Patent Publication Number: US-10328999-B2

Title: System for launch and recovery of remotely operated vehicles

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     The current application claims priority to and the benefit of U.S. patent application Ser. No. 15/402,152, filed Jan. 9, 2017 and issued as U.S. Pat. No. 9,855,999, entitled “SYSTEM FOR LAUNCH AND RECOVERY OF REMOTELY OPERATED VEHICLES”, which in turn claims priority to U.S. patent application Ser. No. 14/593,045, filed Jan. 9, 2015 and issued as U.S. Pat. No. 9,540,076, entitled “SYSTEM FOR LAUNCH AND RECOVERY OF REMOTE OPERATED VEHICLES”, which in turn claims priority to U.S. Provisional Patent Application Ser. No. 61/926,173 filed Jan. 10, 2014, entitled “SYSTEM FOR REMOTE OPERATED VEHICLE”. These references are hereby incorporated in their entirety. 
    
    
     FIELD 
     The present embodiments relate to a launch and recovery system for a Remotely Operated Vehicle (ROV) with a pass-through tether management system that does not require a load line to support a tether climbing component. 
     BACKGROUND 
     Many underwater operations, such as drilling for and production of oil and gas, installation and maintenance of offshore structures, or laying and maintaining underwater pipelines require the use of a remotely operated vehicle (ROV). 
     An (ROV) is a tethered underwater mobile device. ROVs are typically unoccupied, highly maneuverable, and operated by a dedicated crew aboard a vessel. The deployment of an ROV is typically achieved by launching the unit from either a bottom founded host platform, a floating host platform, or from a dynamically positioned marine vessel dedicated specifically for the purpose of supporting an ROV and/or other installation and subsea intervention equipment, e.g. a multi service vessel (MSV). 
     Often when working in rough seas or in deeper water, prior art devices utilize a load-carrying umbilical cable along with a tether management system (TMS). The TMS can be a large garage-like housing which contains the ROV during lowering. The TMS can also be a separate system which sits atop the ROV. 
     The purpose of the TMS is to house the tether and ROV during lowering, and lengthen and shorten the tether during operation. The TMS effectively allows power to be supplied to the ROV, as well as minimizes the effect of cable drag where there are strong underwater currents. 
     The umbilical cable is an armored cable that contains a group of electrical conductors and fiber optics that carry electric power, video, and data signals between the operator and the TMS. Where used, the TMS then relays the signals and power for the ROV down the tether cable. 
     Both bottom founded and floating host platforms can be fixed in position at the site and are normally engaged in collateral activities such as drilling and offshore production or construction. Thus, the operations of the ROV can be limited according to the distance that the ROV can travel from the host platform as well as by restrictions in operating periods due to the collateral activities of the host platform. 
     In the case of dedicated vessel deployment such as an MSV, significant costs can be associated with operation of a fully founded marine vessel and its mobilization to and from the ROV work site. Typically, a dedicated MSV may have a crew of twenty, large cranes with Active Heave Compensation (AHC), and other considerable costs not directly related to the operation of the ROV. 
     ROV operation and monitoring can be controlled from the host platform or MSV by means of an umbilical line between the host platform or MSV and the Tether Management System (TMS) which stores a limited amount of tether to connect to the ROV. It can be seen from this that the operational distance of the ROV can be directly related to the length of the tether capacity on the TMS unit. 
     A need exists for an improved launch and recovery system that utilizes pass-through tether management system concepts and advantages while addressing most prominent drawbacks of current systems. 
     A further need exists for an improved launch and recovery system that can be containerization for standard shipping that can include simple accurate active heave compensation and that has passive guidance for heavy weather deployments. 
     A further need exists for an improved launch and recovery system that include redundant passive overload protection that eliminates the need for hydraulic power units and can have easy dead ROV recovery capability. 
     A further need exists for a pass-through tether management system with a tether climbing component connected to the launch and recovery system enabling a remotely operated vehicle (ROV) to be lifted and deployed in water without the need for an armored umbilical or a load line to support the tether management system. 
     The present disclosure addresses the above needs. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The detailed description will be better understood in conjunction with the accompanying drawings as follows: 
         FIG. 1  depicts a side view of an embodiment of the launch and recovery system. 
         FIG. 2  depicts a side view of an embodiment of the launch and recovery assembly. 
         FIG. 3  depicts a detailed view of one embodiment of the tether climbing component. 
         FIG. 4  depicts an end view of one embodiment of the tether climbing device 
     
    
    
     The present disclosure is detailed below with reference to the listed Figures. 
