CA1054483A - Transducer for conversion of tidal current energy - Google Patents

Abstract

TRANSDUCER FOR CONVERSION OF
TIDAL CURRENT ENERGY

ABSTRACT OF THE DISCLOSURE

A set of aligned transducer units is fixedly disposed in the sea. Each unit includes two atmosphere compartments disposed on the opposite end portions, a sea-water stream due to a tidal current flowing through its lower portion between the compartments, and an impeller disposed between the-compartments. The sea-water stream rotates the impeller to actuate air cylinders disposed in both atmosphere compart-ments communicating with the atmosphere. The air cylinders compress the air to produce high pressure air. The high pressure air from all the cylinders is transported through a pipe to an adjacent shore to be converted to an electrical energy. A four-sided tidal current guide is mounted on each of the opposite sides of the transducer unit. A ballast water room with its control is connected to the underside of the transducer set for floating and sinking purposes.

Description

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This invention relates to an apparatus for utilizing an energy of a tidal current and more particularly to a transducer apparatus for converting an energy of a tidal current to an energy of a high pressure fluid.
There have been previously proposed various attempts to utilize the energy of tidal currents but they have not been satisfactorily operated. It is an object of the present invention to provide a new and improved trans-- 10 ducer apparatus for effectively converting an energy of a tidal currPnt to an energy of a high pressure fluid on a large scale.
In accordance with one aspect of this invention there is provided a transducer apparatus for converting the energy of a tidal current to high pressure fluid energy, comprising, in combination, a housing in the form of a rectangular box, a pair of atmosphere compartments disposed on the opposite end portions of said housing thereof and in fluid communication with each other and ~:` 20 with the atmosphere, a plenum space and a sea-water - channel disposed between said pair of atmosphere compart-ments within said housing, said sea-water channel being overlain with said plenum space to communicate in fluid-flow relationship-with the latter and having both ends open to the exterior of said housing, means for supplying high pressure fluid to said plenum space to maintain con-stant the level of the upper surface of a tidal current rr flowing through said sea-water channel, an impeller dis-m posed within said communicating plenum space and sea-~- 30 water channel so that an upper half thereof is located in : said plenum space and a substantial portion of its lower half is located in said sea-water channel, said impeller ~ including a rotary shaft disposed slightly above and `~ parallel to an interface between the plenum space and the sea-water channel to project in both atmosphere compart-ments, and a mechanism for producing a motive fluid dis-posed in each of said atmosphere compartments to be - operatively coupled to the end of said rotary shaft pro-jecting into the associated atmosphere compartment, the `" :B

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In accordance with another aspect of this in-vention there is provided a transducer apparatus for con-verting the energy of a tidal current to high pressure . fluid energy, comprising, in combination, a rectangular : 10 vessel, a plurality of transducer units disposed in align-ed relationship on the upper portion of said vessel, each of said transducer units including a pair of atmosphere compartments disposed on the opposite end portions thereof and in fluid communication with each other, a plenum space and a sea-water channel disposed between said atmosphere compartments, said sea-water channel being . overlain with said plenum space to communicate with the ;i latter in fluid-flow relationship and having both ends open to the exterior of said vessel, a plurality of tidal current guide walls projecting from said opposite end portions of said housing and disposed in surrounding re-lation to said both ends of said sea-water channel, means for supplying high pressure fluid to said plenum space to maintain constant the level of the upper surface of a tidal current flowing through said sea-water channel, an impeller disposed within the communicating plenum space : and sea-water channel so that an upper half thereof is . located in said plenum space and a substantial portion ofits lower half is located in said sea-water channel, a rotary shaft for said impeller disposed slightly above and parallel to an interface between said plenum space and said sea-water channel to project into both atmosphere . i .~ compartments, fluid compressing cylinder means disposed in . each of said atmosphere compartments to be operatively coupled to the end of said rotary shaft projecting into :. the associated atmosphere compartment, air introduction means projecting from said vessel and connected to said atmosphere compartments disposed in all said transducer units to supply air to all said fluid compressing " ~ :

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~ ~54483 cylinder means, and means on the lower portion of the vessel for controllably submerging said vessel in the sea and maintaining the same stationary.
; The present invention will become more readily apparent from the following detailed description taken in conjunction with the accompanying drawings in which:
Figure 1 is a schematic perspective diagram of .,` a transducer apparatus for converting an energy of a tidal current to an energy of a high pressure fluid con-structed in accordance with the principles of the present : invention and illustrated at its operating position;
`-l Figure 2 is a schematic front elevational view, :; partly in longitudinal section of the vessel shown in ` Figure 1 with parts broken away and with parts omitted;
. 15 Figure 3 is a fragmental side elevational ;` sectional view diagram taken along the line III-III of ; Figure 2;
Figure 4 is a cross sectional view taken along ~ the line IV-IV of Figure 3;
Figure 5 is a longitudinal sectional view of the transducer ,.

