Abstract:
A winch is employed for deploying a probe to a precise depth within a water column for making and recording physical measurement within such water column. More particularly, the winch rapidly unspools a line from an underway vessel, while maintaining minimal but constant line tension, as a probe, tethered to such line, descends within the water column in a “near” free-fall to a predetermined depth and then stops. The line lacks means for communicating its depth to the winch. The probe achieves a predictable descent behavior, even though it is tethered by a line to a winch onboard an underway vessel of unknown velocity and in variable weather conditions. The predictable descent behavior is achieved by maintaining a minimal constant tension on the line within a narrow range. The descent behavior of a probe in “near” free-fall has sufficient predictability to construct an algorithm to correlate descent time with depth. The predictability is sufficient to reduce the risk of collision between the probe and the water bottom to an acceptable level.

Description:
CROSS-REFERENCES  
       [0001]    This application claims priority from U.S. Provisional Application Ser. No. 62/044064, filed Aug. 29, 2014. 
     
    
     FIELD OF INVENTION 
       [0002]    The invention relates to shipboard winches for deploying oceanographic instrumentation for the purpose of profiling vertical water columns. More particularly, the invention relates to winches that employ a computer for controlling the process of raising and lowering oceanographic instrumentation within vertical water columns while underway. 
       BACKGROUND  
       [0003]    In the fields of oceanography and hydrology, a vertical water column may be profiled by lowering a probe through it to measure various characteristics as a function of depth. For example, Seo (U.S. Pat. No. 5,965,994) discloses a winch apparatus attached to a floating platform for lowering a probe through a water column for profiling its temperature, conductivity, etc. Alternatively, probes may be employed for measuring sound velocity, fluorescence, dissolved oxygen, and turbidity. The winch lowers the probe through the water column by unspooling line to which the probe is attached. Alternatively, Archibald (U.S. Pat. No. 4,974,536) discloses a winch apparatus attached to a floating vessel for profiling a water column. Dessureault (U.S. Pat. No. 5,570,303) discloses an automated system for profiling a series of vertical water columns from a moving vessel. While the vessel is underway, the automated system employs a winch affixed to the vessel for alternately lowering and raising the probe through a series of consecutive water columns. 
         [0004]    If the probe includes a depth gauge and if the support line includes a data cable, the probe can communicate depth data back to a control mechanism on the vessel for controlling the descent of the probe. When the probe approaches a depth known to be close to the water bottom, it can transmit an instruction to the controller onboard the vessel to reverse the descent process, so as to prevent a collision between the probe and the water bottom. Alternatively, if the probe is being employed in a body of water of unknown depth, the probe can employ a sonar device for sensing its proximity to the bottom. Unfortunately, the inclusion of a data cable contributes significantly to the weight of the support line and, consequently, to the size and power requirements of the winch. 
         [0005]    In applications wherein collision between the probe and the water bottom is unlikely, e.g., blue water oceanographic applications, underway profiling is possible using a low power winch if the data line is eliminated and a light weight, high strength line is employed. Rudnick et al disclose a profiling system wherein the probe includes a spool of line that unspools as the probe descends into the water column, in a free fail. (Rudnick, D. et al,  J. Atmospheric and Oceanic Technology  (2007), vol. 24, pp 1910-1923, “The Underway Conductivity-Temperature-Depth Instrument.”) After the unspooling process is complete, the winch rewinds the line and draws the probe back to the underway vessel. After the probe is recovered, the process may be repeated for serial profiling. Unfortunately, because this system lacks a communication cable, it is not employable in applications where there is a risk of collision between the probe and the water bottom. Also, in order not to interfere with the free-fall descent of the probe within the water column, the winch rapidly unspools the line into the water during the descent phase. Rapid unspooling can occasionally cause line tangling. This occasional line tangling necessitates that the process be monitored and compromises the reliability of the process. 
         [0006]    Winches can also be employed to control line tension in various applications wherein the line is deployed horizontally. For example, when towing a probe with a tow line, it is important to avoid exceeding the break strength of the tow line. Bailey (US Pat. App. No. 2012/0160143) discloses a vessel for towing a probe. The probe is attached to a tow line, which is attached a winch, which is incorporated into a tow arm. A control system regulates the torque applied to the winch so as to maintain the line tension in the tow line below its break strength. 
         [0007]    In another application, Lindgren (U.S. Pat. No. 4,920,680) discloses a winch for horizontally deploying line from a moving vessel for supporting fish nets. The line unspools from a winch as the vessel moves forward. A control system controls the torque applied by the winch so as to maintain a line tension within an allowable range so as to avoid line breakage. 
         [0008]    Controlling line tension can also be important within industrial applications. For example, in the textile field, Morton (U.S. Pat. No. 5,277,373) discloses an apparatus for winding yarn onto a spool using a dancer arm for maintaining a constant line tension so as to prevent yarn breakage. Conversely, Groff (U.S. Pat. No. 8,205,819) discloses an apparatus for unwinding material from a spool while maintaining constant tension. Groff&#39;s apparatus feeds material into a processor. The processor draws the material from the apparatus, but requires that the material be maintained within a specified tension range as it is being drawn. As the material is drawn, it unspools from a spool, but a brake, engaged with the spool, applies a constant resistive torque so as to create the tension in the material. As the material unspools, it passes through a tension meter which measures the amount of tension. The tension meter then activates a winch motor, rotationally coupled to the spool, which increases or decreases the resistive torque applied thereto, so as to maintain the tension in the material within the required tension range as it unspools. 
