US3712070A

US3712070A - Small portable underwater observation and communication chamber

Info

Publication number: US3712070A
Application number: US00199843A
Authority: US
Inventors: J Macinnis
Original assignee: Individual
Current assignee: Individual
Priority date: 1971-11-18
Filing date: 1971-11-18
Publication date: 1973-01-23
Anticipated expiration: 1990-01-23

Abstract

A portable underwater air retention chamber comprising; air container means having an access opening sufficient at least to receive the head of a diver; tether means attachable to said container means to locate the same in position underwater with said access opening means directed downwardly and defining a predetermined spacing therebeneath, and, removable mooring means attachable to said tether means for securing the same in an underwater location.

Description

United States Patent [191 Macinnis SMALL PORTABLE UNDERWATER OBSERVATION AND COMMUNICATION CHAMBER lnventor: Joseph Beverly Macinnis, 21 Mc- Master Avenue, Toronto, 190 Ontario, Canada [22] Filed: NOV. 18, 1971 [21] Appl.No.: 199,843

Related US. Application Data [63] Continuation-impart of Ser. No. 38,931, May 19,

I970, abandoned.

[52] U.S.Cl ..6l/69 R, 114/1615 [51] Int. Cl ..B63c 11/00 [58] Field Of Search ..6l/46.5, 69, 70; 114/.5 T, 1 14/16 R, 16 E [56] References Cited UNITED STATES PATENTS 3,344,614 10/1967 Byck 61/69 R Jan. 23, 1973 3,379,022 4/1968 Welton ..6l/69 R Primary Examiner-J. Karl Bell Alt0meyGeorge A. Rolston [57] ABSTRACT A portable underwater air retention chamber comprising; air container means having an access opening sufficient at least to receive the head of a diver; tether means attachable to said container means to locate the same in position underwater with said access opening means directed downwardly and defining a predetermined spacing therebeneath, and, removable mooring means attachable to said tether means for securing the same in an underwater location.

12 Claims, 5 Drawing Figures PATENIEDJM23 1915 3.712.070

SHEET 2 BF 2 In van for JOSEPH B. MoclNNlS SMALL PORTABLE UNDERWATER OBSERVATION AND COMMUNICATION CHAMBER This application is a continuation-in-part of application Ser. No. 38,93 1, entitled Small Portable Underwater Observation and Communication Chamber, filed May 19, 1970 now abandoned. V

The present invention relates to a personally portable underwater chamber suitable for underwater observation, communication and the like by a diver, and preferably by a diver provided with independent underwater breathing apparatus.

One of the earliest known forms of underwater assistance for divers is the so-called diving bell." All it consists of is an inverted cup-shaped chamber of varying size in which atmospheric air is entrapped, permitting divers to enter from below and take one or two breaths and resume diving. It is noteworthy that such a diving bell was suspended from the surface by a cable or rope and was of very considerable weight in order to carry downwardly a sufficient volume of air to a sufficient diving depth to provide a reasonable degree of utility to divers at the normal free diving depth. Thus, not only was the chamber tethered from the surface, and in addition was also was of very considerable weight, but it was also movable relative to the sea bed, and was in particular capable of upward and downward movement in response to movement of the vessel to which it was attached.

Possibly due to the development of highly sophisticated underwater diving and breathing apparatus, virtually freeing the individual diver from the need to re-surface at intervals, and the need for any contact with the surface by means of air lines or the like, little or no interest has been shown in this type of static device.

However, the greatly increased interest in underwater exploration and scientific discovery that has taken place in recent years has brought to light certain problems which cannot readily be solved by individual free divers. Thus, for example, the communication between the individual free diver and persons on the surface is generally speaking only possible by telephone involving the use of a tethered telephone cable. Even given such a submarine telephone, the individual diver finds communication somewhat difficult since both his mouth and ears are necessarily covered when diving. In addition, communication between two individual divers is generally speaking possible only to a very limited extent, and in the majority of cases, either where two divers wish to communicate, or where one diver wishes to communicate with the surface, the most practical solution is for the two divers or the individual diver to actually return to the surface. This is particularly unsatisfactory since repeated changes in pressure as the diver returns from diving depths to the surface and back again are generally speaking undesirable since it both wastes valuable diving time, and also subjects the diver to possible health hazards.