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unit embodying the principles of the present invention and shown in Figures 2 and 3;
Figure 6 is a cross sectional view taken along the line VI-VI of Figure 5;
Figure 7 is a longitudinal sectional view taken along the line VII-VII of Figure 5; and Figure 8 is a cross sectional view of that portion of the connection cable shown at dotted line in Figure 1 and disposed on the bottom of the sea.
Referring now to Figure 1 of the drawings, there is illustrated a transducer apparatus for converting an energy of a tidal current to an energy of a high pressure fluid const-ructed in accordance with the principles of the present invention.
The arrangement illustrated comprises a vessel in the form of a rectangular box generally designated by the reference numeral 10 and a plurality, in this case, four of anchoriny chains 12 connected at one end to longitudinal corners of the vessel on the middle portions and at the other ends to respective anchoring blocks 14 disposed on the bottom of the sea 16 as best shown in Figure 2. The vessel 10 further comprises a plurality of sup-porting legs 18 (onl~ two of,which are illustrated in Figure 2) attached to the bottom of the vessel and resting on the bottom of the sea 16. In this way the vessel 10 has been maintained submerged and stationary in the sea.
' As best shown in Figure 2, an air introduction unit generally ., designated by the reference numeral 20 is upwardly extended -, - 4 _. :

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from a machine room 22 disposed on the top surface of the vessel 10 until its free end portion projects beyond the surface of the sea.
As shown in Figure 2, the vessel 10 includes an upper portion in which a transducer assembly 24 is disposed consisting of a plurality, in this case, eight of rectangular transducer units 26 arranged in two rows and four columns, an intermediate portion forming a submergence level control room for controlling a level of submergence of the vessel generally designated by the reference numeral 28, and a lower portion divided into a pair of upper and lower layers. The upper layer includes a plurality, in this case, two of ballast water chambers 30 horizontally aligned with each other and the lower layer includes a plurality, in this case, three of weighting chambers 32 horizontally aligned with one another.
The air introduction unit 20 includes an air intake port 34 having an air cleaner 36, and an inlet pipe 38 connect-ing the air intake port 36 to the machine room 22. The inlet pipe 38 is flexible enough to be responsive to a change in the surface of the sea due to the range of tide and formed of a material resisting to both water and pressure. In view of ships navigating close to the air introduction unit 20, the air intake port 34 is supported to a buoy 40 provided at the top with an indication lamp 42.
Within the machine room 22 there are disposed an electrically operated compressor 44 and a switchboard 46.
The compressor 44 is adapted to compress the air fed into ,~ .

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~54483 the machine rcom 22 through the inlet pipe 38 to supply the compressed or pressurized air t~ all the transducer units 26 -and, if necessary, to the ballast water chambers 30. The switchboard 46 has connected thereto electric leads (not shown) to all electric equipments installed within the vessel 10. To this end, a piping duct 4~ is shown in Figure

