Abstract:
Installation for harvesting energy of ocean currents (IHOC) in deepwaters is based on utilization of a semisubmersible platform and the multiple of vertically oriented Darrieus type hydraulic turbines. The turbines are located as close as possible to ocean surface, where speed of current is usually at its maximum. Since speed of current fluctuate during the seasons a system controlling buoyancy force of that keeps IHOC floating near surface is employed. The mooring system consists of three tethers, which prevent transferring of overturning moment applied to IHOC to anchoring base. The electric power generators are located in a machinery room on a structure well above sea level and would transmit electric power to the shore utilizing flexible cable. During hurricane it will be lowered to the depth preventing turbines from being affected by wave actions, at the same time it would keep machinery room above wave action. For the purpose of delivery assembled on shore Turbine Housing to destination site and installing it there a special convoy is formed consisting of Catamaran Delivery Barge and Stabilizing Platform. 
     The second Embodiment of this invention is designed to harvest energy of tides in deepwaters.

Description:
RELATED APPLICATION 
       [0001]    This Application claims priority from Provisional Patent Application No. 61/203,853 filed Dec. 29, 2008, disclosure of which is incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    This invention relates to harvesting kinetic energy of ocean currents and tides in deepwaters. 
       PRIOR ART 
       [0003]    The U.S. Pat. No. 6,856,036 issued Feb. 15, 2005 to Belinsky, who is also one of two authors of this application, describes Installation for Harvesting Ocean Current (IHOC), which innovation is based on the use of anchored to seabed semisubmersible platform having underwater frame containing at least two vertically oriented rows of Darrieus type turbines and in its capability to keep the semisubmersible platform in vertical position by automatically adjusting the length of one pair of the mooring lines, which change in the length depends on the speed of the current. The Darrieus turbines have vertically oriented central shaft that allows locating machinery room above water level and by this excludes the problem of flooding the machineries rooms of the system utilizing horizontal propeller type turbines. The prior patent has three embodiments, one of which is for harvesting energy of tides in deepwaters. 
       OBJECTIVES 
       [0004]    The objectives of the instant invention are in the improvements of the capabilities of the second and third embodiment of the patented IHOC. 
         [0005]    The first of improvements is in elimination of the need for an automatically operating system for adjusting the length of mooring lines to keep IHOC being oriented always perpendicular to current, because the daily and seasonable change in the current speed, affects the length of the mooring lines. 
         [0006]    The second improvement is in the added capabilities for IHOC for having turbines placed near surface to maximize utilization of the current energy and to sink them significantly below the zone of wave&#39;s action, thus avoiding their distraction during severe stormy weather means. 
         [0007]    The third improvement is in introduction of the means and method of lifting Turbine Housing from Assembling Yard, transporting it in horizontal position in a convoy, which includes also Stabilizing Platform and Anchoring Base, to the designated point, where Anchoring Base is lowered on seabed and Turbine Housing tilts into vertical position and by this completing IHOC installation. 
         [0008]    The fourth improvement is in the means that allows maintenance personnel to board IHOC during stormy seas. 
         [0009]    The fifth improvement is in the means that allows on the regular basis to clean turbines blades from foulings on their surface, which, if not remove timely, increase their drag and by this noticeable reducing turbines efficiency. 
       SUMMARY OF THE INVENTION 
       [0010]    The objectives of the instant invention are achieved through the following innovations: 
       1. Mooring System. 
       [0011]    The new mooring system proves to IHOC two advantages:
       A. The improved IHOC is moored to Anchoring Base on the ocean floor by three equal length tethers forming parallelogram, which keep IHOC in vertical position and perpendicular to current direction regardless to the change in the current speed, force and in the length of its horizontal displacement.   B. The three tethers anchoring arrangement attached to the middle of submerged structure excludes transferring wind and waves moments acting on IHOC to Anchoring Base, by compensating these moments through buoyancy force of IHOC submerged structure and a lever equal to perpendicular from the center of buoyancy to any of three possible axis of IHOC rotation.       
 
       2. Anchoring Base. 
       [0000]    
       
         
           
             Correspondingly to three tethers mooring systems the Anchoring Base is in a form of triangle structure. The new IHOC Anchoring Base is using on its three ends suction buckets, which generates holding power sufficient to substitute gravity mass used by patented IHOC Gravity Anchoring Base. It also has three cones, which are positioned near the Anchor Base center and serve as temporally storage for the tethers during delivery of Anchoring Base to destination site.
 
