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Simulation study on the Influence of EEDI requirements to shiphandling in heavy weather

Nishizaki C., Okazaki T., Yabuki H., Yoshimura Y.

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

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2019

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Vol. 13. no. 4

855--860

EN

In order to reduce the CO2 emission from ships, International Maritime Organization executes the restriction of Energy Efficiency Design Index (EEDI) which limits amount of CO2 when freight of one ton is carried at one mile. Although the realization of higher efficiency of main engine without reduction of engine output is the best solution, it might be impossible. To comply with the EEDI requirements, it is assumed that the ship’s engine power becomes smaller than the existing ship by means of improving the ship propulsive efficiency. However, shiphandling in rough seas is expected to become difficult when the engine power is reduced. In this paper it is shown that the influence of the degraded main engine exerts on the safety of shiphandling in heavy weather based on the simulation study. In these experiments, both the simulation model that decreased engine power corresponding to EEDI requirement and that with the conventional engine power were tested, and masters in active service maneuvered the test ships in the rough seas.

2

Emergency Unberthing without Tug Assistance

Kunieda Y., Yabuki H., Okazaki T.

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

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2015

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Vol. 9, no. 3

367--374

EN

Shipmasters may have to perform unberthing without tugboat assistance when a tsunami warning is issued. Keeping this in mind, we studied emergency unberthing without tug assistance by conducting numerical simulations and full-mission ship maneuvering simulator (SMS) experiments. A panamax class medium-sized bulker and a pure car carrier (PCC) were used as test ships. In the experiments, we established the limitations of basic shiphandling techniques such as stern kick out, backing, and accelerating turn in windy conditions using a mathematical modeling group (MMG)-type mathematical maneuvering model. On the basis of the results, we produced a shiphandling scenario and evaluated it using SMS experiments. We concluded that unberthing without tug assistance in 5 m/s onshore winds is possible. Furthermore, the use of thrusters can greatly reduce the time required for unberthing.

3

On the Development of an Anchor Watch Supporting System for Small Merchant Ships

Yabuki H., Takemoto T., Yamashita K., Saitoh S.

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

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2012

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Vol. 6, no. 3

331--335

EN

This paper describes the results of a study that aimed at developing an effective anchor watch supporting system to prevent dragging anchor accidents of small domestic merchant ships. The authors performed an experimental study using a training ship in order to investigate the characteristics of the hull movement of a ship lying at single anchor, the cable tension caused by the above movement and etc. Based on the results of the study, the authors propose a standard procedure for safe anchor watch and a new anchor watch supporting system using a PC, a DGPS and an anemometer.

4

On the Control of CPP Ships by Steering During In-Harbour Ship-Handling

Yabuki H., Yoshimura Y.

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

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2010

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Vol. 4, no. 2

157--162

EN

This paper describes the results of experimental and simulation studies that aimed at developing effective control methods for single-CPP single-rudder ships during the coasting manoeuvre and the stopping manoeuvre. In order to improve the manoeuvrability of CPP ships under coasting, the authors performed full-scale experiments and confirmed that CPP ships under coasting using the Minimum Ahead Pitch (MHP) of CPP are controllable by steering. A simulation study was also conducted to evaluate the ship-handling method during the stopping manoeuvre that applies a turning moment to the ship by the maximum rudder angle steering prior to the reversing operation of the CPP and it is confirmed that CPP ships can be controlled sufficiently by the proposed method.