2 as extending from the machine room 22 to all the transducer units 26 and has extended therethrough various conduits and pipes (only some of which are shown in Figure 2).
The transducer units 26 are of the same construction and one-of them will now be described in detail. ~s best shown in Figures 5 and 6, the transducer unit 26 includes a housing 50 in the form of a rectangular box and an atmosphere compartment 52 having an upper portion in the form of a rectangular hollow annulus disposed on the entire edge or verge portion of the housing and a lower portion in the form of a pair of rectangular hollow prisms disposed in opposite relationship on the bilateral end portions of the housing 50 and opened into the opposite side portions of the rectangular hollow annulus. The annular portion of the atmosphere compartment 52 has a bottom-somewhat -lower-in level-than the --central horizontal plane of the housing 50 and encircles a plenum space 54 having an upper surface defined by the top wall of the housing 50. The plenum space 54 is underlaid and communicates with a sea-water channel 56 sandwiched between the bilateral prism portions of the atmosphere ~;:.; , .
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~O As shown in Figure 6, a pipe holder 58 is fixedly secured to the inner wall surface of the housing 50 within the annular portion of the atmosphere compartment 52 and adjacent to a suitable one of corners of the housing 50.
A high pressure feed pipe 60 from the compressor 44 in the machine room 22 is extended and sealed through the pipe ` holder 58 along with various conduits and pipes as will be described later. It will readily be understood that all those conduits and pipes extend through the piping duct 48 prior to the connection to the pipe holder 58. The feed pipe 60 is bifurcated within the annular portion of the atmosphere compartment 52 and the bifurcated portions thereof terminate at a pair of spouting ports 62 positioned in opposite relationship within the plenum space 54 adjacent to `- the annular compartment 52 portion. An electromagnetic valve 64 is connected in each of the bifurcated pipe portions 60 for the purpose as will be apparent hereinafter.

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1~54483 In operation, a high pressure fluid, in this case, the air from the compressor 44 is delivered to the plenum space 52 to maintain a constant top surface of a tidal current flowing through the sea-water channel 56 under the control of a plurality in this case, four of level sensors 66 suitably disposed within the plenum space 52. In Figure 5, the top surface of the tidal current is shown as being substantially contacted by the outer bottom wall surface of thè level sensors 66 and also by the outer wall surface of .~:
/o the annular compartment 52 portion.
- An impeller 68 is centrally disposed within the housing 50 of the transducer unit 26 so that an upper half thereof is located in the plenum space 54 while the - substantial portion of a lower half thereof is located in . the sea-water channel 56, that is to say, it is immersed into a tidal current flowing through the channel 56 in operation as best shown in Figure 5. To this end, the impeller 68 includes a rotary shaft 70 hermetically and - rotatably supported on both end portions by a pair of bearings 72 extended and sealed through opposite partitions for the prismatic compartment 52 portions respectively so as to run in substantially parallel to and slightly above ;........................................................................... .
: an interface between the plenum space and sea-water channel 54 and 56 respectively, that is to say, the level of the sea water flowing through the channel 56.

As shown in Figures 6 and 7, the rotary shaf~ 70 is . . .
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provided on the free end portions therPof projecting into those opposite portions of the annular atmosphere compartment 52 consecutive to the prismatic compartment 52 with a pair of similar spur gears 74 respectively. Each spur gear 74 meshes with a pair of spur gears 76 disposed on both sides thereof to be horizontally aligned with each other and with the gear 74. The three meshing gears 74, 76 and 76 are of the same construction and operatively coupled by~individual cranks 78 to respective pistons 80. Each of the pistons 80 is slidably disposed in a fluid cylinder 82 disposed in each of the prismatic atmosphere compartment 52 portions.
The pistons 80 and the associated cylinders 82 form a mechanism for producing a compressed or motive fluid, in this case, air generally designated by the reference numeral 84.
In the example illustrated the three cylinders 82 are juxtaposed with one another and the mating cranks 78 have their phase angles of rotation different from one another by angles of 120 degrees. As shown in Figure 6, those three cylinders 82 include a common air inflow pipe 86 connected in fluid communication with the.bottom portions thereof as :;;
viewed in Figure 7 and opened into the atmosphere compartment . 52 toward the pipe holder 58 with a check valve 88 connected in the open end portion of the inflow pipe 86. The bottom ,~ portion of all the three cylinders 82 are also connected in .. `. fluid communication with a common high pressure delivery . pipe 90 provided with a check valve 92.

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. , , - ~5~83 As shown in Figure 6, and air introduction pipe 94 is extended and sealed through the pipe holder 58 and then opened into the atmosphere compartment 52. The introduction pipe 94 extends through the piping duct 48 and opens into the machine room 22 for the purpose of introducing the air into the atmosphere compartment 52. Also the high-pressure delivery pipe 90 from the cylinders 82 is extended and sealed through the pipe holder 58 and then passed through the duct 48 to reach the machine room 22 for the purpose as will be apparent hereinafter. Further a wiring conduit 96 is shown in Figure 6 as being extended and sealed through the pipe holder 58 and passed through the duct 48. Then the conduit 96 reaches the switchboard 46 disposed in the machine room 22. However the pipes 94 and 96 and the conduit 96 are not illustrated in Figure 2 only for purposes of illustration. In Figure 6, a single electric conductor is shown as extending through the wiring conduit 96. This electric conductor is representative of electric leads connected to the electromagnetic valves 64 disposed in the atmosphere compartment 52 for energi~ation and to the level sensor 66 disposed in ~e plenum space 54 for control purposes.
Those electric leads are connected to the switchboard 46 disposed in the machine room 22 although they are not illust--: -rated in Figure 2 only for purposes of illustration.
- Referring back to Figure 2, the high pressure feed pipe (not shown in Figure 2) from the compressor 44 includes :.