3. Means and Method for Delivery IHOC from Assembling Yard to Destination Site and its Installation There.
 
             The means includes Catamaran Delivery Barge, set of three carriages and a Stabilizing Platform. The method consists of sequence of operation of moving Turbine Housing supported by three carriages from Assembling Yard to piers, engaging Catamaran Delivery Barge with piers, lifting Turbine Housing from carriages, floating Catamaran Delivery Barge with Turbine Housing on it out into open seas, forming convoy consisting of Catamaran Delivery Barge with Turbine Housing, Anchoring Base and Stabilizing Platform between them. After convoy arrives to destination site the installation of IHOC in final position includes steps of lowering Anchoring Base to the seabed including Stabilizing Platform mitigation of the impact between Anchoring Base and seabed, activation of suction buckets and their penetration in seabed, transferring Catamaran Delivery Barge into semisubmersible mode at which Turbine Housing starts to float on its own. After that Catamaran Delivery Barge moves away and Turbine Housing takes ballast in its lower part, which start to tilt it and by this expose itself to current force, which accelerates the tilting of Turbine Housing. When Turbine Housing comes to vertical position all three tethers becomes automatically equally tensioned and on this process of installing IHOC is finished. 
           
         
       
     
       4. Means for Controlling IHOC Submerged Position. 
       [0000]    
       
         
           
             The purpose of these means is to keep turbines as closed as possible to surface, where the speed of current is always at its maximum and during severe storms to lower them on a significant distance from the ocean surface, which would mitigate force of wave&#39;s dynamic force acting on the turbines. This is achieved by controlling the buoyancy force of IHOC. For this purpose the entire structure of IHOC, consists of pipes and tubes forming a vessel that floats. One part of its structure internal volume is used as storage for compressed air and other part of its structure internal volume is used for controlling its buoyancy force by changing water level in it by opening and closing valves and increasing or lowering pressure of compressed air above water level inside this vessel. Thus allows IHOC, besides keeping it floating near surface during seasonal variation of current speed, to sink on a significant depth below ocean surface during hurricane and to keep its machinery Room above stormy waves. 
           
         
       
     
       5. Means for Delivery Maintenance Personnel to IHOC. 
       [0000]    
       
         
           
             For the purpose of allowing maintenance personnel to board IHOC even during stormy seas, the Turbine Housing has an Arrangement consisting of boarding platform and at least three equally spaced cone-adapter. This allows the special Service Vessel to engage its gangway with cone-adopter and by this providing safe condition for maintenance personnel to pass to boarding platform.
 
6. Means for Cleaning Turbine Blades from Foulings.
 
             For the purpose of preventing significant losses in turbines efficiency the improved IHOC provides means for periodical cleaning turbine blades from foulings. These means includes on Turbine Housing guiding poles and rails for a special Blade Cleaning System. This system consists of winch platform and operating platform, which is suspended on four ropes from winch platform and can move vertically along the Turbine Housing. Operating platform has two blade cleaning machines, which can be engaged simultaneously with each of two vertical rows of turbines. Each blade cleaning machine has two arms with cleaning heads on their ends, which allows simultaneously cleaning both sides of turbine blade. 
           
         
       
