Course Stability of a Ship Towing System

Fitriadhy, Ahmad; Yasukawa, Hironori

doi:10.1179/str.2011.58.1.001

Cited by 25 publications

(13 citation statements)

References 2 publications

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“…Similar to what was reported by Fitriadhy et al [6], the increment of towline length had relatively smaller influence on the entire amplitude motion performance of the barge. Although the increase of towline lengths was insignificant in reducing the sway motions, the course stability of the 2B had improved as commented on in Fitriadhy and Yasukawa [4]. Correspondingly, the maximum tension force had decreased by 7.8% as ℓ′ was increased from 1.0 to 3.0.…”

Section: Mesh Independent Studymentioning

confidence: 83%

“…[3] proposed a numerical theory of barge dynamic stability in towing operations with and without the presence of skegs. Then, [4], [5]and [6] developed numerical simulations where the effects of the towline length and tow point locations to the course stability of a towed ship have been addressed. [7], [8] and [9] performed numerical analyses of towed ships' stability in steady winds.…”

Section: Introductionmentioning

confidence: 99%

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Computational fluid dynamics analysis on the course stability of a towed ship

Fitriadhy¹,

Aswad²,

Aldin³

et al. 2017

J. MECH. ENG. SCI.

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Due to the highly complex phenomenon of a ship towing system associated with the presence of a dynamic nonlinear towline tension, a reliable investigation allowing for an accurate prediction of the towed ship's course stability is obviously required. To achieve the objective, a Computational Fluid Dynamic simulation approach is proposed by investigating attainable and precise course stability outcomes, whilst a hydrodynamic description underlying the rationale behind the results is explained. Several towing parameters such as various towline lengths and tow point locations with respect to the centre of gravity of the barge have been taken into account. Here, tug and barge is employed in the simulation as the tow and towed ship, respectively. In addition, a towing velocity is constantly applied on the tug. The results revealed that the course stability of the towed ship increases in the form of more vigorous fishtailing motions as the towline length subsequently increases from 1.0 to 3.0. Meanwhile, the increase of tow point location from 0.5 to 1.0 leads to a significant improvement in the course stability of the towed ship, as indicated by the reduction of the sway and yaw motions by 227% and 328%, respectively. It is concluded that the increase of tow point location is a recommended decision to achieve a better towing course stability for the barge.

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Section: Mesh Independent Studymentioning

confidence: 83%

Section: Introductionmentioning

confidence: 99%

Computational fluid dynamics analysis on the course stability of a towed ship

Fitriadhy¹,

Aswad²,

Aldin³

et al. 2017

J. MECH. ENG. SCI.

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“…Fitriadhy and Yasukawa [8] and Fitriadhy et al [9] presented towing stability results, considering the wind effects and numerical simulation results based on the MMG model. Fitriadhy and Yasukawa [10] proposed a numerical model for the course stability of a towed ship, that is coupled to a tow ship through a towline. Nam et al [11] compared a cross-flow model [12] and the MMG model for the towing simulation of barges in calm water.…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigation on Nonlinear Dynamic Responses of a Towed Vessel in Calm Water

Nam

2020

JMSE

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In this study, we numerically investigated the nonlinear dynamic responses of an autonomous towing system where a vessel is passively towed by a tug via a towline. A three-degrees-of-freedom maneuvering mathematical model is utilized to describe the nonlinear dynamics of the towed vessel in calm sea. The hydrodynamic force acting on the towed vessel is modelled as a modular-type hull force model, which includes linear and nonlinear (third order) damping forces in sway and yawing directions. The towline force is simply modeled as a linear spring. First, the motion responses of a towing system, showing large sway-yaw coupled motions due to unstable towing characteristics, are studied by applying phase plane analysis. For the validation of the present numerical method, the simulation results are directly compared with the model test data. Then, simulation parameters, such as towing speed, initial positions and hull force coefficients, are changed and their resulting limit cycles are investigated. Finally, the effects of towline and tug motion are discussed based on the simulation results. It is found that the dynamic characteristics of the towed vessel come closer to being chaotic due to the nonlinear stiffness effect of the towline and tug motion effect.

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“…Several researchers have attempted various approaches to investigate the performance of the ship towing system in calm water. Inoue et al [1], Lee [2], Kijima et al [3], Fitriadhy et al [4] and Fitriadhy et al [5] analysed the towed barge by numerical approaches. Lee [2] studied the tension of the towline using different material of towline, polyester and nylon while the effect of the towline length, tow point location on barge and tug proposed by Fitriadhy et al [4].…”

Section: Introductionmentioning

confidence: 99%

“…Inoue et al [1], Lee [2], Kijima et al [3], Fitriadhy et al [4] and Fitriadhy et al [5] analysed the towed barge by numerical approaches. Lee [2] studied the tension of the towline using different material of towline, polyester and nylon while the effect of the towline length, tow point location on barge and tug proposed by Fitriadhy et al [4]. Experimental approach was conducted by Im et al [6] to investigate the effect of different towline configuration and employing active thruster to the barge.…”

Section: Introductionmentioning

confidence: 99%

Heave and Pitch Motion Performances of a Ship Towing System Incorporated with Symmetrical Bridle Towline Model

Fitriadhy

Aldin

Mansor

et al. 2019

EPI-IJE

Self Cite

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An investigation on vertical motion characteristics of a ship towing system incorporated with symmetrical bridle towline configuration set a real challenge for the naval architect engineer. This paper presents a Computational Fluid Dynamic (CFD) approach to analyse heave and pitch motion performances in waves. Several towing parameters such as various towline length and towing’s velocity have been taken into account. Here, 1B (barge) is employed in the simulation; and designated as a towed ship. The results revealed that the subsequent increase of the towline lengths has been basically proportional with the increase of her heave motion; while inversely decrease in pitch motions. In addition, the effect of the extending towline length = 1.0 to 3.0 resulted in insignificant effect to the towline tension. However, the increase of the towing’s velocity from 0.509 m/s to 0.728 m/s has led to significantly increase her heave motion and the towline tension by 40.46% and 24%, respectively; meanwhile, the pitch motion barge has sufficiently decreased by 35.94%. This simulation has been beneficial for the towing operator to ensure a higher level of the safety navigation of ship towing system.

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Course Stability of a Ship Towing System

Cited by 25 publications

References 2 publications

Computational fluid dynamics analysis on the course stability of a towed ship

Computational fluid dynamics analysis on the course stability of a towed ship

Numerical Investigation on Nonlinear Dynamic Responses of a Towed Vessel in Calm Water

Heave and Pitch Motion Performances of a Ship Towing System Incorporated with Symmetrical Bridle Towline Model

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