E/V Nautilus Spring 2015 Quality Assessment Report

Multibeam System: 

Summary and Recommendations

  • Heading into the 2015 operating season, the EM302 and associated sensors aboard E/V Nautilus are working well compared to previous evaluations and to other EM302 systems examined recently. The patch test showed no pitch or yaw bias and only a very slight residual angular offset for roll, indicating no major changes to the system geometry.
  • Sensor positions and SIS Installation Parameters should not be changed. A PU Parameters file containing all SIS Installation Parameters and Runtime Parameters were written to disk on the primary acquisition machine (and stored on the shiphouse share) at the end of NA055. If any problems or questions arise with any parameters, this file should be reloaded to restore a functional configuration for SIS. Johnson and Jerram have a copy of this file and can provide it if required.
  • The onboard technical staff have collected routine BIST results throughout the previous year. This practice provides excellent information for tracking system health and should be continued moving forward.
  • System operation from the data lab has greatly simplified multibeam operations during engineering shakedown legs. If possible, additional headset/microphone stations at other desks would provide further flexibility.
  • Ethan Gold documented that the ethernet cables between the switch and TX boards in the TRU cabinet are extremely sensitive to vibration and deformation, resulting in lost connectivity to individual boards. Due to the high vibration environment, this could result in component failure during startup or survey. This occurred once during NA055 and resolved with adjustment of the ethernet cables and a restart of the TRU.
  • The 2013 SAT report included several recommendations to address installation and operation concerns specific to E/V Nautilus (e.g., power supply issues) and to avoid problems commonly experienced aboard other similarly equipped research vessels (e.g., accidental motion sensor alteration). Many of these recommendations have been implemented over the 2013 and 2014 seasons, while a few remain relevant as of NA055
    and are listed below.
    • A removable protective structure, such as a cage-like cover, should be built around the MRU to help prevent accidental impact damage. This structure should be large enough to prevent workers in the TRU room from stepping on the MRU plate, provide secure routing for the cable, and ensure ample air flow for cooling.
    • Ensure cables behind the MRU are supported and not in contact with any other apparatus in the TRU room.

Patch Test Results

Angular Offset Pre-NA055 Value NA055 ‘Residual’ Post-NA055 Value
Pitch -0.12° +0.00° -0.12°
Roll +0.15° -0.02° +0.13°
Yaw +0.11° +0.00° +0.11°
20150409_Nautilus_QAT_Final_v1pt1.pdf6.93 MB