         [0009]    What was needed was an apparatus for profiling water columns in shallow water from an underway vessel without the benefit of a data line for avoiding collision between the probe and the water bottom. What was needed was an apparatus capable of rapidly unspooling line from an underway vessel of unknown velocity and in variable weather conditions so as to enable a free-fall descent by the probe within a water column, with no risk of line tangling. What was needed was an apparatus capable of achieving a profile depth accuracy of 10% or better without the use of depth data communicated along a communication cable and without having any a priori information about the transit speed of the ship. This is complicated by the fact that, for a given target depth, the length of line paid out will vary with ship speed and other factors. What was needed was a way to regularize the descent behavior of the probe such that its descent rate becomes independent of ship speed, to a first approximation. What was needed was a reliable way to parameterize the achieved depth in terms of deployment time. 
       SUMMARY OF INVENTION  
       [0010]    The invention is directed both to an apparatus and to a method for using the apparatus. 
         [0011]    The invention was enabled, in part, by a realization, not appreciated in the prior art, that a probe  102  can achieve a predictable descent behavior, even if it is tethered by a line  104  to a winch  106  onboard an underway vessel  108  of unknown velocity and in variable weather conditions, if the line tension is minimal and maintained constant within a narrow range. The invention teaches that “strict” free-fall is not required for a probe  102  to achieve a predictable descent behavior. The invention also teaches that the descent behavior of a probe  102  in “near” free-fall can have sufficient predictability to construct an algorithm to correlate descent time with depth. The predictability is sufficient to reduce the risk of collision between the probe  102  and the water bottom to an acceptable level. The invention is directed, in part, to a winch  106  capable of rapidly unspooling line  104  from an underway vessel  108  of unknown velocity and in variable weather conditions, while maintaining minimal but constant line tension, as a probe  102 , tethered to such line  104 , descends within a water column in a “near” free-fall. An unexpected benefit of the invention is that maintaining minimal but constant line tension during the unspooling process from an underway vessel  108  substantially eliminates the risk of line tangling in the water and enhances the reliability of the process. The invention discloses that use of an algorithm and the apparatus disclosed herein enables serial profiling of water columns from an underway vessel  108  in shallow water without the need for a communication line to report probe depth so as to prevent collision between the probe  102  and the bottom of the water. 
         [0012]    One aspect of the invention is directed to a shipboard winch  106  controlled by a micro-processor for releasing line  104  from an underway vessel  108  as a probe  102 , to which the line  104  is attached, sinks into a water column. The micro-processor controls the speed by which the winch unspools line  104  so as to maintain a minimal but constant line tension. The microprocessor also employs data inputs for calculating when the sinking probe  102  reaches a target depth. The microprocessor halts the descent process at the target depth by halting the release of line  104  by the winch  106 . 
         [0013]    More particularly, the winch  106  is employable for unspooling, halting, and re-spooling the line  104  attached thereto. The line  104  tethers the winch  106  to a probe  102  having negative buoyancy. The probe  102  contains oceanographic instrumentation for profiling a water column as the probe  102  descends through the column. The winch  106  comprises a frame  110 , a spool  112 , a drive  114 , a boom  116 , a block  118 , a tension meter  120 , and a controller  122 . The winch  106  may also include a power supply for powering the drive  114 . The spool  112  is supported by the frame  110  and is rotatable thereon. The line  104  is attached to the spool  112 . The drive  114  is also supported by the frame  110  and is rotationally coupled to the spool  112  for applying clockwise, resistive, and counterclockwise torque thereto for unspooling, halting, and re-spooling the line  104 . The boom  116  is also supported by the frame  110  and extends distally from the spool  112 . The block  118  is affixed to the boom  116  distally from the spool  112  and is employed for reeving and supporting the line  104 . The tension meter  120  is also supported by the frame  110  and is engageable with the line  104  between the spool  112  and the block  118  for generating a line tension signal as the line  104  unspools. In one embodiment, the tension meter  120  includes a dancer  124 . The dancer  124  may include a rotary encoder  126  for generating the tension signal. Alternatively, the dancer  124  may include a load pin for generating the tension signal. The controller  122  is electronically coupled to the tension meter  120  for receiving the line tension signal. The controller  122  is also electronically coupled to the drive  114  for controlling the unspooling speed for maintaining the line tension signal constant at a set point. Accordingly, the winch  106  maintains the line tension constant at the set point as the line  104  unspools from the winch  106  and the probe  102  descends by negative buoyancy through the water column and the vessel  108  continues to travel forward. 
         [0014]    In a preferred embodiment of this first aspect of the invention, the probe  102  descends no further than a target depth within the water column. This is achieved by employing an algorithm whereby the controller  122  calculates a descent time required for the probe  102  to descend to the target depth under conditions where the line tension is maintained constant at the set point. At the conclusion of the descent time, the controller  122  transmits a halt signal to the drive  114  for halting the descent of the probe  102 . Accordingly, at the conclusion of the descent time, the winch  106  halts the unspooling of the line  104  from the spool  112  and the probe  102  descends no further than the target depth. 
         [0015]    In another preferred embodiment of this first aspect of the invention, the probe  102  re-ascends through the water column after reaching the target depth. After halting the unspooling of the line  104  from the spool  112  at the conclusion of the descent time, the controller  122  transmits a re-spooling signal to the drive  114  for re-spooling the line  104  onto the spool  112 . Accordingly, after halting the unspooling of the line  104  from the spool  112 , the winch  106  re-spools the line  104  onto the spool  112  and the probe  102  re-ascends through the water column. 
         [0016]    In yet another preferred embodiment of this first aspect of the invention, the winch  106  further comprises a level-wind  128  coupled to the spool  112  for unspooling and re-spooling the line  104  evenly onto the spool  112 . 