The present invention utilizes the basic concept of a diving bell, as being an inverted air-filled chamber, constructed in an entirely novel manner, in the creation of a unique and novel concept for a personally portable communication and observation chamber by means of which one or more divers may enter an air-filled chamber and either observe their surroundings more freely, or communicate with one another after removing their mouthpieces, or communicate with the surface by means of a simple form of underwater telephone after removal of their head gear. After a few minutes of such observation or communication the divers simply replace their equipment, and leave the chamber and resume their investigation.

The basic inventive concept is also readily applicable to recreational divers, both with and without underwater breathing apparatus. The inventive concept is readily adaptable to connection with above water air pumping systems so that a free diver without breathing apparatus may dive down, rest and breathe and then return to the surface. Thus the inventive concept is applicable both to commercial and scientific investigations, and also to a wide range of recreational uses, where the use of surface vessels for tethering the chamber, or surface located lifting equipment for moving the chamber is impossible.

It is therefore a general objective of the invention to provide an underwater chamber adapted to be tethered to the bottom of the lake or sea as the case may be, and which may be readily filled with air for use by individual divers, and which may readily be dismantled and removed without the use of special accessories.

More particularly, it is an objective of the present invention to provide such an underwater chamber formed at least in part of a transparent plastic or the like material permitting visual observation from inside the chamber.

More particularly, it is an objective of the present invention to provide such a chamber which incorporates a container adapted to lie on the bottom of the lake or sea as the case may be and which may be filled with any suitable ballast material to tether the same in position, and incorporating means attaching the chamber to such ballast container at a predetermined height permitting the entry and exit of divers thereto.

More particularly, it is an objective of the present invention to provide an underwater chamber having the foregoing advantages which is formed of flexible or rigid, transparent, plastic material which may be readily folded up for movement and storage, and which upon use may be filled with air to form an underwater observation dome.

More particularly it is an objective of the present invention to provide an underwater chamber formed in the shape of a dome or other inverted container which is of appropriate size and shape to receive the head and shoulders of at least two and perhaps three divers, leaving the remainder of the divers body exposed below the chamber, and surrounded by water.

More particularly, it is an objective of the present invention to provide an underwater chamber having the foregoing advantages incorporating a dome or container adapted to receive the head and shoulders of the diver, and incorporating a platform or other support spaced below the chamber or dome upon which the divers can stand.

More particularly, it is an objective of the present invention to provide an underwater chamber having the foregoing advantages which is provided with surface communication facilities whereby a diver may enter the chamber, remove all or part of his head gear, and communicate directly with the surface without the need for returning to the surface himself.

More particularly, it is an objective of the present invention to provide such an underwater chamber which is of low manufacturing cost and of great simplicity in design and may be manufactured and sold for mass recreational use in lakes, swimming pools and the like.

It is a further and related objective of the invention to provide an underwater chamber of the type described, and a lightweight ballast container means preferably formed of wire, or in the form of a cage or the like, adapted to lie on the bed of a body of water, and which may be filled with any suitable ballast material, the dimensions of the ballast container being greater than the dimensions of the underwater chamber means itself, and incorporating an open side for the container, and closure means for such open side, whereby the underwater chamber may actually be fitted within the ballast container, and secured therein by means of the ballast container closure means, thereby rendering the entire assembly safe and secure for shipping or storage thereof without damage to the underwater chamber itself.

BRIEF STATEMENT OF INVENTION The present invention in general comprises the provision of an underwater chamber having an inverted dome-like portion consisting partly or entirely of transparent plastic material, preferably shaped and dimensioned so as to receive and surround the head and shoulders of at least one or more divers, and having around its lower rim a rigid peripheral ring or rim of any suitable shape, to which are attached three or more tethers in the form of wires or ropes, which preferably, although not necessarily, are releasable for ease of handling, lower ends of the tethers being attached to a ballast container, preferably although not essentially being formed of wire mesh material adapted to be filled with stones or other suitable ballast material to a sufficient quantity and mass that the dome, when filled with air at a suitable operating depth, will be firmly moored to the lake or sea bottom. Preferably, the ballast container is provided with a suitable top closure or cover, also of wire mesh or any other suitable material permitting the divers to stand on such a cover without damaging their equipment or moving the ballast itself. Preferably the tethers are of such a length, and the dimensions of the rim of the dome are such that the individual divers may readily enter beneath the dome and stand erect on the ballast container with at least their heads and possibly their shoulders clear of the water level within the air in the dome. Obviously the dome may be of any shape, i.e., hemispherical, or partly spherical, cylindrical, square or the like according to the particular design and purpose desired. As stated, in some cases, surface communication systems are intended to be attached, and in some cases air delivery systems may be attached, or alternatively air may be simply delivered to the underside of the dome by any suitable delivery system, although in the majority of circumstance, sufficient air will be available from the divers breathing equipment.

