GB1559566A - Attachment for a submersible - Google Patents

Description

(54) ATTACHMENT FOR A SUBMERSIBLE (71) NVe, INTERNATIONAL HYDRO DYNAMICS COMPANY LTD., a Canadian Company, of P. O. Box 1059, Station"A" Vancouver, British Columfbia, V6C 2PI, Canada, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed to be particularly described in and by the following statement :- This invention relates to a submersible vessel having an open ended skirt releasably attached to it. The vessel is useful in attaching to under water installations to ransfer men and materials from the vessel to the underwater installation.

Probably the most important underwater installations are the installations referred to as a wellhead cellars in the oil industry.

Pumping stations are positioned under the sea and pumps and the like are installed in wellhead cellars in order to pump the oil from a well into a pipeline. It is, of course, desirable to provide for maintenance of the pumps. A diver can safely work at depths up to 300 feet but below that depth it is necessary to provide a vessel so thtat a maintenance crew can go down to a submarine or similar submersible vessel so that a maintenance crew can go installation to carry out the necessary maintenance.

A device that has proved useful is shown in Canadian patent No. 908,567 issued to Lockheed on August 29,1972. In that patent a seal assembly comprises a resilient, deformable sealing element associated with a submersible capsule that is lowered through the water on a cab ! e. There is a seal surface on the underwater installation and the sealing member and the seal surface mate together to permit a maintenance crew to pass from the capsule into the underwater installation.

The system in the Canadian patent re- quires a , essl to bc lowered on a cable to the underwater installation carrying the maintenance crew. This can be difficult and it is believed desirable to transfer the maintenance crew from a free ranging vessel, for example the small submarines or"submersibles"as they are known- which are powered by their own motors.

It is known to attach so called transfer hulls to those vessels so that the crew of the submersible can pass from the submersible to the transfer hull. From the transfer hull they can move to, for example, an underwater installation or simply out of the transfer hull for underwater exploration.

However the present invention finds its main application in a relatively recent diving technique known as saturation diving.

Saturation diving permits divers to remain at high pressure without decompression, sometimes for weeks. In saturation diving the undersea working pressure for the divers is determined. The divers will work at these pressures, under the sea, for several hours. When the shift or work is comp ! eted th ; ; divers are brought to the surface in a transfer hull maintained at the working pressure. They are brought aboard ship and transfered from the transfer hull to living quarters also maintained at the working pressure. By this means the extremely time-consuming process of decompression of divers, either by bringing them up slowly or by placing them in a decompression chamber, is avoided. The dangers of the too rapid decompression of divers with consequent rapid removal of dissolved nitrogen from their blood have long been known. The best known result is the crippling of divers by the affliction known as"the bends"or caisson disease.

To be useful in saturation diving the transfer hull must be provided with joints able to withstand the external pressure under the sea and the internal pressure on the surface. That is the joint must be able to withstand compressive loads underwater and tensile loads on the surface.

The present invention is, accordingly, a submersible vessel to enable communication with the interior of an underwater installation. There is an opening in the vessel closable by at least one hatch, an open ended skirt attached to the vessel at one end by a releasable attachment that surrounds the opening, the skirt being adapted to receive means to enable its attachment to the underwater installation at its other end. The vessel and skirt form two components and the releasable attachment between them comprises a continuous channel formed in one component, the channel having an open top, a base and opposed sides; discrete first shoulders positioned around the open top of the channel, spaced from the channel base and having undersides opposite the channel base, the first shoulders dividing the top of the channel into at least two parts of a first, greater width, and at least two parts of a second lesser width. A tongue formed on the second component corresponds to the channel in the first component and is of substantially the same width as the parts of lesser width around the top of the channel. Discrete second shoulders are formed on the tongue remote from the second component. The shoulders have undersides opposite the second component, and are shaped to correspond to a portion of the channel adjacent its base. Each of the second shoulders is arranged to be alignable with a part of greater width at the top of said channel, whereby the two components can be brought together and the shoulders on the tongue of said second component can pass through the parts of greater width at the top of the channel in the first components to contact the base of the channel. Relative rotation of the components then moves the underside of the first shoulders into abutment with the undersides of the second shoulders to form a water tight attachment between the two components.

In a preferred embodiment the first component is the vessel-that is the continuous channel is formed in the vessel-and the second component is the open ended skirt.

Desirably there is a flange extending around the opening of the vessel and the channel is formed in that flange. It is also desirable that there be O-rings positioned around the joint. Typically, the 0-rings are positioned in channels positioned on each side of the tongue.

In one embodiment the submersible vessel is a transfer hull that also has a second opening to communicate with a submersible and a hatch to close the second opening so that a maintenance crew can pass from the submersible to the transfer hull and then to the underwater installation.

It is desirable that the skirt have means at its lower end to permit the attachment of adapters to enable the location of the skirt, and thus the transfer hull, on the underwater installation or on the pressurized living quarters on a ship. This adapter may connect, at its lower end, to any conven- tional sealed joint.

