OBJECTIVE 



Inspection of underwater pipelines and structures potentially could be made more cost- 

 effective if the technology for using unmanned free-swimming submersibles were developed. 

 One of the major critical technological areas in the development of such inspection vehicles is 

 the control and data communication link from the vehicle to the surface control platform. 

 The expendable fiber-optic communication link promises to provide rehable high-bandwidth 

 communications if drag-free deployment, spool winding, modulation and multiplexing, and 

 optical interfacing to underwater electronic pressure housings can be developed. 



RESULTS 



Fiber-optic communication links on free-swimming, supervisory-controlled unmanned 

 submersibles were investigated and the specific problem areas outlined above were considered. 

 The use of the supervisory-controlled submersible EAVE WEST, with a deployed fiber-optic 

 communication link for undersea inspection of pipehne and structures, is discussed in this 

 report. Theoretical and experimental results are presented. The entire approach was found 

 to be technologically practical and cost-effective. 



RECOMMENDATIONS 



Since the approach has been determined to be feasible for pipehne and structures 

 inspection, it is recommended that the entire hardware concept be implemented aboard the 

 EAVE WEST submersible and tested in the ocean. Adequate contingency procedures in the 

 event of communication link failure should be implemented in the vehicle control software 

 and also demonstrated during an actual inspection operation. 



