The seafaring labour market in Brazil

The most recent reports on the supply and demand for seafarers suggest that there is an increasing lack of officers for the expanding world's merchant fleet. With a focus on Brazil, this paper discusses a particular seafaring labour market highlighting specific challenges that need to be overcome. The paper looks into the current condition of the imbalance in Brazilian seafaring labour market as well as the prospects for merchant marine officers from the only two maritime schools in the country. Key issues on demand forecast and supply expectation, policy amendment, promoting maritime career, sea career commitment and maritime career empowerment are discussed to illustrate possible means to overcome the imbalance.     

Regression modelling of the employment durations of UK seafaring officers in 1999

This paper presents the results of an econometric analysis of the duration of voyages undertaken by NUMAST deck and engineer officers in 1998-1999. Earlier papers examined the employment profile of the officers, and compared voyage patterns across organization type, company nationality, flag of registry, and ship type. Analysis of the various cross-tabulations of employment duration appeared to show that the key driver is ship type. Using regression analysis, it is shown that ship type does indeed have a significant influence on duration, as does ship size. Flag, organizational type and company type were all found to be statistically unimportant.     

窑洞中开启一扇向海的窗——天津海事局搭建平台促进老区农民转产就业

日前,陕西省延安市政府为19名首批赴天津进行普通海员短期培训的学员举行欢送仪式,由天津海事局、延安市政府牵头主办,天津老促会、延安老促会协调、辅助,天津老促会理事会员单位——天津亿兆缘诚国际船舶管理有限公司具体承办实施的“推进西部海员发展,促进农民转产就业”工作正式拉开序幕。     

The effects of marine cargo delays in law and commerce

With the development of door-to-door intermodal services and the advent of just-in-time supply systems, punctual delivery of cargoes is more than ever a priority both for shippers and for shipowners. This paper is about the incidence of delay in transportation, particularly in the marine mode, and its legal and commercial consequences.

The fundamental legal obligations of marine carriers have always included delivery with dispatch. Thus the law would seem to support the commercial expectations of shippers for reliable performance. The authors discuss the nature of these obligations, investigate their adequacy under modern conditions of trade and report on a survey of Canadian shippers and consignees.

The authors conclude that there appears to be a divergence in the toleration of delay, but that few of the Canadian companies suffering unacceptable delays received, or even sought, financial compensation and none of them planned to do more. The authors speculate about their reasons for absorbing the losses incurred through unacceptable delays. The evidence from the survey is that shippers, in spite of their dissatisfaction with the resolution or outcome of incidents of unacceptable delay, are loath to seek compensation through legal means, but instead prefer to resort to a range of commercial actions.     

The effects of the Chinese fiscal system in shipping: a comparison with the UK regime

Assessing the effects of fiscal systems on investment in shipping by using the discounted cash flow technique has recieved much attention over a number of years. This paper examines the recent change in the business environment of Chinese shipping companies and argues for the relevance of using the same technique in the Chinese context. The technique which has been developed over the years is outlined and the current Chinese and UK fiscal systems applied to shipping are described. Based on the comparison and analysis of the effects of the two systems, some policy implications are made.     

The effects of the Chinese fiscal system in shipping: a comparison with the UK regime

Assessing the effects of fiscal systems on investment in shipping by using the discounted cash flow technique has recieved much attention over a number of years. This paper examines the recent change in the business environment of Chinese shipping companies and argues for the relevance of using the same technique in the Chinese context. The technique which has been developed over the years is outlined and the current Chinese and UK fiscal systems applied to shipping are described. Based on the comparison and analysis of the effects of the two systems, some policy implications are made.     

纵向弯矩下材料随机特性对复合材料船体可靠性的影响

The effects of stochastic characteristics of materials on the reliability of ship hulls made of composite materials under longitudinal moment were extensively studied using reliability and sensitivity calculations of a composite ship hull which was sagging.The reliability indices and failure probabilities of the ship in three kinds of failure modes (buckling,material failure,and ultimate collapse) were calculated by the surface response method and JC method.The importance factors of random variables in stochastic models,such as the model errors in predicting the ultimate longitudinal strength of ship and the longitudinal bending moment that the ship withstands,as well as the stochastic characteristics of materials in the models used,were calculated.Then,the effects of these random variables,including the stochastic characteristics of materials on the reliability index and the failure probability of ships which were sagging,were discussed with their importance factors.The results show that the effects of stochastic characteristics of materials on the reliability of ship hulls made of composite materials should be considered during the reliability assessment of composite ships.Finally,some conclusions and recommendations were given for high-speed ship design and safety assessment.     