         [0017]    In yet another preferred embodiment of this first aspect of the invention, the winch  106  further comprises a proximity sensor  130  attached to the boom  116  proximal to the block  118  for sensing the proximity of the probe  102  to the block  118  and generating a proximity signal when the probe  102  is proximal to the block  118 . The proximity sensor  130  is electronically coupled to the controller  122  for transmitting the halt signal to the drive  114  for halting the re-ascent of the probe  102  when the probe  102  is proximal to the block  118 . Additionally, the winch  106  may further comprise a brake  132  electronically coupled to the controller  122  for halting the rotation of the spool  112  when the controller  122  transmits the halt signal. 
         [0018]    In yet another preferred embodiment of this first aspect of the invention, the winch  106  is mountable onto a vessel  108  and further comprises a base  134  attached to and supporting the frame  110 . The base  134  includes one or more fasteners  136  for fastening the winch  106  to the vessel  108 . Additionally, the base  134  may include a swivel  138  for rotating the frame  110  about an upright axis. 
         [0019]    Another aspect of the invention is directed to a process for using the above shipboard winch  106 . The process employs an algorithm for correlating probe depth with descent time and for stopping the probe  102  at the target depth. The process relies upon the use of a micro-processor controlled winch  106  for maintaining a constant line tension during the descent process. The process is employable for lowering a probe  102  within a column of water to a target depth. The probe  102  is coupled to a line  104  and has negative buoyancy. The line  104  is spooled onto a winch  106 . The process comprises the following step of suspending, unspooling, and halting. In the suspending step, the probe  102  is suspended from the line  104  above the column of water. Then, in the unspooling step, the line  104  from the winch  106  is unspooled for releasing the probe  102  and allowing it to descend within the column of water by negative buoyancy. Simultaneously, the rate of unspooling is controlled for maintaining a constant line tension within the line  104 . The magnitude of the constant line tension is greater than zero but less than the magnitude of the negative buoyancy. Then, in the halting step, at a time calculated for the probe  102  to reach the target depth under the conditions of the unspooling step, the unspooling is halted so as to halt the descent of the probe  102  within the column of water at the target depth. Accordingly, the descent of the probe  102  within the column of water halts at the target depth. In an alternative mode, after the halting step, the process further comprises the additional step of re-spooling the line  104  onto the winch  106  for retrieving the probe  102  from the column of water. In an alternative mode, after the probe  102  breaks the surface of the water during re-spooling step, the process further comprises the additional step of halting the re-spooling of the line  104  onto the winch  106 . 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0020]      FIG. 1  is a perspective view of a winch  106  illustrating the motion of the boom  116  as the frame  110  rotates in either direction about an upright axis upon the swivel base that supports the frame  110  of the winch  106 . 
           [0021]      FIG. 2  is an enlarge perspective view of a portion of the winch  106  of  FIG. 1 , illustrating a detailed view of the dancer  124  of the tension meter  120  in its low tension position (lower position) and in its high tension position (upper position, phantom lines). The action of the level-wind  128  is also illustrated. 
           [0022]      FIGS. 3A-C  are perspective views of an underway vessel  108  illustrating the sequence by which the winch  106  of  FIG. 1  is deployed for profiling a water column. 
           [0023]    In  FIG. 3A , the winch  106  releases a probe  102  in a water column. 
           [0024]    In  FIG. 3B , the winch  106  unspools line  104  while the probe  102  descends into the water column, while maintaining a minimal but non-zero line tension. 
           [0025]    In  FIG. 3C , the winch  106  re-spools line  104  for drawing the probe  102  upward through the water column back toward the vessel  108 . Note that a “water pulley” forces the probe  102  to retrace its path through the water column on its ascent. 
           [0026]      FIG. 4  is an orthogonal front view of the winch  106  of  FIG. 1  illustrating a line  104  passing from a block  118  at the distal end of a boom  116 , through the level-wind  128 , and onto a spool  112 . 
           [0027]      FIG. 5  is an orthogonal side view of the winch  106  of  FIG. 1  illustrating the frame  110 , supported by the swivel base attached to a vessel (not shown) and the attachment of the boom  116  to the frame  110 . 
           [0028]      FIG. 6  is an orthogonal top view of the winch  106  of  FIG. 1  illustrating housing that covers the winch  106  and an overview of the tension meter  120 , level-wind  128 , and boom  116 . 
           [0029]      FIG. 7  is another orthogonal top view of the winch  106  of  FIG. 1 . 
           [0030]      FIG. 8  is a sectional view of the winch  106  of  FIG. 7  illustrating the spool  112 , a drive  114  rotationally coupled to the spool  112 , and a brake  132  engageable with said spool  112 . 
           [0031]      FIG. 9  is a scheme illustrating a work flow diagram for the controller  122 . 
           [0032]      FIG. 10  is a scheme illustrating an algorithm for calculating spool velocity for profiling in shallow water. 
           [0033]      FIG. 11  is a scheme illustrating an overall work flow diagram for operating the winch  106 . 
           [0034]      FIG. 12  is a sectional view of the winch  106  of  FIG. 7  illustrating the probe  102  suspended on a line  104  supported from a block  118  on the boom  116 . The dancer arm of the tension meter  120  is in its elevated high tension position. 
           [0035]      FIG. 13  is a perspective view of a winch  106  illustrating the deployment of a probe  102  having an optional auxiliary floatation attachment  140 , for use in profiling shallow water. 
           [0036]      FIG. 14  is an enlarged perspective view of the optional auxiliary floatation attachment  140  of  FIG. 13 . 
           [0037]      FIG. 15  is a chart recorder printout illustrating an exemplary tension error, spool rpm, and brake status for the full course of an exemplary deployment and retrieval. 
           [0038]      FIG. 16  is a plot illustrating the relationship between descent time and depth for a deep profile using an exemplary winch  106 , winch settings, and probe. The probe is of a type that lacks an auxiliary flotation attachment  140 . The plot is experimentally determined and is specific to the particular the apparatus and setting. The plot is employed by the controller for determining when to send a halt signal. 
           [0039]      FIG. 17  is a plot illustrating the relationship between descent time and depth for a shallow profile using an exemplary winch  106 , winch settings, and probe. The probe is of a type that includes an auxiliary flotation attachment  140 . The plot is experimentally determined and is specific to the particular the apparatus and setting. The plot is employed by the controller for determining when to send a halt signal. 
       