The invention is illustrated, by way of example, only, in the accompanying drawings in which: Figure I is a general view of a submarine having a transfer hull to which is attached a skirt; Figure 2 is detail of Figure I illustrating the invention in more detail; Figure 3 is view of a releasable attachment according to the invention; Figure 4 is a view along the line 4-4 in Figure 3; Figure 5 is a detail of the skirt shown in Figure 2; and Figure 6 is a view along the line 6-6 in Figure 5.

Figure I illustrates a submarine generally indicateS at 2 having a conning tower 4 front view hatch 6 and a rear view hatch 8.

The submarine forms no part of the present invention and is thus illustrated somewhat diagrammatically. A transfer hull 10 is attached to the submarine 2 at a port 12 in the stern of the submarine 2. There is a hatch 14 that sealably closes the passage between the submarine 2 and the transfer hull 10. The transfer hull 10 is located by bolts 16 and, as a safety precaution, the hatch 16 is provided with a viewing port 18. Again these structural details are conventional in the prior art.

At the lower end of the transfer hull 10 there is an opening 20 closable by an inner lockout hatch 22 and an outer lockout hatch 24. Inner lockout hatch 22 pivots on hinge assembly 26. The outer lockout hatch 24 pivots on hinge assembly 28 and its opening and closing is controlled by hydraulic cylinder 30 extending between mounting brackets 32 and 34. The outer lockout hatch 24 is provided with a viewing port 36 and is locked closed by latch assembly 38 that comprises catches 40 loaded by a spring 42 on shaft 44. Catches 40 engage on the lug 46 attached to a flange 48 that surrounds the opening 20 in the transfer hull 10. As is conventional the lockout hatches 22 and 24 are provided with sealing 0-rings 50.

The arrangement of the inner and outer lockout hatch 22 and 24, their hinge assemblies and means to open and close them form no part of the. present invention.

In the illustrated embodiment a skirt 52, open at both its ends, is attached to the transfer hull 10. The attachment is releasable and extends all the way around the opening 20 in the transfer hull 10.

The attachment of the two components, the transfer hull 10 and the skirt 52, is illustrated more clearly in Figures 3 to 6.

Figures 3 and 4 illustrate the part of the releasable attachment formed in the flange 48 that surrounds the opening 20 in the transfer hull 10. Flange 48 is formed with a continuous channel 54 having an open top 56, a base 5 & and opposed sides 60. There are discrete shoulders 62 formed on the sides 60 of the open top 56 of the channel 54. Shoulders 62 have undersides 64 opposite and substantially parallel to the base 58 of the channels 54. These shoulders 64 divide the open top 56 of the channel 54 into a part of a first, greater width 66 and second parts, 68, of lesser width as shown particularly in Figure 3. As illustrated in Figure 4 the open tops 56 of the channels 54 are desirably chamfered at 70 for a purpose to be described later. It is also desirable that the corners 72 of the portions 74 of the channel 54 adjacent its base 58 be rounded as illustrated in Figure 4.

As illustrated in Figure 3 the parts of greater width 66 and the, parts of lesser width 68 are evenly spaced around the channel 54 and are approximately of equal arcuate length. In the illustrated embodi- ment there are eight parts of greater width 66 and eight parts of lesser width 68. However the actual number is merely a matter of choice.

Figures 5 and 6 illustrate the part of the releasable attachment formed, at least in the illustrated embodiment, on the skirt 52.

As illustrated in these drawings there is an upwardly extending tongue 76 formed on the skirt 52 corresponding in radius and dimensions to the channel 54 in the flange 48 on the transfer hull 10. The width of the tongue 76 is substantially the same as the width of the parts 68 of lesser width on the flange 48. There are discrete shoulders 78 formed on the top of the tongue 76 remote from flat upper surface 80 of the skirt 52. In the illustrated embodiment these shoulders 78 are formed on both sides of the tongue 76 and have undersides 82 remote from the upper surface 80 of the skirt 52. Shoulders 78 are shaped to conform to the portion 74 of channel 54 adjacent its base 58. Each shoulders 78 is arranged-as illustrated most clearly in Figure 5-to be alignable with a part 66 of greater width at the open top 56 of channel 54.

The arrangement of the releasable attachment on the two components, skirt 52 and transfer hull 10, is such that the two components can be brought together and the shoulders 78 on the tongues 76 of the skirt 52 pass through the parts 66 of greater width at the open top 56 of the channel 54 in the flange 48 of the transfer hull 10.

The shoulder 78 contacts the base 58 of the channel 54 and fills that portion 74 of the channel 54 adjacent the base 58. Relative rotation of the skirt 52 and of the transfer hull 10-usually carried out by rotation of the skirt 52-moves the undersides 64 and 82 of shoulders 62 and 78 into tight abuting contact to form a fluid-tight attachment between the skirt 52 and the hull 10.

