• Journal of Korea Port Economic Association
• /
• v.28 no.1
• /
• pp.83-104
• /
• 2012

The main purpose of tramp ships in shipping markets is to produce operation profits by minimizing the running days in a contract of the voyage charterparty. It is an especially difficult task for the owners to earn operation profits in the present recessional shipping market. Tramp ships are moving towards globalization in order to look for a variety of cargoes, which are distinguished from the liners operating regularly as per the fixed time schedule. Tramp shipping, therefore, requires special attention every voyage to secure operation efficiency which comes from minimized sea and laytime in port. The laytime is allowed by owners but if the charterers use more laytime than that which is incorporated in the charterparty, then a compensation known as 'demurrage' must be paid to owners. Conversely if the time is shorter this is called 'despatch' and in this case the owners are paid. As the laytime issue in the voyage charter is somewhat delicate, it often causes much disputes between charterers and owners during the cargo handling in ports. This study focuses on the charterers' right and duty on the laytime which is usually applied for the benefit of the charterers. Reference is also made to English law cases to reinforce this study and the conclusion will make relevant suggestions for further research.

• Journal of Korea Society of Industrial Information Systems
• /
• v.27 no.6
• /
• pp.105-114
• /
• 2022

We examine berth allocation problems in tidal bulk ports with an objective of minimizing the demurrage and dispatch associated berthing cost. In the proposed optimization model inventory (or stock) level constraints are considered so as to satisfy the service level requirements in bulk terminals. It is shown that the mathematical programming formulation of this research provides improved schedule resolution and solution accuracy. We also show that the conventional big-M method of standard resource allocation models can be exempted in tidal bulk ports, and thus the computational efficiency can be significantly improved.