I
`
`United States Patent I 191
`Cole
`
`[111
`[45]
`
`3,931,608
`Jan. 6, 1976
`
`[541 CABLE DEPTH CONTROL APPARATUS
`
`3,673.556
`
`6/1972
`
`Biggs .............................. r. 340/? PC
`
`[75] Inventor‘. .llmmy R. Cole, Houston, Tex.
`[73] Assignee: Syntron, Inc., Houston, Tex.
`[22] Filed.
`Apr 25 ‘974
`
`.
`
`.
`
`,
`
`{21 l
`
`Appl- No-: 463,980
`
`[52] US. Cl. .......... ,. 340/7 PC; 1 14/235 B; 340/3 T
`[5 1]
`Int. Cl.2 .......................................... .. 001v 1/28
`[58] Field of Search ______ __ 340/7 PC_ 3 '1‘; [14/235 B
`
`[56]
`
`3 412,704
`3,531,762
`
`References Cited
`UN‘TED STATES PATENTS
`ll/l968
`Buller et al. .................... ,, 340/7 PC
`9/!970
`Tickcll ............................ ., 340/7 PC
`
`Primary E_mml.ner_Maynard R. Wilbur
`Assistant Examiner——-H. A. Birmiel
`Attorney, Agent, or Firm—Pravel & Wilson
`
`ABSTRACT
`[57]
`An apparatus to control the depth in the water of 21 ca
`ble, such as a cable streamer of seismic geophones or
`hydrophones towed behind an exploration boat during
`seismic surveys of submerged formations, and main
`tain the cable at a desired depth while operating at re~
`duced noise levels and with improved operating char
`acteristics.lThe depth at which the cable is maintained
`may be adjusted for a range of Selected depths‘
`12 Claims, 6 Drawing Figures
`
`WESTERNGECO Exhibit 2091, pg. 1
`PGS v. WESTERNGECO
`IPR2014-01477
`
`

`
`U.S. Patent Jan. 6, 1976
`
`Sheet 1 Of3
`
`3,931,608
`
`WESTERNGECO Exhibit 2091, pg. 2
`PGS v. WESTERNGECO
`IPR2014-01477
`
`

`
`US. Patent Jan. 6, 1976
`
`Sheet 2 of 3
`
`3,931,608
`
`WESTERNGECO Exhibit 2091, pg. 3
`PGS v. WESTERNGECO
`IPR2014-01477
`
`

`
`US. Patent Jan. 6, 1976
`
`Sheet 3 of 3
`
`3,931,608
`
`WESTERNGECO Exhibit 2091, pg. 4
`PGS v. WESTERNGECO
`IPR2014-01477
`
`

`
`1
`
`CABLE DEPTH CONTROL APPARATUS
`
`3,931,608
`2
`support shank at spaced portions thereof, so that the
`connecting collars are spaced from each other along
`the cable to stabilize the connection between the sup
`port shank and the cable.
`It is an object of the present invention to provide a
`new and improved apparatus for controlling the depth
`of a cable.
`
`BACKGROUND OF THE INVENTION
`1. Field of the Invention
`The present invention relates to an apparatus for
`controlling the depth of a cable, such as a seismic hy
`drophone streamer, in water.
`2. Description of the Prior Art
`Beginning with early attempts to control the depth of
`submerged seismic cables during exploration, such as a
`single drogue assembly drawn behind the cable in U.S.
`Pat. No. 2,465,696, or the spaced weights and ?oats of
`U.S. Pat. No. 2,729,300, considerable effort has been
`expended to accurately control the cable depth at a
`desired depth.‘
`One approach, as exempli?ed by U.S. Pat. Nos.
