Container Carrier Research Articles

Model and Algorithm for Container Allocation Problem with Random Freight Demands in Synchromodal Transportation

This paper aims to investigate container allocation problem with random freight demands in synchromodal transportation network from container carriers’ perspective. Firstly, the problem is formulated as a stochastic integer programming model where the overall objective is to determine a container capacity allocation plan at operational level, so that the expected total transportation profit is maximized. Furthermore, by integrating simulated annealing with genetic algorithm, a problem-oriented hybrid algorithm with a novel gene encode method is designed to solve the optimization model. Some numerical experiments are carried out to demonstrate the effectiveness and efficiency of the proposed model and algorithm.

DESIGN AND OPERATIONAL ASPECTS OF DIESEL GENERATORS’ POWER AND NUMBER FOR SEAGOING SHIPS

New chapter 4, added to Annex VI of MARPOL convention, put into effect regulations on the ships ‘energy efficiency. It makes mandatory since 1 st January 2013 the so called Energy Efficiency Design Index (EEDI) for new ships and the Ship Energy Efficiency Management Plan (SEEMP) for new and existing vessels of 400 gt and above. There is a huge space to save the energy, improve the ships’ efficiency and reduce the GHG emissions for the sea going ships such as container carriers are. The aspects presented in the paper are based on the contemporary container vessels with the state of the art technology implemented to their design and operational stage. The estimation of the electric power and number of diesel generators with use of the statistical tools is the main aim of the paper. The container vessels fitted only with the diesel generators without any other type of electric generator unit are taken into account in the calculation process. The electric power equation has been determined, applying the multiple regression model with an absolute term, based on the ship’s parameters for the entire range of the container vessels’ load capacity TEU. It shown, the reefer containers RC and the main propulsion rating SMCR are the most important parameters statistically significant. It is calculated as well how the total ship’s electric power is very strictly dependent on the number of diesel generators installed on board. The reefer containers’ number and its assumed power considering the cargo type and the simultaneity coefficient are also presented in the article, as this impact the electric power demand. The different types of Power Management Systems for diesel generators load are discussed at the last stage of the paper.

Measuring hull girder deformations on a 9300 TEU containership

A 9300 TEU container carrier was equipped in 2006 with instrumentation aimed at wave induced accelerations, and motions. In 2010 the system was extended with strain sensors to include structural loads. Section loads for vertical bending could be readily obtained but the originally intended derivation of horizontal bending and torsion from the measured strains was found to be unreliable. This paper addresses an alternative approach that was adopted in the post processing of results. In particular the concept to use acceleration sensors to capture global hull deformations along the length of the hull, and the use of a data fusion procedure to obtain section loads from combined sensor data and finite element calculations. The approach is illustrated by comparison of actually measured accelerations and local strains with values obtained from the data fusion model. It is concluded that the approach is promising but in need of further validation and development. In particular the number and shapes of the modes used may not have been sufficient to represent the true deflection and thus strain distributions along the high loaded areas.

CFD 저항 해석을 이용한 컨테이너선 최적 트림 추정법에 대한 연구

The main objective of the present study is to elucidate a correlation between ship resistances from computational fluid dynamics (CFD) and brake horse powers (BHP) from towing tank in container carriers. The tests were conducted for a range of combinations of trim conditions and speeds. To achieve this goal, 295 cases of numerical simulation have been performed using Star-CCM+ which had been statistically verified to predict ship resistances (Lee & Lee, 2014). Based on the normal distribution of resistance errors in all cases of the 4 container carriers, the confidence interval of numerical error was estimated as [-2.33%,+2.42%] with 95% confidence. The correlation coefficients between the ship resistances of CFD and the brake horse powers of the experiments were higher than 0.93. As a result, the numerical calculation of ship resistances is able to be utilized in order to provide a quick guidance in selection of the optimum loading condition.

