Underwater Sonar Imaging and Evaluation For Y-49 Submarine Cable location and Burial Depth
Hempstead Harbor, NY
W. J. Castle PE & Associates was retained to investigate the Y-49 submarine cable off of Hempstead Harbor in the Long Island Sound. The cable was damaged and a trench created. CASTLE was retained to do a dive survey of the seabed surrounding cable Y49 to locate the extent of cable within the trench, approximately 500 lineal feet. The goals were to determine the nature of the cable trench that was first created in January 2014 and subsequently extended. Also to locate any anchor or anchor chain holes near the strike, and to determine their condition.
Both Side Scan Sonar Imaging and Scanning Sonar Imaging were used to investigate the site. The J.W. Fishers dual frequency SSS-100K/600K PC side scan sonar is a towfish that is pulled behind the vessel and images are generated while it is moved over the bottom. A Trimble ProXT GPS was tied into the processing system for geo-referencing the sonar data. The scanning equipment used was the Kongsberg/Mesotech MS1000 scanning sonar system. The Seafloor Systems Hydrolite-TM single beam fathometric survey equipment was used to collect depths in and around the trench.