`3,375,800 and 3,434,446 (of which applicant is an
`inventor), and also in U.S. Pat. Nos. 3,412,704;
`3,496,526; 3,541,989; and 3,605,674 has used plural
`apparatus, each mounted in a housing about the seis
`mic cable at spaced positions along the length of the
`cable. With this approach, the housing surrounding the
`cable tended to confine undesirable noise in the area of
`25
`the cable which could be sensed by the sensing geo
`phones or hydrophones in the seismic cable. Further,
`with these apparatus, the depth controlling diving
`planes were mounted with the apparatus at the thickest
`portion thereof, increasing the width or cross-section
`span of the apparatus. Also, if the cable were over
`?lled with ?uid, undesirable binding between the hous
`ing and the cable often occurred.
`.
`Other apparatus,,such as in U.S. Pat. Nos. 3,372,66;
`3,611,975; 3,531,762; and 3,531,761 have included
`even larger wing structure connected at a single con
`nector to the cable and were comparatively hard to
`control and unwieldy. Further, the large wing structure
`frequently snared marine weeds and growth and other
`submerged objects. Still other apparatus, such as in
`U.S. Pat. No. 3,434,451 have used two control vehi
`cles, one submerged with the cable, with the other at
`the water surface subject to wave action and thus gen
`erally undesirable.
`Finally, other depth control apparatus, such as in
`U.S. Pat. Nos. 2,709,981.; 3,492,962; 3,199,482;
`3,260,232; 3,560,912; ‘and 2,945,469 were intended
`for depth control of specialized structure and not, so
`far as is known, readily adapted to control the depth of
`seismic cables.
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`BRIEF DESCRIPTION OF THE DRAWINGS
`FIG. 1 is an elevation view of the apparatus of the
`present invention mounted with a cable;
`FIG. 2 is an isometric view, partially exploded, of the
`apparatus of FIG. 1;
`FIG. 3 is an isometric view of an alternative embodi
`ment of the present invention;
`FIG. 4 is an exploded isometric view of portions of
`the apparatus of the present invention;
`FIGS. 5A and 5B are elevation views taken in cross
`section of front and rear portions, respectively, of the
`apparatus of the present invention.
`
`DESCRIPTION OF THE PREFERRED
`EMBODIMENT
`In the drawings, the letter A designates generally the
`apparatus of the present invention for controlling the
`depth of a seismic cable K of the conventional type,
`formed from vinyl or other suitable material, as the
`cable K is towed or pulled forward through a body of
`water in a direction indicated by an arrow 10 (FIG. I)
`behind a seismic exploration vessel of the conventional
`type. Typically, the cable K is ?lled with kerosene or
`suitable liquid for neutral buoyancy in the body of
`water and contains at spaced locations therein plural
`seismic signal sensing geophones or hydrophones
`which sense re?ected seismic signals indicating the
`response of geological features of the area underlying
`the body of water to signals from a seismic source. The
`sensing hydrophones are connected through suitable
`conductors in the cable K to the vessel to permit the
`response of these geological features to be recorded by
`suitable instruments on the vessel.
`Typically, the cable K is several thousand feet in
`length, and plural depth control apparatus A of the
`present invention are mounted at suitably spaced loca
`tions along the cable K to keep the cable K at substan
`tially the same depth along its length, an important
`factor for accuracy in seismic surveying.
`The apparatus A includes a depth control unit or
`assembly D, which includes a force comparator R
`(FIGS. 4, 5A and 5B) which compares the force of
`ambient water pressure at the depth at which the cable
`is operating with a reference force representing the
`desired cable depth, a control body 8 for containing
`the comparator R, and plural diving planes P (FIGS.
`1-3) which respond to the comparator R and move the
`cable K to the desired depth.
`A connector means M mounts the depth control unit
`D to the cable K and includes a support shank S
`mounted between the control body B and the cable K.
`The support shank S further has the diving planks P
`mounted therewith, for reasons to be set forth below.
`The connector means M further includes plural con
`necting collar assemblies C for attaching the support
`shank S to the cable K.
