SUBSTANTIVE MODEL OF SHIP TURN WITH ACCOUNT OF THE LATEST ACHIEVEMENTS IN THEORY AND PRACTICE
https://doi.org/10.33815/2313-4763.2024.2.29.152-163
Abstract
Today, in the scientific and technical literature on the pivot point, the 2-point scheme of ship turn “Center of Gravity – Pivot Point” is used. According to this scheme, the position of the Pivot Point is calculated from the Center of Gravity, which is not entirely correct, since in fact the ship rotates not around the Center of Gravity, but around the Center of Rotation. The Center of Rotation, in turn, can shift relative to the Center of Gravity, in the presence of longitudinal motion. Failure to take these things into account leads to errors in calculating the position of the Pivot Point and the trajectory of the ship's movement around the Pivot Point. For a long time, the concepts of the Center of Rotation and the Pivot Point were confused. Some researchers believed that the Pivot Point shifts in the direction of the ship's movement, others believed that the Pivot Point is located on the opposite side of the midship, relative to the point of application of the lateral force. The 2-point rotation scheme could not combine these two views. In previous works, the authors of this article proposed to use a 3-point rotation scheme, where the third point is the Center of Rotation. The use of a 3-point turn scheme made it possible to explain the dependence of the position of the Pivot Point on both the longitudinal speed and the point of application of the lateral force. The article develops a new substantive model of the ship's turn and a "Memo for the Ship Handlers". The new substantive model and "Memo..." will reduce control errors and increase maneuvering safety, which is especially important in compressed waters. The results obtained are explained by the fact that, unlike known approaches: the new substantive model is built on the basis of a 3-point turn scheme, which takes into account an additional point - the Center of Rotation; the position of Pivot Point is determined relative to the Center of Rotation, and not relative to the Center of Gravity; the position of the Pivot Point is determined on the plane, through the abscissa and ordinate of the Pivot Point.
References
2. Hooyer, H. H. (1991). Behavior and Handling of Ships, Cornell Maritime Press.
3. Domin, S. I. et al. (1991). Keruvannia sudnom, M.: Transport, 359 с.
4. Port Revel Shiphandling. Course manual 2006.pdf https://pdfcoffee.com/ qdownload/manual-2006-ship-handling-pdf-free.html.
5. Chase, G. A. (1999). Sailing Vessel Handling and Seamanship – The Moving Pivot Point, The Northern Mariner/Le Marin Du Nord, Vol. 9. Issue 3, 53–59. https://doi.org/10.25071/ 2561-5467.629.
6. Tzeng, C. Y. (1998). Analysis of The Pivot Point for a Turning Ship, Journal of Marine Science and Technology, Vol. 6, Issue 1, 34–44. https://doi.org/10.51400/2709-6998.2518.
7. Cauvier, H. (2008), The Pivot Point, The PILOT. The official organ of the United Kingdom Maritime Pilots’ Association, Vol. 295. http://www.pilotmag.co.uk/wp-content/uploads/2008/06/pilotmag-295-final-web.pdf.
8. Artyszuk, J. (2010), Pivot point in ship manoeuvring, Scientific Journals Maritime University of Szczecin, Vol. 20, Issue 92, 13–24.
9. Butusina, P. (2011). The Pivot Point Revisited, United Kingdom Maritime Pilots’ Association “The Pilot”, Autumn 2011, № 306. https://ukmpa.org/wp-content/ uploads/2016/06/Pilot-306-web.pdf.
10. Seo, S. G. (2011). The Use of Pivot Point in Ship Handling for Safer and More Accurate Ship Manoeuvring, Proceedings of IMLA, Vol. 1, Issue 29, 271–280. https://www.academia.edu/36456506/The_Use_of_Pivot_Point_in_Ship_Handling_for_Safer_and_More_Accurate_Ship_Manoeuvring.
11. Seo, S. G., Earl, K. (2015). A Paradigm Shift in Shiphandling (The Pivot Point), Warsash Maritime Academy, Southampton Solent University.