The preferred embodiment of the invention will now be described by way of example only and without limitation, and with reference to the following drawings in which like reference devices refer to like parts thereof throughout the various views and diagrams and in which:

FIG. 1 is a perspective illustration of an underwater chamber and ballast container according to the present invention shown in position on the sea bed;

FIG. 2 is a greatly enlarged sectional illustration along the line 22 of FIG. 1;

FIG. 3 is a perspective illustration of a further embodiment of the invention;

FIG. 4 is a partial section along the line 4-4 of FIG. 3, and,

FIG. 5 is a section along the line 55 of FIG. 3.

FIG. 1 shows a form of invention which comprises a dome shaped chamber 10 formed of flexible transparent synthetic sheet plastic material, preferably transparent polyvinyl chloride plastic material or the like, seamed or pleated as at the seam 11 at intervals, somewhat in the manner of an umbrella so as to form it into the desired shape. Obviously, other forms of manufacture producing a chamber 10 of the desired dimensions would be satisfactory and thus the chamber 10 can be of any shape such as cylindrical, square or the like, and may be formed in separate segments of plastic material seamed together as at 1 1, provided such seams 11 are made air tight by heat sealing or welding or the like, or may be moulded or vacuum formed into the desired dome-like or hemispherical shape as shown without the use of seams at all.

The lower fringes of the chamber 10 are folded around a lower ring 12, preferably formed of some light weight material such as tubular aluminum stock or the like, and a further light weight retaining ring 13 is attached and held in position by means of the clamps 14 located at spaced intervals around the circumference of the

rings

12 and 13. It will be seen from FIG. 2 that the lower fringe of the chamber 10 is folded inwardly around the upper retaining ring 13, and is thereby clamped and held firmly between the upper ring 13 and the lower ring 12. A suitable number of attachment lugs 15 are fastened at spaced intervals around the upper retaining ring 13, in order to secure and locate the chamber 10 at a desired location under water on the bottom of the sea or lake as the cause may be. In order to secure and moor the chamber 10 in position, a container or basket generally indicated as 16 is provided into which any suitable ballast such as local stone or rock may be loaded, after the basket or container 16 has been placed in position. The container 16 is preferably formed of open weave heavy wire mesh material as shown having side walls 17 and a bottom 18, and a wire mesh platform or cover 19 hingedly attached as at the hinge 20, and optionally provided with any suitable simple form of fastening device such as the hook 21. Obviously, any other hard wearing material may be substituted for the wire mesh as shown in this preferred embodiment, although the wire mesh is found to be particularly suitable since, when the ballast is removed from the container 16, the open wire mesh material presents little or no resistance to movement through the water thereby facilitating handling by individual divers without the use of special lifting equipment.

The chamber 10 is attached to the ballast container 16 by means of the flexible tether lines 22, attached at their lower ends around the upper circumference of the side walls 17 of the container 16, and preferably incorporating at their upper ends the releasable attachment clips 23, adapted to be clipped around the lugs 15 as shown in FIG. 2, and being releasable to permit separation of the chamber from the ballast container 16 if desired.

In order to accommodate divers of differing heights, it may be considered desirable to make provision for some form of adjustment in the length of the tethers 22, and this may be provided at the upper ends of the tethers 22 by means of the adjustment slides 24. Tethers 22 are preferably formed of flexible rope, wire rope or plastic material suitably treated for underwater use.

In order to provide for communication with the surface, any suitable form of submarine telephone system may be employed, such as the telephone cable 25 and the receiver 26. If the cable 25 is particularly massive it may be desirable to lead it directly to the ballast container 16 and attach it thereto, and then lead the cable 25 upward and attach it to for example, one of the lugs 15. However, the precise details of the attachment of such telephone system are essentially a matter of choice depending upon the particular circumstances and the type of equipment employed.

