Abstract:
A system for transporting wind turbine blades includes a first support structure for supporting a cylindrical root section of a first wind turbine blade and a second support structure aligned with and spaced from the first support structure for supporting a tip section of the first wind turbine blade. A third support structure is included for supporting a tip section of a second wind turbine blade. A fourth support structure is spaced from and aligned with the third support structure for supporting a cylindrical root section of the second wind turbine blade. The first and second wind turbine blades extend with an edge-vertical orientation in opposing directions such that a tip of the first wind turbine blade is disposed horizontally adjacent the cylindrical root section of the second wind turbine blade and a tip of the second wind turbine blade is disposed horizontally adjacent the cylindrical root section of the first wind turbine blade.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    The present application claims the benefit of U.S. Provisional Application No. 61/928,066, filed Jan. 16, 2014 and incorporated herein by reference for all purposes. 
     
    
     FIELD OF INVENTION 
       [0002]    The present invention relates in general to wind turbine blades, and in particular to systems and methods for transporting wind turbine blades. 
       BACKGROUND OF INVENTION 
       [0003]    Wind turbines have become an important source of electrical power worldwide. Generally, wind turbines are supported by a tower and driven by multiple wind turbine blades, each of which is typically tens of meters in length. As efforts are made to increase the amount of electrical power generated per wind turbine, the length of the wind turbine blades has also correspondingly increased. 
         [0004]    The significant length of currently available wind turbine blades, as well as the continuing efforts to design and manufacture even longer wind turbine blades, has presented substantial challenges for those tasked with transporting wind turbine blades from the manufacturer to the wind turbine farms. One particular challenging scenario is the transportation by ship. 
         [0005]    Currently, the blade manufacturer typically bolts fixtures to the blade root and tip sections, which provide points for the blades to be lifted and moved without damage, as well as for securing the blades to ship decks and other transportation vehicles. Although these fixtures are usually designed and fabricated for reuse, in actual practice their components, including the bolts, are often lost or discarded at the wind turbine farms, which can result in a significant, and often avoidable, monetary loss to the wind turbine blade manufacturer. 
         [0006]    The lifting of wind turbine blades on and off of ships, as well the process of securing the wind turbine blades to the ship decks, present a number of other problems. Among other things, in-port time and cost constraints require techniques for quickly and safely lifting the blades on and off of the ship, as well as for efficiently and effectively securing the blades to the ship decks for safe transit overseas. 
         [0007]    Another factor is maximizing the number of wind turbine blades that can be carried per shipload. For example, in some circumstances, the blades are stacked in an edge-horizontal orientation to increase packing density; however, depending on the size of the ship, the loading applied during transport at sea can cause the horizontally-oriented bodies of the stacked blades to flex vertically, which can result in undue stress, contact between vertically adjacent blades, and blade damage. 
       SUMMARY OF INVENTION 
       [0008]    The principles of the present invention are embodied in a system for transporting wind turbine blades, which includes a first support structure for supporting a cylindrical root section of a first wind turbine blade and a second support structure aligned with and spaced from the first support structure for supporting a tip section of the first wind turbine blade. A third support structure is included for supporting a tip section of a second wind turbine blade. A fourth support structure is spaced from and aligned with the third support structure for supporting a cylindrical root section of the second wind turbine blade. The first and second wind turbine blades extend with an edge-vertical orientation in opposing directions such that a tip of the first wind turbine blade is disposed horizontally adjacent the cylindrical root section of the second wind turbine blade and a tip of the second wind turbine blade is disposed horizontally adjacent the cylindrical root section of the first wind turbine blade. 
         [0009]    Wind turbine blade transport systems embodying the present principles realize a number of substantial advantages over the prior art. Among other things, the fixtures typically used to transport wind turbine blades are no longer required, which reduces the unnecessary expenses that are often incurred at the wind farm work sites when fixture components are lost or discarded. Moreover, by packing the wind turbine blades edge-vertical, the effects of the forces typically incurred during ocean transport are minimized. 
