Abstract:
A system including a votex-induced vibration (VIV) suppression device dimensioned to suppress a vortex induced vibration of a support structure, the VIV suppression device having a base portion that encircles at least a portion of the support structure and a support member formed along the base portion. The system further including a collar having a body portion defining an annular channel and a flange portion extending outwardly from the annular channel, the flange portion dimensioned to form a receiving channel around the support structure for receiving the support member. The support member is received within the receiving channel to secure the VIV suppression device to the support structure and the VIV suppression device is capable of rotating around the support structure along the receiving channel.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The application is a non-provisional application of co-pending U.S. Provisional Patent Application No. 61/440,580, filed Feb. 8, 2011 and incorporated herein by reference. 
    
    
     FIELD 
     A VIV suppression device and mating collar system for supporting the VIV suppression device along a support structure. 
     BACKGROUND OF THE INVENTION 
     A difficult obstacle associated with the exploration and production of oil and gas is management of significant ocean currents. These currents can produce vortex-induced vibration (VIV) and/or large deflections of tubulars associated with drilling and production. VIV can cause substantial fatigue damage to the tubular or cause suspension of drilling due to increased deflections. VIV suppression devices of a variety of sizes and shapes can be attached to the tubular to suppress these ocean current effects on the tubular. One such device is a helical strake, which consists of vanes that are wrapped in a helical pattern around the tubular. While helical strakes, if properly designed, can reduce the VIV fatigue damage rate of a tubular in an ocean current, they typically produce an increase in the drag on the tubular and hence an increase in deflection. Thus, helical strakes can be effective for solving the vibration problem at the expense of worsening the drag and deflection problem. 
     Another solution is to use fairings as the VIV suppression device. Typical fairings have a substantially triangular shape and work by streamlining the current flow past the tubular. A properly designed fairing can reduce both the VIV and the drag. Fairings are usually made to be free to weathervane around the tubular with changes in the ocean current. Fairings are usually designed with a specific chord-to-thickness ratio (chord divided by thickness), with the chord measured from the tip of the fairing nose to the tip of the fairing tail, and the thickness measured across the fairing normal to the flow direction, thus the chord is typically at least a little larger than the thickness. 
     One of the most important components of the overall system cost of fairings is the installation costs. For many applications, the cost of installation can exceed the cost of the fairing system hardware. In particular, drilling risers require fast installation times for fairings due to the very large cost associated with the drilling rig, where the rig is priced by the day. Fairing installation, however, can be time consuming, which in turn drives up costs. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The embodiments disclosed herein are illustrated by way of example and not by way of limitation in the figures of the accompanying drawings in which like references indicate similar elements. It should be noted that references to “an” or “one” embodiment in this disclosure are not necessarily to the same embodiment, and they mean at least one. 
         FIG. 1  illustrates a side view of one embodiment of VIV suppression devices and collars positioned around a support structure. 
         FIG. 2  illustrates a cross-sectional side view of one embodiment of VIV suppression devices and collars positioned around a support structure. 
         FIG. 3  illustrates a cross-sectional side view of one embodiment of a collar having flanges. 
         FIG. 4  illustrates a top view of one embodiment of a collar having flanges. 
         FIG. 5  illustrates a front view of one embodiment of a collar having flanges. 
         FIG. 6  illustrates a top view of one embodiment of a VIV suppression device having a support member. 
         FIG. 7  illustrates a front view of one embodiment of a VIV suppression device having a support member. 
         FIG. 8  illustrates a cross-sectional side view of another embodiment of a VIV suppression device and a collar. 
         FIG. 9  illustrates a cross-sectional side view of a bottom end and a top end of one embodiment of adjacent VIV suppression devices having bearings. 
         FIG. 10  illustrates a cross-sectional side view of one embodiment of a collar having a bearing. 