`Considering the apparatus A more in detail, the con
`necting collar assemblies C (FIG. 5A) each include a
`cylindrical inner race 12 formed of two half-cylinder
`members 14 and 16 which are semi-circular in cross
`
`SUMMARY OF THE INVENTION
`Brie?y, the present invention provides a new and
`improved apparatus for controlling the depth of a seis
`mic cable. The apparatus includes a depth control
`means for regulating the depth of the cable having a
`comparator which compares the force of ambient
`water pressure at the depth where the cable is operat
`ing with a reference force representing the desired
`cable depth, a control body for containing the compar
`ator, and diving planes which respond to the compara
`tor to move the cable to the desired depth. A connector
`which includes a support shank mounted between the
`control body and the cable, with the diving planes
`mounted to the support shank, and a connecting collar
`to attach the support shank to the cable, mounts the
`control body to the cable.
`The connecting collar for each support shank is pref
`erably in the form of plural collars mounted with the
`
`WESTERNGECO Exhibit 2091, pg. 5
`PGS v. WESTERNGECO
`IPR2014-01477
`
`

`
`3,931,608
`3
`section and mounted to each other by screws 18 or
`other suitable attaching means. The inner races 12 are
`mounted at desired positions with the cable K spaced
`from each other. The inner races 12 may be mounted
`with the cable K and held in place therewith by being
`cemented to the cable K by a suitable adhesive cement
`or glue or by being mounted between tape strips
`wrapped about the cable K at each end of such races.
`The inner races 12 have a reduced diameter center
`section formed adjacent a surface 12a thereof, between
`end shoulders 12b and 120. The center section of the
`inner races 12 is adapted to receive an outer race or
`locking collar 20.
`The locking collar 20 is preferably formed of two
`half-cylinder members 21 and 22 which are semi-circu
`lar in cross-section and mounted to each other by
`screws 23 or other suitable attaching means. The lock
`ing collar 20 is freely rotatably movable with respect to
`the inner race 12. When the depth control unit D and
`the support shank S are mounted therewith, in a man
`ner to be set forth, the weight of such structure causes
`such structure to ride beneath the cable K (FIG. I).
`The locking collar 20 has a pair of locking slots 24
`formed therein at diametrically opposed portions
`thereof so that a locking pin 26 of the support shank S
`may be mounted therewith to mount the support shank
`S with the cable K.
`The locking pin 26 is preferably a screw with a
`threaded portions 260 thereof mounted in a suitable
`socket 28 formed in the support shank S. The locking
`pin 26 has an enlarged head portion 26b extending
`upwardly from an upper surface 30 of the support
`shank S.
`The locking slot 24 includes an enlarged insertion
`aperture or ori?ce formed adjacent a surface 24a
`formed at a forward portion of the locking slot 24 with
`respect to the direction of movement of the cable K. A
`reduced width retaining groove 24b is formed in the
`locking slot 24 extending rearwardly from the insertion
`aperture.
`An enlarged slot 24c adapted to receive the head 26!;
`of the locking pin 26 is formed inwardly in the locking
`collar 20 of the retaining groove 24b so that the head
`26b of the locking pin 26 may be moved rearwardly in
`the locking slot 24 to mount the support shank S to the
`cable K.
`A quick release lock or latch L is mounted with the
`support shank S adjacent the forward locking pin 26 to
`lock the support shank S to the connecting collars C.
`The lock L includes a locking dog 32 mounted in a
`socket 34 formed adjacent a forward end of the support
`shank S. The locking dog 32 is adapted to move into
`the locking slot 24 of the forward locking collar 20
`(FIG. 5A).
`A resilient spring 36 is mounted in the socket 34
`beneath the locking dog 32 to urge such locking dog
`into a position in the locking slot 24 to prevent inadver
`tent forward movement of the support shank S and
`depth control unit D with respect to the cable K and
`thereby lock the support shank S and depth control
`unit D to the cable K.