         [0010]    In addition, the stability provided by these transport system allows for a significant reduction in the number of chains, cables, and/or composite fiber lines required to secure the wind turbine blades to the deck of a ship or other transportation vehicle. Furthermore, the principles of the present invention provide for the modular construction of wind turbine transport packs of different configurations, as needed to transport wind turbine blades of varying lengths, differing numbers of wind turbine blades, and/or to meet constraints such as limits on available ship deck and/or hold space. Blade transport systems embodying the inventive principles, when not in use, can be disassembled for storage and transport in standard land-sea shipping containers. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0011]    For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which: 
           [0012]      FIGS. 1A-1C  are respectively top, side, and end views of a generic wind turbine blade suitable for describing the principles of the present invention (the dimensions shown provide a reference as to scale and relative proportions and may vary in actual practice); 
           [0013]      FIG. 2A  is a top perspective view of a representative wind turbine blade pack embodying the principles of the present invention, as loaded with wind turbine blades similar to those shown in  FIGS. 1A-1C ; 
           [0014]      FIG. 2B  is a top plan view of the loaded wind turbine blade pack shown in  FIG. 2A ; 
           [0015]      FIG. 2C  is a side elevational view of the loaded wind turbine blade pack shown in  FIG. 2A   
           [0016]      FIG. 2D  is a partial side elevational view showing in further detail the root-to-tip interleaving of adjacent wind turbine blades loaded into the wind turbine blade pack of  FIG. 2A ; 
           [0017]      FIG. 2E  is a top plan view illustrating the root-to-tip interleaving of a representative pair of horizontally adjacent wind turbine blades loaded into the wind turbine blade pack of  FIG. 2A ; 
           [0018]      FIG. 3A  is an elevational view of one of the two substantially similar end frames of  FIG. 2A , shown without the associated wind turbine blades installed within the wind turbine blade pack; 
           [0019]      FIG. 3B  is an exploded view of the end frames shown in  FIG. 3A ; 
           [0020]      FIG. 3C  is an exploded view of one of the wind turbine blade root support assemblies shown in  FIG. 3A ; 
           [0021]      FIG. 3D  is a top plan view showing in detail the cylindrical ends of a pair of horizontally adjacent wind turbine blades supported by corresponding blade root support assemblies, as shown in  FIG. 3C , and the corresponding end frame shown in  FIG. 3A ; 
           [0022]      FIG. 4A  is an exploded view of one of the two substantially similar middle frames shown in  FIG. 2A ; 
           [0023]      FIG. 4B  is a side plan view showing one of the substantially similar wind turbine blade tip section support structures of  FIGS. 2C and 2D  in further detail, as supporting a corresponding wind turbine blade tip section; 
           [0024]      FIG. 4C  is an exploded view of the wind turbine blade tip section support structure shown in  FIG. 4A ; 
           [0025]      FIG. 4D  is an end plan view of one end the wind turbine blade tip section support structure shown in  FIG. 4A  in an open state; and 
           [0026]      FIG. 4E  is an end plan view of the opposing end of the wind turbine blade tip section support structure shown in  FIG. 4A , in a closed state. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0027]    The principles of the present invention and their advantages are best understood by referring to the illustrated embodiment depicted in  FIGS. 1-4  of the drawings, in which like numbers designate like parts. 
         [0028]      FIGS. 1A-1C  are conceptual diagrams of a generic wind turbine blade  100  suitable for describing the principles of the present invention. Currently there are a number of wind turbine blade constructions used worldwide, although a typical wind turbine blade  100  will include a root with a cylindrical section  101  and skin panels or shells supported by the root, which extend to a blade tip  102  and provide the surfaces of the blade airfoil. Longitudinally extending bolts, discussed below, attach cylindrical section  101  to the rotor hub of the associated wind turbine. Each manufacture typically provides a reinforced blade tip section  103  for allowing wind turbine blade  100  to be secured, transported, and supported without damage to the outer shell or root. 
         [0029]    Representative dimensions are shown in  FIGS. 1A-1C  to provide the reader with a sense of scale, although wind turbine blades of 75 meters or more are currently viable and the trend in the wind turbine industry is to use increasingly longer blades. (Generally, longer turbine blades, and increased airfoil surface area, allow for an increase in power output from the wind turbine.) Application of the principles of the present invention are generally not dependent on the particular configuration or dimensions of the wind turbine blade itself. 
         [0030]      FIG. 2A  provides a top perspective view of a representative loaded wind turbine blade pack  200  embodying the principles of the present invention. Wind turbine blade pack  200  is most advantageously used for the securing a set of wind turbine blades during transport by ship, although other applications are possible. In the following discussion, wind turbine blade pack  200  is being used on a ship deck, which could by an upper (open) ship deck or a deck within a ship&#39;s hold. As discussed below, the modular construction of wind turbine pack  200  provides flexibility such that wind turbine pack  200  may be used in circumstances where the available deck or hold space differs. 