Structural Safety Assessment of a 1100 TEU Container Ship, Based on a Enhanced Long Term Fatigue Analysis

This paper is focused on an enhanced integrated method for structural safety assessment of maritime ships under extreme random wave loads. In this study is considered an 1100 TEU container test ship, with speed range 0 to 18 knots. The most comprehensive criteria for ships structural safety evaluation over the whole exploitation life is based on the long term ship structures analysis, that includes: stress hot-spots evaluation by 3D/1D-FEM hull models, computation of short term ship dynamic response induced by irregular waves, long term fatigue structure assessment. The analysis is enhanced by taking into account the ships speed influence on hydroelastic response. The study includes a comparative analysis on two scenarios for the correlation between the ships speed and waves intensity. The standard constant ship speed scenario and CENTEC scenario, with total speed loss at extreme waves condition, are considered. Instead of 20 years ship exploitation life estimated by classification societies rules from the long term structural safety criteria, the enhanced method has predicted more restrictive values of 14.4-15.7 years. The numerical analyses are based on own software and user subroutines. The study made possible to have a more realistic approach of ships structural strength assessment, for elastic and faster ships as container carriers, in compare to the standard one based only on naval rules, delivering a method with higher confidence in the designed structural safety.

Sea Trails of Large Container Ships

The container carrier shipping industry faces nowadays a similar phenomenon that happened in the 90s with crude oil carriers: an imaginable gigantism not-forecasted even by the most optimistic specialists. In the last 20 years the demand in transportation by containers continuously grew. The reaction of Carriers was quick under this demand growth and began an exacerbate competition not only in size of their fleets but in the size of their vessels as well. Before building a new vessel, a set of simulations and tests of prototypes and models is done, in order to apply corrections of the initial projects but, the practice showed that each vessel is different and its behavior at sea, too. In order to be acquainted to dealing with the various situations at sea, the true measurements of the vessels performance are done in her sea trials. The purpose of this paper is to update this Sea trials process, to detail it and to bring the contemporary element: measurement technologies, calculations, mathematical models.

An integrated container management model for optimizing slot allocation plan and empty container repositioning

This article proposes an integrated container management model to jointly optimize slot allocation plan for loaded containers and reposition for empty containers in a shipping network. The proposed model employs linear programming to formulate loaded and empty container shipping problems in a bi-level structure. In upper level the loaded container slot allocation plan aims to maximize operational profits for each service route; whereas in lower level the reposition of empty containers aims to minimize transportation costs for the entire shipping network. The surplus or deficient empty containers resulted from the upper problem are fed into the lower problem. To demonstrate the applicability of the proposed model, a real case of an intra-Asian short-sea container carrier is presented. The results show that the proposed model can serve as a decision support tool to facilitate the liner to ship the loaded and empty containers in a coordinative way.

선체 저항에 대한 수치 해석의 통계적 신뢰도 분석

A wide scope of numerical simulations was performed to predict model-ship resistances by using STAR-CCM+ and OpenFOAM. The numerical results were compared with experimental measurements in towing tank to analyze statistical reliability of the present simulations. Based on the normal distribution of resistance errors in 113 cases of container carriers, tankers and very large crude-oil carriers, the confidence intervals of numerical error were estimated as [-2.64%,+2.32%] and [-1.82%, +1.87%] with 95% confidence in STAR-CCM+ and OpenFOAM, respectively. The resistance errors of liquefied natural gas carriers with single- and twin-skeg were confident in the ranges of [-2.51%,+2.64%] and [-2.29%, +1.46%], respectively. The grid uncertainty of resistance coefficients for KCS was also quantitatively analyzed by using a grid verification procedure. The grid uncertainty of OpenFOAM (5.1%) was larger than 4.4% uncertainty of STAR-CCM+ although OpenFOAM provided statistically more confident results than those of STAR-CCM+. It means that a grid system verified under a specific condition does not automatically lead to statistical reliability in general cases.

Technical Note: PreSquat – Workshop on Numerical Prediction of Ship Squat in Restricted Waters

In September 2013, the PreSquat workshop on numerical prediction of dynamic squat of ships in shallow and restricted waters was held by the University of Duisburg-Essen, the Federal Waterways Engineering and Research Institute (BAW) and Germanischer Lloyd (GL) in Mülheim, Germany. The purpose of the workshop was to benchmark the capabilities of available numerical methods for squat prediction through comparison with experimental data for a large container carrier of Post-Panamax type. With the exception of one test case the comparison with model test results was blind, i.e. the test results were not provided prior to the workshop. This technical note describes the model tests and the numerical results submitted to the workshop.

