## 4 Discussion and Conclusions
During ascent, loosening and looping of the wire (when it is unwound from the drum) may occur owing to the surface waves, thereby posing a problem for underwater winches. Therefore, before ascent, the profiler obtains data on surface waves to avoid operation in stormy weather conditions. If the wire tension weakens, then overlapping of its turns on the winch drum may occur. Hence, it is of utmost importance to control the wire tension and reverse the direction of the winch drum rotation to generate the required tension for the wire. Another problem is that strong currents can sink the device. To reduce this effect, the winch was programmed to spool more wiring to allow the profiler to rise to the sea surface. When the profiler surfaced, it transmitted the observational data to a server on the land. This makes the profiler useful for operational oceanography applications, particularly for providing the observational data for assimilation in mathematical models for diagnosis and forecasting. Data transfer to and from the profiler Winchi has been designed with regard to the mobile phone link. In the future, satellite communication options will be included. The effort to build the carbon observational site in the Gelendzhik area is in accordance with two projects: Advancing Black Sea Research and Innovation to Co-Develop Blue Growth within Resilient Ecosystems (BRIDGE-BS) ([[https://cordis.europa.eu/project/id/101000240](https://cordis.europa.eu/project/id/101000240)]([https://cordis.europa.eu/project/id/101000240](https://cordis.europa.eu/project/id/101000240)), last accessed: 12 December 2021) and Developing Optimal and Open Research Support for the Black Sea (DOORS) ([[https://cordis.europa.eu/project/id/101000518](https://cordis.europa.eu/project/id/101000518)]([https://cordis.europa.eu/project/id/101000518](https://cordis.europa.eu/project/id/101000518)), last accessed: 12 December 2021), both for 2021-2025 under the umbrella of the EU Horizon 2020 program. In particular, the BRIDGE-BS project targets the development of capabilities necessary to understand and predict the impact of climate-driven and anthropogenic multi-stressors on services stemming from Black Sea ecosystems. The key ecosystem services at the Northeastern Black Sea pilot site, which shares the same infrastructure as the carbon observational site in the Gelendzhik area, will include carbon sequestration in the sea. In a broad oceanographic context, by developing the new observational profiling platform--Winchi, we are taking a step forward to create and apply innovative technologies that can help in long-term multidisciplinary oceanographic observations at fixed locations in the sea coastal zone. **Author Contributions:** Conceptualization, A.G.O. and A.V.O. ; methodology, D.A.S. and S.V.V. ; software, O.Y.K. ; validation, N.M.K. and V.M.O. ; formal analysis, A.G.O. ; investigation, O.Y.K. and D.A.S. ; resources, A.G.Z. ; data curation, O.Y.K. ; writing--original draft preparation, A.G.O. ; writing--review and editing, M.V.E. ; visualization, A.G.O. and O.Y.K. ; supervision, A.G.O. ; project administration, A.G.Z. ; and funding acquisition, V.V.K. All authors have read and agreed to the published version of the manuscript. **Funding:** The research and development of the new tethered profiler Winchi was carried out within the framework of the assignment of the Ministry of Science and Higher Education of Russia No 0128-2021-0018 and supported in part by the Russian Fund for Basic Research via grant No 19-05-00459. **Acknowledgments:** The collaboration with colleagues from the southern branch of SIO RAS is appreciated. We sincerely thank the two anonymous reviewers for their careful reading of our manuscript and their many insightful comments and suggestions. **Conflicts of Interest:** The authors declare no conflict of interest.