# US 8,770,129 B2 · Dual mode fiber optic cable system for underwater remotely operated vehicle > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,770,129 B2 - Document ID: US8770129B2 - Status: Granted - Kind: B2 - Application number: 13/531,112 - Filed: 2012-06-22 - Published: 2012-12-27 - Granted: 2014-07-08 - Earliest claimed: 2011-06-23 - Assignees: Bluefin Robotics Corporation - Applicants: Graham Hawkes; Charles Chiau; Adam Wright - Inventors: Graham Hawkes; Charles Chiau; Adam Wright - Web page: https://patentgrep.com/patent/US8770129B2 ## CPC - B63C 11/34: Diving chambers with mechanical link, e.g. cable, to a base (manipulators B25J; {externally attached cofferdams and the like B63B17/0018;} diving chambers without mechanical link to a base B63G8/00; caissons adapted to laying foundations E02D23/00 - E02D27/00) - B63C 11/42: with independent propulsion or direction control - B65H 75/425: {attached to, or forming part of a vehicle, e.g. truck, trailer, vessel} - B65H 75/4484: {Electronic arrangements or adaptations for controlling the winding or unwinding process, e.g. with sensors} - G01L 5/103: using sensors fixed at one end of the flexible member - H02G 11/02: using take-up reel or drum - B65H 2701/32: Optical fibres or optical cables - H02G 1/10: in or under water - B63C: LAUNCHING, HAULING-OUT, OR DRY-DOCKING OF VESSELS; LIFE-SAVING IN WATER; EQUIPMENT FOR DWELLING OR WORKING UNDER WATER; MEANS FOR SALVAGING OR SEARCHING FOR UNDERWATER OBJECTS (floating nets, floating slipways, or the like for recovering aircraft from the water B63B35/52) - B65H: HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES - G01L: MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE (weighing G01G) - H02G: INSTALLATION OF ELECTRIC CABLES OR LINES, OR OF COMBINED OPTICAL AND ELECTRIC CABLES OR LINES ## Abstract A cable containing an optical fiber is used to transmit data between an underwater remotely operated vehicle (ROV) and a support vessel floating on the surface of the water. The ROV pulls the cable through the water and as the ROV dives away from the support vessel, the optical fiber is released from the support vessel. Excess tension in the cable can damage the optical fiber and the tension can be highest close to the ROV. To prevent potential damage to the optical fiber, the ROV can store a portion of the cable and release the cable if the detected tension approaches the maximum working load. When the tension drops to a lower safe level, the release mechanism can stop releasing the cable. ## Claims ### Claim 1 A cable tension control apparatus comprising: a cable that includes an optical fiber for transmitting data between a controller on a surface vessel and a remotely operated underwater vehicle; a first storage device coupled to the surface vessel for storing a first portion of the cable; a spool mounted on the remotely operated underwater vehicle for storing a second portion of the cable; a release mechanism which controls the removal of the second portion of the cable from the spool; and a tension sensor for detecting the tension in the cable; wherein the first portion of the cable is released from the first storage device when the tension in the cable is lower than a predetermined value and the second portion of the cable is released from the spool by the release mechanism when the tension sensor detects that the tension in the cable is greater than the predetermined value. ### Claim 2 (depends on 1) The apparatus of claim 1 wherein the predetermined value is greater than 50 pounds of tension. ### Claim 3 (depends on 1) The apparatus of claim 1 wherein the release mechanism includes a block bonded to the second portion of the cable and mechanical locks which prevent the block from moving until the tension in the cable is greater than the predetermined value. ### Claim 4 (depends on 1) The apparatus of claim 1 further comprising: an optical slip ring; wherein the data is transmitted through the optical slip ring. ### Claim 5 (depends on 1) The apparatus of claim 1 wherein the release mechanism includes a rate controller for controlling the rate that the second portion of the cable is removed from the spool when the tension in the cable exceeds the predetermined value. ### Claim 6 (depends on 5) The apparatus of claim 5 wherein the rate that the second portion of the cable is removed from the spool is proportional to the tension of the cable above the predetermined value. ### Claim 7 (depends on 5) The apparatus of claim 5 wherein the removal rate controller includes a torque controller which controls the rotational friction of the spool. ### Claim 8 (depends on 1) The apparatus of claim 1 wherein release mechanism includes a pulley and the cable is wrapped around the pulley two or more times. ### Claim 9 (depends on 8) The apparatus of claim 8 wherein the pulley is locked when the tension in the cable is below the predetermined value. ### Claim 10 (depends on 8) The apparatus of claim 8 wherein the pulley is coupled to a torque controller for controlling the rotational friction of the pulley. ### Claim 11 A cable tension control apparatus comprising: a cable that includes an optical fiber for transmitting signals between a controller on a surface vessel and a remotely operated underwater vehicle; a first storage device coupled to the surface vessel for storing a first portion of the cable; a second storage device on the remotely operated underwater vehicle for storing a second portion of the cable; a release mechanism which controls the removal of the second portion of the cable from the second storage device; and a tension sensor for detecting the tension in the second portion of the cable; wherein the first portion of the cable is released from the first storage device when the tension in the cable is lower than a predetermined value and the second portion of the cable is released from the second storage device by the release mechanism when the tension sensor detects that the tension in the cable is greater than the predetermined value. ### Claim 12 (depends on 11) The apparatus of claim 11 wherein the predetermined value is greater than 50 pounds of tension. ### Claim 13 (depends on 11) The apparatus of claim 11 wherein the release mechanism includes a block bonded to the second portion of the cable and mechanical locks which prevent the block from moving until the tension in the cable is greater than the predetermined value. ### Claim 14 (depends on 11) The apparatus of claim 11 further comprising: an optical slip ring; wherein the data is transmitted through the optical slip ring. ### Claim 15 (depends on 11) The apparatus of claim 11 wherein the release mechanism includes a rate controller for controlling the rate that the second portion of the cable is removed from the storage device when the tension in the cable exceeds the predetermined value. ### Claim 16 (depends on 15) The apparatus of claim 15 wherein the rate that the second portion of the cable is removed from the storage device is proportional to the tension of the cable above the predetermined value. ### Claim 17 (depends on 15) The apparatus of claim 15 wherein the removal rate controller includes a torque controller which controls the removal rate from the storage device. ### Claim 18 (depends on 11) The apparatus of claim 11 wherein release mechanism includes a pulley and the cable is wrapped around the pulley two or more times. ### Claim 19 (depends on 18) The apparatus of claim 18 wherein the pulley is locked when the tension in the cable is below the predetermined value. ### Claim 20 (depends on 18) The apparatus of claim 18 wherein the pulley is coupled to a torque controller for controlling the rotational friction of the pulley.