    
    
     DETAILED DESCRIPTION 
     Computer Controlled Winch: 
       [0040]    One aspect of the invention is a winch  106  that employs a micro controller  122  and various data input to maintain a constant line tension during probe  102  descent. 
         [0041]    The smart winch  106  is a device employed to profile a water column by lowering a probe  102  through it, the probe  102  being suspended from a support line  104  to which the smart winch  106  is attached via a spool  112 . Importantly, the smart winch  106  maintains a constant line tension as it lowers a probe  102  through a water column. 
         [0042]    The smart winch  106  includes a motor  114  for driving the spool  112 , a controller  122  for controlling power applied to the motor  114 , a spool  112  rotationally driven by the winch motor  114  for spooling the line  104 , a sensor for measuring spool rotation and line speed, a level-wind  128  for reloading the line  104  back onto the spool  112 , and an electrically operated brake  132  for braking spool rotation. Additionally, and crucially for the invention, it also includes a tension meter  120  for measuring line tension during descent. 
         [0043]    As the probe  102  descends through the water column, the line tension meter  120  continuously measures the line tension using a rotary encoder  126  and sends that information to a micro controller  122 ; in turn, the micro controller  122  repeatedly communicates to the motor controller  122  and brake  132  for adjusting the rotational velocity of the spool  112  and the line speed in order to maintain a constant line tension. In essence, line tension information is continuously feed back to the motor controller  122  for varying the rotational speed of the spool  112  and the line speed so as to maintain a constant line tension. 
       Method for Controlling Probe Depth: 
       [0044]    Another aspect of the invention is a process that employs the smart winch  106  together with an algorithm to achieve a profile depth specified by the operator, without the benefit of a communication cable. The algorithm correlates descent time with descent depth under conditions of constant line tension. Profiling may be initiated by the operator specifying a depth to which the smart winch  106  will deliver the probe  102 . Collision between the probe  102  and the water bottom is avoided by the operator specifying a depth that is less than the depth of the water bottom. 
         [0045]    The depth of the probe profile is controlled without using a depth gage, without using a proximity sensor  130  for sensing proximity to the ocean floor, and without relying on a correlation between unwound line length and spool rotation. The target depth specified by the operator is achieved to within 10% accuracy without any real time depth feedback from the probe  102 . 
         [0046]    When a minimal but constant line tension is maintained, an algorithm correlates the depth of the probe  102  with the time of the descent. To a first approximation, this is independent of the vessel speed and other environmental factors. An operator specifies the desired depth of the probe profile, and a micro controller  122  employs an algorithm to calculate the time required for the probe  102  to descend to the desired depth. The micro controller  122  then stops the winch motor  114  and applies the brake  132  when the probe  102  reaches the desired depth. 
         [0047]    Mimicking the behavior of a free-falling probe  102 , the smart winch  106  is able to obtain accurate and repeatable profiles independent of a wide spectrum of environmental conditions and of ship speed. The only information required at the time of the deployment is the current water depth or the target profile depth. 
       Tension Feedback Mechanism: 
       [0048]    Indirect measurement of line tension is provided by a lever arm which uses a torsion spring and line tension to maintain contact with the line  104  at all times, via a roller. The lever arm is situated between a pulley and a spool  112 , which are held stationary in terms of translation. Line  104  is routed through all structures, and the fixed geometry ensures that movement of the lever arm is caused primarily by changes in line tension rather than changes in line position. The lever arm&#39;s restoring torque establishes a one-to-one correspondence between a particular line tension and a corresponding arm angle at that tension. A rotary encoder  126  provides feedback on the arm angle. 
       Algorithm: 
       [0049]      FIG. 10  illustrates a scheme for an exemplary algorithm for calculating spool velocity for profiling in shallow water. 
         [0050]    Tension control is achieved via two nested control layers, arranged such that the output of one layer serves as the input to the lower layer. 
         [0051]    The lower control layer, called the Velocity Layer, is a standard Proportional Integral Derivative (PID) controller that modulates power applied to the motor  114  in order to achieve and maintain a commanded motor velocity at a defined acceleration and deceleration rate. Encoder feedback ensures that the specified motor velocity is maintained despite external disturbances and forces, and acceleration/deceleration rates are chosen to allow the system to respond to rapidly changing conditions. 
         [0052]    The tension Layer computes the changes in motor velocity needed to maintain a chosen line tension. The lever arm angle associated with the desired line tension becomes the setpoint for the algorithm, simplifying the tension maintenance task from a dynamics problem to a kinematics problem. 
         [0053]    A control law is chosen to provide asymptotic convergence of the arm angle towards this setpoint position. In the current embodiment, the control law takes the form of a first-order differential equation that relates the tension arm&#39;s desired angular velocity to its angular error relative to the setpoint. This control law yields a response that is asymptotically stable. 
         [0054]    Because the lever arm is in constant contact with the line  104 , a change in the length of line  104  running through the tension feedback mechanism (its “arc length”) will elicit a corresponding change in the arm angle. Similar to the relationship between line tension and arm angle, there is again a one-to-one correspondence between arc length and arm angle, provided that the lever arm has not reached its lower endpoint. Since rotation of the spool  112  ultimately controls arc length, control is established via the following chain: 
         [0000]      Line Tension←Arm Angle←Arc Length←Spool Rotation←Motor
 