12. Seo, S. G. (2016). Safer and More Efficient Ship Handling with the Pivot Point Concept, The International Journal on Marine Navigation and Safety of Sea Transportation, Vol. 10, Issue 4, 605-612. https://doi.org/12.12716/1001.10.04.09.
13. Cummins, T. (2020), Scientific Fact: The ‘traditional’ understanding of the ship’s pivot point is wrong! A review of the ship’s pivot point: Science, Maths and Observation, Harbour Pilot, Portsmouth International Port. https://www.marine-pilots.com/articles/81904-scientific-fact-traditional-understanding-of-ships-pivot-point-is-wrong.
14. Cummins, T. (2020). Where is the centre of a ship’s rotation?, A review of the ship’s pivot point: Science, Maths and Observation, Harbour Pilot, Portsmouth International Port. https://www.marine-pilots.com/articles/84506-review-of-ships-pivot-point-science-maths-and-observation-where-is-centre-of-ships-rotation.
15. Fossen, T. I. (2021). Handbook of marine craft hydrodynamics and motion control: second edition, Norwegian university of science and technology, Wiley.
16. Tovstokoryi, O. M., Zinchenko, S. M., Nahrybelnyi, Ya. A., Tymofeiev, K. V. (2023), Rozrakhunok velychyny zmishchennia tsentru obertannia sudna, Naukovyi visnyk KhSMA, № 26–27, 44–55. https://doi.org/10.33815/2313-4763.2023.1–2.26–27.044–055.
17. Zinchenko, S., Kobets, V., Tovstokoryi O., Kyrychenko, K., Nosov, P., Popovych, I. (2023). Control of the Pivot Point Position of a Conventional Single-Screw Vessel, CEUR-WS.org, Vol. 3513, p.130–140, ICST-2023. https://ceur-ws.org/Vol-3513/paper11.pdf.
18. Zinchenko, S., Tovstokoryi, O., Sapronov, O., Petrovskyi, A., Ivanov, A., Tymofeiev, K. (2022). Development of automatic control methods of vessel rotation around the pivot point without drift, Technology Audit and Production Reserves, Vol. 6(2(68), 16–21. https://doi.org/10.15587/2706-5448.2022.269364.
19. Zinchenko, S., Tovstokoryi, O. (2020). What is the Pivot Point and how to use it to control the vessel, Materials of the XII International Scientific and Practical Conference "Advanced Information and Innovative Technologies for Transport (MINTТ – 2020), May 27–29, 2020, Kherson.
20. Dr. Knud Benedict. (2020). Pivot Point Demo. Hochschule Wismar, Institute ISSIMS, Department of Marine Studies. https://www.youtube.com/watch?v=zc9C5EWlFOE.
21. Dr. Knud Benedict. (2020). Pivot Point Position at Stopped ship: only thusters, no propulsion, Hochschule Wismar, Institute ISSIMS, Department of Marine Studies. https://www.youtube.com/watch?v=EYTF9lNUEt8.
22. Dr. Knud Benedict. (2020). Pivot Point position for ship moving ahead or astern, Hochschule Wismar, Institute ISSIMS, Department of Marine Studies. https://www.youtube.com/watch?v=v1I8c6aaFgo&t=16s.
23. Dr. Knud Benedict. (2020). Pivot Point on specific aspects, Hochschule Wismar, Institute ISSIMS, Department of Marine Studies. https://www.youtube.com/ watch?v=Dqf5sr_nNxM&t=9s.
24. Gripoli, M. (2022). Ships & Tugs: Pivot Point. https://www.standbyengine.it/ lessons/ships-tugs-pivot-point.
25. Brittain, S. (2023). Skillful captain docking a big ship in a narrow place: Pivot point, rudder force, transvese effect. https://www.youtube.com/watch?v=jP5mdg5pm7s.
26. Ghosh, S. (2024). What Is The Pivot Point of a Vessel?, Marine Navigation. https://www.marineinsight.com/marine-navigation/pivot-point-of-a-vessel/#google_vignette.