This fluid-tightness is assisted by the provision of 0-rings 84 located in channels 86 positioned on either side of the tongue 76 and surrounding the flat upper surface 80 of the skirt 52.

Location of the shoulders 78 on tongue 76 within the wider portions 66 in the channel 54 is facilitated by the chamfer 70 at the open top 56 of channel 52 and chamfer 88 shown at the top of the shoulder 78.

Although not shown in the drawings it is desirable that the undersides 82 of the shoulders 78. be chamfered or relieved at their"leading"edges, that is the edges that first contact the undersides 64 of shoulders 62 when the two components are rotated relative to each other. This is to ease compression of the 0-rings and to avoid cutting the rings. Such an arrangement is conventional in the use of O-ring seals. A chamfer that moves the underside 64 about 1/8th inch downwards on the first inch of rotation is typical.

Although the illustrated embodiment shows the tongue 76 and its attendent shoulders 78 formed on the skirt 52 and the channel 54 formed in the flange 48 of the transfer hull 10 the positioning of the tongue 76 and of the channel 54 can be reversed.

As illustrated in Figure 2 the skirt 52 may be provided with a flange 90 at its lower end formed with an arrangement of open top channels and shoulders as described for the flange 48 on the transfer hull 10. This permits the attachment of a wide variety of adapters using the same joint used to attach skirt 52 to transfer hull 10. However, it should be em, phasized that this arrangement is not essential. Any means of attaching adapters to the skirt 52 can be used. This permits the attachment of a wide variety of adapters using the same joint used to attach skirt 52 to transfer hull 10. Usually the adapter will be such as to permit ease of attachment of the skirt 52 to the underwater installation.

The submersible vessel of the present invention permits communication of the interior of the transfer hull 10-and thus by use of the hatch 14, the interior of the submarine 2-to an underwater installa tion. The use is as follows. Before entering the water the skirt 52 is attached to the transfer hull 10 as described above. The submarine with its attached transfer hull and skirt 52 then enters the water and locates the underwater installation. Once there, the adapter attached to the lower end of the skirt 52 is attached in a water tight manner to the underwater installation.

A maintenance crew can pass from the submarine 2 into the transfer hull 10 by opening port 12. Water is then pumped from the portion of skirt 52 beneath the outer Icckout hatch 24. Inner lockout hatch 22 is then opened, followed by opening of outer lockout hatch 24. Visual inspection to determine whether it is safe to open the outer lockout hatch 24 can be carried out by viewing through the viewing port 36.

An openable top formed on the underwater installation-usually in the form of a hatch -can be opened and access thus gained to the underwater installation.

However, the preferred use does not involve people moving from the submarine 2 to the underwater installation but merely from the transfer hull to the installation and back when the work at the installation has been completed.

Claims (7)

1. WHAT WE CLAIM : 1. A submersible vessel to enable communication with the interior of an underwater ; an opening in the vessel closeable by at least one hatch ; an open ended skirt attached to the vessel at one end by a releasable attachment that surrounds the opening, the skirt being adapted to receive means to enable its attachment to the under water installation at its other end, the vessel and skirt forming two components and the releasable attachment between them comprising : a continuous channel formed in one component, the channel having an open top, a base and opposed sides; discrete first shoulders positioned around the open top of the channel, spaced from the channel base and having undersides opposite the channel base, the first shoulders dividing the top of the channel into at least two parts of a first, greater width and at least two parts of a second, lesser width; a tongue formed on the second component to correspond to the channel in the first component and of substantially the same width as the said part of lesser width around the top of said channel ; discrete second shoulders formed on the tongue, remote from the second component, the shoulder having undersides opposite the second component and being shaped to correspond to the portion of said channel adjacent its base, each second shoulder being arranged to be alignable with a portion of greater width at the top of said channel, whereby the two components can be brought together and the shoulders on the tongue of the second component pass through the parts of greater width at the top of said channel in said first component to contact the base of said channel, relative rotation of the components then moving the undersides of the first shoulders into abutment with the undersides of the second shoulders to form a sealed attachment be- tween the two components capable of withstanding internal or external pressure.
2. 2. A submersible vessel as claimed in claim 1 in which the first component is the vessel and the second component is the open ended skirt.
3. 3. A submersible vessel as claimed in claim 2 in which a lange extends around the opening in said vessel and in which the channel is formed in the flange.
4. 4. A submersible vessel as claimed in claim 1 having eight parts of greater width and eight parts of lesser width arranged in a circle around the opening, each of said parts being of approximately the same arcuate length.
5. 5. A submersible vessel as claimed in claim 1 including O-rincs positioned in channels on each side of the tongue.
6. 6. A submersible vessel as claimed in claim 1 in which the vessel is a transfer hull having a second opening to communicate with a submarine and a hatch to close said second opening.
7. 7. A submersible vessel substantially as herein described with reference to the accompanying drawings.