         [0055]    An equation relating the tension arm&#39;s angular velocity to the angular velocity of the spool  112  allows a chosen line tension to be maintained by modulating the velocity of the motor  114  which drives the spool  112 . 
       Optional Wireless Data Transfer: 
       [0056]    To shorten delays between profiles, after resurfacing, a wireless communication interface may be employed for transferring data from internally logging sensors in the probe  102  to the shipboard computer. As a result, pseudo-real time profiles of the water column are achieved using rapid wireless data transfers without the use of communication cables. After the data transfer is complete, the probe  102  is ready for its next profile. Data from the probe  102  can be employed to calibrate the depth accuracy of the next deployment. Additionally, the winch may receive data from shipboard sensors such as a depth sounder or GPS. Data from these sensors can be used to enhance automated operation and to simplify probe data management. For example, by reading the depths reported by a sounder, the winch can automatically identify the maximum depth and set a target depth with an appropriate safety margin. This can be used to deploy a probe automatically without requiring the user to manually enter a target depth beforehand. As another example, the winch can also read the vessel&#39;s current GPS position and automatically log the location that the probe was deployed at. This feature provides automatic geo-tagging of the probe data, relieving the user of the burden of having to manually track the locations that probe data was collected at, especially on a moving vessel that may cover wide geographic areas. 
       Operation: 
       [0057]    In the most basic implementation of the system, the operator enters the profile depth and starts the deployment of the probe  102 . From that time on, the winch  106  operates autonomously. The computer in the winch  106  controls the line payout until the sensor reaches its target depth and then switches to recovery mode to reel in the sensor until the original launch position is reached again. The operator has the option of aborting the deployment any time and recovering the instrument manually. As soon as the probe  102  is within range of the wireless connection, the shipboard computer initiates the data download from the probe  102 , processes the profile into a suitable format, feeds these data into the surveying system, and prepares the sensor for the next deployment. The operator can either repeat the profile with the current setting or choose a different profile depth. Apart from these actions, the only other operations required by the user is lowering the probe  102  to its launch position at the beginning and recovering the instrument after completion of the survey operation. 
         [0058]    An overall scheme for operating the winch  106  is illustrated in  FIG. 11 . The operating steps are summarized as follows:
       1. Probe ( FIG. 11 :  1 ) collects data of physical quantities in the water column. Data are automatically uploaded to shipboard computer ( FIG. 11 :  12 ) via wireless transfer.   2. Block ( FIG. 11 :  2 ) attaches to the winch frame and routes the line ( FIG. 11 :  3 ) from the spool ( FIG. 11 :  5 ) to the probe ( FIG. 11 :  1 ).   3. Line high-strength line made of Ultra High Molecular Weight Polyethylene (UHMWPE).   4. Levelwind ( FIG. 11 :  4 ) couples to the spool ( FIG. 11 :  5 ) via geared belt drive and ensures proper line distribution on the line drum ( FIG. 11 :  5 ).   5. Spool holds up to 2500 m of UHMWPE line.   6. Gearbox reduces the motor RPM and drives the spool ( FIG. 11 :  5 ) via a custom hub.   7. Winch motor brushless DC motor ( FIG. 11 :  7 ) that pays out line on probe deployment and reels in line ( FIG. 11 :  3 ) on probe recovery.   8. Brake ( FIG. 11 :  8 ) attaches to the rear shaft of the motor ( FIG. 11 :  7 ). Is used to stop the probe descent at the end of deployment and engages in case of power failures.   9. Proximity sensor ( FIG. 11 :  9 ) integrated into the block ( FIG. 11 :  2 ). Senses the line angle which is used to estimate the distance of the probe ( FIG. 11 :  1 ) to the ship.   10. Tension sensor ( FIG. 11 :  10 ) pivotal system sensor which measures tension of the line ( FIG. 11 :  3 ) during probe deployment.   11. Line speed sensor incremental encoder which reports the rotational speed of the spool ( 5 ). This information is integrated to estimate the amount of line ( FIG. 11 :  3 ) paid out.   12. Motor controller controls the motor ( FIG. 11 :  7 ) speed according to feedback from the spool encoder ( FIG. 11 :  11 ).   13. Micro controller translates the target depth from the shipboard computer (operator) into deployment time. Adjusts the motor speed to keep the line tension at a preset value during probe deployment.   14. Shipboard computer Manages probe ( FIG. 11 :  1 ) settings and data download. Interfaces with the operator and controls winch actions via the micro controller ( FIG. 11 :  13 ).       
 