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Before explaining the present disclosure in detail, it is to be understood that the disclosure is not limited to the specifics of particular embodiments as described and that it can be practiced, constructed, or carried out in various ways. 
     While embodiments of the disclosure have been shown and described, modifications thereof can be made by one skilled in the art without departing from the spirit and teachings of the disclosure. The embodiments described herein are exemplary only, and are not intended to be limiting. 
     Specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis of the claims and as a representative basis for teaching persons having ordinary skill in the art to variously employ the present embodiments. Many variations and modifications of embodiments disclosed herein are possible and are within the scope of the present disclosure. 
     Where numerical ranges or limitations are expressly stated, such express ranges or limitations should be understood to include iterative ranges or limitations of like magnitude falling within the expressly stated ranges or limitations. 
     The use of the word “a” or “an” when used in conjunction with the term “comprising” in the claims and/or the specification may mean “one,” but it is also consistent with the meaning of “one or more,” “at least one,” and “one or more than one.” 
     The use of the term “optionally” with respect to any element of a claim is intended to mean that the subject element is required, or alternatively, is not required. Both alternatives are intended to be within the scope of the claim. Use of broader terms such as comprises, includes, having, etc. should be understood to provide support for narrower terms such as consisting of, consisting essentially of, comprised substantially of, and the like. 
     Accordingly, the scope of protection is not limited by the description herein, but is only limited by the claims which follow, encompassing all equivalents of the subject matter of the claims. Each and every claim is incorporated into the specification as an embodiment of the present disclosure. Thus, the claims are a further description and are an addition to the preferred embodiments of the present disclosure. 
     The inclusion or discussion of a reference is not an admission that it is prior art to the present disclosure, especially any reference that may have a publication date after the priority date of this application. The disclosures of all patents, patent applications, and publications cited herein are hereby incorporated by reference, to the extent they provide background knowledge; or exemplary, procedural or other details supplementary to those set forth herein. 
     The present embodiments relate to a launch and recovery system for a Remotely Operated Vehicle (ROV) with a pass-through tether climbing component that does not require a load line to support a tether climbing component. 
     The present disclosure provides a system with a remotely operated vehicle tether or umbilical passing through a tether climbing component and going direct to the ROV. The novelty of the present disclosure is that the ROV can have virtually unlimited excursion distances at a working depth, limited only by the amount of tether able to be stored at the launching point. Further, the ROV can have virtually unlimited deployment time lengths by making use of embodiments wherein the ROV can recharge the tether climbing component while at a desired depth. 
     In industry, often the terms “tether” and “umbilical” are used to describe equipment which perform similar functions. Typically, “umbilical” is used for an armored communication, power, and control line. Similarly, tether is used for an unarmored communication, power, and control line. For the purposes of this disclosure, the terms tether, remotely operated vehicle tether, and umbilical shall be used interchangeably to mean any communication and/or power and/or control line. 
     The tether or umbilical acts as the load line. In such an embodiment, a traction system can move the tether climbing component along the length of the tether, with a separate mechanism for attachment of the ROV and, optionally, a separate mechanism to lower/remove the system from the water. 
     A tether climbing component can maintain the tether or umbilical directly below the launch point at the desired working depth, thereby avoiding any slack or impacts of current forces on the ROV. Extra equipment, such as load lines or additional winches for deploying a load line, can be eliminated, as the tether serves as the load line. 
     The tether climbing component can be controlled optionally by direct cable, a communication line with a motor and a power source, or with wireless communications such as an acoustic, radio, microwave, laser, and the like. 
     The embodiments eliminate the need for armored umbilicals to support a TMS. The embodiments significantly reduce the winch size, power requirements, and deck space requirements for launch and recovery of remotely operated vehicles. The embodiments, therefore, provide an alternative that can reduce the current total ROV systems deck weight by more than 40 percent. 
     The embodied system allows for the use of a smaller transport vessel and requires a smaller deck space which allows for a safer and less crowded work environment. 
     The present embodiments also eliminate the need for pre-tensioning and need for lebus grooved drum liners as with current armored umbilical winches. With the present embodiments, no bird caging or subsequent umbilical replacements are required. 
     The embodiments can provide a continuous umbilical or tether direct to the ROV, thereby eliminating the need to terminate an armored umbilical and separate delivered power to a TMS and the ROV. The continuous umbilical increases reliability and eliminates the need for an electrical and fiber optic rotary slip ring at the TMS. The present embodiments have significantly fewer connections and fewer parts and systems than current systems. Fewer connections and parts means that troubleshooting is simplified and downtime and repair costs are drastically reduced. 