`Releasing pins 38 (FIG. 4) are mounted with the
`locking dog 32 extending outwardly therefrom through
`vertically elongated slots 40 formed in the supporting
`shank S. The releasing pins 38 may be gripped and
`moved downwardly in the slots 40 to overcome the
`force of the spring 36 and move the locking dog 32 out
`of the locking slot 24. When the locking dog 32 is
`
`removed from the locking slot 24 in this manner, the
`supporting shank S and the depth control unit D may
`be moved forward to a position where the heads 26b of
`the locking pins 26 pass through the apertures in the
`locking slot 24 so that the support shank S and depth
`control unit D may be dismounted and removed from
`the cable K.
`The support shank S includes a prow or rounded
`leading surface 42 (FIGS. 3 and 4) sloping downwardly
`from an upper leading portions 420 (FIG. 5A) thereof,
`and a center body portion 44 and a tapered trailing end
`or tail portion 46 (FIG. 4) for improved hydrodynamic
`characteristics during movement of the apparatus A
`with the cable K through the water. Vertically extend»
`ing sockets 44a and 44b are formed in the upper sur
`face 30 of the center body portion 44 of the support
`shank S so that suitable screws 48 or other attaching
`means may be inserted to connect the support shank S
`to the control body B of the depth control unit D.
`An upwardly extending cavity 50 is formed in the
`support shank in the center body portion 44 thereof so
`that a moment arm 52 may transmit motion of the
`comparator R of the depth control unit D to the diving
`plane P. A threaded upper portion 520 of the moment
`arm 52 is inserted into a socket in a center portion 54a
`of a diving plane shaft 54.
`The diving plane shaft 54 is mounted in a transverse
`opening extending through the center body portion 44
`adjacent a surface 44c and is rotatably movable with
`respect to the support shank S so that the diving planes
`P may move with respect to the support shank S in
`response to the comparator R to adjust the depth of the
`cable K, in a manner to be set forth.
`The diving plane shaft 54 has receiving slots 54b and
`540 formed at outer ends thereof so that the diving
`planes P may be inserted therein. Suitable openings are
`formed in the diving plane shaft 54 transverse to the
`receiving slots 54b and 54c so that screws 56 or other
`suitable attaching means may be used to mount the
`diving planes P to the diving plane shaft 54. It is to be
`noted that the diving planes P are mounted with the
`support shank 8 rather than the control body B of the
`diving control unit D, for reasons to be set forth.
`The control body B includes a tubular spring holding
`accumulator assembly H. a tubular coupling member G
`and a cylindrical nose piece N. The accumulator as
`sembly H, coupling member G and nose piece N are of
`like diameter, somewhat larger in horizontal cross-sec
`tion than the width of the support shank S. Typically.
`the members of the control body B are 2.3 inches in
`diameter, while the shank S is 1 inch in width.
`The nose piece N is mounted at an upper surface 58
`with a lower surface 60 of the support shank S, which
`is curved to recieve the exterior of the tubular control
`body B therein, by a forward one of the mounting
`screws 48. The nose piece N includes a prow member
`62 formed on a leading surface thereof. The prow
`member 62 conforms to the con?guration of the lead
`ing surface 42 of the support shank S along a rear
`wardly sloping center portion 620 thereof, and further
`includes tapering side surfaces 62b and 620 formed
`extending outwardly and rearwardly on the front por
`tion of the nose piece N from the center portion 620
`thereof past the connection between the nose piece N
`and the support shank S. The prow member 62 thus
`extends outwardly past the mounting connection be
`tween the diving planes P and the support shank 8
`thereby serving to deflect marine growth and debris
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`WESTERNGECO Exhibit 2091, pg. 6
`PGS v. WESTERNGECO
`IPR2014-01477
`
`

`
`5
`away from the movable connection or mounting be
`tween the diving planes P and the support shank S
`(FIG. 3) to reduce snagging and catching of such ma
`rine growth and debris which might otherwise occur.
