• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.9
• /
• pp.51-56
• /
• 2016

Corrugated bulkheads have many advantages compared to stiffened bulkheads, and they have thus been used for the cargo tank bulkheads of commercial vessels, such as bulk carriers, product oil carriers, and chemical tankers. Various studies have been carried out to find the optimum corrugation shape for bulk carriers, but optimum design studies for chemical tankers with bulkheads made of high-priced materials are scarce. The purpose of this study is to develop a minimum weight design method for horizontal corrugated bulkheads for a chemical tanker. An evolution strategy (ES) that searches for a reliable global optimum point was applied as an optimization technique, and the structural safety of the optimum design was verified through structural analysis using the finite element method (FEM). The results were compared with those of an existing ship, which showed a weight reduction of about 14% with equivalent structural strength.

• Journal of Ocean Engineering and Technology
• /
• v.24 no.2
• /
• pp.41-46
• /
• 2010

This paper deals with the problem of developing a new decision procedure for the freeboard of a coastal chemical tanker going on the coast. The decision procedure is mainly constructed with the algorithm of estimating statistically the time period that deck wetness will last on the deck of the ship. Deck wetness is one of the most important safety factors for sailing of a coaster. It generally means the situation in which the amplitude of the relative motion between the deck and the surface of the wave exceeds the freeboard. Therefore, in this paper, we proposed that the time during which the amplitude remains above the level of the freeboard should be appraised on the basis of statistical theory. A series of numerical calculations were executed for four different coastal chemical tankers (199G/T Type II, III & 499G/T Type II, III). It was demonstrated that the present decision procedure of freeboard is practical for planning the type of coaster sailing in the sea.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.17 no.2
• /
• pp.143-148
• /
• 2011

Daesan Harbor is developing under the Industrial Complex or Petrochemistry Development Plan making the port the main hub-port in the West coast. Because of this development. the traffic volume is expected to increase to 9,1.95 incoming vessels by 2020, an increase of 167% compared to 2008 figure. This study thoroughly analyzes and evaluates a systematic and comprehensive use of the fairway in the Daesan Harbor. It establishes a future oriented and safe marine transportation environment upon appropriate examination of the total fairways and sailing assistance facilities.

• Journal of Advanced Marine Engineering and Technology
• /
• v.40 no.4
• /
• pp.301-306
• /
• 2016

During the initial stage of propulsion shaft design, the shaft alignment process includes a thorough consideration of lateral vibration to verify the operational safety of the shaft. However, a theoretical method for analyzing forced lateral vibrations has not been clearly established. The methods currently used in classification societies and international standards can only ensure a sufficient margin to avoid the blade-passing frequency resonance speed outside the range of ${\pm}20%$ of the maximum continuous rating (MCR) for the engine. Typically, in shaft alignment analyses, longer center distances between the support bearings promote affirmative results, but the blade order resonance speed can approach the lower limit for lateral vibration. Therefore, this matter requires careful attention by engineers, and a verification of the theoretical analysis by experimental measurements is highly desirable. In this study, both theoretical and experimental analyses were conducted using strain gauges under two draught conditions of vessels used as 50,000-DWT oil/chemical tankers, introduced recently as eco-friendly ships. Based on the analyses, the influence of the lateral vibration on the shafting system and the system's reliability was reviewed.

• Journal of Advanced Marine Engineering and Technology
• /
• v.40 no.3
• /
• pp.191-197
• /
• 2016

The shaft system of a vessel becomes stiffer because of larger engine power, whereas the hull structure becomes more flexible because of scantling optimization conducted by using high-tensile thick steel plates. The draught-dependent deformation of the hull affects each bearing offset and reaction force comprising the subsequent shaft system. This is the reason that more sophisticated shaft alignments are required. In this study, an FE analysis performed under the expected operating conditions of two (2) vessels, as maximum draught change and to analyze the shaft alignment using the relative bearing offset change, which was derived from an FE analysis of the 50,000 DWT oil/chemical tanker, which has become an eco-friendly vessel in recent years. Based on this, the influence of the hull deflection on the bearing offset was reviewed against results for shaft alignment conditions.