         FIG. 11  illustrates a side view of an embodiment of an installation system for VIV suppression devices and collars. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In this section we shall explain several preferred embodiments with reference to the appended drawings. Whenever the shapes, relative positions and other aspects of the parts described in the embodiments are not clearly defined, the scope of the embodiments is not limited only to the parts shown, which are meant merely for the purpose of illustration. Also, while numerous details are set forth, it is understood that some embodiments may be practiced without these details. In other instances, well-known structures and techniques have not been shown in detail so as not to obscure the understanding of this description. 
       FIG. 1  illustrates a side view of one embodiment of VIV suppression devices and collars positioned around a support structure. VIV suppression devices  101  are positioned around support structure  102  and restrained axially by collars  103 . Support structure  102  may be any structure that experiences VIV. Representatively, support structure  102  may be an underwater tubular structure. VIV suppression devices  101  may be any type of device suitable for suppressing VIV of support structure  102 , for example, fairings. In some embodiments, the fairings are tail fairings that do not include a strap to attach the tail fairing to an underlying support structure. Alternatively, the fairings may be full fairings, meaning the fairing tail extends from a cylindrical body that wraps around tubular  102 . Alternatively, each of VIV suppression devices  101  may be any type of suppression device that is positioned around tubular  102  and held in place axially using collars  103 , for example, a tubular fairing, a helical strake or a VIV suppression device that encircles the underlying tubular and has other shapes and sizes (e.g. round, square, rectangular, etc). Each of VIV suppression devices  101  may be the same type of device or different types of devices. For example, they may be any combination of fairings and helical strakes. 
     Collars  103  are positioned between each of VIV suppression devices  101  to axially restrain VIV suppression devices  101  along support structure  102 . In this aspect, collars  103  are of a size and dimension that allows them to be tightly secured around support structure  102  at a desired position. In one embodiment, collars  103  may be substantially cylindrical structures that have a clam shell type configuration that allows them to be opened and tightly closed around support structure  102  to hold them in place. In some embodiments, VIV suppression devices  101  may mate with collars  103  in a manner that axially restrains VIV suppression devices  101  along support structure  102  and holds VIV suppression devices  101  around support structure  102  while still allowing VIV suppression devices to rotate around support structure  102 . Collars  103  and/or VIV suppression devices  101  may be dimensioned such that VIV suppression devices  101  weathervane around the entire circumference of support structure  102 , only a portion of support structure  102 , or, alternatively, do not weathervane at all. Since collars  103  mate with VIV suppression devices  101 , a typical installation sequence along support structure  102  may include the installation of a collar  103 , then the installation of a VIV suppression device  101 , then the installation of a collar, etc. alternating between VIV suppression devices and collars. 
     VIV suppression devices  101  and collars  103  may be made of metal (such as stainless steel, copper, aluminum, INCONEL®, brass, or other metal), plastic (such as acrylonitrile butadiene styrene (ABS), polyvinyl chloride (PVC), polyethylene, or other plastic), wood, rubber (such as urethane), fiberglass, other composite, material, synthetic material, or any suitable material. VIV suppression devices  101  and collars  103  may be made of the same material or may be made of different materials. More than one material may be used in the construction of VIV suppression devices  101  and/or collars  103 . VIV suppression devices  101  and collars  103  may be made by any suitable means including molding, forming, or the like. 
     In one embodiment, collars  103  mate with VIV suppression devices  101  through mating members on abutting sides of collars  103  and VIV suppression devices  101 . Mating collars  103  with their respective VIV suppression devices  101  provides several installation advantages. In particular, as previously discussed, VIV suppression devices  101  may be tail fairings. Tail fairings are typically secured around the associated supported structure using one or more straps that attach to opposing sides of the tail fairing and wrap around the support structure. Installation of each tail fairing is time consuming because each strap must be secured to the fairing and around the support structure. For example, it can take on average 5-6 minutes to install a tail fairing around a support structure using a strap. By mating collars  103  with VIV suppression devices  101  (e.g. tail fairings), a strap or other securing mechanism that wraps around the support structure is no longer needed to secure the VIV suppression device around the support structure. In particular, the components disclosed herein allow for the installation of, for example, a tail fairing in approximately 1-2 minutes. Thus, significantly reducing installation time and, in turn, installation costs. 