     
         [0019]    There are two preferred Embodiment of improved IHOC. Embodiment A is designed to harvest energy of current, Embodiment B is designed for harvesting tides. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0020]    FIG.  1 —IHOC in operating position (Elevation). 
           [0021]    FIG.  2 —IHOC in operating position (Plan). 
           [0022]    FIG.  3 —Turbines Assembly General Arrangement (Elevation). 
           [0023]    FIG.  4 —Turbines Assembly General Arrangement (Side View). 
           [0024]    FIG.  5 —Turbines Assembly General Arrangement (Plan). 
           [0025]    FIG.  6 —Section A-A from  FIG. 4   
           [0026]    FIG.  7 —Section B-B from  FIG. 4   
           [0027]    FIG.  8 —Section C-C from  FIG. 4   
           [0028]    FIG.  9 —Detail I from  FIG. 3 . 
           [0029]    FIG.  10 —Plan View from  FIG. 9 . 
           [0030]    FIG.  11 —Detailed II from  FIG. 3 . 
           [0031]    FIG.  12 —Plan View from  FIG. 11 . 
           [0032]    FIG.  13 —Detail III from  FIG. 4 . 
           [0033]    FIG.  14 —Section D-Detail from  FIG. 13 . 
           [0034]    FIG.  15 —Section E-E from  FIG. 13 . 
           [0035]    FIG.  16 —Anchoring Base (GAB); Elevation. 
           [0036]    FIG.  17 —Anchoring Base (GAB); Plan. 
           [0037]    FIG.  18 —Stabilizing Platform (Elevation). 
           [0038]    FIG.  19 —Stabilizing Platform (Plan). 
           [0039]    FIG.  20 —Section through IHOC Assembling Yard. 
           [0040]    FIG.  21 —Plan of Assembling Yard. 
           [0041]    FIG.  22 —Turbines Assembly moved on piers. 
           [0042]    FIG.  23 —Catamaran Delivery Barge engaged with piers. 
           [0043]    FIG.  24 —Section F-F from  FIG. 23 . 
           [0044]    FIG.  25 —Catamaran Delivery Barge with TLP moved from piers (Elevation). 
           [0045]    FIG.  26 —Catamaran Delivery Barge with TLP moved from piers (Plan). 
           [0046]    FIG.  27 —IHOC Convoy during transportation (Elevation). 
           [0047]    FIG.  28 —IHOC Convoy during transportation (Plan). 
           [0048]    FIG.  29 —IHOC Convoy at installation site. 
           [0049]    FIG.  30 —Process of lowering Gravity Anchoring Base ( 1 ). 
           [0050]    FIG.  31 —Process of lowering Gravity Anchoring Base ( 2 ). 
           [0051]    FIG.  32 —Process of lowering Gravity Anchoring Base ( 3 ). 
           [0052]    FIG.  33 —Process of lowering Turbine Housing in water 
           [0053]    FIG.  34 —Catamaran Delivery Barge moves away from Turbines Assembly. 
           [0054]    FIG.  35 —Process of Turbine Housing inverting in vertical position ( 1 ). 
           [0055]    FIG.  36 —Process of Turbine Housing inverting in vertical position ( 2 ). 
           [0056]    FIG.  37 —Turbine Housing in vertical position ( 3 ). 
           [0057]    FIG.  38 —IHOC Group Installation (Elevation). 
           [0058]    FIG.  39 —IHOC Group Installation (Plan). 
           [0059]    FIG.  40 —System for cleaning turbine blades from foulings. 
           [0060]    FIG.  41 —Detail IV from  FIG. 40 . 
           [0061]    FIG.  42 —Plan from  FIG. 41 . 
           [0062]    FIG.  43 —Section H-H from  FIG. 40 . 
           [0063]    FIG.  44 —Service Vessel at IHOC (Elevation). 
           [0064]    FIG.  45 —Service Vessel at IHOC (Plan). 
           [0065]    FIG.  46 —Section L-L from  FIG. 3 . 
           [0066]    FIG.  47 —IHOC—Embodiment B. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     EMBODIMENT A 
       [0067]      FIGS. 1 and 2  show general arrangement of the IHOC in installed position. The IHOC  21  consists of Turbines Assembly  23 , four tethers  25 , power cable  26  and Anchoring Base (AB)  27 . The power cable  26  on its way from the IHOC bottom to gravity anchoring base is connected in several places to one of the tethers. The gravity-anchoring base  27  would have means connecting it to power cable going to the shore.  FIGS. 3 through 12  illustrate design of Turbine Housing  23 , it consists of two vertical rows  31  of Darrieus turbines, frame  33  and machinery room  35 . It also includes a system  36  for controlling Turbine Housing  23  buoyancy force during its submerged position. Each row  31  of Darrieus turbines contains four turbines  37 . Each turbine  37  consists of three two blades turbines  39 ,  40  and  41 , shifted in plane on 120 degrees and attached to a common vertical shaft  43 , which is supported from horizontal displacement by bearing arrangements  45  located between turbines  37  and from vertical displacement by trust bearing  46  located on the lower pontoon  57 . Each two blade turbine has two blades  47  and two spokes  48 . To the top of vertical shaft  43  is attached gear wheel  49 , which is engaged with tooth gear  51 . Gear  51  is attached to a vertical power shaft arrangement  53 , which is going upward to machinery room  35 . 
