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Technical Specification
The streamlined hull consists of two symmetric epoxy fiberglass/Kevlar shells with openings in front and stern providing a continuous flow-through of ambient water. A tapered concrete ram bow clears obstacles, absorbs shocks and compensates the upward pull of the tow line. Three PVC skids (a central of 2.8 m and two lateral of 0.8 m length) provide a steady course (typically ± 1°) and low pitch (± 2°) and roll (± 1°) angles. A stable dive, soft landing is achieved by adjusting winch slack to ship speed. A stable ground contact (zero pitch) can be maintained at tow speeds of 2-4 knots. The tow cable length is dynamically adjusted to about 3.5 times water depth. In the case of a collision with large obstacles, a break point at the bow releases the tow cable. Subsequently, the sled can be recovered by a trailed Kevlar safety line with head buoy.
NERIDIS II
| Total dimensions | Length: 3.2 m, width: 1.2 m, height: 0.6 m (without fin) |
| Total weight | 420 kg (in air), 120 kg (in water) |
| Transmitter moment | 61 Am² peak (48 V / 21 A) |
| Power | 24VDC (deep sea battery with 40 Ah) |
| Tow speed | 2 - 4 knots |
| Tow cable length | 3.5 times water depth (20° tow angle) |
| Sampling rate | EM (25 Hz), CTD (1 Hz), motion (5Hz) |
| Mission duration | 8 h (61 Am²), 12 h (43 Am²) |
NERIDIS III
| Total dimensions | Length: 5.2 m, width: 1.2 m, height: 0.8 m |
| Total weight | 710 kg (in air), ~250 kg (in water) |
| Power | Two 24V/12V LithiumIon Packs (40Ah) |
| Mission duration | 10 - 14 h |
| Sensors (realized) | - Frequency Domain EM (concentric-coaxial) - Conductivity-Temperature-Depth (Turbidity) probe (seawater) - Motion control (heading, roll, pitch, 3D acceleration) |
| Sensors (in prep.) | - Network camera - Shear resistance - Upward looking profiling ADCP - Sediment sampling |
| Modular concept | Sensor configuration is based on 3-8 specific modules (each module provides a loading space of 0.7x1.2x0.5 m - length x width x height) |