       FIG. 2  illustrates an exploded cross sectional side view of a portion of a mating collar and VIV suppression device arrangement. The portion illustrated in  FIG. 2  corresponds to portion  130  identified in  FIG. 1  with dashed lines. From this view, it can be seen that collar  103  includes a body portion that defines annular channel  106  and flange portions  104  that extend outwardly from annular channel  106 . Annular channel  106  may be dimensioned to receive strap or band  112  or other securing mechanism for securing collar  103  around support structure  102 . In particular, strap  112  encircles collar  103  once it is positioned around support structure  102  and can be tightened so that collar  103  fits snuggly around support structure  102 . 
     Flange portions  104  may be of any desired size and shape, and may be attached to collar  103  by any suitable means, including mechanical fastening, chemical bonding, welding, or clamping. It is important to note that collar  103  and one or more flange portions  104  may be of a single piece construction so that there is no need for an additional fastening means to fasten one or more flange portions  104  to collar  103 . 
     Flange portions  104  may be substantially planar structures that extend outwardly from a side wall of annular channel  106 . Flange portions  104  may extend from only one side of annular channel  106  or both sides of annular channel  106  such that flange portions  104  extend from both a top and bottom of collar  103 . The terms top and bottom refer to opposing ends of the vertically aligned collar  103 . For example, the top is the end of collar  103  facing the sky and the bottom is the end of collar  103  facing the sea floor, when collar  103  is positioned around support structure  102 . Flange portions  104  may extend from the sidewall of annular channel  106  at an angle of approximately 90 degrees. In this aspect, flange portions  104  form an L-shaped structure with the sidewall of annular channel  106 . Alternatively, flange portions  104  may have other shapes (e.g. a curved shape) and extend at other angles (e.g. less than 90 degrees) to accommodate other geometries of mating support members  105  extending from VIV suppression device  101 . For example, flange portions  104  may have a shape such that they form a C-shaped, U-shaped, or V-shaped structure with the sidewall of annular channel  106 . Support members  105  may be T-shaped or C-shaped, instead of rectangular as shown in  FIG. 2 . The above described configuration provides for fast installation. Note that it is possible to preinstall one or more components. It is also possible to install one or more support members  105  and/or one or more collar flange portions  104  during vessel installation of the system. 
     Flange portions  104  may form an annular receiving channel  110  around support structure  102  for receiving support member  105 . Support member  105  may extend from one or both ends of VIV suppression devices  101 .  FIG. 2  illustrates support member  105  extending from a top end  114  of VIV suppression device  101  and another support member  105  extending from bottom end  116  of the abutting VIV suppression device. Receiving channel  110  may be of any size and shape suitable for receiving and mating with support member  105 . Representatively, in embodiments where support member  105  is a substantially rectangular protrusion extending from an end of VIV suppression device  101  in an axial direction, receiving channel  110  may have a substantially rectangular or square cross-sectional dimension with an open end so that support member  105  can be inserted into receiving channel  110 . Other sizes and shapes (e.g. C-shaped, U-shaped or V-shaped) may also be suitable so long as receiving channel  110  is capable of receiving and mating with support member  105 . 
     Where VIV suppression device  101  includes support member  105  extending from both ends (see  FIG. 7 ), both ends can be secured within receiving channel  110  of the respective adjacent collar  103 . Since both the top and bottom ends of VIV suppression device  101  are inserted into receiving channel  110 , VIV suppression device  101  is restrained from axial motion along support structure  102  while still allowing VIV suppression device  101  to weathervane around support structure  102  as support member  105  slides within receiving channel  110 . In addition, receiving channel  110  formed by flange portions  104  prevents VIV suppression device  101  from being able to pull away normally from support structure  102 . In this aspect, an additional securing mechanism (e.g. a strap, band or the like) is not needed to secure VIV suppression device  101  to support structure  102 . 