       Exemplary Protocol: 
       [0073]    Telemetry data from an exemplary protocol is illustrated in  FIG. 15 . The profiling protocol is as follows: 
         [0074]    Firstly, the operator enters the target profile depth into the software and starts the deployment. The target profile depth is translated via a pre-programmed dive table ( FIG. 16  or  FIG. 17 ) into to a deployment time. This dive table is specific to the sensor-tail spool combination. Now, the probe  102  moves into launch position over the water. This encoder count of the spool encoder for this position had been saved during the initial setup. As seen in  FIG. 15  (1), the line tension oscillates rapidly because of the swell. As seen in  FIG. 15  (2), when launch position is reached, the motor stops and the brake  132  engages. 
         [0075]    As seen in  FIG. 15  (3), the program then enters payout mode in which the motor is sped up until the tension meter  120  reaches the pre-defined setpoint angle of the rotary encoder  126  of the tension meter  120 . This setpoint angle corresponds to approximately 0.5 lb of line tension. The whole angular range (˜167 degrees) of the tension meter  120  covers a line tension range of no tension to full line tension (over 70 lb). The setpoint line tension of 0.5 lb occurs approximately midway through the angular range (˜90 degrees from full tension in the plot). 
         [0076]    As seen in  FIG. 15  (4), once the setpoint tension angle is achieved, the motor control loop varies the motor speed to maintain the angle to the tension meter  120  at the setpoint. From the graph it can be seen, that the obtained accuracy is less than +/−10 degrees from the set point (or ˜0.3-0.7 lb of line tension). 
         [0077]    As seen in  FIG. 15  (5), once the end of the calculated deployment time is reached, the brake  132  engages and the probe&#39;s descent is stopped. After a variable, user-chosen hold-time, the brake  132  disengages and the probe  102  is reeled in at preset (also user-settable) spool speed (typically between 50-250 rpm or 0.5-3 m/s line speed). During reel-in, the tension meter  120  hovers around the upper maximum of the angular range (full line tension). The reel-in continues automatically at this speed until the spool encoder count equals the count from the original launch position. At this point, the data are downloaded from the probe  102  and the system is ready for the next profile. 
       Exemplary List of Commercially Available Component for Winch: 
       [0078]      
         [0000]    
       
