Gates Acoustic Services was tasked by University of Alaska, Fairbanks, to investigate and quantify acoustic issues associated with operation of the R/V SIKULIAQ. An at-sea investigation was accomplished during ship operations in deep water out of San Juan, Puerto Rico on September 12-18, 2014.
During the at sea test on SIKULIAQ, the primary goal was to determine ship acoustic and bubble sweepdown characteristics and to assess their potential impacts to sonar performance. The Kongsberg EM 302 sonar was the primary focus of this testing with the Kongsberg EM 710 as a secondary priority. Additional goals of this test were to determine propeller cavitation characteristics and to obtain a preliminary snapshot of the expected acoustic background of the sonar region in open water conditions.
The following objectives were accomplished for this testing:
- The noise levels of the sonar hydrophones were measured using internal Built In Self Test (BIST) routines for the EM 302 and EM 710 sonars.
- Data was acquired from the internal noise routines of the TOPAS sub bottom profiling sonar.
- The controlling sources of sonar acoustic levels were investigated.
- The noise levels of reference hydrophones were measured at selected speeds and vessel conditions.
- Propeller cavitation characteristics were assessed.
- The presence of bubble sweepdown was assessed.
- The noise of the ship bow thruster was measured.
- Various machinery was measured for vibration levels.