     The continuous umbilical in the present embodiments allows for unlimited excursion distance from the launch point, as the distance is limited only by total tether length less the working depth. The present embodiments also allow for ROV touchdown monitoring from a lay vessel. 
     The embodiments provide simpler re-terms for the tether or umbilical. The user only needs to cut back and re-connect at the ROV or connect a whole spare umbilical or tether. Traditional tether replacements are typically a full day job; that replacement time is significantly reduced with the present embodiments. 
     In embodiments, a capstan or traction winch can be coupled to a low-tension storage reel, thereby reducing the horsepower required since the load on the traction winch is applied at constant diameter. No additional power is required regardless of the depth capacity of system. Further, the speed can be constant throughout deployments at any depth. 
     Various embodiments can eliminate hydraulic power units (HPU) completely, therefore removing costly HPU issues, such as leaks and maintenance. All-electric embodiments reduce the possibility of environmental disasters by eliminating the need for hydraulics entirely from the system. 
     The present embodiments disclose a launch and recovery system for a remotely operated vehicle comprising a launch and recovery assembly, tether climbing component, and a remotely operated vehicle. 
     The launch and recovery assembly can comprise a crane and a winch and a remotely operated vehicle tether. “Crane and winch” refers to any known mechanism for lowering and raising equipment as known to persons having ordinary skill in the art. “Remotely operated vehicle tether” refers to any connecting member or structure in communication with the crane and winch and the ROV, allowing the ROV to be raised and lowered by the crane and winch. 
     The tether can serve as the load line to lower the ROV and the tether climbing component into water (or any other operational area). In embodiments, the ROV tether can be spooled on the winch, or spooled separately and passed through the winch (such as with a capstan winch type arrangement). The length of the tether is the limiting factor as to how far the ROV can be deployed. In embodiments, the tether can be spooled on the winch for storage and operation. 
     In instances where an extremely heavy ROV and tether climbing component are to be deployed, a separate deployment frame can be employed and attached the tether climbing component to minimize load on the tether. Such a deployment frame can utilize a second winch to traverse the air/water interface prior to releasing the tether climbing component. Otherwise, a single winch can be utilized to lower the tether climbing component and the ROV, as well as pay in and pay out tether. 
     In embodiments, an active and/or passive heave compensation system can be utilized in conjunction with the presently disclosed system to minimize the effect of waves and/or vessel heave on the tether climbing component and the ROV. 
     In embodiments, the ROV can be detachably secured to the tether climbing component to allow for minimized load on the tether while traversing the air water interface. 
     The tether climbing component can comprise a frame, a tether climbing device secured to the frame, a motor connected to the tether climbing device to pay in and out the remotely operated vehicle tether, and a power source. 
     The frame can be any housing or structure that holds and positions the components of the tether climbing device as needed. A tether climbing device can be secured to the frame and be in communication with the ROV tether. In embodiments, the frame can also have a connector or latch to detachably be secured to the ROV. In embodiments, the frame can have a connector or latch to detachably be secured to the deployment frame. 
     The tether climbing device can have a traction mechanism to grip the ROV tether and climb up and down the tether. Such a mechanism can be a mechanical traction device utilizing friction and a motor. Other embodiments are contemplated utilizing magnetic or electromagnetic means to position the tether climbing device on the ROV tether. 
     Upon reaching a desired depth, the tether climbing device can maintain a desired depth by climbing up or down the tether. In embodiments, the desired depth can be a range of depths, to eliminate constant corrections of depth by the tether climbing component. 
     A remotely operated vehicle can be attached to the remotely operated vehicle tether opposite the tether climbing component from the crane and winch. Upon reaching a desired depth, the tether climbing component can remain substantially stationary relative to the launch point while the ROV is given an excursion length of tether to perform its duties. 
     For example, a tether climbing device and ROV can be lowered to a desired working vertical depth of 100 meters. The tether climbing component can be controlled to maintain its depth between 98 meters and 102 meters, thus accounting for up to a two-meter heave of the body of water. If the tether climbing component leaves this desired depth range, the component will climb up or down the tether to reach 100 meters. The ROV may need to travel 50 meters horizontally to accomplish its tasks. The winch can continue to pay out tether to give the ROV the necessary excursion distance. The tether climbing component would continue to climb the tether as this tether is payed out in order to maintain its desired depth. When the ROV has completed its tasks, and the tether is payed back in by the winch, the tether climbing component can climb down the tether until it reaches the ROV. 