     Flange portions  104  and support members  105  may be made of the same or different materials as each other and collar  103  and VIV suppression device  101 , respectively. Representatively, flange portions  104  and support members  105  may be made of metal (such as stainless steel, copper, aluminum, INCONEL®, brass, or other metal), plastic (such as ABS, PVC, polyethylene, or other plastic), wood, rubber (such as urethane), fiberglass, other composite, material, synthetic material, or any suitable material. Still further, more than one material may be used in the construction of flange portions  104  and support members  105 . Flange portions  104  and support members  105  may be made by any suitable means including molding, injection forming, or the like. Flange portions  104  and support members  105  may be integrally formed as a single unit with collar  103  and VIV suppression device  101 , respectively, or separately formed and attached to the preformed structure, for example, by mounting or bolting the pieces together. 
     Representatively, as illustrated in the exploded cross-sectional side view of  FIG. 3 , in one embodiment, flange portions  104  are separate structures that are attached to a preformed substantially U-shaped collar  103 . It is noted that similar to  FIG. 2 , the portion illustrated in  FIG. 3  corresponds to portion  130  identified in  FIG. 1  with dashed lines. Collar  103  is shown adjacent to support structure  102 , and contacts support structure  102  once strap  112  is tightened around the circumference of support structure  102 . Strap  112  is attached to collar  103  by fastener  107 . Fastener  107  may be, for example, a bolt or other similar fastening mechanism. Strap  106  may, however, be attached to collar  103  by any suitable means, including mechanical fastening, banding, welding, chemical bonding, or by making strap  112  and collar  103  in a single piece. Alternatively, collar  103  may be tightened around support structure  102  by other means and strap  112  omitted. For example, collar  103  may be a clam shell structure having a spring and bolt mechanism that can be used to tighten the free ends together and accommodate variations in the diameter of support structure  102 . 
     Flange portions  104  may have a substantially L-shaped profile and may be attached to sidewalls  120 ,  122  of collar  103  by any suitable fastening means  108 , including mechanical fastening, banding, welding, chemical bonding. Alternatively, collar  103  and one or more collar flange portions  104  may be formed as a single integrally formed piece. Although L-shaped flange portions  104  are illustrated, as previously discussed, flange portions  104  may be of any desired geometry to accept a VIV suppression device and act to constrain the device while still allowing for rotation around the underlying support structure. 
     Fasteners  107  and  108  may be countersunk, but as noted above, other attaching mechanisms may be used. Fasteners  107  and  108  may be made of made of metal (such as stainless steel, copper, aluminum, INCONEL®, brass, or other metal), plastic (such as ABS, PVC, polyethylene, or other plastic), wood, rubber (such as urethane), fiberglass, other composite, material, synthetic material, or any suitable material. More than one material may be used to make each component, and they may, or may not, be made of the same material. 
       FIG. 4  illustrates a top view of one embodiment of a collar. Collar  103  is shown placed around support structure  102 . Since flange portion  104  extends outwardly from a top and bottom portion of collar  103 , only a top flange portion  104  can be seen from this view. In particular, it can be seen that in one embodiment, flange portion  104  is attached to the annular channel of collar  103  using fasteners  108 . Collar  103  may be a clam shell type structure such that a first section  103   a  and second section  103   b  of collar  103  are movably attached together with optional hinge  109  at one side and collar fastener  118  at an opposite side. Hinge  109  and fastener  118  may be attached to abutting sections of flange portion  104  or the body portion of collar sections  103   a  and  103   b.    
     Although fasteners  108  are illustrated, fasteners  108  may be replaced by other attachment methods, including other methods of mechanical fastening, banding, welding, chemical bonding, or by integrally forming collar  103  with flange portions  104  as a single piece. Hinge  109  is optional, but may be required if collar  103  is too stiff to be easily placed around the support structure  102 . Hinge  109  may be constructed by any suitable method, including: termination of flange portion  104  in the hinge area so that the material stiffness is lower; thinning of the collar  103  and/or flange portion  104  material; use of a different material in the hinge area; or any other suitable hinges that are commercially available. More than one hinge may be used, and the collar  103  and flange portion  104  may be hinged differently, or in different locations. Collar fastener  118  may be replaced by other suitable means of fastening, including mechanical fastening methods, banding, welding, or chemical bonding. Collar fastener  118  may include spring mechanisms that assist in the accommodation of changes in the outside diameter of support structure  102 . 