         [0031]    In the illustrated embodiment, end frames  202   a - 202   b  and middle frames  203   a - 203   b  each define four (4) longitudinally aligned 5×3 arrays of rectangular subframes  201 , which are shown fully loaded with thirty (30) wind turbine blades  100 . Each set of four longitudinally subframes  201  supports and secures a pair of wind turbine blades, which are disposed root-to-tip with the airfoil edges extending vertically within the subframes  201 , as shown in detail in  FIG. 2B . Advantageously, edge-vertical packing according to the principles of the present invention provides increased blade support in light of the forces applied during typical ship borne transit, minimizes blade flexing, and reduces the probability of cracked or damaged blade shells. 
         [0032]    While  FIG. 2A  shows a configuration of wind turbine pack  200  comprising four 5×3 aligned arrays of subframes  201 , the modular construction of wind turbine pack  200  generally allows end frames  202   a - 202   b  and middle frames  203   a - 203   b  to define arrays of subframes  201  having m number of horizontal rows and n number of vertical columns for securing up to m×n×2 number of wind turbine blades  100 . For example, in the smallest configuration, end frames  202   a - 202   b  and middle frames  203   a - 203   b  define four single longitudinally aligned subframes  201  for transporting and securing one or two wind turbine blades  100 . Similarly, 2×2 aligned arrays of subframes  201  will accommodate up to eight (8) wind turbine blades, 5×1 aligned arrays of subframes  201  will accommodate up to ten (10) wind turbine blades, and so on. Advantageously, wind turbine pack  200  can be customized depending on the number of wind turbine blades being transported, any limitations on ship deck or hold space, and similar factors. 
         [0033]    Wind turbine blade pack  200  is secured and stabilized by a series of conventional maritime fasteners  204 , such as chains, cables, or composite fiber lines, which extend from fastening points  205  on the ship deck to fastening points  206  on end frames  202   a - 202   b  and middle frames  203   a - 203   b . While four exemplary fasteners  204   a - 204   d , along with the associated fastening points  205   a - 205   d  and  206   a - 206   d  are indicated for reference, in actual practice the number of fastening devices  204  used may vary significantly, as necessary to secure the loaded wind turbine blade pack  200  to the ship deck. In a typical application  100  or more fasteners may be required to secure a loaded turbine blade pack  200  the ship deck; however, because wind turbine blade pack  200  provides significant support and stability to wind turbine blades  100 , the number of fasteners  204  required may be substantially reduced in view of existing methods of securing wind turbine blades to ship decks, which typically may require 300 or more similar fasteners. In addition, by providing fixed attachment fastening points  205  on wind turbine pack  200 , interference between the wind turbine blades  100  and fasteners  204  is minimized. 
         [0034]      FIG. 2C  is a side elevational view showing the packing of wind turbine blades  100  in wind turbine blade pack  200 .  FIG. 2D  shows one end of packed wind turbine blade pack  200  in further detail. The reinforced tip section  103  of each blade  100  is supported by a blade tip support assembly (“taco”)  207  and the corresponding cylindrical root section  101  is supported by a blade root support assembly (“saddle”)  301 , discussed below in conjunction with  FIGS. 3A-3D . For example, blade tip support assembly  207   b  supports the reinforced tip section  103  of wind turbine blade  100   b , blade tip support assembly  207   c  and blade tip support assembly  207   d  supports the reinforced tip section  103  of wind turbine blade  100   d . The spacing of end frame sections  202   a - 202   b  and middle frame sections  203   a - 203   b  will therefore depend on the length of the wind turbine blades  100  being secured, as well as the location of reinforced blade sections  103 . Advantageously, the modular construction of wind turbine blade pack  200  allows the spacing between end frames  202   a - 202   b  and middle frames  203   a - 203   b  to be set to accommodate wind turbine blades of different lengths and with reinforced sections in different locations. 
         [0035]    Blade tip support assemblies  207  are discussed in further detail below in conjunction with  FIGS. 4A-4E . However, generally, each blade tip support assembly  207  includes a U-shaped receptacle for receiving the blade edge in reinforced tip section  103  of the corresponding wind turbine blade  100 . A pair of opposing flaps contract onto the opposing blade outer surfaces to secure and stabilize the wind turbine blade tip section. 
