Maritime security and seafarers’ welfare: Towards harmonization

This article examines the negative situation surrounding seafarers’ welfare in the post 9–11 shipping world. Its main focus is the denial of shore leave which has become a prime source of disharmony since the implementation of post 9–11 security measures. It discusses the implementation of these measures which has been at the expense of seafarers’ customary right to shore leave.     

Predicting the chloride penetration of fly ash concrete in seawater

In this study, a model for predicting chloride penetration in fly ash concrete under long-term exposure in a marine environment is developed. The empirical model was based on 2-, 3-, 4-, and 5-year investigation of concretes in a marine site. Regression analysis of the data was carried out by applying Fick's second law of diffusion to generate an empirical formula for predicting chloride concentration in concrete. The model uses the water to binder (W/B) ratio, fly ash content, distance from the concrete surface, and exposure time. Model validation revealed that the predicted chloride concentration levels were within a ±25% error margin (R² = 0.91 ? 0.99) in the samples used to develop the model. The model was also verified using data from previous laboratory and field studies. Most predicted chloride concentration levels were within a ±30% margin of error from field samples. The model also predicted the strong effect of fly ash and W/B ratio on reducing chloride diffusion in concrete. Results clearly indicated that a high volume fly ash replacement (up to 50% by weight of binder) and a low W/B ratio will yield good chloride resistance in concrete under long-term exposure in a marine environment.     

船船水动力相互作用的CFD分析研究（英文）

A numerical study of ship-to-ship interaction forces is performed using a commercial CFD code, and the results are compared with experimental data and with the results of a panel method analysis. Two ship models have been used in the interaction forces analysis: a tug and a tanker, advancing parallel to each other with different lateral distances and two different values of the fluid depth. Computations are carried out with four different flow models: inviscid and viscous flow with the free surface modeled as a rigid wall and inviscid and viscous flow with the deformable free surface. A fair agreement was obtained with available experimental data and results obtained by panel method. The influence of viscosity in the computations is found to be comparatively weak, while the wavemaking effects may be important, at small magnitude of the horizontal clearance.     

A study of the response of chlorophyll-a biomass to a winter upwelling event off Western Iberia using SeaWiFS and in situ data

Observations of a winter upwelling event off Western Iberia shelf/slope in the area of influence of the Western Iberia Buoyant Plume (WIBP) were conducted in February 2000. Spatial patterns and time evolution of the chlorophyll-a (chl-a) biomass are analysed, based on in situ and satellite data. SeaWiFS-derived chl-a concentration L2 products were used to track the chlorophyll front and estimate its westward migration velocity (maximum up to 29 km day⁻¹), as well as to characterize the frontal system and its evolution. A method associating the type of spectral signature of a pixel to the fraction of chlorophyll probed by SeaWiFS enabled the estimation of the chl-a biomass within error intervals. High chlorophyll concentrations (for wintertime) were observed over the shelf and slope, up to large distances to the coast. Due to the WIBP, a shallow Ekman layer developed, being nearly coincident with the stratified upper meters. The transport comprised westward advection and stretching of the plume, with little entrainment with the offshore deep mixed layer waters. The relative enlargement of the total area of the Inside-Front Zone (IFZ) during the upwelling event was roughly accompanied by the maintenance of the average biomass per unit of area, considering the water column up to depths of interest. This suggests that there was a net increase of chl-a biomass inside the water column associated with the IFZ, roughly proportional to the increase in the IFZ area. Retention of phytoplankton in the shallow stratified nutrient-rich waters of the WIBP was a key factor for this increase in chl-a biomass.     

Damage detection of offshore jacket structures using frequency domain selective measurements

The development of damage detection techniques for offshore jacket structures is vital to prevent catastrophic events. This paper applies a frequency response based method for the purpose of structural health monitoring. In efforts to fulfill this task, concept of the minimum rank perturbation theory has been utilized. The present article introduces a promising methodology to select frequency points effectively. To achieve this goal, modal strain energy ratio of each member was evaluated at different natural frequencies of structure in order to identify the sensitive frequency domain for damage detection. The proposed methodology opens up the possibility of much greater detection efficiency. In addition, the performance of the proposed method was evaluated in relation to multiple damages. The aforementioned points are illustrated using the numerical study of a two dimensional jacket platform, and the results proved to be satisfactory utilizing the proposed methodology.     