In operation, the ballast container 16 which being of wire mesh construction is relatively light, together with the dome l0 and the

rings

12 and 13 may either assembled together by fastening the clips 23 to the lugs 15 at the surface, or may be taken to the bottom separately. In any event the container 16 is placed on the bottom, with the closure 19 open and any available ballast material such as rocks-and the like is then loaded into the container 16 and when it is full, the closure 19 is lowered, and preferably fastened in position by means such as the hook 21. The dome 10, if it is still unattached, is then clipped to the tethers 22 as shown, and the diver will place his head and shoulders within the dome 10, which at this point is still full of water, and discharge a certain quantity of air, preferably by operation of the regulator on his breathing equipment, (not shown) and such air willescape into the interior of the dome 10. As soon as this is done, the dome 10 will then be buoyant and will immediately rise above the container 16 thereby drawing the tethers 22 taut, and the diver can then continue to release more air into the chamber 10 until all the water is expelled therefrom. As soon as a diver wishes to communicate, he simply swims beneath the chamber 10, and then stands erect placing his feet on the closure 19 of the container 16 and placing his head and shoulders within the chamber 10. He then removes the mouth piece of his breathing equipment, and if necessary part of his head gear, and uses the telephone receiver 26 as desired. When finished he simply replaces his mouth piece and his head gear and swims away. It is anticipated that the individual diver will not remain within the chamber 10 for any extended period of time and the volume of air within the chamber 10 is anticipated as being sufficient for any normal brief usage. However if the diver should wish to continue standing within the chamber 10 for any length of time, then at intervals he will release additional air from his breathing equipment by operation of the regulator (not shown) thereby refreshing the air supply within the chamber 10. Similarly, if two or three such divers should wish to communicate with one another then they may stand on the closure 19 and place their heads and shoulders within the chamber 10 and remove their breathing mouth pieces and speak.

In many cases, especially in the case of recreational divers, it will be desirable to provide an underwater chamber, and ballast means which may readily be packaged and shipped or stored, for example in the trunk of a car, and moved from place to place and installed and removed perhaps for an afternoons use or for a weekends use, in many different locations, and the entire assembly may in fact be subject to much greater wear during shipping and storage than while in use underwater. In particular, the transparent plastic chamber may itself be readily damaged during such shipping or storage where it will be likely to be subjected to much greater hazards than when actually in use. In addition, it greatly facilitates use and in particular the filling with air, of the chamber if it is made of a rigid or semi-rigid material rather than a strictly flexible material.

Accordingly, by the practice of a further embodiment of the invention, as illustrated in FIG. 3, a chamber 30 is provided of transparent thermo-plastic material which may either be injection moulded or vacuum formed, or formed by any suitable plastic forming technique, so that the chamber 10 is provided with a substantially permanent dome-like shape as shown. A reinforced attachment ring 31 is provided around the periphery of the chamber 30 as shown, being formed of metal, or reinforced plastic or any other suitable material providing sufficient strength to support the chamber 30, and attached thereto by any suitable means such as adhesives, rivets or the like, or any other means suitable for the purpose (not shown). Attachment lug means 32 are provided at intervals around the ring 31, and the same may be attached to the tether ropes or wires 33 by means of the spring clips 34, or any other suitable attachment means, or even in some cases simply by knotting the rope 33 if desired.

In order to anchor the chamber 30 in position, ballast container means indicated generally as 35 are provided, again formed of wire mesh material, or metal rods arranged at spaced intervals, to provide a basket member 36 which is of generally cylindrical construction, and having a flat bottom 37 adapted to lie on the bed of a body of water. The top'of the container or basket 36 is left completely open, and the basket 36 is of such dimension that it is of sufficient diameter and depth to readily receive the entire chamber 30 and reinforcing ring 31 therein for shipping and storage.

Preferably, in order to avoid contact of the dome 30 with the structure of the basket 36, the reinforcing ring 31 is of slightly greater diameter than the dome 30, and the interior open diameter of the basket 36 is just sufficient to receive the ring 31 therein, but is not substantially oversize with relation thereto. In this way, the basket 36 provides a secure container for the dome 30, without permitting the dome 30 to move around therein to any substantial extent. Similarly, the depth of the basket 36 is such that it is sufficient to accommodate the dome 30 therein, and permit the lid 38 to be closed thereover without actually contacting the top of the dome 30. In this way, unnecessary contact between the structure of the basket 36 and the dome 30 is prevented.