`A piston chamber 64 is formed extending inwardly
`into the nose piece N. The piston chamber 64 contains
`air at atmospheric pressure therein and is connected by
`a conduit 66 formed in the nose piece N and a connec
`tor tube 67 through a coupling hose 68 to the accumu
`lator assembly H, for reasons to be set forth.
`The comparator R includes a piston 70 mounted for
`relative movement in the piston chamber 64 of the nose
`piece N. A rolling diaphragm seal 72 (FIG. 4) is
`mounted at a center portion thereof with the piston 70
`by a diaphragm seal washer 73, with a washer 74 and a
`mounting nut 75 used to firmly secure the seal washer
`73 in place on a threaded front end of a piston rod 76.
`The diaphragm 72 is mounted along outer portions
`thereof between the nose piece N and the coupling
`member G by a plurality of suitable screws 80 or other
`suitable fastening means which pass through suitable
`openings 81 formed in the coupling member G and
`opening 720 in seal 72 into sockets formed in the nose
`piece N. A working chamber 82 is formed in a central
`portion of the coupling member G. A passage slot 84 is
`formed extending between an upper surface 85 of the
`coupling member G adjacent the chamber 50 in sup
`port shank S and the work chamber 82 in the coupling
`member G. The connection between the support shank
`S and the coupling member G adjacent the passage slot
`84 permits ambient water pressure to enter the work
`chamber 82 so that such pressure may work against the
`piston 70, for reasons to be set forth.
`The moment arm 52 extends from the chamber 50
`through the passage slot 84 into the work chamber 82
`with a yoke 86 (FlG. 4) formed at a lower end thereof
`mounted with connector pins 88 formed extending
`outwardly from the piston rod 76 at a portion rearward
`of the connection to the piston 70.
`A forward mounting collar 90 of the accumulator
`assembly H is mounted along a center insertion piece
`92 thereof in a rear socket adjacent a surface 94 of the
`coupling member G. The collar 90 has a socket formed
`therein adjacent a surface 95 to receive a rearward one
`of the mounting screws 48 and attach the accumulator
`assembly H to the lower surface 60 of the support
`shank S. The piston rod 76 extends from the working
`chamber 82 and the coupling member G into the accu
`mulator assembly H through a central opening formed
`adjacent a surface 900 of the mounting collar 90.
`A cylindrical mounting shoulder member 96 is
`formed extending rearwardly from the mounting collar
`90 to mount therewith an inner accumulator sleeve 100
`and an outer accumulator sleeve 102. The inner accu
`mulator sleeve 100 and the outer accumulator sleeve
`102 are concentrically mounted with respect to each
`other and form therebetween an accumulator reservoir
`104 in connection through a connector tube 106,
`mounted in a socket formed in the collar 90, with the
`piston chamber 64 in the nose piece N through a con
`nection which includes the coupling hose 68, connect
`ing tube 67 and conduit 66.
`The accumulator reservoir 104 contains air therein
`and receives excess air forced from the piston chamber
`64 due to forward movement of the piston 70 therein.
`When the piston 70 moves rearwardly in the chamber
`64, air passes from the accumulator reservoir 104 to
`the piston chamber 64 through the connection set forth
`
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`3,931,608
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`above to maintain air pressure in chamber 64 substan
`tially constant.
`A rear mounting collar 108, having a forwardly ex
`tending mounting shoulder 110 formed thereon to
`mount therewith the inner accumulator sleeve 100 and
`the outer accumulator sleeve 102, seals the rear end of
`the accumulator reservoir 104. The mounting collar
`108 has a rearwardly tapering external surface 108a
`formed thereon for improved hydrodynamic flow char
`acteristics.