         
               
               
               
               
             
           
               
                   
               
               
                 Component 
                 Manufactur 
                 Model 
                 Specs 
               
               
                   
               
             
             
               
                 Motor - brushless, 
                 Anaheim 
                 BLK322D- 
                 BLDC motor, 80 mm Frame, 
               
               
                 48 V, 840 W 
                 Automation 
                 48V-3000- 
                 48 VDC, 3000 RPM, 157 mm 
               
               
                   
                   
                 20EE 
                 length, Dual Shaft, Rated 
               
               
                   
                   
                   
                 Torque 378 oz-in, Torque 
               
               
                   
                   
                   
                 Constant 13.88 oz-in/A 
               
               
                 Gearbox - 
                 Anaheim 
                 GBPNR-0801- 
                 1 Stage, 5:1 Ratio, Rated 
               
               
                 planetary, single 
                 Automation 
                 CS-005- 
                 Torque 592 in-lbs, Max 
               
               
                 stage, 5:1, RA 
                   
                 BLK32-748-01 
                 Torque 946 in-lbs, Backlash 
               
               
                   
                   
                   
                 &lt;15 arcmin 
               
               
                 Brake - 6 Nm, 
                 Anaheim 
                 BRK-28H 
                 Max Torque 72 in-lb, Voltage 
               
               
                 2.5 lb 
                 Automation 
                   
                 24 VDC, Power 17 Watts, 
               
               
                   
                   
                   
                 Weight 1.92 lbs 
               
               
                 Spool - ABS 
                 Mossberg 
                 5541-1410 
                 12″ outer diameter, 6.5″ inner 
               
               
                   
                 Industries 
                   
                 spool diameter, 7″ inner 
               
               
                   
                   
                   
                 width, 8.4″ overall width 
               
               
                 Line - Spectra 
                 Innovative 
                 LP Gold 500 
                 500 lb breaking strength, 
               
               
                   
                 Textiles 
                   
                 1,500 yds length 
               
               
                 Spool Encoder 
                 US Digital 
                 E5-2500-236- 
                 Incremental Rotary Encoder, 
               
               
                   
                   
                 IE-S-D-3-B 
                 Optical, 2500 cycles per 
               
               
                   
                   
                   
                 revolution, 10,000 pulses per 
               
               
                   
                   
                   
                 revolution, −25 to +100 C. 
               
               
                 Tension Sensor 
                 US Digital 
                 MAE3-P12- 
                 Absolute Rotatry Encoder, 
               
               
                 Encoder 
                   
                 236-220-7-B 
                 Magnetic, 12-bit PWM output, 
               
               
                   
                   
                   
                 4096 positions per revolution, 
               
               
                   
                   
                   
                 250 Hz, −40 C. to +125 C. 
               
               
                 Power Supply - 
                 Mean Well 
                 RS-2000-48 
                 90~264 VAC Universal Input, 
               
               
                 48 VDC, 2000 W 
                   
                   
                 48 VDC Output, 42.0 A, 2016 
               
               
                   
                   
                   
                 W 
               
               
                 Power Supply - 
                 Mean Well 
                 MDR-20-24 
                 85~264 VAC Universal Input, 
               
               
                 24 VDC, 24 W 
                   
                   
                 24 VDC Output, 1.0 A, 24 W 
               
               
                 Motor Controller - 
                 Roboteq 
                 HBL 1660 
                 Brushless DC Motor 
               
               
                 brushless 
                   
                   
                 Controller, Single Channel, 
               
               
                   
                   
                   
                 150 A, 60 V, Hall sensors in, 
               
               
                   
                   
                   
                 Encoder in, USB, CAN, and 
               
               
                 Shunt Regulator 
                 Advanced 
                 SRST50 
                 50 V clamping voltage, 95 W 
               
               
                   
                 Motion 
                   
                 rated power dissipation 
               
               
                   
                 Controls 
                   
                   
               
               
                 Microcontroller 
                 GHI 
                 G400-D 
                 400 MHz 32-bit ARM 9 
               
               
                   
                 Electronics 
                   
                 processor, 1.4 MB Flash 
               
               
                   
                   
                   
                 memory, 92 MB RAM, 67.6 × 
               
               
                   
                   
                   
                 31.75 × 4.1 mm, −40° C. to 
               
               
                   
                   
                   
                 +85° C., GPIO, UART 
               
               
                 Boom (Davit) 
                 Tigress 
                 88974 
                 High Quality Fixed Carbon, 
               
               
                   
                 Outriggers 
                   
                 74″ length, 50 lb breaking 
               
               
                   
                   
                   
                 strength vertical 
               
               
                   
               
             
          
         
       
     