The visual effects of port redevelopment alternatives

Abstract

In the early 1970s, Seattle Piers 90/91 were declared surplus federal property by the GSA. These obsolescent half‐mile‐long piers and their adjacent uplands were purchased by the Port of Seattle for redevelopment. This urban waterfront site of almost 200 acres presents the Port of Seattle with a number of severe planning problems. While it is the last large deep‐water site on Elliott Bay, it is also in a very sensitive location, since it is overlooked on two sides by vocal residential communities with a history of active intervention in development projects on visual and other environmental grounds.

At Piers 90/91, public concerns over the visual effects of port redevelopment include:

1. nuisance effects of night‐operations lighting on adjacent hillside residences;

2. nighttime obstruction of distant views due to increased foreground illumination;

3. day and night view obstruction by tall structures such as container‐handling cranes;

4. alteration of the character of both day and nighttime views by new port facilities.

As part of a program to study the effects of alternative redevelopment strategies for Piers 90/91, the Port has undertaken a through examination of the visual effects of different uses, their visual appropriateness, and the ways by which adverse visual effects can be mitigated. The results were incorporated into an environmental impact statement which documented compliance with the Seattle Shoreline Master Program and with view protection and glare provisions of the City's S.E.P.A. guidelines.

A systematic Visual Resource Management (VRM) approach was successfully employed on this coastal zone project. Major elements included visibility mapping, key view selection, analysis of existing visual character, simulation of alternatives, assessment of relative visual compatibility, and determination of effective mitigation measures. Community involvement has also been a critical element in this approach to assessing and managing the visual effects of redevelopment in a major urban port.     

长波作用下与KC数相关的柔性植被对海岸结构物受力的影响(英文)

Extreme coastal events require careful prediction of wave forces.Recent tsunamis have resulted in extensive damage of coastal structures.Such scenarios are the result of the action of long waves on structures.In this paper,the efficiency of vegetation as a buffer system in attenuating the incident ocean waves was studied through a well controlled experimental program.The study focused on the measurement of forces resulting from cnoidal waves on a model building mounted over a slope in the presence and absence of vegetation.The vegetative parameters,along with the width of the green belt,its position from the reference line,the diameter of the individual stems as well as the spacing between them,and their rigidity are varied so as to obtain a holistic view of the wave-vegetation interaction problem.The effect of vegetation on variations of dimensional forces with a Keulegan-Carpenter number(KC) was discussed in this paper.It has been shown that when vegetal patches are present in front of structure,the forces could be limited to within F*￡1,by a percentile of 92%,90%,55%,and 96%,respectively for gap ratios of 0.0,0.5,1.0,and 1.5.The force is at its maximum for the gap ratio of 1.0 and beyond which the forces start to diminish.     

The effects of free surface and end cell on flow around a finite circular cylinder with low aspect ratio

Vortex-induced motion is an oscillatory phenomenon which occurs to a floating body with low aspect ratio. The basic phenomenological study about the effects of free surface and end cell on flow around a finite fixed circular cylinder was investigated in this study using particle image velocimetry and hydrodynamic force measurement. It was found from the former experiment that the wake of the cylinder is influenced by the both end cell and free surface. Blowup and back flow are generated from the end cell, and their effects are suspended by free surface. The result of hydrodynamic force measurement showed the effect of Reynolds number, Froude number, and the aspect ratio of the floating body on the hydrodynamic force. Fluctuating components of hydrodynamic coefficients decrease for increasing Reynolds number, Froude number, and the aspect ratio. On the other hand, the mean drag coefficient increases as Froude number increases and decreases as the aspect ratio increases. The interpretation to these results was discussed in comparison with flow structures observed in the experiment. In addition, it was found that the effect of Reynolds number on the mean drag coefficient changes at different aspect ratios. A possible interpretation to this phenomenon was proposed.     

The effects of chord length and boundary conditions on the static strength of a tubular T-joint under brace compression loading

Non-linear finite element analysis is used to assess the static collapse strength of a sample tubular T-joint configuration subjected to compressive brace loading. Two series of models are used to assess the effects of varying the chord length L, one series having simply supported chord ends and the other having fixed chord ends. It is shown that chord length and boundary conditions can have a significant influence on static collapse loads. The results are discussed in the light of current design procedures.     

The effects of slow steaming on the environmental performance in liner shipping

The environment issue is one of the significant challenges that the liner shipping industry has to face. The International Maritime Organization (IMO) has set a goal to reduce greenhouse gas (GHG) emissions from existing vessels by 20–50% by 2050 and develop the Energy Efficiency Operational Indicator (EEOI) as a measure for energy efficiency. To achieve this goal, IMO has suggested three basic approaches: the enlargement of vessel size, the reduction of voyage speed, and the application of new technologies. In recent times, liners have adopted slow steaming and decelerated the voyage speed to 15–18 knots on major routes. This is because slow steaming is helpful in reducing operating costs and GHG emissions. However, it also creates negative effects that influence the operating costs and the amount of GHG emissions at the same time.