`A rearwardly tapered fairing 112 is mounted at a rear
`end portion 108!) of the collar 108. A depth control
`knob 114 having a knurled external surface 114a and a
`central connector opening ll4b formed therein is
`mounted at the rear of the fairing 112. A connector
`screw 116 is mounted with the depth control knob 114
`passing through a central opening formed in the fairing
`112 adjacent a surface 112a thereof.
`A rear spring mounting block 118 receives a
`threaded forward end 116a of the connector screw 116
`therein. A washer 120 and nut 122 are mounted with
`the connector screw 116 to firmly secure the spring
`mounting block 118 with the screw I16.
`The spring mounting block 118 has grooves formed
`along an external surface thereof so that a reference
`spring 124 of the comparator R may be ?xedly
`mounted therewith along a rear portion of such refer
`ence spring. The reference spring 124 extends for
`wardly within the accumulator assembly H in the inte
`rior of the inner accumulator sleeve 100 to a forward
`spring mounting block 126 which has grooved external
`surfaces formed thereon to receive coils of the spring
`124. The forward spring mounting block 126 has a
`central opening formed therein to receive a threaded
`rear end 128 of the piston rod 76 and mount the spring
`124 at a forward portion thereof with the piston rod 76.
`The reference spring 124 of the comparator R is thus
`mounted in the control body B between a rear end
`portion mounted with rear mounting block 118 and a
`forward portion mounted with a forward mounting
`block 126. The spring 124 responds to relative move
`ment between the mounting blocks 118 and 126 by
`compressing or expanding.
`The mounting block 118, connector screw 116 and
`control knob I14 connect the rear end of the spring
`114 to fairing 112 of the control body 8 so that forces
`stored in the spring 124, due to relative movement
`between the mounting blocks I18 and 126, are exerted
`on the piston rod 76 and piston 70 of the comparator R
`attempting to move the piston rod 76 and piston 70
`rearwardly with respect to the control body B.
`The ambient water pressure at the depth of operation
`of the cable K is present in the work chamber 82 of the
`control body B, as has been set forth, and exerts a force
`on the piston 70 and seal 72 attempting to move the
`piston 70 forward into the piston chamber 64 of the
`control body B. The magnitude of the water pressure
`force on the piston 70 is dependent on the depth at
`which the cable K is operating. since ambient water
`pressure is proportional to depth in the water. The
`reservoir 104 in the accumulator assembly H permits
`the air pressure in the piston chamber 64 to remain
`substantially constant by permitting air to be forced
`from or drawn into the chamber 64 in response to
`movement of the piston 70.
`The force exerted by the spring 124 on the piston rod
`76 and piston 70 in opposition to the force due to ambi
`ent water pressure on the piston 70 may be adjusted to
`
`WESTERNGECO Exhibit 2091, pg. 7
`PGS v. WESTERNGECO
`IPR2014-01477
`
`

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`20
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`3 931,608
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`a desired magnitude by rotating the depth control knob
`114, causing the threaded rod 116 to rotate, so that
`mounting block 118 mounted therewith rotates the
`spring 124 causing the forward mounting block 126
`and front end of spring 124 to rotate on the threaded
`end 128 of the piston rod. Rotational movement of the
`forward mounting block 126 and front end of spring
`124 in this manner causes rearward or forward relative
`movement of the forward mounting block 126 with
`respect to the rear mounting block 118 along the axis,
`compressing or expanding, respectively, the spring 124,
`increasing or decreasing the force exerted by the spring
`124 on the piston rod 76.
`In this manner, the force of spring 124 may be set at
`a reference magnitude representing that force caused
`by the pressure of water at the desired operating depth
`of the cable K working against the area of the piston 70
`and seal 72. A scale or other suitable force measuring
`means may be connected to the apparatus A at the
`connector opening ll4b in the depth control knob 114
`for calibration of the force exerted by the spring 124.
`In the operation of the present invention, the con
`necting collars C are mounted in pairs at suitable loca
`tions along the length of the cable K. The collars C in
`a pair are mounted spaced from each other a distance
`equal to the spacing between the locking pins 26 of the
`support shank S.
