Sentry Specifications & Sensors



Depth capability: 6,000 meters
Dimensions: Length: 2.9m (9.7ft)
Width (with fins extended): 2.2m (7.2ft)
Width (without fins): 0.8m (2.7ft)
Height 1.8m (5.8ft)
Weight: 1,250 kg (2,750 lb) without extra science gear
Operating range: 70-100 km (38-54) depending on speed, terrain and payload
Operating speed: 0-1.2m/s (0-2.3 knots)
Propulsion: 4 brushless DC electric thrusters on pivoting wings
Energy: Lithium Ion batteries, 13 kWh
Bus power: 48-52 Volts DC
Endurance: 20-40 hours depending on mission type
Recharge time: 10 hours (16 hours total turnaround)
Descent/Ascent speed: 40m/min for both descent and ascent, 2400m/hr
Navigation: USBL Navigation with real-time Acoustic Communications and/or Long Baseline (LBL) using acoustic transponders, Doppler Velocity Log (DVL), and Inertial Navigation System (INS)

Science & Engineering Sensors

Sentry is equipped with a standard suite of scientific and engineering sensors. In addition, Sentry is a sufficiently flexible platform that additional sensors can be interfaced by PIs according to their specific interests and scientific needs. All sensors are rated to 6,000 meters (19,685 feet) except as noted.

Vehicle Sensors
  • Pressure: Paroscientific 8B7000-I, Digiquartz depth sensor, rated to 7,000 m. (23,000 ft)
  • Doppler Velocity Logger (DVL): RDI, 300kHz
  • Attitude sensors (pitch, roll, heading-internal)
  • PHINS inertial navigation (internal)
  • Forward looking sonar: Blue View P900 Imaging Multibeam (limited availability)

Geophysical Sensors
  • Multibeam mapping sonar: Reson 7125, 400 kHz, 512 beams, 50-200m track spacing
  • Edgetech 4 kHz to 20 kHz = 4-24 kHz chirp subbottom profiler
  • Three high precision, digital, 3-axis fluxgate magnetometers will be installed in 2011; 2 mounted midships (port, starboard) in a horizontal gradient mode and a 3rd mounted centrally within the vehicle above the other two in a vertical gradient mode.

Oceanographic Sensors
  • CT sensor: Seabird 49 CTD
  • Optical Backscatter (OBS): Seapoint Turbidity Meter
  • Seafloor photography: 1Kx1K, 12 bit color still camera with strobe, rated to 6,000 meters (19,685 feet) (11MP option soon)
  • Oxygen Sensor: Aandara Optode

Project-specific sensors interfaced to Sentry by PIs during recent cruise
  • Eh electrode (redox sensor) – Dr. Koichi Nakamura, Japan
  • TETHYS (in situ mass spectrometer) - Dr. Rich Camilli, WHOI, USA
  • SUPR Biological Sampler – Dr. Chip Breier, WHOI, USA

Note: All sensor data are stored on the vehicle and retrieved upon recovery