       Definitions: 
       [0079]    Base: The lowest layer of mechanical structure for supporting a structure above it. 
         [0080]    Block: A pulley having a sheave enclosed between two cheeks or chocks. 
         [0081]    Boom: An arm supported directly or indirectly from a base for supporting a load distally from such base. 
         [0082]    Brake: A mechanical device for inhibiting motion, i.e., for slowing or stopping a moving or rotating object or preventing its motion or rotation. A solenoid brake is a brake that is turned on and off by an electrical solenoid. A preferred solenoid brake employs a spring to engage the brake when unpowered. The solenoid releases the brake when powered. 
         [0083]    Clockwise and Counterclockwise Torque: A torque is a measure of the turning force on an object such as a spool for increasing or decreasing angular momentum or for maintaining angular momentum in the presence of rotational friction. Clockwise and counterclockwise torques are turning forces of opposite direction. 
         [0084]    Controller: A chip, expansion card, or stand-alone device that interfaces with a peripheral device. In a computer, the controller may be a plug in board, a single integrated circuit on the motherboard, or may be integrated into an external device. 
         [0085]    Dancer: A type of tension meter having a roller supported by one or more swing arms biased by gravity and/or springs. A line under tension unspooling or re-spooling from or onto a spool displaces the roller from its rest position, causing the swing arms to rotate away from the rest position. A rotary encoder or load pin detects the displacement of the swing arms from their rest position and generates a tension signal. 
         [0086]    Unspool: The action of unwinding a line, wire, cable, or thread upon a spool. 
         [0087]    Drive: A generic term for a device that delivers torque to a spool. An electric motor rotationally coupled to a spool is an exemplary drive. 
         [0088]    Fastener: A hardware device that mechanically joins or affixes two or more objects together. 
         [0089]    Frame: a mechanical structure for supporting functional components. 
         [0090]    Halt: The action of bringing something to an abrupt stop. 
         [0091]    Halt signal: A signal or instruction for bringing something to an abrupt stop. 
         [0092]    Level-wind: A device for winding a line evenly onto a spool. 
         [0093]    Load pin: A transducer employable for converting a force, for example line tension, into an electrical signal. 
         [0094]    Line: A cord having light weight and high strength for bearing elevated line tension for towing or other purposes, without undergoing line breakage. 
         [0095]    Line tension signal: An electronic signal generated by a tension meter for indicating the tension is a line. 
         [0096]    Negative buoyancy: The attribute of an object having a density greater than the fluid in which the object is immersed, causing such object to sink within the fluid. 
         [0097]    Probe: a device employable for descending through the length of a water column for collecting, storing, and transmitting data about such water column. 
         [0098]    Proximity signal: A signal sent to the controller when a probe being retrieved from a profile breaks the surface of the water. 
         [0099]    Reeve: The act of passing a line through a block or similar device. 
         [0100]    Resistive torque: A resistive torque is a measure of the turning force on an object such as a spool for decreasing angular momentum toward zero. Resistive torque may result from rotational friction or from the active application of a turning force in opposition to the angular momentum. 
         [0101]    Re-spool: The action of rewinding a line, wire, cable, or thread upon a spool. 
         [0102]    Re-spooling signal: A signal sent by the controller to the driver for applying torque to the spool for re-spooling a line. 
         [0103]    Rotary encoder: An electro-mechanical device, also called a shaft encoder, that converts the angular position or motion of a shaft or axle to an analog or digital code. 
         [0104]    Rotatable: Capable of rotation. 
         [0105]    Set point: A line tension selected for unspooling a line during the descent portion of a water column profile; in the invention, the line tension is maintained constant at the “set point” during unspooling so as to enable the controller to apply an algorithm for correlating probe depth with the time duration of descent. 
         [0106]    Spool:
       1. A cylinder, usually having a low-flange, upon which and/or from which line, wire, cable, or thread etc is wound for later use. When incorporated into a winch and employed for towing or pulling a load, the line tension is transferred to the spool, so that the force of towing is born by the spool.   2. The action of winding a line, wire, cable, or thread upon a spool.       
 
         [0109]    Swivel: A mechanical device that connects an apparatus to a base and allows the connected apparatus to rotate horizontally about an upright axis anchored in the base. 
         [0110]    Target depth: A depth selected by a user or computer to which data for a water column profile is desired, the depth usually be less than the depth of the water bottom. When profiling a water column, it is desired that the probe descend to the target depth and not beyond. 
         [0111]    Tension meter: A device for detecting tension and generating a signal proportional thereto. 
         [0112]    Upright axis: An axis substantially perpendicular to the surface of a body of water. 
         [0113]    Vessel: A craft designed for transportation on water. 
         [0114]    Water column: A substantially vertical column of water through which a probe of negative buoyancy descends under the force of gravity. 
         [0115]    Winch: A mechanical device employable for pulling in (winding-up) or letting out (unwinding) or otherwise adjust the tension of a line. In a preferred winch, the line is wound-up or unwound onto or from a spool and the winch provides the power for such winding or unwinding.