Proceedings of the Thirty-second (2022) International Ocean and Polar Engineering Conference
Shanghai, China, June 5–10, 2022
Copyright © 2022 by the International Society of Offshore and Polar Engineers (ISOPE)
ISBN 978-1-880653-81-4; ISSN 1098-6189

www.isope.org

Experimental and Numerical Study of Towing Characteristics of Damaged Ship
Min-Guk Seo, Namwoo Kim, Yong-Guk Lee, Sa Young Hong1, Hyuek-Jin Choi
Korea Research Institute of Ships & Ocean Engineering (KRISO), Korea

and examined the change in towing performance according to the widthof the barge, the presence or absence of skegs, and the length of thetowing line. Nam et al. (2014) conducted a model test to evaluate thetowing stability of a transportation barge and investigated the effect ofskeg, length of towing line and towing speed on towing stability.
In the case of the numerical analysis method, once the equation of motion
for the towed ship is established, the towing performance can beevaluated for various towing conditions and environmental conditions.
However, the simulation result is significantly affected by thehydrodynamic coefficient. So the use of accurately derived coefficients
either by model test or CFD is very important in case of numericalsimulations. Yasukawa et al. (2006) performed a towing simulations andcompared them with the model test results for a barge. The MMG(Manoeuvring Mathematical Modeling Group) model was applied to theequations of motion of the barge, and the lumped mass method was used
for the towing line. Nam et al. (2013) applied the MMG model and thecross-flow model proposed by Wichers (1988) to the equations of motionof the towed ship. Effects of the towing line length and the hydrodynamic
coefficients on towing performance were investigated. Seo et al. (2021)
evaluated the towing characteristic of a towed ship using the MMG
model and cross-flow model. The change in towing performance undervarious conditions (towing speed, type and length of towing line, number
and arrangement of tug boats and pushers) was investigated. Furthermore,
the towing performance of the damaged ship was evaluated.
In this study, model tests and numerical analyses were conducted toestimate the towing characteristics of a damaged ship. The model test
was performed in the DOEB. Three towing scenarios were applied, andtowing performance was evaluated according to ship states, towing
conditions, and environmental conditions. KIMAPS was employed fornumerical analysis. The MMG model, including rudder force, wasapplied, and the linear tether model was adapted to the towline. The
numerical results were compared with the model test results to validate
the numerical method.

ABSTRACTThe number of marine accidents in Korea is steadily increasing, and thenumber of accidents involving oil tankers that can cause severe marine
pollution is also growing accordingly. Therefore, a scientific-baseddecision making support system in the initial emergency response of anaccident is needed. Emergency towing simulation technology is one of
the essential technologies for this support system.
In this study, a series of model tests and numerical analyses have been
performed to examine the towing characteristics of a damaged ship. The
model test was conducted in the Deep Ocean Engineering Basin (DOEB).
By doing the model test, various towing scenarios, ship states, andtowing conditions were investigated. KIMAPS (KRISO Integrated
Multi-body And Positioning Simulation system), an in-house programdeveloped by the KRISO, was used for the numerical analysis. In thisprogram, the MMG model was adopted to simulate the behavior of thetowed ship. And the rudder force is considered to check the rudder effectin the towing simulation. A linear tether model with only tensile force
was applied to the towline, and the tug boat was assumed to be a constantmoving point. The numerical results were compared with the model test
to validate the numerical analysis

KEY WORDS: Damaged ship; Emergency towing; Model test;
Numerical simulation
INTRODUCTION
The number of marine accidents in Korea is steadily increasing, and thenumber of oil tanker accidents that can cause severe marine pollution is
also continuously increasing. (e-Korea Indicator, 2020). Therefore, ascientific-based decision making support system in the initial emergency
response of an accident is required. Emergency towing simulation
technology is one of the essential technologies for this support system.
Model tests and numerical simulations are used to evaluate the towing
characteristics of ships. The model test can directly determine the towing
performance under a specific condition, while the effect of scale ratio
should be considered in the model test. Latorre (1998) mentioned thatthe resistance of the model ship was overestimated and the towing
stability of the model ship was evaluated as more stable than the actualship. Yasukawa et al. (2006) conducted a towing model test for barges
1

MODEL TESTThe model test was conducted at Deep Ocean Engineering Basin (DOEB)
of KRISO, and the following figure shows the interior view of the DOEB.
The purposes of the model test are as follows:

Corresponding author

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