly, the submersible camera system 10 described above allows for easy removal of the camera cassette 70, while preventing the ingress of water into the hull 100 of the vessel. In addition, the camera cassette 70 can be replaced within the skin fitting housing 12 as fitted to hull 100 of the vessel, thereby eliminating the need for significant repair measures such as boat lifting, hull cutting, and / or the need for divers to replace the camera cassette.

[0053] It will be understood that the embodiments illustrated above show applications of the invention only for the purposes of illustration. In practice the invention may be applied to many different configurations, the detailed embodiments being straightforward for those skilled in the art to implement.

[0054] In particular, it will be understood that the present invention is not limited to applications for cameras installed in boat hulls, and the present invention has wider application to the installation of instruments and tools in the walls of any vessel. Thus, a camera is just one example of an instrument that could be used in the present invention, and other instruments can be used as well or instead. For example, the present invention could be used to view or measure conditions inside a reaction vessel or a pipe, as well as in surface water craft, underwater craft, aircraft, and land craft. The sealing techniques can be adapted to cope with the required conditions of fluid type (water or other liquid, air or other gas), pressure and intended environment (temperature, corrosiveness, acidity, salinity etc). For the use case of a through-hull camera, one or more O-rings provided on the camera cartridge 70 and / or the skin fitting housing 12 may suffice or be supplemented with other means such as non-corrosive sealing grease, such as silicone grease.

[0055] Moreover, although the foregoing description uses the expression cassette to describe how a camera or other instrument is mounted to the housing, it should be understood that the expression "cassette" should only be construed to mean a holder for the instrument allowing it to be sea I i ngly fitted in the housing.

Claims

1. A system for installing an instrument in a wall of a vessel, the apparatus comprising:a housing comprising a bore, the housing configured to be mounted in the wall of the vessel;a valve within the bore of the housing; anda cassette comprising the instrument, the cassette being configured to be inserted into the bore of the housing,wherein a seal is formed between the cassette and at least a part of the bore when the cassette is at least partially disposed in the bore and the valve is open.

2. The system according to claim 1, wherein the valve comprises a rotational means for adjusting an orientation of the valve between an open position and a closed position.

3. The system according to claim 2, wherein the valve comprises a ball valve, the ball valve comprising a ball and a conduit in the ball, and the cassette is configured to be inserted into the conduit.

4. The system according to claim 3, wherein the rotational means comprises a tool engagement means configured to receive a driving tool for adjusting the orientation of the conduit of the ball valve.

5. The system according to claim 4, wherein the tool engagement means comprises a slot formed in the ball and a keyway configured to be positioned within the slot.

6. The system according to claim 4 or claim 5, wherein the housing comprises an aperture, and wherein the tool engagement means is at least partially disposed in theaperture.

7. The system according to any one of claims 3 to 6, wherein the rotational means is configured to rotate the conduit between an open position and a closed position, wherein, in the open position, the conduit of the ball valve is aligned with the bore of the housing to form a substantially continuous surface, and, in the closed position, the conduit of the ball valve is substantially perpendicular to the bore of the housing.

8. The system according to any preceding claim, wherein the housing comprises: a first flange configured to abut an external surface around the hole in the hull of the vessel;a first threaded portion at a first end of the housing; anda locking ring comprising a first aperture, the first aperture comprising a third threaded portion configured to engage with the first threaded portion to secure the housing to the hole in the hull of the vessel.

9. The system according to any preceding claim, wherein the housing comprises a first shoulder within the bore, the ball of the ball valve configured to abut the first shoulder.

10. The system according to claim 9, further comprising a first anti-friction ring between the ball of the ball valve and the first shoulder within the bore.

11. The system according to claims 8 to 10, further comprising a housing end cap comprising a fourth threaded portion configured to engage a second threaded portion within the bore at a second end of the housing.

12. The system according to claim 11, wherein the housing end cap comprises a second shoulder configured to abut the ball of the ball valve opposite to the first shoulder.

13. The system according to claim 12, further comprising a second anti-friction ring between the ball of the ball valve and the second shoulder of the housing end cap.

14. The system according to claims 11 to 13, wherein the housing end cap comprises a second aperture and a fifth threaded portion within the second aperture.

15. The system according to claim 14, further comprising an open ring cap, the open cap ring comprising a sixth threaded portion configured to engage the fifth threaded portion of the housing end cap.

16. The system according to claim 14, further comprising a closed back cap, the closed back cap comprising a seventh threaded portion configured to engage the fifth threaded portion of the housing end cap.

17. A housing for mounting an instrument in a wall of a vessel, the housing comprising:means for mounting the housing in a hole in the wall;a bore for receiving a cassette comprising the instrument; anda valve within the bore,at least a part of the bore being configured to form a seal with the cassette when the cassette is at least partially disposed in the bore and the valve is open.

18. A cassette for insertion into a housing according to claim 17, the cassette comprising:a cassette body having a diameter corresponding to a diameter of the bore of the housing; andan instrument provided within the cassette body,the cassette body is configured to form a seal with and at least a part of the bore when the cassette body is at least partially disposed in the bore.

19. A method of installing a cassette comprising an instrument into a system according to any one of claims 1 to 16, the method comprising:inserting a cassette into a bore of a housing such that the cassette forms a seal with the housing;rotating the valve from a closed position to an open position; andfurther inserting the cassette into the housing through the conduit in the ball valve.

20. The method according to claim 19, wherein the system comprises an open ring cap, the method further comprising:fastening the open ring cap onto an end of the housing once the cassette has been inserted into the housing.

21. A method of removing a cassette comprising an instrument from a system according to any one of claims 1 to 16, wherein the cassette comprises a marker, the method comprising:withdrawing the cassette from a valve until a marker on the cassette is visible; rotating the valve from an open position to a closed position;removing the cassette from the bore of the housing.

22. The method according to claim 21, wherein the system comprises a closed back cap, the method further comprising:fastening the closed back cap onto an end of the housing once the cassette has been removed.

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