     Hinge  109  and collar fastener  118  may be made of metal (such as stainless steel, copper, aluminum, INCONEL®, brass, or other metal), plastic (such as ABS, PVC, polyethylene, or other plastic), wood, rubber (such as urethane), fiberglass, other composite, material, synthetic material, or any suitable material. More than one material may be used to make each component, and they may, or may not, be made of the same material. 
       FIG. 5  illustrates a front view of one embodiment of a collar. From this view, it can be seen that flange portions  104  extend outwardly from both sides of annular channel  106  formed by the body portion of collar  103 . Strap  106  is positioned within annular channel  106  and attached to collar  103  using fasteners  107 . Strap  106  may act as a strength member for the overall collar  103 , or may act as an anode, or any other desired function. Strap  106  may be attached to collar  103  by any suitable means, including mechanical fastening, banding, welding, chemical bonding, or by making strap  106  and collar  103  in a single piece. Similarly, flange portions  104  may be attached to collar  103  by any suitable means, including mechanical fastening, banding, welding, chemical bonding, or by making collar  103  and one or more flange portions  104  as a single piece. 
     Strap  106  may be made of metal (such as stainless steel, copper, aluminum, INCONEL®, brass, or other metal), plastic (such as ABS, PVC, polyethylene, or other plastic), wood, rubber (such as urethane), fiberglass, other composite, material, synthetic material, or any suitable material. More than one material may be used to make strap  106 . 
       FIG. 6  illustrates a top view of one embodiment of a VIV suppression device having support members. In this embodiment, VIV suppression device  101  is illustrated as a fairing having a tail portion  604  that extends from a base portion  602  that is positioned along the underlying support structure. Alternatively, a full fairing (i.e. a fairing having a tail portion extending from a body portion that encircles an underlying structure), or any other type of VIV suppression device that weathervanes about the underlying structure, such as a multi sided device (e.g square, rectangular, etc.), splitter plate(s), or other fairings (e.g. long chord fairing, perforated fairing, etc.). 
     As previously discussed, support member  105  extends in an axial direction from the top and bottom of VIV suppression device  101  so that it can be received within receiving channel  110  formed along the top and bottom ends of the abutting collar  103 . From this view, it can be seen that support member  105  may also extend beyond the sides of base portion  602  if VIV suppression device  101  and curve around the underlying support structure  102 . Representatively, support member  105  may be a single structure having a length greater than a width of body portion  602  such that when it is attached along the annulus of base portion  602 , it extends beyond the opposing sides of body portion  602 . In other embodiments, support member  105  may be two separate structures that are attached or formed at opposing sides of body portion  602 . 
     Support member  105  can be rounded or curved similar to the outer surface of support structure  102  so as to facilitate rotation around the underlying support structure  102 . Support member  105  may cover only a small portion, or it may cover a large portion, of the support structure circumference. Representatively, support member  105  may have a length that is length than the entire circumference of support structure  102  such that it encircles only a portion of support structure  102 . Support member  105  may be made of one continuous integrally formed piece or separate sections. 
       FIG. 7  illustrates a front view of one embodiment of a VIV suppression device. From this view, it can be seen that support members  105  may have the same length such that they each cover the same portion of the underlying support structure circumference, or they may have different lengths such that they cover different portions of the support structure. Support members  105  may be identical in shape, material and construction, or they may be different in shape, material, and construction. 
       FIG. 8  illustrates an exploded side cross-sectional view of another embodiment of a VIV suppression device and collar. It is noted that similar to  FIG. 2 , the portion illustrated in  FIG. 8  corresponds to portion  130  identified in  FIG. 1  with dashed lines. In this embodiment, collar  103  is adjacent to support structure  102 . Strap  112  encircles collar  103  and is attached to collar  103  by fastener  107 . Flange portions  104  extend outwardly from annular channel  106  formed by the body portion of collar  103 . In one embodiment, flange portions  104  extend from, and are attached to, sidewalls of annular channel  106  by fasteners  108 . 