Referring now to FIG. 5, it will be seen that the reinforcing ring 31 is attached to the dome 30 by means of an outwardly extending attachment flange 41 formed of plastic material integrally with the dome 30 in one piece. Around the attachment flange 41 are provided two generally L-shaped

metal bracket members

42 and 43, which when placed in position as shown in FIG. form an incomplete rectangle in section. Between the

brackets

42 and 43 there is provided an annular strip of rubber or synthetic rubber or plastic material 44, and a plurality of bolt members 45 extend through the bracket 43, and make threaded engagement with threaded recesses in the bracket 42. In this way, the rubber annular strip 44, which is preferably formed slightly oversized, may be placed between the

brackets

42 and 43 which are then drawn together by means of the bolts 45 arranged therearound at spaced intervals thereby squeezing and compressing the rubber 44. The attachment flange 41 which fits within the space provided between the upper surface of the rubber ring or strip 44, and the overlying portion of the bracket 43, is firmly gripped, without an actual positive clamping action which might otherwise crush or damage the plastic material. Preferably, the attachment plug means 32 are provided with threaded bolt members (not shown) extending through the entire reinforcing ring 31, and being fastened by any suitable means such as nuts or suitable threaded recesses formed in the upper portion of the bracket 43, or in any other suitable manner.

in order to close the open top of the basket 36 and at the same time to provide a supporting platform upon which divers may stand while their heads are located within the air space retained within the chamber 30, a top closure member 38 is provided, comprising a plurality of wires or metal rods, and a peripheral reinforcing ring 39 extending around the periphery thereof. Any suitable hinge means such as the hinge 40 may be provided between the basket 36 and the top closure member 38, whereby the same may be swung to and fro to open and close the same. if desired, any suitable form of retaining or locking means (not shown) may be provided for holding the top closure 38 down in position, although generally speaking this will not be required since the forces of gravity will usually be sufficient.

The operation of this further embodiment of the invention is exactly the same as described above. When the basket or container 36 has been emptied of ballast material, such as stones S, the diver or divers can then simply place the container 30 in the basket or container 36 and close the lid or closure member 38 and swim to the surface, and place it in the trunk of a car or any other suitable vehicle for removal to a new site. In this way, the relatively fragile dome or chamber 30 is completely protected against possible damage while in transit or in storage, and is yet maintained readily available for use.

For purely recreational and sports uses, the invention may be employed even without the use of underwater diving or breathing equipment at all. In this case, the chamber and the container 16 may be placed in position for example in a swimming pool or the like, and air can be introduced into the chamber 10 simply by passing an air pipe below the lower ring, and bubbling air into the chamber 10 until all of the water is expelled. Swimmers may then merely dive down to the chamber 10, rest there for a moment, and swim back to the surface while progressively exhaling in accordance with recommended safety procedures.

On the other hand, in commercial or scientific exploration, it is anticipated that several of the chambers 10 may be located at spaced intervals along the bottom of the sea or a lake near a shipwreck or area of scientific interest, all of which are connected by a telephone cable and provided with separate telephones, and a diver may then swim from one such chamber to another and report his progress along a predetermined path of investigation without the need for resurfacing at intervals which would otherwise greatly slow down his progress, and cause possible health hazards due to repeated variations in pressure.

It will be understood that for purposes of this description reference has been made to the sea bed or lake bed and similar locations. It will of course be understood that the chamber 10 according to the invention may be utilized in many different underwater locations, and may not always in all cases stand directly on such sea bed. Thus for example, it is possible that the invention might be employed on any underwater object whether a natural object such as the bed of the sea or the bed of a lake or river, of for example the deck ofa sunken ship, or on some form of artificial submarine foundation for a building. Accordingly, for the purposes of the following claims reference to an underwater location is to be understood as being a comprehensive term encompassing all possible locations and positions where such chamber may be placed, whether of natural or artificial or man made origin.

It will be further appreciated that while mooring the device by means of ballast as disclosed is a convenient method, other means may be preferable in certain circumstances. Thus, the ballast container may be moored by means of one or more anchors, pegs, rods or ties (not shown), or by securing it to some underwater structure.

Clearly, the chamber of the invention as described, when filled with air, will be adequate at the average diving depth. However, if it should be desired to operate below about feet then air will no longer be safe due to narcosis, and a special mixture of oxygen and helium will then be required. It will therefore be understood that whenever air is referred to herein the terms includes air and/or any breathing mixture which may be safely used.

The foregoing is a description of a preferred embodiment of the invention. The invention is not to be taken as limited to any of the specific features as described, but comprehends all such variations thereof as come within the spirit and scope of the appended claims.