A comparative study on pollutant emissions and hub-port selection in Panama Canal expansion

Located between the Pacific and Atlantic Oceans, the Panama Canal has reduced both transit time and costs for the container shipping industry in particular. Once canal expansion is completed, container carriers will immediately face emission reduction demands in North America, and will be required to address problems regarding hub port selection for transshipments in the wider Caribbean region (WCR). This will occur because of the upsizing of mother vessels in trunk routes and the global promotion of the use of liquefied natural gas (LNG) as ship fuel under what is known as the clean-lines strategy. As a result, canal expansion will facilitate changes in ship size related to hub selection, pollutant emissions and the use of fuel alternatives which must be addressed by carriers, in particular in regards to the emission control area (ECA) requirements of North America, the US Caribbean and the WCR region. In this study, we use the activity-based method to estimate pollutant emissions and trunk route deployments from Asia to the East Coast of North America. The results show that slow-steaming yields substantially reduced emissions, and that the upsizing of mother vessels after canal expansion will increase pollution emissions accordingly. However, shipping companies that use hub-port selection to plan intercontinental transshipment strategies and conform to a fuel-efficient strategy can substantially reduce emissions. The innovation of this article is in its analysis of actual fuel use, emissions reductions and hub selection in the aftermath of canal expansion. The implementation of this strategy requires converting from heavy oil to LNG fuels, as well as changes in shipbuilding technology, port industries, related infrastructure and regulations on environmental protection of various governments.

Time series prediction of nonlinear ship structural responses in irregular seaways using a third-order Volterra model

To predict the nonlinear structural responses of a ship traveling through irregular waves, a third-order Volterra model was applied based on the given irregular data. A nonlinear wave–body interaction system was identified using the nonlinear autoregressive with exogenous input (NARX) technique, which is one of the most commonly used nonlinear system identification schemes. The harmonic probing method was applied to extract the first-, second- and third-order frequency response functions of the system. To achieve this, a given set of time history data of both the irregular wave excitation and the corresponding midship vertical bending moment for a certain sea state was fed into the three-layer perceptron neural network. The network parameters are determined based on the supervised training. Next, the harmonic probing method was applied to the identified system to extract the frequency response function of each order. While applying the harmonic probing method, the nonlinear activation function (i.e., the hyperbolic tangent function) was expanded into a Taylor series for harmonic component matching. After the frequency response functions were obtained, the structural responses of the ship under an arbitrary random wave excitation were easily calculated with rapidity using a third-order Volterra series. Additionally, the methodology was validated through the in-depth analysis of a nonlinear oscillator model for a weak quadratic and cubic stiffness term, whose analytic solutions are known. It was confirmed that the current method effectively predicts the nonlinear structural response of a large container carrier under arbitrary random wave excitation.

Numerical Prediction of the Hydrodynamic Forces on a Post-Panamax Vessel in the Third Set of Panama Locks

In 2007–2008, Flanders Hydraulics Research built a 1/80-scale model of the third set of Panama locks and carried out model tests with a post-Panamax 12,000 twenty-foot equivalent units (TEU) container carrier model to assess the navigation behavior in the locks. In this paper, the computational fluid dynamics (CFD) method was used to predict numerically the hydrodynamic forces acting on the ship model passing through the locks. By solving the Reynolds-averaged Navier-Stokes (RANS) equations in combination with the renormalization group (RNG) k−ε turbulence model, the unsteady viscous flow around the ship was simulated and the hydrodynamic forces on the ship hull were calculated. User-defined functions were compiled to define the ship motion. Grid regeneration was dealt with by using the dynamic mesh method and sliding interface technique. Under the assumption of low ship speed, the influences of free-surface elevation were neglected. The proposed method was validated by comparing the numerical results with the data of model tests. Numerical calculations were performed at different ship speeds, water depths, eccentricities, approach wall configurations, guide wall angles, maneuver types, and bottom level height differences; the numerical results were illustrated to analyze the influence of these factors on the hydrodynamic forces. This study can provide a certain guidance on the lock design and the safe maneuvering of ships navigating in the third set of Panama locks.

Measurements in a container ship of wave-induced hull girder stresses in excess of design values

This paper describes full-scale measurements of the wave-induced vertical bending moment amidships a 9400 TEU container carrier and focuses on the effect of the hydro-elastic high-frequency vibration on the extreme hogging wave bending moment. One extreme event, where the vertical wave-induced hogging bending moment amidships slightly exceeds the design value, is analysed and the measurements are verified by the use of the relationship between measurements of accelerations and strains and simple beam theory. The measurements are found to be reliable. In the extreme case, the high-frequency vibrations caused by impulsive loads are observed to be of the same magnitude as the rigid-body wave-induced response and thus acts to double the total vertical bending moment amidships. It was also found that even though the ship is sailing in bow quartering seas, only the 2-node vertical vibration mode is apparently excited. Following the extreme event analysis and verification, three hours of strain measurements are used for establishing a Gumbel distribution for the extreme value prediction, and it is found that the probability of exceeding the rule design wave bending moment by 50% in the given sea state is quite significant. Finally, the hydro-elastic behaviour of the hull girder is assessed by simple approximations using the measured statistical properties and closed-form expressions and the agreement with the actual measurements is found to be good.