     Similar to the previously described VIV suppression devices, VIV suppression devices  101  include support members  110  that are received within receiving channel  110  formed between flange portions  104  and support member  102 . In this embodiment, however, support members  110  also form a portion of grooves  111  formed within the ends of VIV suppression devices  101 . Flange portions  104  fit within grooves  111  and keep VIV suppression device  101  from being able to slide axially along support structure  102  or pull away normally from support structure  102 . However, since flange potions  104  are positioned within respective grooves  111 , VIV suppression devices  101  are able to slide around support structure  102  and weathervane with changes in current direction. 
     Since, in this embodiment, flange portions  104  serve as a male piece that mates with female piece, grooves  111 , of VIV suppression devices  101 , flange portions  104  may consist of other geometries such as an “I” cross section or a “T” cross section, or any other cross section that allows it to mate and interlock within grooves  111 . Similarly, grooves  111  may be of any suitable shape or cross section that allows them to serve as the female piece in the interface with flange portions  104 . For example, flange portions  104  may form a triangular structure with the outermost end being the wide portion of the triangle and grooves  111  may have a triangular cross-sectional shape complimentary to flange portions  104  such that flange portions  104  can interlock within grooves  111  and prevent VIV suppression devices  101  from pulling away from support structure  102 . Flange portions  104  may be separate from collar  103 , or one or more flange portions  104  and collar  103  may be of a single piece construction. Each of the flange portions  104  attached to collar  103  may be identical or they may be different in size, shape, geometry, attachment, material, or construction. 
     Grooves  111  may be constructed in any suitable manner, including molding grooves  111  into VIV suppression devices  101 , or cutting VIV suppression devices  101  to form grooves  111  at each end. In some embodiments, grooves  111  may be substantially annular grooves having a curvature similar to that of support structure  102  so that they follow the curve of the base portion of VIV suppression devices  101 . In this aspect, when flange portions  104  of the abutting collars  103  are inserted within grooves  111 , VIV suppression devices  101  are able to rotate around collars  103  and the associated support structure  102 . 
       FIG. 9  illustrates a cross-sectional side view of a bottom end and a top end of adjacent VIV suppression devices. VIV suppression devices  101  may be substantially similar to the previously discussed devices except in this embodiment, bearings  1002  are attached to support members  105 . In one embodiment, bearings  1002  may be pads that provide a bearing surface between the support members  105  and the associated collar and flanges. 
     Any number of bearings  1002  may be used. Representatively, in one embodiment, all of the interfacing surfaces between the collar flanges and the collar (or collar flanges) will have one or more bearings. Bearings  1002  may be located on support members  105 , or in embodiments such as that of  FIG. 8 , within grooves  111  of VIV suppression devices. Additionally, or alternatively, bearings  1002  may be formed on portions of the associated collars contacting VIV suppression devices  101 . For examples, as illustrated in  FIG. 10 , bearings  1002  may be provided on an outer surface of the collar flange or annular channel  106  that contacts support members  105  of VIV suppression devices  101 . 