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~54~83 a plurality of branches 98 (only two of which are illustrated in Figure 2) extended through the submergence control room 28 where an electromagnetic valve 100 is connected in each branch 98. Then the branches 98 are opened into the ballast chamber 30. It will readily be understood that the electromagnetic valves 100 are connected to an electric lead (now shown) to the switchboard 46 ~see Figure 2).
As best shown in Figure 4, a pair of ballast drain pumps 102 are disposed in the submergence control room 28 and connected to respective drain pipes 104. Each drain pipe 104 is provided with a check valve 106 and extends in water tight relationship through the side wall of the chamber 28 unit it terminates at an open end slightly projecting into the exterior of the vessel or the sea water. Each drain pipe 102 includes a suction pipe 102 opened adjacent to the bottom of the ballast room 20 (see Figure 2~. Further a hoisting winch 106 is disposed in each of-the corner portions of the chamber 28 isolated from the remaining portion thereof to be driven by an electric motor 108 disposed adjacent to the hoisting winch 106 within the remaining chamber portion. To pay out and take up the associated chain 12, the pumps and motors 102 and 108 respectively are adapted to be energized through electric leads (not shown~ to the switchboard 46 in the machine room 22.
As shown in Figure 2 each of the ballast chambers .
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1~54483 includes a gate 110 disposed on the outer wall thereof.
As also shown in Figure 2, the machine room 22 has a flexible watertight cable sheath 112 extended therefrom.
The cable sheath 112 is trained over the bottom of the sea 16 unit it lands at a shore adjacent to the vessel 10 as shown in Figure 1. As shown in Figure 8, the cable sheath 112 is relatively flat so as to present a low resistance to tidal currents and contains a flexible, compressed-air feed pipe 114 and a pair of flexible electric cables 116 extended . ro therethrough. Further a weight 118 in the form of a ; discrete sheets aligned with one another is disposed on the bottom of the cable sheath 112 in order to stably lay the cable sheath 112 on the bottom of the sea 16.
- In the machine room 22 the compressed air pipe 114 is connected to the high pressure delivery pipe 90 connected to the fluid cylinders 82 and a plurality of electric ; conductors extending through one of the electric cables 116 are electrically connected through the switchboard 46 to associate equipments installed within the vessel 10 such ~0 as electric motors, electromagnetic valves etc. in order to - energize them. Similarly a plurality of electric conductors extending through the other cable 116 are connected through the switchboard 46 to associated controls such as the level -sensors 66 and adapted to transmit control signals in the form of carrier waves therethrough.
~` Referring back to Figure 1, the cable sheath 112 .