     As will be readily apparent to persons having ordinary skill in the art, coupling the presently disclosed system with an active and/or passive heave compensation system, either with or without a deployment frame, can aid the tether climbing component in maintaining a desired depth with fewer corrective climbs up or down the tether. 
     In embodiments, the tether climbing device can allow the remotely operated vehicle tether to bend only in one direction, and/or align the remotely operated vehicle tether to exit the tether climbing device in a substantially vertical orientation. In embodiments in which the tether climbing component is towed with a traveling launch point, the tether climbing device can align the remotely operated vehicle tether to exit the tether climbing device in a substantially horizontal orientation, or any angle desired by persons having ordinary skill in the art. 
     In embodiments, the tether climbing component comprises a power source, such as a battery. In situations, wherein it is desirable for the ROV to be deployed for extended time periods without recovery, the power source may be rechargeable by the ROV, which in turn may have a larger battery, or receive power directly from the tether. For example, the tether climbing component can have a connector for attaching to and receiving power from the ROV. In other embodiments, the power source can be capable of electrically or magnetically induction charging from the ROV when the ROV is positioned proximate the tether climbing component. 
     In embodiments, the tether climbing component can further comprise a motor or a jet configured to move and/or adjust the attitude and/or inclination of the tether climbing component under water. 
     In embodiments, the tether climbing component can further comprise a fin to stabilize or align the tether climbing component in fluids. This may be especially useful when the tether climbing component is being towed, and it is desirable to make the tether climbing component more hydrodynamic and/or aerodynamic. 
     In embodiments, the tether climbing component can further comprise a ballast weight. In instances, wherein it is desirable to deploy the ROV at great depths, a ballast weight may be necessary to allow the tether climbing component to reach the desired depth which it must then maintain. Persons having ordinary skill in the art can determine if a ballast is necessary based upon the desired working depth. 
     In embodiments, the tether climbing component can further comprise a transmitter and receiver for communications. Such equipment can be wired directly, or wireless communication. Any known wireless communication means known to persons having ordinary skill in the art can be utilized, such as acoustic, radio, microwave, laser, and the like. 
     The present disclosure also includes a method of deploying a remotely operated vehicle. 
     The method can include: providing the launch and recovery system as described and claimed, deploying the remotely operated vehicle into a liquid, lowering the tether climbing component to a desired depth, and maintaining the tether climbing component at the desired depth by using a motor to pay in or out the remotely operated vehicle tether, thereby causing the tether climbing component to climb up or down the tether. 
     In various embodiments, the method can comprise any single step or combination of: attaching a deployment frame and a second winch to the tether climbing component to allow for lowering of heavy ROVs, recharging a power source in communication with the tether climbing component with the power supplied to the remotely operated vehicle, and wherein recharging the power source occurs through a physical connection, a contact area, or a proximity charging means. 
     Turning now to the Figures,  FIG. 1  depicts a side view of an embodiment of the launch and recovery system  10  as it is used from a launch point  2 , which is depicted here as a water vessel. 
     A tether climbing component  30  can be connected to the launch and recovery assembly  12 . While prior art devices required load lines  24   a  and  24   b , the present embodiments do not require them unless used with a deployment frame. In the event a deployment frame is utilized, it can be detachably secured to the tether climbing component  30 , and the load lines  24   a  and  24   b . Upon traversing the air water interface and entering the water, the deployment frame can be detached from tether climbing component  30 . 
     The tether climbing component  30  can have its own power supply. In embodiments, an acoustic transmitter receiver  19  can be connected to or in communication with the launch point  2  for communicating with the tether climbing component  30  The tether climbing component  30  can have a tether climbing component acoustic transmitter/receiver  25  for communicating with the acoustic transmitter receiver  19  deployed from the launch point  2 . Other similar means of communication with the tether climbing component can be utilized as discussed above. 
     The launch and recovery assembly  12  can have a base frame  14  for mounting removably to the launch point  2 . In embodiments, one or more pivot arms  16   a  can secure to the base frame  14 . 
     Power supply  7  can power the launch and recovery assembly  12 , which can raise the tether climbing component from the deck of the launch point  2 , and then pivot the pivot arms until the tether climbing component is positioned overboard of the hull of the offshore object. The tether climbing component can then be lowered below the water surface  3 . 
