International Journal of Maritime Engineering

The Technology Solutions of Service Quality for Ship Repair Service Providers

Yu-Chang Hsu, Hua-An Lu, Ching-Wu Chu — Mon, 22 Jan 2024 00:00:00 +0000

Ship repair service providers (SRSPs) are divided into repair shops and repair yards. The process of evaluating the service quality of SRSPs is detailed in the ship management and operation procedures held by ship-owners, who must evaluate SRSPs annually to ensure the continued provision of high-quality maintenance and repair services. The high-quality repair services provided by SRSPs can also enhance the strength of ship-owners; ensure the ship successfully passes Flag, PSC, and CLASS inspections; and maintain the ship’s seaworthiness. This study combined fuzzy quality function deployment (FQFD) and grey relational analysis (GRA) to evaluate the service quality of SRSPs. The research findings revealed that “reasonable pricing and discount conditions” and “high-quality repairs and reliability-centred guarantee service” are the technical solutions that must be prioritised by repair shops and yards, respectively. Moreover, the evaluation criteria, technical solutions, and research results discussed in this study provide a reference for ship-owners and SRSPs.

Prediction of Baltic Dry Index Based on GRA-BiLSTM Combined Model

B C Liu, X Y Wang, S M Zhao, Y Xu — Mon, 22 Jan 2024 00:00:00 +0000

The Baltic dry index (BDI) is not only one of the most important indicators of shipping costs but is also an important barometer of global trade and manufacturing sentiment. The BDI is highly volatile and subject to complex factors, which make it difficult to predict. In this paper, a neural network model-based BDI forecasting system was proposed to effectively forecast the BDI. We used the gray relational degree analysis method to select seven factors with higher correlation from 15 factors affecting the variation of BDI index to be used as input indicators for the bi-directional long short-term memory (BiLSTM) model to forecast BDI. From the experimental results, the prediction model proposed in this paper had an excellent prediction effect on the BDI. The mape value of the prediction result was 9.19%. The accuracy was better than the common machine learning models SVR and REG and the neural network model LSTM. In addition, in order to further optimize the prediction performance of the combined model GRA-BiLSTM, this paper introduced the MIV method to conduct an in-depth analysis of the contribution of each variable to the prediction results. Rice price, Shanghai securities composite index and crude oil price were found to be the three most relevant indicators to the prediction accuracy of the model.

Analyzing Naval Fleet Modelling with a Tactics Perspective – The Case of Implementation of Autonomous Vessels

H Liwång, J Kindgren, J Granholm, T Tärnholm — Mon, 22 Jan 2024 00:00:00 +0000

Development of autonomous vessels is expected to create a paradigm shift in how warfare is conducted. Therefore, there is need to explore the possibilities and limitations in developing integrated systems for defence at sea to support innovation. Fleet modelling can analyse functions and other design options such as autonomous platform’s and evaluate their added effect in naval operations. However, due to the complexity of naval operations, it is not feasible to create a tool that covers all aspects needed to mimic reality. This study, from the perspective of naval tactics, investigate the value of a tool that analyses potential fleet architectures including autonomous platforms. The study identifies that the tool creates relevant mental models for future naval fleets by identifying feasible fleet compositions. However, the proposed fleet combinations are only tested against a limited set of tactical needs and can only be seen as a starting point for development.

Assessment of Seafarers’ Mental Workload: A Study on High Speed Craft

C Kartoglu, Y E Senol, S Kum — Mon, 22 Jan 2024 00:00:00 +0000

High speed craft has become prominent in maritime industry. Sophisticated electronic navigation equipment on bridge increases mental demands of high speed craft navigator. In the present study, mental workload of high speed craft navigators has been assessed in terms of bridge navigation operations. For this purpose, the pairwise comparison of the effects of Electronic Chart Display and Information System, Automatic Radar Plotting Aid, Automatic Identification System and autopilot on mental workload and Revised NASA Task Load Index questionnaires were carried out. High speed craft navigators sorted berthing, unberthing, navigation in coastal waters, navigation in restricted waters, and navigation on open sea operations according to their mental workload levels. In addition, they indicated the factors mostly affecting mental workload and the remarkable suggestions to keep the optimum level of mental workload. As result of these findings, considerations have been made for increasing the safety of high speed craft navigation.

Design, Development and Commissioning of the Boldrewood Towing Tank – A Decade of Endeavour

B Malas, L Creasey, D Buckland, S R Turnock — Mon, 22 Jan 2024 00:00:00 +0000

The process of design, build and eventual commissioning of the towing tank on the Boldrewood Innovation Campus is described. The design brief required a facility that would have a capability to test models at a commercial scale but that would be effective as teaching environment for the next generation of Naval Architects as well as providing a flexible space for future fundamental research. Each of these provided their own challenges but the eventual solution of a 138 m long, 3.5 m deep, 6 m wide facility has more than met the initial aspirations. Equipped with 12 independent 0.5 m wavemaking flaps at the West end, a passive beach at the East end, a deployable side beach along the South wall for post run wave absorption and a monocoque Aluminium alloy carriage, the Boldrewood towing tank has now been successfully operating for more than a year. The carriage position and speed are controlled by a twin winch arrangement using a laser positioning system and low embodied energy composite cables. The carriage can reach a maximum speed of 10 m/s with controllable acceleration rates and can have up to four constant speed phases per run. Initial commissioning results and comparisons with benchmark data for the KCS hull confirm the accuracy and repeatability of the facility. In particular, the position and speed of the carriage are known to a high level of precision. To date research and consultancy work has spanned the performance of high speed vessels, uncrewed underwater and surface vessels, wave energy and tidal current systems, floating platforms for wind turbines, performance sport work for sailing, kayaking, rowing and swimming, open water propeller tests as well as conventional displacement vessel testing for self-propulsion and resistance. All ship science and maritime engineering students use the facility as part of their taught modules in every year of their programme as well as for individual, MSc and group projects as appropriate. It has also made a strong impact on the many thousands of visitors a year to the campus for science and engineering open days.