         [0068]    Frame  33  consists of upper pontoon  55 , lower pontoon  57  and middle pontoon  59 , two vertical columns  61  connecting upper and lower pontoons  55  and  57 , and machinery support column  63  all of which are pipe type structures with hollow inside. To one of the columns  61  are attached two rails  62  for guiding Blade Cleaning System. The middle pontoon  59  consists of two side pontoons  65  and  66 , two cross pontoons  67  and tripod support  67 A. Tripod support  67 A has on its front end bottom one tether  25  attachment  69 . Each side pontoons  65  and  66  have on the bottom of their rear ends has one tether  25  attachment  69 . These three tether  25  attachments form a triangle area center of which coincides with IHOC center of buoyancy. 
         [0069]    For transportation purposes the Turbines Assembly  23  has front trust point  68  and pair of middle trust points  69  and  70 . 
         [0070]    The system  36 , which controls Turbine Housing  23  buoyancy force, includes the inner space of side pontoons  65  and  66 , which are partially field with water and compressed air (see  FIG. 47 , sheet  2 ). The proportion of water and compressed air inside them is achieved through compressed air outfit  71  and remote operated valve  72 , which allow water to flow out or inside pontoons  65  and  66 . The system  36  also includes the inner space of lower pontoon  57  as storage for compressed air. Machinery Room  35  will include two generators, compressors and controls post, which are not shown. 
         [0071]      FIGS. 9 and 10  illustrate bearing arrangements  45 , which provides horizontal supports vertical shaft  43  along its height by at least two units per turbine. Each unit  45  consists of ring base  75 , at least three equally spaced roller  77  with supports  79 . Each ring base  75  is connected to vertical supports  61  by at least two beams  81 . 
         [0072]      FIGS. 11 and 12  illustrate Arrangements for attaching Service Vessel  179  and Blade Cleaning System  180  to IHOC  21 . Base  83  for attaching to IHOC Blade Cleaning System consists of symmetrically located pair of vertical poles  85  with cone head and a support  87 . The Arrangement  89  for attaching Service Vessel  179  Personnel Transfer Station  181  to IHOC  21  consists of boarding platform  91 , hand rails  93  and an open cone-adapter  95 . 
         [0073]      FIGS. 13 through 15  illustrate engagement of gear wheel  49  with vertical power shaft arrangement  53 , which consists of vertical tube  97 , shaft  99 , tooth gear  51  and trust bearing  101  with support  103  attached to upper pontoon  55 . 
       Anchoring Base. 
       [0074]      FIGS. 16 and 17  Illustrate Anchoring Base  27  positioned on the ocean floor. It consists of a frame  105 , three suction buckets  106 , each consisting of a cylinder  107 , top plate  108  and connector  110 . All suction buckets  106  are interconnected by three beams  111  through connectors  110  forming triangle structure. In the center of triangle structure is positioned central ring  112 , which serves as a hub to which beams  113  and  114  are attached. Near center ring  112  are located equally spaced three cones  116 , which serve as a storages for tethers  25  during Anchor Base  27  transportation to destination site. Location of three tethers  25  attachment points forms a triangle, which area center coincides with Anchoring Base geometrical center. Each suction bucket  106  has an electric pump  118  with the capability to be disconnected after suction bucket is fully immersed into seabed soil and flowing up to ocean level. 
       Stabilizing Platform. 
       [0075]      FIGS. 18 and 19  illustrate design of stabilizing platform  155 , which provides conditions for the Anchoring Base  27  to descend and land flat on the ocean floor. It also provides to Anchoring base  27  electric powers to operate their suction pumps. It consists of a pontoon  157 , four legs  158 , winch platform  159 , winch  160 , hoisting line  161  and hoisting line quick release device  162 . It also includes electric power cable drum  163  with cable  164 , electric power generator  165  and control post  166 . 
         [0076]      FIGS. 20 and 21  illustrate Catamaran Delivery Barge  127  and Assembling Yard  125 , which expands into three piers one central  129  and two side piers  131 . Turbine Housing  23  is positioned on three carriages, one central carriage  133  and two side carriages  135 . 
       Catamaran Delivery Barge. 
       [0077]    Catamaran Delivery Barge  127 , see  FIGS. 22 through 25 , consists of two pontoons  137  each having rear upward extended columns  139  and two upward extended columns  140  near the middle of pontoons  137 . Two rear upward extended columns  133  are interconnected by two crossbeams upper  141  and lower  143 . The rear upward extended columns  140  are interconnected by only one crossbeam  145 . For the purpose of engaging with Turbine Housing Catamaran Delivery Barge  127  has three points of contact, one of point of contacts is a support pillow  149 , which is located on the middle of Crossbeam  143 , and two points contacts in the form of support stools  151  (see  FIG. 24 ), located on both pontoon  137  in the area near the rear extended upward columns  140 . Inside of extended upward columns  140  would be located compressors and control posts, which are not shown. 