This study started with the basic question: Is it true that as voyage speed reduces, the operating costs and CO₂ emissions can be reduced at the same time? If this is true, liners will definitely decelerate their voyage speed themselves as much as possible so that they can increase their profits and improve the level of environmental performance. However, if this is not true, then liners will concentrate just on increasing their profits by not considering environmental factors. This led the authors to set out three objectives: (1) to analyze the relationship between voyage speed and the amount of CO₂ emissions and to estimate the changes by slow steaming in liner shipping; (2) to analyze the relationship between voyage speed and the operating costs on a loop; and (3) to find the optimal voyage speed as a solution to maximize the reduction of CO₂ emissions at the lowest operating cost, thus satisfying the reduction target of IMO.     

Unsteady finite-depth effects during resistance tests on a ship model in a towing tank

This paper covers an extension of the study of Doctors et al. (J Ship Res 52(4):263–273, 2008) on oscillations in wave resistance during the constant-velocity phase of a towing-tank resistance test on a ship model to the case of relatively shallow water. We demonstrate here that the unsteady effects are very prominent and that it is essentially impossible to achieve a steady-state resistance curve in a towing tank of typical proportions for a water-depth-to-model-length ratio of 0.25. This statement is particularly true in the speed region near a depth Froude number of unity. However, on the positive side, we show here that an application of unsteady linearized wave-resistance theory provides an excellent prediction of the measured total resistance, when one accounts for the form factor in the usual manner. Finally, a simple application of the results to the planning and analysis of towing-tank tests is presented.     

垂直入射时覆盖薄吸声涂层的高频反射特性分析

涂层隐身是水下目标声隐身的一个主要方法.针对水雷的特点,本文研究了水下目标覆盖薄吸声涂层的高频反射特性.根据垂直入射时多层介质的声传播理论,利用多层均匀复合结构的传递矩阵,研究了水中多层结构的高频反射特性,通过Matlab编程仿真了高频下覆盖薄吸声涂层时吸声涂层的厚度,杨氏模量,损耗因子对反射系数的影响.最后对吸声涂层的厚度对反射系数的影响进行了试验研究.结果表明,在高频范围目标表面覆盖薄吸声涂层可以有效减小目标回波信号强度,提高其声隐身能力.     

考虑流体粘性作用的双体船运动和波浪载荷预报

利用源汇分布法计算双体(或多体)剖面的水动力系数,在此基础上,对二维切片理论在双体船的垂向运动和波浪载荷预报上的应用进行了拓展,考虑了流体粘性的作用,比较了不同航速、不同片体间距和片体间水动力相互干扰等因素对运动和载荷预报的影响.算例结果表明,该方法能较好地预报双体船在规则波中的运动响应和波浪载荷.     

舰船双绞线电缆耦合影响预测与仿真

针对舰船工程中的电缆耦合问题,着重探讨双绞线电缆的电磁耦合影响.提出了双绞线电缆单位长度的分布参数模型,分析了容性耦合与感性耦合的影响,并由此建立了双绞线电缆的电磁耦合数值预测模型.仿真结果表明,在非平衡终端情况下,双绞线能够显著减小感性耦合;通过平衡双绞线的终端,能够消除容性耦合.     

Numerical simulation of interference effects for a high-speed catamaran

The simulations of the flow around a high-speed vessel in both catamaran and monohull configurations are carried out by the numerical solution of the Reynold averaged Navier–Stokes (RANS) equations. The goal of the analysis is the investigation of the interference phenomena between the two hulls, with focus on its dependence on the Reynolds number (Re). To this aim, numerical simulations are carried out for values of Re ranging from 10⁶ to 10⁸ for two different values of the Froude number (Fr = 0.30, 0.45). Wave patterns, wave profiles, limiting streamlines, surface pressure and velocity fields are analyzed; comparison is made between the catamaran and the monohull configurations. Dependence of the pressure and viscous resistance coefficients, as well as of the interference factor, on the Reynolds number is investigated. Verification and validation for both resistance coefficients and wave cuts is also performed.     

Numerical prediction of wave-induced long-term extreme load effects in a flexible high-speed pentamaran

The theory and procedure established by Wu and Moan in 1996 and 2005 and Wu and Hermundstad in 2002 were applied to a high-speed transatlantic pentamaran containership. Nonlinear time-domain simulations of ship motions and load effects were carried out in different sea states. The simulated responses were validated against model tests with satisfactory results. The short-term probabilities of exceedance were estimated by using different stochastic analysis procedures. The long-term probabilities of exceedance were obtained based on the short-term results. These served as information about loading in a reliability-based design approach. The load effects in a semiprobabilistic design were also calculated at an appropriate probability of exceedance level.