     Bearings  1002  may be of any size, shape, dimension and material suitable for minimizing the friction and/or minimizing any binding of VIV suppression devices  101  so that they are free to weathervane about an underlying structure with less friction or binding. Representatively, bearings  1002  may be made of metal (such as TEFLON®, stainless steel, copper, aluminum, INCONEL®, brass, or other metal), plastic (such as ABS, PVC, polyethylene, or other plastic), wood, rubber (such as urethane), fiberglass, other composite, material, synthetic material, or any suitable material. Coatings on the materials (such as TEFLON® coating) may also be used. More than one material may be used to make each of bearings  1002 , and each of the bearings  1002  may, or may not, be made of the same material (i.e. one bearing may have one material composition, and another bearing may have the same, or a different material composition). Bearings  1002  may be attached to VIV suppression devices  101  or collar  103  by any suitable attachment means, for example, an adhesive, mechanical 
     Bearings  1002  may be of any size, shape, dimension and material suitable for minimizing the friction and/or minimizing any binding of VIV suppression devices  101  so that they are free to weathervane about an underlying structure with less friction or binding. Representatively, bearings  1002  may be made of metal (such as TEFLON®, stainless steel, copper, aluminum, INCONEL®, brass, or other metal), plastic (such as ABS, PVC, polyethylene, or other plastic), wood, rubber (such as urethane), fiberglass, other composite, material, synthetic material, or any suitable material. Coatings on the materials (such as TEFLON® coating) may also be used. More than one material may be used to make each of bearings  1002 , and each of the bearings  1002  may, or may not, be made of the same material (i.e. one bearing may have one material composition, and another bearing may have the same, or a different material composition). Bearings  1002  may be attached to VIV suppression devices  101  or collar  103  by any suitable attachment means, for example, an adhesive, mechanical attachment means (e.g. bolt) or chemical attachment means, or they may be integrally formed with VIV suppression devices  101  or collar  103 . 
       FIG. 11  illustrates a side view of an embodiment of an installation system for VIV suppression devices and collars. VIV suppression devices  101  and collars  103  may be substantially similar to any of the previously discussed devices and collars. In one embodiment to facilitate underwater installation of the VIV suppression system  1102 , VIV suppression devices  101  and collars  103  are mated with one another as previously discussed (e.g. by positioning collar flanges against the support members or grooves of the VIV suppression devices) and aligned along cable  1102 . Cable  1104  may then be lowered into the water along the underwater support structure. Collars  103  may initially be in an open position such that once system  1102  is properly aligned along the underwater support structure, a diver, remotely operated vehicle (ROV) or other means may be used to clamp collars  103  around the support structure. Alternatively, collars  103  may be in a closed position such that they are opened and closed underwater. Since VIV suppression devices  101  are mated with collars  103 , they are also attached to the support structure. Suppression system  1102  may be installed vertically or horizontally. In addition, various arrangements and substitutions may be made for cable  1104 , and any number of VIV suppression devices  101  and collars  103  may be used. For example, collars  103  and VIV suppression devices  101  may be positioned along cable  1104  in the desired alignment (i.e. alternating collar  103  and devices  101 ) without mating them together. Once the cable  1104  is lowered into the water and aligned with the desired support structure, installation may include installing one of collars  103  around the support structure, mating the adjacent VIV suppression device  101  with the installed collar  103  and then installing and mating a second collar  103  at the other end of VIV suppression device  101 . 
     While the foregoing written description of the invention enables one of ordinary skill to make and use what is considered presently to be the best mode thereof, those of ordinary skill will understand and appreciate the existence of variations, combinations, and equivalents of the specific embodiment, method, and examples herein. The invention should therefore not be limited by the above described embodiment, method, and examples, but by all embodiments and methods within the scope and spirit of the invention. 
     It should also be appreciated that reference throughout this specification to “one embodiment”, “an embodiment”, or “one or more embodiments”, for example, means that a particular feature may be included in the practice of the invention. Similarly, it should be appreciated that in the description various features are sometimes grouped together in a single embodiment, Figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects may lie in less than all features of a single disclosed embodiment. Thus, the claims following the Detailed Description are hereby expressly incorporated into this Detailed Description, with each claim standing on its own as a separate embodiment of the invention. 
     In the foregoing specification, the invention has been described with reference to specific embodiments thereof. It will, however, be evident that various modifications and changes can be made thereto without departing from the broader spirit and scope of the invention as set forth in the appended claims. Representatively, VIV suppression devices that utilize a flange or protrusion inserted into a portion of a collar such that the device is held against the underlying support structure such as a tubular and is free to weathervane around the tubular are described. It is contemplated, however, than any type of mechanism for mating a VIV suppression device to a collar that prevents the VIV suppression device from pulling away from the support structure and allows the VIV suppression device to slide around the collar may be used. For example, the VIV suppression device may be fixedly attached to a ring that rotates within the collar or rotatably attached to a ring that is fixed within the collar and/or the support structure. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense.