Abstract:
Disclosed is a sectionalized mast track that solves problems associated with furling and reefing sails on yachts, particularly large yachts. The inventive mast track includes mast track sections that are secured to a mast with hinges. Securing pins connect the sections to each other such that all the sections pivot together along the centerline defined by hinges. The securing mechanisms also make it possible to remove a single mast track section at a time. Embodiments of the inventive mast track have a cross section that absorbs wind-generated compressive forces exerted by battens, reducing chafing, and eliminates the need for sail slides, which would otherwise lock the sail in place during furling and reefing. The inventive mast track may also be configured to couple to an articulating sail feeder that bends and rotates freely, but limits the axial twist of the sail as during furling and reefing.

Description:
RELATED APPLICATIONS 
     This application is related to U.S. patent application Ser. No. 12/437,086, “Mega Yacht Mast Tracking System with Articulating Sail Feeder,” filed May 7, 2009, now U.S. Pat. No. 8,001,916, and U.S. patent application Ser. No. 12/437,076, “Mast Track with External Headboard Car,” also filed May 7, 2009 and currently pending. The subject matter of this application is also related to U.S. Pat. No. 6,371,037, “Sail Furling System,” to Cook et al. filed on Dec. 26, 2000. 
     The above-referenced applications and patent are incorporated herein by reference in their entireties. 
     BACKGROUND OF THE INVENTION 
     Modern yachts have fore and aft sails, including a mainsail supported by a mast. The mainsail, which is triangular, is hitched at its bottom edge, or foot, to a boom that can swing about the lower part of the mast in either direction in relation to the longitudinal axis of the boat. The mainsail is raised or lowered by hoisting a halyard coupled to the upper corner, or head, of the mainsail. Raising the halyard causes the sail to extend such that the sail&#39;s forward edge, or luff, runs parallel to the mast. 
     Various track and slide assemblies have been used to guide the sail along the mast, making it easier to raise and lower the sail. These assemblies also link the aft edge of the mast to the sail luff. Typical assemblies include low-friction sail slides, attached to the luff at regular intervals, that fit onto a rail or into a track that extends along the longitudinal axis of the mast. 
     Prior art track and slide assemblies use tracks or rails that extend along the mast from the boom to the top of the mast. Some tracks and rails are attached to the mast, whereas others are integrally formed with the mast itself. Both integral and non-integral tracks and rails stiffen the mast. In addition, both integral and non-integral tracks and rails are difficult to maintain: if a sail slide becomes irretrievably jammed in the track, the entire track (or mast, for integral tracks) must be removed. Alternatively, the crew must go aloft to fix the problem in place. Both options are time-consuming for yachts with taller masts, and going aloft can be dangerous and impractical, depending on the conditions. 
     Conventional sail slides, which run in a channel or groove in a mast track, are attached to the mainsail with shackles or are sewn in position. Unfortunately, friction between the slides and the track causes the slides to lock in place, preventing the sail from being raised or lowered. For example, twisting or torquing forces by the mainsail exerted on rectangular slides bind the slides to the track, preventing sliding movement and making it impossible to control the mainsail. Pulling forces exerted on the slides by the mainsail may pull the slides from the track, depending on the design of the groove. 
     Ball track slides, which use plastic balls and a rail mounted on the mast to absorb loads except those in the direction of movement, do not suffer from friction locking. High loads flatten the balls, however, degrading the balls&#39; bearing-like action. Ball track slide assemblies also weigh more than conventional assemblies and are more susceptible to jams due to corrosion and dirt. In addition, the rails for ball track slides tend to be much heavier than the tracks for conventional sail slides. 
     The linkage between the slides and the sail luff also affects the utility of the track and slide assembly. If the slides are rigidly coupled to reinforcements, or battens, attached to the luff of the sail, then wind pushing on the battens may cause the battens to push, in turn, on the slides, disrupting the link between the slides and the sail. These forces may also detach the slides from the track. 
     SUMMARY OF THE INVENTION 
     Embodiments of the present invention include a sectionalized mast track for a yacht and methods of raising and lowering a sail using a sectionalized mast track. The mast track may include plural mast track sections arranged in a column configured to be attached to a mast. Each section includes an upper receiver and a lower receiver oriented along the longitudinal axis of the column. Adjacent sections may be secured to each other with respective securing pins, each of which is configured to be received by a lower receiver of one mast track section and an upper receiver of an adjacent mast track section. 
     Certain embodiments of the mast track may include mast track sections that are configured to be individually detached from the mast. In addition, the inventive mast track may be configured allow the mast to bend and compress. The mast track may also be configured to allow for thermal expansion and contraction of the mast. Embodiments of the mast track are configured such that the mast track sections pivot together about a common centerline that runs parallel to the longitudinal axis of the mast. 
     Each mast track section may also include a beveled or round upper or lower surface, which may vary in angle depending on the location of particular mast track section along the mast. Adjacent mast track sections may also be separated by an interstitial space, which may differ for different pairs of adjacent mast track sections. In some embodiments, adjacent mast track sections at the top of the mast are separated by smaller interstitial spaces than adjacent mast track sections at the bottom of the mast. 
     Further embodiment mast tracks may include respective securing mechanisms to secure each securing pin. These securing mechanisms may be configured to secure the securing pin in both an extended position and a retracted position. Example securing mechanisms may include a slot that runs parallel to the lower receiver of a mast track section. The slot may be configured to receive a screw to secure the corresponding securing pin. 
     Still further embodiment mast tracks may include a channel configured to guide a headboard car along an axis substantially parallel to the longitudinal axis of the mast. In addition, mast tracks may have a cross section that forms a batten receptacle (also known as a luff extrusion). Example cross sections include a batten guide formed of two substantially parallel batten guide arms. A luff passage formed in a luff extrusion body connects the batten guide to a luff rope slot also formed in the luff extrusion body. The luff rope slot may be substantially parallel to a longitudinal axis of the mast. 
     Yet further embodiment mast tracks may be configured to be coupled to an articulating sail feeder. Example articulating sail feeders include binge tracks arranged in an articulating column with a longitudinal axis substantially parallel to a mast of a yacht, where the hinge tracks are configured to receive a sail luff. Limiting pins and ball joints in the articulating column enables lateral and rotational movement of the sail. The limiting pins, which are disposed between respective pairs of adjacent hinge tracks, limit the movement of a given hinge track with respect to a neighboring hinge track. The ball joints, which are also disposed between respective pairs of adjacent hinge tracks, receive a tensioning line that runs along the longitudinal axis of the articulating column. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing will be apparent from the following more particular description of example embodiments of the invention, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating embodiments of the present invention. 
         FIG. 1  is an elevation view of a yacht employing an example sectionalized mast track of the present invention. 
         FIG. 2  is an elevation view of part of a mast, sail, and example sectionalized mast track of the present invention. 
         FIG. 3  is an elevation view of a securing mechanism used to couple adjacent mast track sections according to embodiments of the present invention. 
         FIGS. 4A and 4B  are perspective views of upper and lower hinges, respectively, used in embodiments of the present invention. 
         FIG. 5  is a plan view of a mast track cross section according to embodiments of the present invention. 
         FIGS. 6A and 6B  are plan and elevation views, respectively, of a sail, external headboard car, and headboard suitable for use with an example inventive mast track. 
         FIG. 7  is a plan view of a mast track cross section suitable for use with an internal headboard car according to alternative embodiments of the present invention. 
         FIG. 8  is an elevation view of a mast, sail, and articulating sail feeder suitable for use with embodiments of the present invention. 
         FIGS. 9A and 9B  are, respectively, an elevation view of an example articulating sail feeder and a plan view of a hinge track of the example articulating sail feeder in the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A description of example embodiments of the invention follows. 
       FIG. 1  shows a yacht  10  with a mast  20  and a boom  26 . The boom  26  stores a sail  30 , which may be raised with a halyard (not shown) and a headboard ear  28  to capture wind and propel the yacht  10 . The headboard car  28  is coupled to a headboard  29  that reinforces the head  38  of the sail  30  to prevent high loads from tearing apart the head  38 . A mast track  24  guides the headboard car  28  and a luff rope (not shown; also known as a sail bolt rope or bolt rope) stitched into the forward edge, or luff  36 , of the sail  30  along an axis parallel to the long axis of the mast  20 . Although the headboard car  28  shown in  FIG. 1  travels along a channel on the outside of the mast track  24 , alternative headboard cars may be configured to travel within a groove internal to the mast track  24 . 
     The sail  30  shown in  FIG. 1  is a fully battened mainsail  30  with battens  32  that run generally parallel to the bottom edge, or foot  40 , of the sail  30  from the luff  36  (leading edge) to the trailing edge, or leech  37 , of the sail  30 . The battens  32  are stitched into batten pockets  34  in the sail  30 . Standard battens (not shown) run only partway from the luff  36  to the leech  37 , trading long-term performance for reduced chafing and easier handling. Battens may be oriented in other directions or combinations of directions; for example, alternative battens may run perpendicularly from the leech  37  to intersect the foot  40  and the luff  36  at substantially complementary angles. 
     Full battens  32  support roach  42 , the sail area that lies outside a straight line from the head  38  to the lower aft corner, or clew  39 , of the sail  30 . Typically, the supporting battens  32  are about three times longer than the roach  42  that they support. Roach  42  enhances sail performance by adding 15-30% more sail area to a triangular sail, such as the sail  30  shown in  FIG. 1 . More importantly, mainsails with roach  42  have elliptically shaped heads and planforms that improve performance on all points of sail, particularly to weather. 
     Unfortunately, full-length battens  32  reduce the life of the sail  30  by chafing against the batten pockets  34  and/or the sail bolt rope (not shown), which is sewn into the edge of the sail  30  to prevent fraying. The same forces that pull the sail  30  taut to propel the yacht  10  push the battens  32  towards the mast  20 , causing the battens  32  to chafe against the batten pockets  34 . Eventually, this chafing causes the battens  32  to tear or fray the sail bolt rope and to poke through the forward ends of the batten pockets  34 . Reinforcing the batten pockets  34  alleviates this problem on vessels with smaller sails, but reinforcement is not sufficient to withstand chafing due to the larger compressive forces exerted on battens  32  in larger sails. In addition, compression increases friction on the sail slides that run in conventional mast tracks, making it difficult to raise, lower, or reef the sail  30 . 
     An articulating sail feeder  80  coupled to the bottom of the mast track  24  limits the sail&#39;s range of motion as the sail  30  is fed into the boom  26  by a boom furler (not shown), making it easier to reef and furl the sail  30 . In yachts  10  without the present inventive articulating sail feeder  80 , the sail  30  deforms in the space above the boom  26  during winding, causing folds in the ends of the winding. The articulating sail feeder  80  moves with the sail  30  as the sail  30  is being furled or reefed, preventing deformation and relieving stress on the sail bolt rope. The articulating sail feeder  80  allows the sail  30  to move and rotate freely from side to side (i.e., laterally), while preventing the sail from twisting too much around an axis parallel to the long axis of the mast  20 . 
       FIG. 2  is an elevation view of a mast  20 , sail  30 , and mast track  24  according to embodiments of the present invention. The mast track  24  includes multiple mast track sections  200  coupled to the mast  20  with upper hinges  220  and lower hinges  222 . The mast track sections  200  are coupled to each other with securing pins  210  that can be locked in place. Unlocking the securing pins  210  makes it possible to remove or replace an individual mast track section  200  without removing the entire mast track  24 . This feature is particularly useful on large yachts, which may have mast tracks  24  that extend for tens of meters. 
     Because the securing pins  210  fix the mast track sections  200  to each other, the mast track sections  200  pivot together along a common centerline defined by the upper and lower hinges  220 ,  222 . This centerline runs parallel to and just aft of the longitudinal axis of the mast  20 . The mast track sections  200 , hinges  220  and  222 , and securing pins  210  are typically machined to ensure tight enough tolerances so that they fit together well and pivot smoothly. 
     The inventive mast track  24  also withstand the bending and compressing forces exerted on the mast by the sail  30 . For example, hoisting the sail  30  increases the weight aloft, compressing the mast  20  and the mast track  24 . For large yachts, the compression can be as great as 1 mm/m. Spaces between neighboring mast track sections  200  offset the effects of this compression. Because compression increases towards the bottom of the mast  20  and mast track sections  200 , the amount of space between adjacent mast track sections  200  may depend on the location of the mast track sections  200 . For instance, mast track sections  200  at the bottom of the mast  20  may be separated by larger distances than the sections  200  at the top of the mast  20 . 
     Other forces may cause the mast  20  and mast track  24  to bend. These forces include the weight of the sail  30 , forces exerted by wind, and, for masts  20  and mast tracks  24  made of different materials, expansion and compression forces due to mismatched coefficients of thermal expansion. Beveling or rounding off the upper and lower edges  204  and  202 , respectively, of each mast track section  200  allows the mast track  24  to bend more easily. Each mast track section  200  may be beveled or rounded to a degree that depends on the mast track section&#39;s  200  location on the mast  20 . 
       FIG. 3  is a plan view of the connection between adjacent mast track sections  200 ′ and  200 ″. The upper mast track section  200 ′ is coupled to the mast  20  with a hinge pin  224  that fixes the mast track section  200 ′ to an upper hinge  220 , shown in greater detail in  FIG. 4A . A washer  226  separates the hinge  220  from the section  200 ′, allowing the section  200 ′ to pivot about the longitudinal axis of the hinge pin  224 . The lower mast track section  200 ″ is similarly connected to a lower hinge  222 , shown in greater detail in  FIG. 4B , with the hinge pin  224 . Alternatively, the sections  200 ′ and  200 ″ may be connected to the upper and lower hinges  220  and  222  with separate upper and lower hinge pins, respectively. 
     The mast track sections  200 ′ and  200 ″ are connected to each other with a securing pin  210  that fits into an upper receiver  218  in the lower mast track section  200 ″ and a lower receiver  216  in the upper mast track section  200 ′. The securing pin  210  is fixed in place with a screw  214  that fits into a slot  212  along the lower receiver  216 . The securing pin  210  can be retracted into the lower receiver  216  by loosening the screw  214 , pushing the securing pin  210  up, then tightening the screw  214 . Retracting the securing pin  210  and removing the hinge pin  224  makes it possible to remove a single mast track section (e.g., section  200 ′) at a time without having to remove the entire mast track  24 . When separate upper and lower hinge pins are used, only one of the upper and lower hinge pins may need to be removed to remove the mast track section. 
     Typically, the lower receiver  216  is long enough to accommodate the entire securing pin  210 , allowing the securing pin  210  to be stowed so that one of the mast track sections  200  may be removed from the mast  20 . The upper receiver  218 , on the other hand, is usually not configured to receive the entire securing pin  210  in order to prevent the pin  210  from becoming stuck in the upper receiver  218 . For example, the securing pin  210  may be five inches long, the lower receiver  216  may be five inches high, and the upper receiver  218  may be two and a half inches high. Those skilled in the art will appreciate that this is one of many suitable ways to secure adjacent mast track sections  200  to each other. 
     Mast tracks  24  with the inventive luff extrusion cross section  300  may be fabricated of carbon fiber, 6005 aluminum alloy, or any other suitable material. Generally, suitable materials are at least moderately strong; capable of bending, flexing and twisting; suitable for machining, welding, and brazing; and corrosion resistant (or able to be treated or coated with corrosion-resistant material). Mast tracks  24  may be made by machining, extrusion, or any other suitable manufacturing techniques. The height of each mast track section  200  depends on the height of the mast  20  and the number of sections  200  desired. 
       FIGS. 4A and 4B  are perspective views of the upper and lower hinges  220  and  222 , respectively. Each hinge  220 ,  222  includes a flange  240  for connecting the hinge  220 ,  222  to the mast  20  and hole  242  for a hinge pin  224  ( FIG. 3 ). The holes  242  may be blind holes or through holes. The hinges  220 ,  222  may also include holes  244  for set screws or pins for securing the hinge pins  224 . Hinges  220 ,  222  may be made of aluminum or any other suitably light, strong material capable of withstanding corrosion. 
       FIG. 5  is a plan view of a mast track cross section, or luff extrusion  300 , suitable for use with an external headboard car  28 . The Tuff extrusion  300  solves the problem of batten poke or chafing by providing a batten guide  302  that receives battens along the length of the mast track  24 , such as the full battens  32  shown in  FIGS. 1 and 2 . Unlike the batten receptacles disclosed in U.S. Pat. No. 6,371,037 to Cook et al., the present inventive luff extrusion  300  also eliminates problems associated with friction-locked sail slides by providing a channel  310  for a headboard car  28  ( FIG. 1 ) that disposes with the need for sail slides. 
     The luff extrusion  300  includes a pair of substantially parallel batten guide arms  304  that form the batten guide  302 . A luff passage  306  connects the batten guide  302  to a luff rope slot  308  configured to hold a luff rope sewn into the luff  36  of a sail  30 . As wind fills the sail  30 , compressing the battens  32  ( FIG. 1 ), the battens  32  push against the forward edge of the batten guide  302 , reducing chafing on the batten pockets  34  ( FIG. 1 ). The batten guide arms  304  also stabilize battens  32  subject to rotational forces, such as those shown in  FIG. 2C . 
     As shown in  FIG. 5 , the headboard car channel  310  is formed substantially next to (i.e., abeam of) the luff rope slot  308 , defining a travel axis for the headboard car  28  ( FIG. 1 ) that is substantially coincident with the axis formed by the luff rope slot  308 . Because the headboard car  28  and the luff rope (not shown) travel along the same axis, torque on the headboard car  28  or the headboard  29  ( FIG. 1 ) in the plane of the sail  30  is less likely to cause the headboard car  28  to shift, jam, or stick in the headboard car channel  310 . As a result, the luff rope and headboard car  28  travels freely up and down an axis parallel to the longitudinal axis of the mast  20 . 
     The luff extrusion  300  may also include a hinge pin tunnel  340 , a connector tunnel  342 , and a feeder ball seat  344 . The hinge pin tunnel  340  can be used to hold hinge pins  224  ( FIG. 3 ) that connect the mast track  24  to hinges  220  and  222  ( FIGS. 2 ,  3 ,  4 A and  4 B) on the mast  20 . The hinges  220 ,  222  and hinge pins  224  allow the mast track  24  to pivot about the longitudinal axis of the mast  20 . Similarly, the connector tunnel  342  can be used to connect mast track sections  200  to each other so that all the sections  200  pivot on one centerline. 
     In a preferred embodiment, the luff extrusion  300  is almost six inches long and varies in width from just under two inches just forward of the headboard car channel  28  to about one and a quarter inches at the channel  28  itself. The headboard car channels  310  are each just under one inch wide and about one-quarter inch deep. The batten arms  304  are about one and three-quarter inches long, forming a batten guide  302  with a length of one and three-quarter inches and a width of about one inch. The luff passage  306  may be about one-fifth inch wide and about one-quarter inch long; the luff rope slot  308  can be about three-eighths inch in radius. Edges of mast tracks  24  with the present inventive luff extrusion cross section  300  may be beveled, chamfered, and/or radiused as appropriate. For example, the upper and lower faces of the mast track sections  200  may be beveled at an angle of 1.5° from the forward edge of the channel  310  to the after edge of the batten guide arms  304 . In addition, the headboard car channels  310  may be beveled or flared at one or both ends of each mast track section  200  to more easily receive the headboard car  28 . 
       FIGS. 6A and 6B  are, respectively, plan and elevation views of a sail  30 , headboard car  28 , and mast track  24  with the present inventive luff extrusion cross section  300 . The headboard car  28 , which is coupled to the head  38  of a sail  30  via the headboard  29 , includes a guide  452  formed of two substantially parallel arms  454  that fit around the outside of the luff extrusion  300 . The arms  454  on the headboard car  28  have channels  460  that mate with the complementary channels  310  on the luff extrusion  300 . Bearings (not shown) between the channels  310  on the luff extrusion  300  and the channels  460  on the headboard car  28  allow the headboard car  28  to travel freely along an axis substantially parallel to the mast  20 . 
     Because the headboard car  28  travels smoothly along the bearings between the channels  460  and  310 , the sail  30  can be raised and lowered with a halyard (not shown) attached to the headboard car  28 . In contrast to conventional sails, which are raised with halyards attached directly to the head  38  or the headboard  29 , sails  30  coupled to headboard cars  28  in embodiments of the present invention do not need sail slides to ensure smooth travel of the sail up and down the mast. As a result, sails  30  raised with headboard cars  28  configured with luff extrusions  300  of the present invention do not suffer from the compression- and torque-induced friction that locks sail slides into place. 
     In a preferred embodiment, the headboard car  28  is made of aluminum or any other suitably strong, light, and corrosion-resistant material. The guide  452  is wide enough and long enough to substantially accommodate the luff extrusion  300 . For example, the arms  454  may be about five inches long and spaced about two inches apart. The edges of the headboard car  28  may be beveled, chamfered, and/or radiused as appropriate. 
       FIG. 7  is a plan view of an alternative mast track cross section  500  with an internal headboard car  528 . The cross section  500  includes a pair of substantially parallel batten guide arms  504  that form a batten guide  502 , which connects to a luff rope slot  508  via a luff passage  506 . Each batten guide arm  504  terminates in a hook shape  512  or similar configuration that defines a headboard car channel  510  inside the batten guide  502 . The internal headboard ear  528 , which may be round or disc-shaped (i.e., shaped like a hockey puck), travels in the space defined by the batten guide  502  along an axis defined by the headboard car channel  510 . The hooks  512  retain the headboard car  528  within the batten guide  502 . 
     The batten guide  502  receives battens  32  sewn in the sail below the headboard car  528 . As compressive forces push the battens  32  forward, the battens  32  push against the batten guide  502 , rather than chafing against the forward edges of the sail bolt rope. Similarly, the batten guide arms  504  hold the battens  32  as the battens  32  twist and rotate, reducing friction between the battens  32  and the respective batten pockets  34 . 
     The alternative cross section  500  also includes a connector tunnel  542  and a hinge pin tunnel  540 , which are configured to retain a tensioning line  86  and limiting pins  90 , respectively. The connector  542  may also be configured to receive ball joints  94  with a ball joint seat (not shown). 
     Of course, other configurations of headboard car channels are possible. For example, the headboard car  28  could ride on channels formed by everted channels, protrusions, or rails that stick out from a mast track  24  with the inventive luff extrusion cross section. The channels may include more than two channels on each side, or may be formed further forward or aft along the inventive luff extrusion. The channels may be integral to the cross section or may formed by fixing additional parts to the mast  20  or mast track  24 . 
       FIG. 8  shows an example articulating sail feeder  80  coupled to the bottom of a mast track  24 . The lower end of the articulating sail feeder  80  is suspended from the mast  20  above the boom  26  to allow free lateral movement of the sail  30  as the sail  30  is raised or lowered using the headboard car  28  coupled to the headboard  29 . The articulating sail feeder  80  flexes and twists as the sail  30  is wound down, reducing deformation of the sail  30  and eliminating folds in the ends of the winding. The articulating sail feeder  80  also reduces stress on the bolt rope by flexing and bending, making it easier to wind or unwind the sail  30 . In addition, the articulating sail feeder  80  may be configured to enable limited twist or rotation about an axis parallel to the longitudinal axis of the mast  20  as the sail  30  is furled or reefed. The articulating sail feeder  80  may also flex fore and aft (i.e., in the plane of the page) or abeam (i.e., into and out of the page). 
     A feeder  82  at the bottom of the articulating sail feeder  80  guides the sail  30  into and out of the articulating sail feeder  80 , which includes several hinge tracks  84  arranged in a column between the feeder  82  and the bottom edge of the mast track  24 . A threaded tensioning line  86  runs through the hinge tracks  84  along the interior of the column. A nut  88  secures the lower end of the tensioning line  86  in a bottom hinge track  85 . Adjusting the nut  88  changes the tension of the tensioning line  86 , altering the articulating sail feeder&#39;s range of motion. Alternatively, the tension of the tensioning line  86  can be adjusted with a hydraulic or pneumatic cylinder. 
       FIGS. 9A and 9B  are elevation and plan views, respectively, of the articulating sail feeder  80  and some of its components, including hinge tracks  84 , limiting pins  90 , and ball joints  94 . The articulating sail feeder  80  includes plural hinge tracks  84  arranged in an articulating column  81  like vertebrae in a spine. Limiting pins  90  and balls joints  94  arranged between respective pairs of adjacent hinge tracks  84  limit the motion of the column  81 . 
     As shown in  FIG. 9A , each limiting pin  90  is formed of upper and lower truncated conical sections, or frustums  91  and  93 , attached to a flange  92 . The flange  92  separates a respective pair of neighboring hinge tracks  84 , which receive the upper and lower frustums  91  and  93  in respective recesses  340 . In a preferred embodiment, the limiting pins  90  are formed of nylon that has a low coefficient of thermal expansion, high strength, and high rigidity, such as Nylatron GS. Typically, the edges of the limiting pins  90  are beveled or radiused and the pins  90  themselves are deburred. 
     The cone angle of the sides of the frustums  91  and  93  fixes the maximum bend angle between adjacent pairs of hinge tracks  84 , preventing the articulating column  81  from bending too much in one direction or another. Because the limiting pins  90  are symmetric about the longitudinal axis of the column  81 , they permit universal axial motion (i.e., rotation) about the longitudinal axis of the column  81 . 
     Each ball joint  94  is disposed between a respective pair of neighboring hinge tracks  84  in seats  344  aft of the limiting pin recesses  340  and forward of batten guides  302  shown in  FIG. 9B . The ball joints  94  receive a tensioning line  86  that runs through the column  81  via holes along the diameters of the ball joints  94 . Like the limiting pins  90 , the ball joints  94  may be formed of nylon that has a low coefficient of thermal expansion, high strength, and high rigidity, such as Nylatron GS. Typically, the edges of the ball joints  94  are beveled or radiused and the ball joints  94  themselves are deburred. 
     The tensioning line  86  may be a flexible wire, cable, rod, synthetic rope, or any other suitable line or cable. As shown in  FIG. 9A , the tensioning line  86  includes a threaded end  87  that receives a nut  88 . Increasing the tension on the tensioning line  86  by tightening the nut  88  presses (vertically compresses) the hinge tracks  84  together, reducing the column&#39;s range of motion. Conversely, reducing the tension on the tensioning line  86  by loosening the nut  88  relieves pressures on the hinge tracks  84 , increasing the column&#39;s range of motion. Other embodiments may includes other tensioning means such as hydraulic or pneumatic cylinders arranged at the upper end, lower end, or both ends of the tensioning line  86 . 
       FIG. 9B  shows the cross section  300  of the hinge of a hinge track  84 ; this cross section  300  is also known as a luff extrusion. A hinge track  84  with the luff extrusion cross section  300  shown in  FIG. 9B  solves the problem of batten poke or chafing by providing a batten guide  302  that receives battens along the length of the mast  20 , such as the full battens  32  shown in  FIG. 1 . The present inventive hinge track cross section  300  also eliminates problems associated with friction-locked sail slides by providing a channel  310  for a headboard car  28  that eliminates the need for sail slides. As described above with respect to the mast track sections  200 , the upper and lower surfaces of the batten guide arms  304  may be beveled (e.g., by 2.5°) to allow the articulating column  81  to bend and flex along the plane of the sail  30 . 
     The cross section  300  also includes a hinge pin tunnel  340  configured to receive limiting pins  90  and a ball seat  344  configured to receive ball joints  94 . Each hinge track  84  has a connector tunnel  342  that connects the upper and lower ball seats  344 , as shown in  FIG. 6C . The tunnels  340  and  342  may extend through the entire thickness of the hinge track  84  with a constant shape and size. Alternatively, they may be configured to have upper and lower receptacles to prevent neighboring limiting pins  90  and ball joints  94  from touching each other. 
     In a preferred embodiment, the hinge tracks  84  are each about five and a half inches long, about two inches high, and vary in width from just under two inches just forward of the headboard car channel  28  to about one and a quarter inches at the channel  28  itself. The headboard car channels  310  are each about seven-eighths of an inch wide and about one-quarter inch deep. The batten guide arms  304  are just under one and three-quarters inch long, forming a batten guide  302  of same length and a width of about one inch. The luff passage  306  may be about one-fifth of an inch wide and about one-quarter of an inch long. The luff rope slot  308  has a radius of about three-tenths of an inch. Edges of hinge tracks  84  with the present inventive luff extrusion cross section  300  may be beveled, chamfered, and/or radiused as appropriate. 
     While this invention has been particularly shown and described with references to example embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims. 
     For example, the generic term yacht as used herein includes sailing vessels, boats, and ships of various sizes, including mega-yachts, which may be 40 feet or longer. Similarly, the generic term sail includes mainsails, which are used primarily to propel yachts. Likewise, the generic term mast includes mainmasts and other masts. In addition, the terms luff rope, sail bolt rope, and bolt rope may be used interchangeably. 
     Further, the various dimensions, materials, and surface or edge processing are for purposes of non-limiting illustration. Other dimensions, materials, and manufacturing processing are suitable.