Potential Impacts of Maritime Risk on Maritime Traffic Flows and Regional Economies: Case Study at the Straits of Malacca and Singapore

This paper analyzes the vulnerability of the Straits of Malacca and Singapore (SoMS) to maritime risks. The impacts of the risk events on international cargo flows, transshipment at major ports, and domestic economies are simulated with an international cargo traffic simulation model and a spatial general equilibrium model. Both container cargoes and dry/liquid cargoes are covered. Three cases are analyzed: sea-lane blockade at the SoMS, stop of the service at Singapore Port, and increase of loading/unloading time at all ports in the world. Results show that the risks which occur at the SoMS impact on the economies in the whole Asia; container carriers may change transshipment ports — from littoral ports to other East Asian ports — if the risk events were to actually occur; and the economic impacts of the risk events depend on the cases and the countries. Finally, the implication to the maritime security policy is discussed.

Performance of marine and offshore paint systems: Correlation of accelerated corrosion tests and field exposure on operating ships

Corrosion resistance is an important property requirement for marine paint systems used in naval industry such as for ship's topsides and superstructures, which obliges testing the coating performance in order to make a durable selection of the paint systems. This can be achieved by performing laboratory accelerated corrosion tests recommended for C5M corrosivity class (in particular the standard neutral salt spray test ISO 9227 or the cyclic corrosion test ISO 20340‐Annex A) which give results in a rather short delay (up to 6 months) compared to field exposures in marine atmospheres (several years). It is however well known that these tests may not be fully representative of real ship environmental conditions.The aims of the present study were thus to compare and estimate the correlation of various accelerated corrosion tests including standardized tests (ISO 9227, ISO 20340, ISO 16701) and newly developed test conditions to field exposures on worldwide operating ships (container carrier vessel and oceanographic ship) and on conventional static marine atmospheric sites (C5M). Fifteen different marine paint systems commonly used for offshore and naval application were selected for the study. From the results, the exposure conditions on the container vessel were the most aggressive ones compared to static exposures after 2 years. The best correlation to such field exposure was observed using the cyclic test ISO 16701 with a deviation inferior to 25%, an acceleration factor of 4 and comparable corrosion aspect. If all testing conditions involving NaCl 5 wt% (including ISO 20340) showed a superior acceleration factor (e.g., about 12), a larger deviation (50%) was however found indicating that these tests did not accelerate the corrosion degradation of the paint systems similarly to field exposures. In addition, conditions for an optimization of ISO 20340 annex A test were found.

A service flow model for the liner shipping network design problem

Global liner shipping is a competitive industry, requiring liner carriers to carefully deploy their vessels efficiently to construct a cost competitive network. This paper presents a novel compact formulation of the liner shipping network design problem (LSNDP) based on service flows. The formulation alleviates issues faced by arc flow formulations with regards to handling multiple calls to the same port. A problem which has not been fully dealt with earlier by LSNDP formulations. Multiple calls are handled by introducing service nodes, together with port nodes in a graph representation of the problem, and by introducing numbered arcs between a port and a novel service node. An arc from a port node to a service node indicate whether a service is calling the port or not. This representation allows recurrent calls of a service to a port, which previously could not be handled by LSNDP models. The model ensures strictly weekly frequencies of services, ensures that port-vessel draft capabilities are not violated, respects vessel capacities and the number of vessels available. The profit of the generated network is maximized, i.e. the revenue of flowed cargo subtracted operational costs of the network and a penalty for not flowed cargo. The model can be used to design liner shipping networks to utilize a container carrier’s assets efficiently and to investigate possible scenarios of changed market conditions. The model is solved as a Mixed Integer Program. Results are presented for the two smallest instances of the benchmark suite LINER-LIB-2012 presented in Brouer, Alvarez, Plum, Pisinger, and Sigurd (2013).