What l claim is:

1. A portable underwater air retention chamber adapted to be anchored on the bed of an underwater location comprising;

air container means having an access opening sufficient at least to receive the head ofa diver;

tether means attachable to said container means to locate the same in position underwater with said access opening means directed and defining a predetermined spacing therebeneath;

a manually portable lightweight container for ballast defining an opening through which ballast can readily be inserted and removed thereby adapting the same to lie on the bed of said underwater location, or be moved from place to place as desired;

platform means co-extensive with said ballast container supported and located thereby at an elevation above the bed to support a diver thereon beneath said air container means, and,

said tether means being attached at intervals around said ballast container whereby to locate said air container means spaced directly above said platform means when the same is rendered buoyant by air therein.

2. The apparatus as claimed in claim 1 wherein said air container means includes a dome member of flexible transparent material, and a retaining ring around the periphery of said dome.

3. Apparatus as claimed in claim 1 wherein said tether means comprises a plurality of flexible rope like members, attachable at spaced intervals to said air container.

4. Apparatus as claimed in claim 1 wherein said tether means incorporate means for adjusting the length thereof whereby to vary the spacing therebeneath.

5. Apparatus as claimed in claim 1 including container closure means forming said platform means whereby to provide a support for a diver when using said air container means.

6. Apparatus as claimed in claim 1 wherein said air container means includes a dome member of flexible transparent material, and a rigid mounting ring means, and attachment lug means spaced therearound for attachment of said tether means thereto.

7. Apparatus as claimed in claim 1 wherein said air container means is formed of flexible material, having a generally circular periphery, and including at least two attachment rings, said flexible material being folded between two adjacent said rings and clamped therebetween, and including clamping means holding said two rings together.

8. Apparatus as claimed in claim 1 wherein said ballast container incorporated removable closure means for said container whereby the same may be filled and emptied with ballast underwater.

9. Apparatus as claimed in claim 1 wherein said ballast container comprises a wire mesh basket member of predetermined shape and size adapted to contain ballast adequate to moor said apparatus in a desired underwater location, said platform means being removably locatable over said basket member and supported thereby.

10. Apparatus as claimed in claim 1 wherein said air container means is of predetermined diameter, and wherein said ballast container defines an interior space therewithin of a diameter greater than said air container, and an access opening thereto of sufficient diameter to permit said air container to be introduced into said ballast container for shipping and storage.

11. Apparatus as claimed in claim 1 wherein said air container means is formed of a rigid transparent dome, of partially hemispherical shape, and defining a generally circular lower periphery of predetermined diameter, said rigid dome having a predetermined height, and wherein said ballast container defines an interior s ace of predetermined diameter and de th greater an said predetermined diameter and heighr'of said dome, whereby said dome may be introduced into said ballast container for shipping and storage.

12. Apparatus as claimed in claim 1 wherein said air container defines a rigid transparent dome, of predetermined diameter, and having a lower periphery, and including a reinforcing ring extending around said lower periphery, and having a diameter greater than said predetermined diameter of said dome, said tether means being attached to said reinforcing ring, and wherein said ballast container defines an interior space having a predetermined diameter greater than said predetermined diameter of said reinforcing ring, having a depth greater than the predetermined height of said dome, whereby said dome and reinforcing ring may be introduced into said ballast container for shipping and storage.

Claims

1. A portable underwater air retention chamber adapted to be anchored on the bed of an underwater location comprising; air container means having an access opening sufficient at least to receive the head of a diver; tether means attachable to said container means to locate the same in position underwater with said access opening means directed and defining a predetermined spacing therebeneath; a manually portable lightweight container for ballast defining an opening through which ballast can readily be inserted and removed thereby adapting the same to lie on the bed of said underwater location, or be moved from place to place as desired; platform means co-extensive with said ballast container supported and located thereby at an elevation above the bed to support A diver thereon beneath said air container means, and, said tether means being attached at intervals around said ballast container whereby to locate said air container means spaced directly above said platform means when the same is rendered buoyant by air therein.

11. Apparatus as claimed in claim 1 wherein said air container means is formed of a rigid transparent dome, of partially hemispherical shape, and defining a generally circular lower periphery of predetermined diameter, said rigid dome having a predetermined height, and wherein said ballast container defines an interior space of predetermined diameter and depth greater than said predetermined diameter and height of said dome, whereby said dome may be introduced into said ballast container for shipping and storage.