         [0000]    The Process of Transferring Turbine Housing from Assembly Yard to Catamaran Delivery Barge. 
         [0078]    The process starts by relocating Turbine Housing  23  from Assembling Yard  125  to piers  129  and  131  using carriages  133 ,  135  and  136 , which support Turbine Housing at three trust points—one  68  and two  70 .  FIG. 22  illustrates Turbine Housing already moved on the pier  129  and piers  131  from the Assembling Yard  125 . 
         [0079]    Catamaran Delivery Barge  127 , before approaching Turbine Housing  23  on the piers, takes ballast to sunk to the depth that would position its engagement points ( 149 ,  135  and  136 ) below the engagement points (one  68  and two  70 ) on the Turbine Housing. The Catamaran Delivery Barge  127  movement toward the Turbine Housing  23  would stop after its engagement points ( 149 ,  135  and  136 ) would match the corresponding engagement points (one  68  and two  70 ). At this position Catamaran Delivery Barge starts to refloat and, after supports stools  151  and support pillow  149  got in contact with trust point  68  and two trust points  70  on Turbine Assembling  23 , would lift Turbine Housing  23  from carriages  133 ,  135  and  136 . By next step Catamaran Delivery Barge  127  with Turbine Housing on it moves out of piers area, which illustrated by  FIGS. 23 and 24 . 
         [0080]    The process of assembling convoy for towing Turbine Housing  23  to installation side.  FIGS. 27 and 28  illustrate assembled Convoy  170  for towing Turbine Housing  23  to destination site, which consists of Catamaran Delivery Barge  127 , Anchoring Base  27 , floating on compressed air filled in the suction buckets  106 , and Stabilizing Platform  155 . At the first the Stabilizing Platform  155  would be attached to Anchoring Base by hoisting line  161  and electric cable  163 . After this the upper ends of three tethers  25 , which are stored on Anchor Base  27  cones  116 , would be connected to the Turbine Housing three points of contact  69  with some slack in each of them. These connections would allow tugs  172  to tow Turbine Housing  23  and group of tugs  174  to tow, through towing lines  176 , the interconnected Anchoring Base  27  and Stabilizing Platform  155  simultaneously together as a Convoy  170 . The slackened tethers  25  would allow compensating for minor variation in the speed of tugs in group  172  and  174 . 
       The Process of Installing IHOC at the Destination Site. 
       [0081]      FIG. 29  illustrates Convoy  170  arrived to destination point. At this position tugs  172  and  174  would keep all convoy  170  stalled by working only against the current. 
         [0082]      FIGS. 30 through 32  illustrate the process of lowering Anchoring Base  27  to ocean bottom, which consists of the following steps:
       At the initial position Anchoring Base  27  starts to vent compressed air from suction bucket  106  and this initiates it sinking.   During sinking it would tension hoisting line  161  through a sling  167  and a sheave  168  (see  FIG. 30 ) to a certain level after which winch  160  would starts to payout hoisting line  161  under some tension, which would keep Anchoring Base  27  horizontal position during the controlled decent.   About 10 meters before reaching ocean bottom the winch  160  stops paying out and this would pull down Stabilizing Platform  155  down. The increased force in hoisting line  161  would further stabilize Anchoring Base  27  horizontal position.   When Anchoring Base  27  reaches the ocean bottom and suction buckets  106  would start penetrating soil under their own weight the Stabilizing Platform  155  would slack the hoisting line and by this Stabilizing Platform  155  would gradually refloat to initial position. Simultaneously the electric pumps  118  on Anchoring Base  27  would start pump out water from suction buckets  106  and by this pressing them further into soil.   After suction buckets  106  would be completely inserted in soil the command would be sent to electric pumps  118  to disconnect from Anchoring Base  27  and flow up. Simultaneously would be given command to activate the quick release device  167 , which would be released one end of hoisting line  161 , which would let sheave  163  and sling  162  to free fall and would allow the winch  160  will pull up the remaining length of hoisting line  161 .         
         [0088]      FIGS. 33 and 34  illustrate the process of Catamaran Delivery Barge  127  lowering Turbine Housing  23  in water and disengaging from it. During this process the Catamaran Delivery Barge  127  would take water ballast in its both of its pontoons  151  and by this it sink its pontoons  151  below ocean surface and on a distance that would lower Turbine Housing  23  in water. Stability of Catamaran Delivery Barge  127  would be provided by four extended columns  139  and  145 , which put Catamaran Delivery Barge  127  into semisubmersible mode. The frame  33  of Turbine Housing  23 , which is designed from pipes and hollow vessels, would provide sufficient buoyancy to float Turbine Housing  33  horizontally. After Turbine Housing  23  starts to float tugs  172  would let Catamaran Delivery Barge  127  to drift under their control down the current stream. Simultaneously the Turbine Housing  23  would also start to drift down the stream. 
         [0089]      FIGS. 35 through 37  illustrated the process of Turbine Housing  23  inverting from horizontal position to vertical position under current force. It would be initiated by ballasting lower part of frame  33 , which would initially slightly incline it and by this increasing area affected by current, which would start to turn Turbine Housing around a points to which one pair of tethers  25  are attached. 
       Systems Servicing IHOC. 
     Blade Cleaning System. 
       [0090]      FIGS. 40 through 43  illustrate Blade Cleaning System  180  for cleaning turbine blades from foulings. It consists of winch platform  182  and operating platform  184 . Winch platform  182  has, for the purpose of attaching to IHOC, two outreach legs  185  with bushings  187 , which engage with guiding poles  85  (see  FIG. 11 ). Outreach Legs  185  are attached to base  189  on which are located two winches  191 . Each of the winch  191  consists of drive  193 , gearbox  195  and two drums  197  with hoisting lines  199  winded up by one end on them and by other end connected to frame  201  of operating platform  184 . Operating platform  184  consists of a frame  201  having two horizontal guides  203  and two sets of guiding rollers  205  embracing guiding rails  62  (see  FIGS. 3 and 7 ). It also includes two blade cleaning machines  207  and  208 . Each  207  and  208  machine consists of a base  209 , two arms each having cleaning heads  211 ,  212  and hydraulic cylinders  213  and  212 . 
       Operation of Blade Cleaning System  180 . 
       [0091]    Floating Crane would bring to IHOC on its hook winch platform  182 , which would have operating platform  184  suspended on four hoisting lines  199  as close as possible to winch platform. Than Floating Crane would lower winch platform  182  on IHOC in a manner that bushings  187  of winch platform  182  would come in contact with poles  85  through theirs cones, which would guide bushings  187  to rest on poles  85  supports  87 . After this the winches  191  would start to pay out hoisting lines  191 , which would start to lower operating platform  184 . 
         [0092]    During the lowering process the two sets of guiding rollers  205  would get in contact with two guiding rails  62 , which would prevent operating platform  184  from any horizontal movement under current and wave forces. When on the way dawn operating platform  184  reaches the first blade  47 , both blade cleaning machines  207  and  208  would be in position in which cleaning machine  208  is shown on  FIG. 43 . When operating platform  184  stops, the blade cleaning machines  207  and  208  would start moving toward blades  47 . After cleaning machines reach the blades  47 , the hydraulic cylinders  215  and  217  would bring cleaning heads  214  in contact with blade  47  surface. During continue movement of cleaning machines along the blade  47  section the cleaning heads would clean a strip equal to their width. After cleaning heads  214  would get out of contact with blade  47 , the operating platform would be lowered on a distance equal to the cleaned strip width. After these cleaning machines  207  and  208  would be pulled back and cleaning heads  214  would get in contact with blade  47  and on the way back would clean one more strip. This operation would be repeated until the vertical length of blade  47  would allow. (0038) When all blade&#39;s surface is cleaned, cleaning machines  207  and  208  would be retracted to their initial position and both row of Darrieus turbines  31  would be rotated on the angle between blades and a new cycle of blades  47  cleaning would start. 
       Service Vessel. 
       [0093]      FIGS. 44 and 45  illustrates Service Vessel  179  engaged with IHOC  21  through Personnel Transfer Station  181  and cone-adapter  95  on IHOC  21 . 
       EMBODIMENT B 
       [0094]      FIG. 47  Illustrates IHOC application for harvesting energy of tides in deepwaters. Because of Darrieus turbine capability to rotate in the same direction, regardless of current direction, design of IHOC for harvesting energy of tides differs from the design for harvesting energy of currents only by having two anchoring arrangement, each consisting of Anchoring Base  27  and set of tethers  25 , located opposite to each other.