`The depth control knob 114 for each of the appara
`tus A is then used to adjust the force of the reference
`spring 124 to correspond to the desired operating
`depth for the cable K during the survey.
`The cable K is then passed out or played out from the
`vessel, typically from a reel on the vessel, as the vessel
`moves slowly forward, so that the cable K takes the
`form of an elongate streamer behind the vessel. As the
`cable K is being so placed, the apparatus A are then
`connected to the cable K with the support shank S by
`inserting the locking pins 26 into the insertion aper
`tures in the locking slots 24 of locking collars 20 and
`sliding the apparatus rearwardly so that the lock L
`locks the apparatus in place on the cable K.
`It is to be noted that the connecting collars C and
`locking pins 26 permit the apparatus A to be promptly
`and easily connected to and disconnected from the
`cable K while the cable K is being placed in or removed
`from the water behind the vessel, with the lock L per
`mitting a secure locking of the apparatus A from the
`cable K. Further, the lock L permits quick release of
`the apparatus A from the cable K by depressing the
`releasing pins 38 and moving the shank S and depth
`control unit D forward with respect to the connecting
`collars C when such cable is being reeled into the ves
`sel.
`Once the cable K is in the water, the apparatus A
`55
`maintains the cable streamer K at the desired operating
`depth by utilizing pressure-controlled diving planes P
`to apply “lift” forces to the streamer K as it is being
`towed by the vessel. The operating depth of the appara
`tus A is controlled by forces reacting on the compara
`tor R. The spring 124 exerts a force on the piston 70 in
`a first direction and ambient or static water pressure
`exerts a force on the piston 70 in an opposite direction
`to the spring 124. Any unbalance of these two forces on
`the comparator R, such as when the cable K is not at
`the proper depth, causes the moment arm 52 to rotate
`the diving planes P through the diving plane shaft 54 to
`a position so that the towing movement of the cable K
`causes the apparatus A to move to the desired depth.
`
`When the cable K is close to the surface of the water,
`the spring 124 exerts a force on the piston 70 causing
`the diving planes P to assume a “dive" position (FIG.
`2). Under tow, the apparatus A moves the cable K
`toward its preset depth. With increasing depth, the
`water pressure on the piston 70 causes a force to be
`exerted that approaches the magnitude of the force of
`the spring 124, causing the diving planes P to rotate
`toward a horizontal or zero “lift“ position (FIG. 1). As
`the apparatus A reaches the preset depth the diving
`planes P assume their zero “lift” position and the cable
`K remains at the desired level unless acted upon by
`external vertical forces.
`Should external vertical forces cause the streamer K
`to deviate from the preset depth, the comparator R
`senses this deviation and causes the diving planes P to
`rotate in a direction to compensate for the effect of the
`external force.
`Due to the mounting of the diving planes P with the
`reduced thickness support shank S rather than the
`control body B and due to relatively small diameter
`control body B, the apparatus A moves through the
`water with less drag and turbulence thus reducing the
`noise that may be introduced into the hydrophones
`while the cable K is being towed through the water.
`Additionally, the separation distance of the control
`body B from the cable K by shank S causes the turbu
`lence and resultant noise produced by the control body
`B to be partially dissipated into the surrounding water,
`so that noise introduced into the hydrophones is re
`duced as contrasted to a large housing completely sur
`rounding the cable. Also, mounting the diving planes P
`and diving plane shafts 54 with the support shank S
`with the comparator R spaced therefrom in the control
`body B permits use of an increased length moment arm,
`correspondingly increasing the amount of torque ap
`plied to the diving planes P for each movement of the
`piston rod 76.