         [0036]    The interleaving (packing) of a representative pair of wind turbine blades  100 , in this example wind turbine blades  100   c  and  100   d , within wind turbine blade pack  200  is shown in further detail in the top plan view of  FIG. 2E . The blade root support assembly (saddle)  301  elevates the cylindrical root section  101  of each pair of horizontally interleaved pair of wind turbine blades with respect to the tip  102  of the opposing blade of the pair. Hence, the curved tip section  102  (see  FIG. 1B ) of one blade curls underneath the cylindrical root section  101  of the other. The curling of the tip of one blade under the cylindrical root section of the other, in addition to the edge-vertical orientation, helps reduce the horizontal distance required to pack each pair of blades. 
         [0037]      FIG. 3A  is an end elevation view of end frame  202   a , which is shown without installed wind turbine blades  100  for clarity. The configuration of opposing end frame  202   b  is similar. 
         [0038]    Each end frame  202  is supported on the ship deck by a bottom beam  300 , which is preferably fabricated from steel. In one embodiment, each bottom beam  300  is received within a shoe on the ship deck (not shown), although bottom beams  300  may also be fastened to the ship deck by welding, bolts, brazing, or other similar conventional techniques. Preferably, bottom beams  300  of end frames  202  are wider than the bottom beams of middle frames  203 , discussed below. Each subframe  201  of each end frame  202  includes a blade root support assembly  301  (“saddle”), which supports and stabilizes the cylindrical root section  101  of a corresponding wind turbine blade  100 . 
         [0039]    An exploded view of one end frame  202  is shown in  FIG. 3B . The array of subframes  201  of each end frame  202  is constructed from a set of outer vertical beams  303 , horizontal beams  304 , and interior vertical beams  305 . Vertical beams  303  and  305  and horizontal beams  303  are preferably fabricated from steel. 
         [0040]    Outer vertical beams  303  form columns defining the lateral edges of the given end frame  202 . Interior vertical beams  305  are shared by horizontally adjacent subframes  201 . Horizontal beams define the top and bottom vertically adjacent subframes  201 . 
         [0041]    Outer vertical beams of vertically adjacent subframes  201  bolt together at plates  306  and with the associated horizontal beams  304  at plates  307 . Interior vertical beams  305  of vertically adjacent subframes  201  are bolted together, along with the adjacent horizontal beams  304 , at steel crosses  308 . 
         [0042]    Preferably, bottom beam  300  of each end frame  202  is formed from multiple steel sections  302   a - 302   e , which are fastened together using conventional techniques such as welding or brazing. Outer vertical steel beams  303  and interior vertical steel beams  304  are preferably bolted to plates  309  disposed in slots in bottom beam  300 . 
         [0043]    In the preferred embodiment of end frames  202 , the various structures forming the assembly (e.g., outer vertical beams  303 , horizontal beams  304 , and inner vertical beams  305 ) are fastened together with bolts or similar removal fastening devices, which advantageously allows end frames  202  to be quickly assembled and disassembled for use, movement, and storage. In alternate embodiments, end frames  202  may also be assembled using other techniques such as welding, brazing, or the like. 
         [0044]    An exemplary blade root support assembly (saddle)  301  is shown in further detail in the exploded view of  FIG. 3C . Blade root support assemblies  301  in the array of subframes  201  of each end frame  202   a - 202   b  are similar. 
         [0045]    In this example, blade root support assembly  301  is supported by a pair of interior vertical steel beams  305   a  and  305   b  and a pair of horizontal steel beams  304   a  and  304   b , discussed above in conjunction with  FIG. 3B . A pair of opposing strap support assemblies  310   a - 310   b  support and adjust the length of a conventional flexible strap  311 . When wind turbine blade pack  200  is loaded, strap  311  lies underneath and supports the cylindrical root section  101  of the associated wind turbine blade  100 . 
         [0046]    Ears  212   a - 212   b  include apertures for receiving bolts that thread into the end of the cylindrical root section  101  of the associated wind turbine blade, as shown in  FIG. 3D . (These bolts also fasten the wind turbine blade to the hub of the wind turbine, as known in the art). 
         [0047]      FIG. 3D  is a top plan view showing exemplary cylindrical root sections  101   a  and  101   e  of a pair of exemplary horizontally adjacent wind turbine blades  101   a  and  101   e  within loaded wind turbine blade pack  200  of  FIG. 2A  (see  FIG. 1A ). As shown in  FIG. 3D , a second flexible strap  313  extends around the periphery of each cylindrical root section  101  and attaches to either end frame bottom beam  300 , in the case of the lowest row in the array of subframes  201 , or horizontal steel beam  304  disposed immediately below, in the case of rows in the array of subframes  201  above the bottom row. In the example of  FIG. 3D , straps  313   a  and  313   e  respectively secure and stabilize the cylindrical root sections  101   a  and  101   e  of wind turbine blades  101   a  and  101   e  of  FIG. 2A . 