Optimizing empty container logistics based on a collaborative network approach

Current global production patterns have led to the emergence of systemic, chronic and structural trade imbalances between major trading regions. Increasing transportation led to a growth in the amount of full containers and subsequently to preceding and ensuing empty container movements. Empty container management is substantial to overcome the complex problem of empty container repositioning, storage and ownership conditions. Because of growing cost pressures and the continuous search for efficiency improvements, collaborative design approaches in the empty container management are becoming increasingly important. One approach is the joint use of containers by several container carriers and container leasing companies. Therefore, the aim of this article is to introduce a mathematical optimization approach, which optimizes container logistics networks and quantifies potential savings considering the establishment and operation of container pooling. It will be shown that positive economic effects can be generated by the implementation of container pooling, compared with non-cooperative behavior of container owners and leasing companies. In addition, port operators will be able to handle rising container volumes without major capacity adjustments. Further studies need to focus on practical implications of container pooling models and empirical evidence of the mathematical approach.

Factors influencing container carriers’ use of coastal shipping

Coastal shipping is one of the most sustainable and economically competitive modes of transportation. This study employs the analytic hierarchy process (AHP) method to determine the importance of various factors influencing container carriers’ use of coastal shipping. A three-level hierarchical structure with the 17 attributes is proposed and tested. A previous AHP survey in Taiwan has indicated that port policy and infrastructure is the most critical factor influencing the coastal shipping by container carriers followed by operational cost, operational strategy and operational efficiency. Overall, the results indicate that the five most important attributes influencing the use of coastal shipping are simplified customs procedures; leasing a dedicated terminal; transhipment time; a favourable port charge system and efficient terminal operations.

Slow steaming impacts on ocean carriers and shippers

Ocean container carriers have implemented slow steaming (reduced vessel speeds) in recent years to improve fuel efficiency and lower greenhouse gas emissions. However, many shippers oppose the practice due to increased pipeline inventory associated with longer transit times. Given this conflict, this article seeks to quantify the costs and benefits of slow steaming relative to carriers and shippers. We simulate a high volume Asia-North America container trade lane to estimate slow steaming impacts under different vessel speeds, volumes and fuel prices. Under current conditions, the results justify slow steaming practices, revealing extra slow steaming as the most beneficial vessel speed with a 20 per cent reduction in total costs and a 43 per cent reduction in carbon dioxide emissions. Extra slow steaming is also optimal for future volumes and a wide range of fuel prices. Furthermore, the results detail carrier and shipper cost trade-offs, thus offering practical evidence and transparency to the industry on how to create financial equity in facilitating contractual-based agreements for vessel speed standards.

수직날개를 부착한 선박의 조파저항 성능 추정 기법의 검증

본 연구에서는 개발된 선미부에 수직날개를 부착한 선박의 조파저항성능을 예측할 수 있는 수치해석기법의 검증에 관한 것이다. 수치해석기법은 비점성 유동장 해석기법인 랜킨소오스 패널법과 와류격자법을 사용하여 개발하였으며, 자유수면 경계조건의 비선형성은 반복해법을 사용하여 만족시켰고, 선박의 트림과 침하량을 구하는 알고리즘을 포함하고 있다. 수치해석을 위한 선체표면의 패널을 생성하기 위하여 패널절단법을 사용하였다. 4000TEU 컨테이너 운반선을 대상 선박으로 하여 선미부 6개소의 서로 다른 위치에 수직날개를 부착하여 수치해석을 수행하였으며, 수치해석기법의 타당성을 검증하기 위하여 상용 점성 유동장 해석 프로그램인 FLUENT를 사용하여 선체 주위의 점성 유동장을 계산하였고, 모형시험을 수행하여 얻은 실험 결과를 수치해석 결과와 서로 비교하였다. In this paper the developed prediction technique of wave-making resistance performance for a ship attached with a vertical blade had been verified. Numerical analysis program as a prediction technique had been developed using the Rankine source panel method and the vortex lattice method(VLM). The nonlinearity of the free surface conditions was fully taken into account using the iterative method and the trim and the sinkage of the ship were also considered in the numerical analysis program. Panel cutting method was applied to get hull surface panels. Numerical computations were carried out for a 4000TEU container carrier and the vertical blade was attached 6 different locations astern. To investigate the validity of the numerical analysis program the commercial viscous flow field analysis program FLUENT was used to obtain the viscous flow field around the ship and the model test was performed. The model test results were compared with the numerical analysis results.