Type Approval of ballast water treatment system (BWTS) is virtually in a dual structure between the International Maritime Organization (IMO) and the United States Coast Guard (USCG). For that reason, all oceangoing vessels are required to install a type-approved system by both IMO and USCG. It is recognized that obtaining USCG type approval in UV-type systems are assumed to be practically difficult because it entails a specific requirement which states that counting organisms be conducted by the Fluorescein diacetate (FDA) method. Under such situation, the elimination performance for test water was evaluated by simulating UV transmittance (UVT) to verify the capability of the ECOMARINE® UV system.
Although test water at 82% of UVT was within the discharge standard in case of TRC: 250m3/h, test water at 43% of UVT exceeded the discharge standard when the flow rate was reduced to 50m3/h. In addition, it could be assumed that the removal performance of S-sized plankton by the RC filter contributed to the reduction of UVT and based on which, it was estimated that UVT can be reduced by 2.6% and 11.1% if S-sized plankton is removed by 50% and 90%, respectively. Since the 10% reduction of UVT is equal to one-third reduction of treatment flow rate, this difference may be operationally indispensable.
Based on these results, it is highly likely that USCG Type Approval is granted to the ECOMARINE® UV system at practical treatment flow rates and UVTs by FDA method.
International convention on Standards of Training, Certification and Watch keeping for seafarers (STCW) was amended in Manila, the Philippines in 2010. The amendments will come into force on 1 January 2017. To meet the competence requirements for marine engineers, the implementation of Engine-room Resource Management training (hereafter, ERM training) was adopted as mandatory. The role of a practical ERM training model has become more important for marine engineers working in a complex system. The purpose of this study is to examine which ERM training best suits engine-room simulation education. First, in this paper, the characteristics of total human errors were investigated using 298 marine accident records from the Japan Marine Accident Inquiry. Second, the common factors of these accident records, namely the latent factors, were determined using covariance structure analysis. Furthermore, System Dynamics (SD) was employed to find the relationships between the latent factors and the technical support to gather the clues for a practical ERM training method. The model includes a data set of actual cases from records of marine accident inquiries and a hypothetical data set. The results show that the support of the onshore management and behavior characteristics of engineers which influence each other in a delicate balance could be expressed in a chronological order.
The following experiments and analyses were carried out to develop technology that complies with the IMO Tier III NOx regulations without deterioration of the specific fuel consumption (SFC). First, changes in engine performance and exhaust gas characteristics were investigated using an oxygen reduction membrane (ORM) while varying the oxygen concentration in the suction air from 21 to 17%. Next, the utility and limits of the NOx reduction technology based on the ORM were determined by analyzing the results. Additionally, the oxygen concentration in the suction air was lowered using the ORM, after which experiments in combination with water mixed fuel (WMF) technologies were carried out and the results were analyzed. Based on the results, the following conclusions were made: (1) The IMO Tier III NOx regulations can be met by reducing the oxygen concentration in the suction air to 17% at 75, 50, and 25% load. (2) The SFC deteriorates with decreasing oxygen concentration. This behavior intensifies particularly at oxygen concentrations of 19% or less, e.g., the SFC deteriorates by about 3% at 17% oxygen concentration. (3) By mixing water in the fuel with the oxygen concentration adjusted to 19%, the IMO regulations can be met without increasing the SFC. Finally, a discussion regarding compliance of the proposed technology with IMO regulations is made from the point of view of the operator.
Torque control method is most commonly used when tightening bolted joints because of its easy operation. However, the method involves the essential problem of fairly large scatter in bolt force. It has been reported that even if the same torque is applied, bolt forces show a considerable scatter, e.g., ranging from 25% to 35%. A scatter in the coefficients of friction on nut bearing surface and thread pressure flank is a primary source of bolt force scatter. Meanwhile, the effect of equivalent friction diameters at nut bearing surface and bolt head surface cannot be ignored. The scatter in equivalent friction diameter is caused by imperfect geometry, i.e., the flatness deviation at the bearing surfaces. In this paper, the magnitudes of equivalent friction diameters are evaluated in detail by FEA, using the measured data of flatness deviation for a number of commercial nuts and bolts. It is shown that the bolt force is likely to be scattered by as much as 10% of the target value, owing to flatness deviation. Based on comprehensive calculations by considering imperfect geometry, a strategy to effectively suppress bolt force scatter is proposed.