         [0048]    An exploded view of one of the middle frames  203   a - 203   b  is provided in  FIG. 4A . Each middle frame  203  includes a bottom beam  400 , which preferably is formed from steel beam sections  401   a - 401   e , which are fastened together, as well as to the ship deck, using conventional methods such as welding, brazing, or bolting. 
         [0049]    Middle frames  203 , in the illustrated embodiment, include outer vertical beams  402 , horizontal beams  403 , and interior vertical beams  404 . Preferably, outer vertical beams  402 , horizontal beams  403 , and interior vertical beams  404  are fabricated from steel. 
         [0050]    Outer vertical steel beams  402  bolt together at plates  407  to form columns defining the lateral edges of the given middle frame  203   a - 203   b . Horizontal steel beams  403  define the top and bottom of each subframe  201  in the array of subframes  201  defined by the middle frame  203 . 
         [0051]    Plates  406  on horizontal beams  403  bolt to plates  405  on outer vertical beams  402 . Interior vertical beams  404  and horizontal beams  403  bolt together through steel crosses  408  to form the array of subframes  201 . Plates  409  allow outer vertical beams  402  and interior vertical beams  404  to be bolted to beam sections  401   a - 401   e  of bottom beam  400 . 
         [0052]    As with end frames  202 , in the preferred embodiment of wind turbine blade pack  200 , the various structures forming the assemblies of middle frames (e.g., outer vertical beams  402 , horizontal beams  403 , and interior vertical beams  404 ) are fastened together with bolts or similar removal fastening devices, which advantageously allows middle frames  203  to be quickly assembled and disassembled for use, movement, and storage. In alternate embodiments, middle frames  203  may also be assembled using other techniques such as welding, brazing, or the like. 
         [0053]      FIG. 4B  is a side elevational view of one of two symmetrical sides of a representative blade tip support assembly  207 , in this example, blade tip support assembly  207   b  supporting and stabilizing the reinforced tip section  103  of wind turbine blade  100   b  (see  FIG. 2D ). A corresponding exploded view is shown in  FIG. 4C . 
         [0054]    Each blade tip support assembly  207  includes a steel U-shaped receptacle  410 , which is adapted to receive the edge of the reinforced tip section  103  of the corresponding wind turbine blade  100 . U-shaped receptacle  410  is supported by steel U-shaped ribs  413   a - 413   d  and a steel U-shaped liner  417 . 
         [0055]    A pair of opposing flaps  411   a - 411   b  extend from the upper edges of U-shaped receptacle  410  and are supported by support structures  418   a - 418   b . Raps  411   a - 411   b  and support structures  418   a - 418   b  rotate around a corresponding pair of hinges formed by shafts  412   a - 412   b , tubes  416   a - 416   b , and tubes  420   a - 420   b . In particular, shafts  412   a - 412   b  rotate within tubes  416   a - 416   b , which are disposed along the upper edges of an U-shaped liner  417  and U-shaped ribs  413   a - 413   d . Tubes  420   a - 420   b  are fastened to the lower edges of flap support structures  418   a - 418   b  and rotate along with shafts  412   a - 412   b.    
         [0056]    Flaps  411   a - 411   b  pivot in response to torque applied to threaded screws  414   a - 414   d . In the illustrated embodiment, flap  411   a  pivots in response to torque applied to threaded screws  414   a  and  414   b , which respectively move through the threaded bores of nuts  415   a  and  415   b  supported by slots formed in the ends of U-shaped ribs  413   a - 413   d  (see  FIGS. 4B and 4C ). Similarly, flap  411   b  pivots in response to torque applied to threaded screws  414   c  and  414   d , which respectively move through the threaded bores of nuts  415   c  and  415   d  supported by slots formed in the opposite ends of U-shaped ribs  413   a - 413   d ). 
         [0057]    Bolt holes  419  though the lower portions of ribs  413   a - 413   d  allow blade tip support assembly  207  to be bolted to the underlying horizontal steep beam  403  of the corresponding subframe  201 . 
         [0058]      FIG. 4D  is a end plan view of representative blade tip support assembly  207   a  in the open position, which allows edge of the associated reinforced turbine blade tip section  103  to be inserted and removed from U-shaped receptacle  410 . In the open position, flaps  411   a  and  411   b  have been retracted using threaded screws  414   a - 414   b.    