     The tether climbing component can latch to a remotely operated vehicle  92  (ROV) prior to being raised, or alternatively rest on the ROV  92 . The ROV  92  and tether climbing component can then be deployed together into the body of water. Once in the water, the ROV  92  can de-latch from the tether climbing component (if latched) and the ROV tether  42  can pay out through the tether climbing component for operation of the ROV. 
     In embodiments in which the weight of the ROV  92  and tether climbing component  30  in air is too great to be supported by the remotely operated vehicle tether  42 , a separate deployment frame and winch can be latched to the tether climbing component  30  for traversing the air/water interface and entering the water. The deployment frame can then be detached from the tether climbing component  30 . In embodiments, the deployment frame can be similar or identical in structure to the tether climbing component  30 . Using a second winch and a load line in conjunction with the deployment frame can still minimize necessary equipment as compared to prior art, as the deployment frame only needs to enter the water prior to detaching from the tether climbing component  30 , and need not be lowered fully to working depth. 
       FIG. 2  depicts a side view of an embodiment of the launch and recovery assembly. A base frame  14  can be used in embodiments to house the components of the system. 
     The remotely operated vehicle (ROV) tether  42  for paying out over a sheave can be attached to the cross member. 
     A constant tension tether assembly  26  can be utilized in embodiments for paying in and out of an ROV tether  42 . The constant tension tether assembly can have a movable sheave  46  for receiving the ROV tether from a sheave  23   c  on the cross member. The constant tension tether assembly can have an upper stationary sheave  44  for receiving the ROV tether  42  from the movable sheave  46 . The constant tension tether assembly can have a storage reel  40  with a motor  47 . The storage reel  40  with a motor  47  can be the winch used to lower a tether climbing component and ROV, as well as pay in and out tether after reaching a desired depth. 
     In embodiments, a launch and recovery assembly  12  can have a hydraulic power unit  74  connected to actuator  17   b  for positioning pivot arms  16 . 
     The movable sheave  46  can roll up and down on a rail  51  and can be mounted at a 90-degree angle to the base frame  14 . The movable sheave can slide in a first direction  60  along the rail  51  during deployment of the ROV tether causing payout of ROV tether from the storage reel and can slide in a second direction  61  on the rail  51  during recovery of ROV tether to ensure proper spooling on storage reel  40 . 
       FIG. 3  depicts a detailed view of one embodiment of the tether climbing component. The tether climbing component can have a tether climbing device  36  mounted on a plate  50  (which can act as the frame of the tether climbing component) showing the front side  52 . The plurality of gear connecting sheaves  56   a  and  56   b  can be mounted in a spaced apart relationship on the front side. One or more pinch rollers  59   a ,  59   b  can be mounted to the plate. Each pinch roller can be mounted opposing a respective traction sheave. 
     The ROV tether  42  from the launch and recovery assembly can be received between a first pinch roller  59   a  and first gear connecting sheave  56   a . The ROV tether rolls around the first gear connecting sheave  56   a  to a second gear connecting sheave  56   b , then rolls around the second gear connecting sheave to a second pinch roller  59   b  opposite the second gear connecting sheave through the optional latch mechanism  34  for connecting to an ROV. The gear connecting sheaves  56   a  and  56   b  can be motorized to allow for the tether climbing component to climb up and down tether  42  as necessary. 
       FIG. 4  depicts an end view of one embodiment of the tether climbing device  36  shown in  FIG. 3  used in the tether climbing component with gears and sheaves mounted thereto. One or more gears  58   a ,  58   b  can be mounted on a back side  54  of the plate  50  in a spaced apart relationship. A motor  38  for climbing tether  42 , latch mechanism  34 , one or more gear connecting sheaves  56   a ,  56   b , and front side are also shown. In embodiments, the plate  50  can also act as a shaftless bearing housing, allowing for inserts to absorb thrust and radial loads. The plate can not only provide structural support to the tether traction device, but can contain sheets or strips of bearing materials in a cavity between components located on either side of the plate. These bearing materials can be made of polymers such as TEFLON®, or any suitable material desired by persons having ordinary skill in the art. 
     In embodiments, a single gear connecting sheave can be utilized to ensure that the tether bends only in one direction, i.e. there is no reverse bend induced by the tether climbing component. 
     In claimed embodiments, the launch and recovery assembly deploys the tether climbing component overboard with an ROV and supports the tether climbing component and ROV with the tether, wherein the ROV is disengaged for tethered operation while maintaining the tether climbing component at an operational depth. 
     While the disclosure emphasizes the presented embodiments and Figures, it should be understood that within the scope of the appended claims, the disclosure may be embodied other than as specifically enabled herein.