`Further, with the plural connecting collar assemblies
`C mounted at relatively spaced locations with the cable
`K from each other a form of precision bearing assembly
`is achieved, and a more stabilized and less unwieldy
`connection of the apparatus A to the cable K is permit
`ted so that stabilizer fins at the rear of the control body
`8 are not required, further reducing the drag and tur<
`bulence and attendant noise during movement through
`the water. Further, the connecting collars C cause the
`apparatus A to more closely follow the movement of
`the cable K, for example, when the course of the seis
`mic vessel pulling or towing the cable K is changed.
`In the event it is desirable or necessary to adjust the
`depth of the cable K, this adjustment can be quickly
`made with the control knob 114 in the manner above.
`Further, since the knob 114 is mounted in a position
`accessible externally of the control body B without
`requiring removal of any protective covers or disassem
`bly of the apparatus A, this adjustment can be quickly
`accomplished.
`In the event that the range of operating depths of the
`cable K is to be significantly changed, the spring 124
`may be replaced by a spring having a greater (or lesser)
`spring constant according to the new desired range of
`operating depths.
`In an alternative embodiment of the present inven
`tion (FIG. 3), the control body B is mounted with the
`cable K and operates in the manner set forth above. In
`addition, a ?otation tube assembly T, hollow and sealed
`against water pressure and having no internal operating
`
`35
`
`45
`
`50
`
`60
`
`65
`
`WESTERNGECO Exhibit 2091, pg. 8
`PGS v. WESTERNGECO
`IPR2014-01477
`
`

`
`20
`
`3,931,608
`10
`5. The structure of claim 1, wherein:
`parts; and further having an external con?guration
`said support shank means is smaller in width than
`corresponding to the control body B, is mounted by a
`support shank S, of the type set forth above, having
`said control body means along an axis transverse a
`longitudinal axis of the cable wherein the lateral
`locking pins 26, to the connecting collars C at locking
`span of said diving plane means is reduced.
`slots 24 diametrically opposed from those receiving the
`6. The structure of claim 5, further including:
`support shank S and control body B. The ?otation tube
`assembly T is used when neutral buoyancy of the appa
`a prow member formed on a leading rod of said con
`trol body, said prow member deflecting marine
`ratus A in the water is desired. Further, having upper
`growth and debris away from the mounting of said
`and lower structure mounted to the cable K with sup
`diving plane means with said support shank means
`port shanks S and connecting collars C of the type set
`to reduce snagging and catching of such marine
`forth, stability in the vertical plane in the presence of
`growth and debris by the apparatus.
`cross-currents or during turning of the vessel towing
`7. An apparatus for controlling the depth in water of
`the cable K is provided.
`Additionally, in the control body of the apparatus A
`a seismic cable, comprising:
`a. depth control means for regulating the depth of the
`the piston chamber 64 may be subjected to a substan
`cable, said depth control means comprising:
`tial vacuum and evacuated, rather than pressurized
`l. comparator means for comparing the force of
`with air, and a metal diaphragm used as diaphragm 72.
`ambient water pressure at the depth where the
`However, the spring 124 or other suitable structure
`cable is operating and a reference force repre
`must provide the force of the atmospheric pressure on
`senting the desired cable depth;
`the piston 70 which is not present in evacuated cham
`2. control body means for controlling said compar
`ber 64.
`The foregoing disclosure and description of the in
`ator means; and
`3. diving plane means responsive to said compara
`vention are illustrative and explanatory thereof, and
`various changes in the size, shape, and materials as well
`tor means for moving the cable to the desired
`depth; and
`as in the details of the illustrated construction may be
`b. connector means for connecting said depth control
`made without departing from the spirit of the inven
`tion.
`means to the cable, said connector means compris
`ing:
`I claim:
`1. An apparatus for controlling the depth in water of
`I. support shank means mounted between said
`control body means and the cable, said support
`a seismic cable, comprising:
`shaft having said diving plane means therewith;
`a. depth control means for regulating the depth of the
`2. connecting collar means for attaching said sup
`cable, said depth