Session: 15-07-01 Ship Manoeuvring, Resistance and Propulsion

Submission Number: 183844

Study on Stability of Ship Manoeuvrability at Slow Speed Under Harsh Ocean Environment 

ABSTRACT
This study considers the maneuvering performance of a very large tanker at slow speed under adverse weather conditions. The primary concern of this study is to find any appropriate criteria to evaluate the stability of ship manoeuvrability in harsh ocean environment. The minimum power requirement is a big issue in ship safety in harsh environment, and the operational and environmental settings are specified by the International Maritime Organization(IMO) to ensure the minimum ship speed. In the IMO guideline, 2-knot ship should be kept in such condition. However, this speed may be too slow to get a enough rudder control force. This study started from the curiosity if such slow speed can be adequate in ensure the ship manoeuvrability.
In this study, numerical simulations, based on seakeeping-maneuvering coupling analysis, are adopted to evaluate the maneuverability of the target ship. The method of solution is a three-dimensional Rankine panel method combined with the Maneuvering Modeling Group (MMG) model. To account for low-speed operation under environmental conditions, a ship speed PID control is applied to determine the appropriate propeller RPS during the simulation. The maneuvering performance is analyzed from various perspectives under irregular waves, focusing on the yaw-checking ability and course-keeping ability. The maneuvering indices were applied and suggested to compare the influence of ship operational speed, wave peak period, and environmental heading. Based on this study, the stability of ship manoeuvring is observed and an appropriate criteria to predict the stability is suggested.
Keywords: ship manoeuvrability, manoeuvring in waves, manoeuvring stability, minimum power requirement,
REFERENCES
[1] International Maritime Organization (IMO). Amendments to the Annex of the Protocol of 1997 to Amend the International Convention for the Prevention of Pollution from Ships, 1973, as Modified by the Protocol of 1978 Relating Thereto; MEPC.203(62); IMO: London, UK, 2011.
[2] International Maritime Organization (IMO). Guidelines for Determining Minimum Propulsion Power to Maintain the Manoeuvrability of Ships in Adverse Conditions; MEPC.1/Circ.850/Rev.3; IMO: London, UK, 2021.
[3] Lee, J.H.; Kim, Y. Study on ship operation performance in actual seaways using time-domain free-running simulation. Proc. Inst. Mech. Eng. Part M J. Eng. Marit. Environ. 2021, 235(4), 885-904.
[4] Seo, M.G.; Kim, Y. Numerical analysis on ship manoeuvring coupled with ship motion in waves. Ocean Eng. 2011, 38(17-18), 1934-1945.

Presenting Author: Heesuk Yang Seoul National University

Presenting Author Biography: Mr.Heesuk Yang is a PhD student at the Department of Naval Architecture & Ocean Engineering, Seoul National University. He research interests are ship hydrodynamics, particularly ship manoeuvring in waves and seakeeping analysis. He has several publications as co-author in international journals and conferences about the coupled seakeeping-manoeuvring in waves, analysis of ship manoeuvrability, and the digital twin for ship operation.

Authors:

Yonghwan Kim Seoul National University
Heesuk Yang Seoul National University