         [0059]      FIG. 4E  is a end plan view of the opposing end of representative blade tip support assembly  207   a  in the closed position, which allows flaps  411   a - 411   b  to contact corresponding surfaces of the corresponding reinforced turbine blade tip section  103  and retain and stabilize that reinforced turbine blade tip section  103  within U-shaped receptacle  410 . (The wind turbine blade tip section  103  is not shown in  FIG. 4E  for clarity.) In the closed position, flaps  411   a  and  411   b  have contracted towards the surfaces of the wind turbine blade using threaded screws  414   a - 414   b.    
         [0060]    In use, wind turbine blade pack  200  is assembled as it is being loaded with wind turbine blades  100 . Generally, the bottom steel beams  300  of end frames  202   a - 202   b  and ( FIG. 3A ). The vertical beams  303  and  305  for the lowest row of the array subframes  201  are fastened to bottom steel beams  300  of each end frame  202   a - 202   b  ( FIG. 3B ). The blade root support assemblies  301  are fastened to vertical beams  303  and  305  for each subframe  201  in the row ( FIG. 3C ). 
         [0061]    Similarly, the lower steel beams  400  of middle frames  203   a - 203   b  are fastened to the ship deck and vertical steel beams  402  and  404  for the lowest row of the array of subframes  201  are fastened to bottom steel beams  400  (FIGURES. Blade tip support assemblies  207  are fastened to bottom steel beams  400  of middle frames  203   a - 203   b  for the lowest row. 
         [0062]    The wind turbine blades  100  are then loaded into the lowest row in the arrays of subframes  201 . The cylindrical root section  101  of each blade is lowered onto strap  311  of the corresponding root support assembly  301  while the reinforced blade tip section  103  is lowered into U-shaped receptacle  410  of the corresponding blade tip support assembly  207 . The cylindrical root section  101  of each blade is bolted into the corresponding blade root support assembly  301  through ears  312  ( FIG. 3D ). Straps  313  are disposed around the periphery of each cylindrical root section  100  and fastened to the bottom steel beam  300  of the corresponding end frame  202  ( FIG. 3D ). Flaps  411   a - 411   b  for each blade tip support assembly  207  are then retracted into contact with the surfaces of the corresponding reinforced blade tip section  104  ( FIG. 4E ). After the lowest row in the arrays of subframes  201  are loaded and the wind turbine blades secured, the horizontal beams  303  of end frames of  202   a - 202   b  ( FIG. 3B ) and the horizontal beams  403  of middle frames  203   a - 203   b  ( FIG. 4A ) are fastened into place. 
         [0063]    This process of assembling and loading wind turbine blade pack  200  repeats for each subsequent vertically adjacent row of subframes  201  until the entire m row by n column array of subframes  201  is assembled and loaded. Fastening devices  204  secure and stabilize the entire loaded assemble to the ship deck. 
         [0064]    Wind turbine blade packs embodying the principles of the present invention realize substantial advantages over the prior art. Among other things, by packing the wind turbine blades with their edges disposed vertically, not only is the packing density increased, but the wind turbine blades are now in a position better suited to withstand the forces applied during a typical sea journey. In addition, the stability provide by the structure of the wind turbine blade pack allows for a substantial reduction in the number of cables, chains, and composite fiber lines that are required to secure and stabilize each wind turbine blade to the ship deck. 
         [0065]    Moreover, the use of wind turbine blade packs according to the present principles reduces or eliminates the need for the fixtures normally required for transporting wind turbine blades. In turn the expenses incurred from lost or discarded fixture components is advantageously reduced. 
         [0066]    Furthermore, the embodiments of the present invention are modular and scalable. By varying the distances between end and middle frames, wind turbine blades having different lengths and/or having reinforced tip sections in different locations can be accommodated. Different arrays of subframes can be assembled as needed to transport a particular number of wind turbine blades and/or to meet constraints such as limitation on the deck or hold space available. When not in use transporting wind turbine blades, the structural components of the wind turbine packs can be disassembled for transportation and storage in a standard air-sea transportation container. 
         [0067]    Although the invention has been described with reference to specific embodiments, these descriptions are not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as alternative embodiments of the invention, will become apparent to persons skilled in the art upon reference to the description of the invention. It should be appreciated by those skilled in the art that the conception and the specific embodiment disclosed might be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims. 
         [0068]    It is therefore contemplated that the claims will cover any such modifications or embodiments that fall within the true scope of the invention.