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i~54~83 after having landed at the shore enters a cable house 120 located in proximity of the shore. In the housing 120 the compressed-air pipe 114 is provided with a check valve (not shown) and then leaves the housing 120 until it i5 connected to a high pressure tank 122 disposed adjacent to the cable house 120. On the other hand, the pair of electric cables ` 116 enter a remote control cottage 126. A high pressure - feed pipe 128 from the tank 122 is connected to a high pressure fluid operated motor (not shown) disposed in an ~0 electric power generation plant 130 adjacent to the remote control cottage 126. The motor is operatively coupled to an * electric generator (not shown) disposed in the plant 130 and connected at the output to a transmission system 132.
The generator is also adapted to supply an electric power ` to the vessel 10 through the power cable 116.
Mounted on the opposite side portions of the vessel 10 are a plurality of guides 134 for guiding the tidal current to flow into the sea-water channels 56. Each of the guides 13 comprises four side walls 136 extending at a right angle to adjacent walls and projecting from the vessel 10, the four walls 136 being disposed in surrounding relation to one of the openings 56' of the sea-water channel 56. The guide 134 is coextensive in cross section with the housing 50, so that the guides 134 cover the entire area of the side wall portions : of the vessel 10 in which the transducer units 26 are housed.
The tidal current, once flown into the guides 134, is trapped i: .' "~
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~C~54~3 therein and prevented from escaping out of the guides 134 over the side walls 136 under increased pressure within the guides 134 due to continuing influx cf the tidal current. With the increased pressure is the guides 134, the tidal current therein is foxcibly fed into the sea-water channels 56 through the op~nings 56' and caused to flow through the channels 56 at an increased rate of speed. Furthermore, the guides 136 act as a sea-water collector in the case where.a.direction of the tidal current is varied so as to be out of alignment with the longi-.
tudinal direction of the sea-water channels 56.
The arrangment thus far described.is operated as follows:
The vessel 10 with the gates 110 brought into their closed position is towed to a predetermined position on the surface of the sea and then gates 110 are opened to permit the sea water to be introduced into the ballast water chambers 30. The sea water is also introduced into all the sea-water channels 56 until it will possibly fill each transducer unit 26 up to a part of the plenum space 54. In that case the longitudinal axis of each channel 56 preferably lies in a direction of a tidal current.
In this way the vessel 10 is submerged in the sea until the supporting legs 20 of the vessel 10 rest on the bottom of the sea 16. Then the four anchoring chains 12 connected to the respective anchoring blocks 14 dorp on the bottom of the sea 16 to maintain the vessel substantially stationary by having the anchoring blocks 14 biting into the bottom of the sea 1~ as shown in Figure 2.

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- :.. ' . ' ; , ' . :' 163 5~483 An actuation signal from the remote control cottage 126 is delivered through the control cable 116 to the compressor 44 in the machine room 22 to drive it from a source of electric power disposed therefor in the room 22 to supply a high pressure air to each of the plenum spaces 52 through the high pressure pipe 60 to increase a fluid ~ pressure within that plenum space 52 to depress the level of ;, the sea water flowing through the associated sea-water channels 56. Upon the sea water flowing through each . ~0 channel 56 reaching a predetermined level as determined by the associated level sensors 66, the electromagnetic valves 64 in each atmosphere compartment respond to a`control signal ~= from the remote control cottage 126 fed thereto through the control cable 116 to be closed to stop the supply of the high pressure air to the associated plenum space 52 to maintain the predetermined sea level in the mating sea-water channel 56. If the sea level in a particular channel 56 exceeds the predetermined magnitude, the associated sensors 68 are operated to open the corresponding electromagnetic valves 64 in responsive to a control signal from the control cottage 126. In this way, the level sensors 68 cooperate with the associated electromagnetic valves 64 to maintain the predetermined sea level in each of the sea-water channels 56.
At the same time, a tidal current due to the particular tide continues to flow through each sea-water channels 56 in one or the other of the directions. It will readily be .~ ' .
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~.~54483 understood that the tidal current flowing through each channel 56 is reversed in direction in response to a change in tide from one to the other of the reflux and flux.
Within each of the transducer unit 26 the tidal current flowing through the associated sea-water channel 56 causes the rotation of the impel:Ler 70 in a direction as determined by the direction of flow thereof. The rotation of each impeller 70 causes the actuation of the associated compressed air mechanism 84 through the mating spur gears 74, 78 and 78 and the cranks 80. Thus the air spouted into each atmosphere compartment 54 from the associated atmosphere pipe 90 and sucked into the cylinders 82 through the corresponding pipe 86 is compressed and the compressed air as a motive fluid is delivered through the mating high pressure pipes 90 to the compressed air feed pipe 114.
Then the compressed air flowing through the pipe 114 within the cable sheath 112 is entered into the high pressure tank 122. The compressed air accumulated in the tank 122 is fed to the fluid operated motor (not shown) disposed in the power generation plant 130 to rotate the electric generator (not shown) connected to the motor to produce an electric power.
The electric power is adapted to be transmitted through the transmission system 132.
It is.noted that once the electric power hasi been produced in the power generation plant 130, the compressor 44 is switched to be energized with a part of that electric . . , '. .
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power through the power cable 116.
When the vessel 10 is to be subject to the periodic inspection or if a failure has occurred in the vessel 10 for any reason, control signals from the remote control cottage 126 are fed to the vessel 10 through the control cable 116 to close the gates 110 and to drive the drain pumps 102 to drain the ballast chambers 30. At the same time the electromagnetic valves 100 are opened to aid the drainage of the ballast chambers 30 until the vessel 10 is /o floated up on the sea surface. Thereafter the periodic inspection can be effected. Alternatively the failure can be removed.
Then the process as above described is repeated to put the vessel 10 in operation.
Thus it is seen that the present invention has provided an apparatus capable of effectively piciking up and utilizing an energy of a tidal current in large-scaled manner adjacent the bottom of the sea and also permitting ships to navigate in the vicinity of the present apparatus without any hindrance. Further the present invention provides an unattended apparatus through the utilization o~ the remote control performed on land.
While the present invention has been illustrated and described in conjunction with a single preferred embodiment thereof it is to be understood that numerous changes and modifications may be resorted to without . . .:
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departing from the spirit and scope of the present invention.
For example, the present invention is equally applicable to . apparatus requiring the high pressure fluid other than the . electric power generation plant as above described.