Port and terminal selection by deep-sea container operators

This paper deals with the importance of port choice and container terminal selection for deep-sea container carriers. The paper focuses on the research question: on what basis do deep-sea container operators select container ports (strategy) and container terminals (financial reasons) in the Hamburg–Le Havre range over others? In answering this research question, three dimensions are addressed in detail: the buying decision characteristics; port choice strategy; and terminal selection. The results show that strategic considerations at company level are important. For port choice the most important criteria from a carrier's perspective are: availability of hinterland connections; reasonable tariffs; and immediacy of consumers (large hinterland). In addition to these criteria, shipping lines attach great value to often neglected factors, such as feeder connectivity, environmental issues and the total portfolio of the port. The study reveals that port selection and terminal selection are not the same with terminal selection criteria mainly depending on: handling speed; handling costs; reliability; and hinterland connections. The analysis also brought forward that the decision making is different per container carrier, per trade and per port type, implying that a one size fits all approach is not relevant.     

Challenges to apprehension and prosecution of East African maritime pirates

The coast of East Africa, the Gulf of Aden and nearby waters of the Indian Ocean stand as the most pirate-ridden area of the seas at this time and naval forces from many nations have descended upon the region to ensure the safe passage of commercial vessels; yet piracy for ransom continues. The US, the North Atlantic Treaty Organization (NATO) and now the European Union deploy their navies to disrupt raids, intercept and capture pirates attacking ships passing through the region. However, apprehending pirates is only effective if they can also be brought to a court capable of adjudicating their guilt. Increasingly, the captured suspects are being disarmed and released, lacking a reliable nearby littoral state to prosecute them. In this region, with few viable states either willing or capable of holding piracy trials, apprehending pirates meets only part of the challenge of abating the practise. What is needed is a court system capable of adjudicating these cases; yet a thicket of both law and custom limits the ability of seagoing states to adequately arrest and hand over to reliable prosecution high seas pirates. This article addresses the problems inherent in abating piracy by these means off the coast of East Africa.     

Productivity change of the Spanish Port System: impact of the economic crisis

ABSTRACT

The main goal of this study was to assess the impact of the economic crisis on the productivity growth of the Spanish Port System (SPS). The Malmquist Productivity Index (MPI) was estimated for the 28 Port Authorities of the SPS, for a ‘non-crisis period’ (2005–2008) and a ‘crisis period’ (2008–2011). From a policy perspective, the MPI is a very useful approach for assessing the productivity change because it can be decomposed into the catching-up index and the frontier productivity index. The results showed that the economic crisis did not impact all of the Spanish Port Authorities equally. Some Port Authorities presented higher productivity growth during the crisis period than in the non-crisis period. Further analysis by the Mann–Whitney test revealed that Port Authority investments and productivity growth were statistically related. Information provided by this study may be very useful for stakeholders and decision-makers, in terms of long-term strategic planning and improving the competitiveness of the SPS. The findings illustrate that the economic crisis should not be seen as an international tragedy, but as an opportunity to adapt port traffics and installations to new needs and market demands.     

Productivity change in Nigerian seaports after reform: a Malmquist productivity index decomposition approach

ABSTRACT

During the 1990s, Nigerian seaports were considered inefficient, unsafe due to massive cargo theft (wharf rat phenomenon) and one of the most expensive port systems in the world. This resulted in long turnaround times for ships and increased container dwell times. As a result, port operations were transferred to the private sector through concession contracts. This paper employs a Malmquist productivity index (MPI) technique to benchmark pre-and post-reform total factor productivity growth of the six major Nigeria seaports (Apapa, Calabar, Onne, Port Harcourt, TinCan Island and Warri) for the period 2000–2011 which represents six years before (2000–2005) and six years after (2006–2011) the reform. The results indicate progress in technical efficiency of the ports after reform but deterioration in technological progress. Overall productivity growth was higher in the pre-concession period compared to the post-concession period. The source of pre-concession period productivity growth was technological progress while the change in productivity of the post-concession period is generated by an increase in scale efficiency. This suggests that concessionaires have not brought in the much anticipated investment in modern technology to drive port efficiency. The ports of Calabar and Apapa experienced the highest productivity growth while lowest result was Onne.     

The Value of a Spillover Fishery for Spiny Lobsters Around a Marine Reserve in Northern New Zealand

The contribution that Leigh Marine Reserve in northern New Zealand makes to the local spiny lobster fishery was examined by comparing the catch characteristics of Jasus edwardsii around the reserve boundary with those from Coastal Leigh, 0.3-2 km from the reserve, and Little Barrier Island, 22-30 km from the reserve. Seasonal trends were apparent in the reserve catch characteristics, consistent with lobster movements into and out of offshore fishing areas adjacent to the boundary. No significant difference was detected in catch per unit effort (kg.trap haul -1 ) among locations. However, the catch around the marine reserve consisted of fewer but larger lobsters than at Little Barrier Island, while the size and number of lobsters caught per trap haul at Coastal Leigh was intermediate between the other two locations. Catch rates around the reserve were more variable than at the other sites, but on average, the amount of money made per trap haul was similar to Little Barrier Island and Coastal Leigh.