• Journal of Advanced Marine Engineering and Technology
• /
• v.40 no.4
• /
• pp.288-294
• /
• 2016

In modern ships, the shafting system often becomes stiff owing to the high engine power, whereas the hull structure becomes more flexible owing to optimization using high-tensile-strength thick steel plates; therefore, more sophisticated shaft alignments are required. In this study, strain gauge-based measurement was conducted under five vessel operating conditions and bearing reaction forces and hull deflections affecting shaft alignment were analyzed for a 50,000 dead weight tonnage oil/chemical tanker that has gained repute as an eco-friendly vessel in recent years. Furthermore, the analytical results from each technique-theoretical calculation, jacking ups, and strain gauges-were cross-checked against each other in order to enhance the degree of accuracy and reliability of the calculation.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.27 no.1
• /
• pp.97-112
• /
• 2021

This study introduces lessons learned from investigation and analysis of major domestic and overseas cases of marine chemical incidents involving hazardous and noxious substances (HNS) during maritime transportation by chemical tankers carrying petrochemical products in bulk. The study then suggests plans to improve domestic marine HNS training curricula based on these lessons. Lessons learned from six incident cases are classified into the following six categories: 1) incident-related information, 2) safety, 3) pollution, 4) response, 5) salvage and 6) others. Based on these six categories, it is suggested that the curriculum provided by the Marine Environment Research & Training Institute for marine pollution prevention managers aboard noxious liquid substance carriers should be changed from the existing two-day training of eight subjects (16 h) to a three-day training of sixteen subjects (24 h). In addition, it is proposed that the marine chemical incident response course of the Korea Coast Guard Academy should be changed from the existing five-day training of fifteen subjects (35 h) to a six-day training of thirty-two subjects (48 h). These results are expected to contribute to sharing experiences and lessons learned about response to marine chemical incidents and to be used as basic data for improving the education and training courses for response personnel in preparedness for marine HNS incidents.

• Special Issue of the Society of Naval Architects of Korea
• /
• 2013.12a
• /
• pp.1-7
• /
• 2013

In past decades, a maximum standard vessel size for chemical tankers is not normally larger than 55,000 TDW due to the characteristic of chemical product shipment which is so variable but small quantity unlike single product carries such as crude oil tankers. These days, as demand of very large chemical tanker is rising due to the change of market trend of chemical product shipment, 75,000 TDW class chemical tanker has been developed. The newly developed vessel's structure has been designed based on CSR (Common Structural Rule) for double hull oil tankers (hereafter CSR) published by IACS (International Association of Classification Societies). However, due to the large difference from typical oil tankers, many items should be specially considered such as on deck transverse and corrugated bulkheads. In addition, two longitudinal bulkheads without upper stool have been constructed in order to maximise the number of cargo tanks and the volume of each cargo tanks. In this study, key word of the vessel has been briefly reviewed and the structural reliability of the proposed vessel has been investigated.

• Journal of the Society of Naval Architects of Korea
• /
• v.58 no.2
• /
• pp.97-104
• /
• 2021

Together with the emerging of the Eco-ship, the application of large-diameter and high-efficiency propeller required more careful attention than before in the design of the shafting system. After the adoption of Environmentally Acceptable Lubricants (EAL) to the stern tube lubrication oil, a number of aft stern tube bearing accidents have been reported, and a variety of institutions have actively conducted research on the cause relationship. This study attempted to find the cause of the accident by measuring the alignment of the shafting system of a medium-sized product/chemical tanker with aft stern tube bearing damage and analyzing the reaction force of each bearing. In addition, a reasonable solution to the correction of the shaft alignment was suggested and the feasibility was reviewed. Through various measured data and analysis, the actual installation of shafting system was slightly different from the design drawing condition, but it was found that each bearing load distribution was within the allowable range. Therefore, it was confirmed that the cause of this accident was due to the dissatisfaction the misalignment slope of aft stern tube bearing rather than the effect of the bearing overload. As a solution to this cause, countermeasures such as double slope were suggested in the aft stern tube bearing, and the characteristics of EAL also seem to have an indirect effect.