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Claims (5)

Claims:

1. A transducer apparatus for converting the energy of a tidal current to high pressure fluid energy, comprising, in combination, a housing in the form of a rectangular box, a pair of atmosphere compartments disposed on the opposite end portions of said housing thereof and in fluid communication with each other and with the atmosphere, a plenum space and a sea-water channel disposed between said pair of atmosphere com-partments within said housing, said sea-water channel being overlain with said plenum space to communicate in fluid-flow relationship with the latter and having both ends open to the exterior of said housing, means for supplying high pressure fluid to said plenum space to maintain constant the level of the upper surface of a tidal current flowing through said sea-water channel, an impeller disposed within said communicating plenum space and sea-water channel so that an upper half thereof is located in said plenum space and a substantial portion of its lower half is located in said sea-water channel, said impeller including a rotary shaft disposed slightly above and parallel to an interface between the plenum space and the sea-water channel to project in both atmosphere compartments, and a mechanism for producing a motive fluid disposed in each of said atmosphere compartments to be operatively coupled to the end of said rotary shaft projecting into the associated atmosphere compartment, the arrangement being such that, with the apparatus submerged in the sea, tidal current flows through said sea-water channel to drive said impeller to cause said motive fluid producing mechanism to produce higher pressure air from lower pressure air.

2. A transducer apparatus as claimed in Claim 1, further comprising a pair of guides mounted respectively on the opposite end portions of said housing for guiding the tidal current to flow into said sea-water channel.

3. A transducer apparatus as claimed in Claim 2 wherein each of said pair of guides comprises four side walls projecting from said housing and disposed in surrounding relation to one of said both ends of said sea-water channel.

4. A transducer apparatus as claimed in Claim 1 wherein said mechanism for producing the motive fluid includes at least one fluid cylinder means for compressing lower pressure air to produce higher pressure air.

5. A transducer apparatus for converting the energy of a tidal current to high pressure fluid energy, comprising, in combination, a rectangular vessel, a plurality of transducer units disposed in aligned relationship on the upper portion of said vessel, each of said transducer units including a pair of atmosphere compartments disposed on the opposite end portions thereof and in fluid communication with each other, a plenum space and a sea-water channel disposed between said atmosphere compartments, said sea-water channel being overlain with said plenum space to communicate with the latter in fluid-flow re-lationship and having both ends open to the exterior of said vessel, a plurality of tidal current guide walls projecting from said opposite end portions of said housing and disposed in surrounding relation to said both ends of said sea-water channel, means for supplying high pressure fluid to said plenum space to maintain constant the level of the upper surface of a tidal current flowing through said sea-water channel, an im-peller disposed within the communicating plenum space and sea-water channel so that an upper half thereof is located in said plenum space and a substantial portion of its lower half is located in said sea-water channel, a rotary shaft for said im-peller disposed slightly above and parallel to an interface between said plenum space and said sea-water channel to project into both atmosphere compartments, fluid compressing cylinder means disposed in each of said atmosphere compartments to be operatively coupled to the end of said rotary shaft projecting into the associated atmosphere compartment, air introduction means projecting from said vessel and connected to said atmosphere compartments disposed in all said transducer units to supply air to all said fluid compressing cylinder means, and means on the lower portion of the vessel for controllably submerging said vessel in the sea and maintaining the same stationary.