## 2 Development of the Profiler
### Design
The housings are made of polyacetal POM-C. The suspension bar is made of ultra-high molecular weight polyethylene. Photo from 2019. The Winchi profiler includes a wet compartment and pressure-proof housing (Figure 5). In the wet compartment, stationary oscillating spool and line rollers rotate around the spool. A line roller is mounted on the rotor, which, in turn, is mounted on the shaft of the motor drive. The line roller revolves around the stationary spool, which reciprocates back and forth, winding a line on the spool. The reciprocation is controlled by a mechanism that works with the rotation of the motor shaft. On the winch spool, a wire of 60 m in length and a diameter of 2.5-3 mm can be placed. The Dyneema(r) core of the wire has a working stretch of \(<\)1%, while the UV stable core cover protects against abrasions and generates the lowest friction in the rollers. The pressure-proof housing includes a 24-V DC geared motor (Figure 6), a rechargeable battery pack 930 W h assembled with Nickel Manganese Cobalt cells (Figure 7), and a microprocessor control unit (MCU). The motor driver is configured to power up to 300 W. The profiler hardware is based on a 32-bit ARM microcontroller. The profiler enters sleep mode between profiling cycles to conserve energy. For accurate time synchronization in sleep mode, the MCU uses a \(\pm\)5 ppm clock generator with a consumption of up to 1 uA. Figure 5: Layout of the tethered profiler Winchi: (1)—wet compartment for the winch spool (2) and line rollers mounted at the rotor (3), (4)—pressure-proof housing to accommodate the motor drive (5), microprocessor control unit (6) and battery (7), (8)—environmental sensor suite (see Section 2.2 below), (9)—connector, (10)—GPS/GSM module (see Section 2.3 below), (11)—clamps, (12)—outrigger, (13)—suspension bar, (14)—bypass rollers, (15)—wire, and (16)—wire tension sensor. Figure 6: The winch mounted on the DC geared motor with a motor speed controller. External devices can be connected via four serial ports of UART equipped with converters to the standard RS232, allowing data exchange at 90 kbps (maximum). A 24-bit ADC is used at each of the four analog channels to digitize signals of 0-5 V at 100 Hz (maximum). Two I2C buses with power amplifiers are used to connect low-power digital sensors. The telemetry and measurement data are stored in the SD card supporting the SD input/output (SDIO) specifications. At a short distance, the exchange of the command and data is carried out via Bluetooth. The environmental sensor suite is mounted on the profiler side, opposite to the wet compartment. Connectors are installed at the housing end cap. One connector can be used for an additional sensor. The other one is allocated to connect to the communication module. The embedded software is an RTOS-based modular framework. Its functionality can be expanded by adding a custom code to accommodate specific functions of the profiler. The diagnostic and programming software is implemented as a cross-platform desktop GUI application, which can be expanded to match additional features. The overall design of the profiler is compact. One technician of an inflatable boat can deploy and recover the profiler owing to its light weight (~30 kg) and small dimensions (length of 1620 mm and diameter of 170 mm).