Scour and Sedimentology
Acoustic Velocimeter for geophysics and marine applications
- Marine Geophysics
- Geoacoustic Studies
Seabed Terminal Impact Newton Gradiometer
STING is a self-contained, tethered probe with a streamlined body and a long (up to three metres), slender steel shaft protruding from the nose cone. The unit is released from a vessel so that it drops freely through the water, reaching terminal velocity, and impacts into the sea floor vertically with its calibrated shaft and foot. Internal microprocessor-based electronics record the deceleration as the shaft embeds itself into the layers of the bottom sediment.
Applications for STING include
- Sub-sea cable and pipeline route selection
- Sediment deposition determination
- Harbour surveys
- Environmental impact surveys
- Ground truthing for sub bottom acoustic profiling systems
- Pre-dredging seabed assessment
- Selection of appropriate equipment and methods in salvage operations
The system consists of:
- Newton Gradiometer probe recording deceleration
- One-metre shaft segment with standard contact foot. (shaft extensions and additional foot sizes available)
- Battery charger
- RS232 data download cable with sub-sea connector and serial port plug
- Communications and Data Analysis software
- Storage container suitable for shipping
Submersible distance measurement system.
Characteristics Distance measurement: Range: 20 to 200 cm Resolution: 0.41 mm Accuracy: 2mm in the range 20 to 70 cm Accuracy: 5 mm in the range 20 to 200 cm Acoustic transducer frequency: 2MHz, 3.6° opening at -3dB. Water height measurement range: 20m (maximum immersion 30m) Accuracy: 6cm, resolution: 0.8cm. Internal clock with calendar. Automatic start of measurements controlled by water height. Sampling rate: programmable from 1s to 99hrs. A fast and cyclic acquisition mode allows to monitor the swell thanks to the water height sensor. Memory autonomy: eight months at 5 min sampling rate. Energy autonomy: up to 4 years, at 5min sampling rate. User replaceable lithium batteries.
Dimensions: Housing: length 240mm, diameter 80 mm max. Transducer: length 300mm, diameter 58 mm. Cable : length 5.5m, diameter 9mm. Total weight: 2.6kg (with optional pole)
Options: A pole of length 300mm and diameter 20mm can be added to the S-Altus for insertion into the ground. A stainless steel support can be supplied for installation of the Altus on a mud flat
Applications: Study of mudflats or beach level variations in relation to tidal currents, swell etc. Monitoring of erosion or sedimentation rate of coastal, estuarine, port or river beds. Wave recorder function.
Autonomous Turbidity, Pressure and Temperature data logger.
20m, 100m and 300m range.
Characteristics Turbidity Sensitivity: 0 – 750 NTU, possible to measure up to 2,000 TU. Other measurement ranges upon request. Resolution: < 0.03% Accuracy: < 2%. Response time: < 2s (90%). Depth Range: 20m (STBD20), maximum immersion depth : 30m, Accuracy : 0.3% (6 cm), Resolution: 0.6 cm. Depth Range: 100m (STBD100), maximum immersion depth : 200m, Accuracy : 0.3% (30 cm), Resolution: 3cm. Depth Range: 300m (STBD300) , maximum immersion depth : 400m, Accuracy : 0.3% (90 cm), Resolution: 9 cm. Temperature range: -5°C to +35°C Response time: < 1s (90%). Memory autonomy: 600,000 data points (1Mb with data compression). Energy autonomy: 3 years at 10min sampling rate, 6 months at 1min. Material: Plastic. Dimensions: length 300 mm, diameter 26 mm.
Applications The STBD allows measurement of turbidity or the concentration of suspended particles, in coastal or estuarine environment. It can also be used for: Evaluation of sediment transport Evaluation of suspended biomass Pollutant tracking Tracking of river run-offs in deep ocean environment using profiling. Also available in 6000m range and with reduced measurement ranges (down to 2.5NTU).