Maritime Technology and Research

Response control of TLP with single TMD under wind, wave, and current

Suja T. P. — 2024-07-24

Offshore Tension Leg Platforms (TLP) are hybrid structures that encounter large offsets under rough sea states. They impose large displacements, resulting in operational challenges under extreme sea states. The key to safe topside operation is to minimize responses in flexible modes using appropriate control mechanisms. The present study evaluates the response control of TLP with tuned mass damper under different sea state environments. The damper is positioned such that the mass center of the primary and secondary system is concurrent. It is enabled only with surge motion, which controls the platform surge motion by tuning their frequency ratios. Response control in surge motion is assessed for different mass ratios of the damper. Results show that the RMS value of surge response is effectively reduced for a mass ratio of 0.3, while other mass ratios do not show effective control; the maximum reduction in the surge amplitude is about 26 %. The response reduction is essentially due to the phase shift between the nature of the responses with and without tuned mass damper. In addition, the damper helps improve the recentering capabilities observed from the phase plots.

Highlights

TLP response control is achieved by passive damper
The novelty is tuning of the TMD for the critical mass ratio
It increases the operational safety and stability of the TLP and is suitable for hybrid compliant platforms like TLP

Service excellence at sea: User satisfaction with Belawan Samudera Fishing Port, Indonesia

Dumas Ailuul Syahrianda — 2024-06-24

The aim of this study was to assess the influence of service quality on user satisfaction at Belawan Samudera Fishing Port, Indonesia, a critical hub of fish logistics and supply chain in the Malacca Strait. The study used a mixed-method approach by combining surveys, observations, and in-depth interviews with key informants, and was conducted in August and September 2023. The evaluation of the fishing port service quality was based on five dimensions: tangibility, reliability, responsiveness, assurance, and empathy. The study involved a total of 66 respondents with an overall satisfaction rating of 75.5 %, indicating that users generally provided positive feedback. However, three port facilities did not meet the standards of the Minister of Maritime and Fisheries Affairs Decree Number 8 of 2012. The study showed deficits in the empathy and assurance aspects, and focus on enhancements to increase customer satisfaction is proposed. This study highlighted that optimizing operational efficiency and user satisfaction required improvements in regulatory compliance and quality management at the fishing port.

Highlights

Fishing port is a critical hub for fish logistics and supply chain
Ensuring customer satisfaction in the management of fishing ports is essential for achieving service excellence and efficient port operations
The evaluation of fishing port service quality is based on five elements of service quality: reliability, responsiveness, assurance, empathy, and tangibility
Improvements in quality management and compliance with regulations aim to maximize operational efficiency and fishing port satisfaction

Evaluation of ship turnaround time and cargo trade delays of Nigerian ports in the post privatization regime

Mbachu Justice C. — 2024-08-05

The study evaluated the ship turnaround time and cargo trade delays of Nigerian ports in the post privatization regime. The objectives of the study were, among other things, to investigate the existence of delays in ship turnaround time (STRT) operations and processing of shipping (cargo) trade in Nigerian seaports. The study used ex-facto research design, employing secondary data sourced from different sources as explained later in the work. The Net Output Model approach for estimating value of time lost, the paired sample-test, and the log-linear multiple regression analysis methods were used to analyze the data obtained. It was found that there exists disproportionate levels of delay in ship turnaround time operations in the individual seaports of Nigeria, such that, in each of the Onne, Lagos Apapa, Warri, Rivers, and Calabar ports, the delay encountered by ship operators in shipping operations is 1.878, 5.340, 3.470, 2.810, and 2.440 days, respectively. The Nigerian port sector average delay in ship turnaround time operations is 9.20 days. The result of the study also indicated the existence of 9.00, 16.73, 14.10, 15.60, and 13.40 day delays in the processing of shipping trade in each of the Onne, Lagos Apapa, Warri, Rivers, and Calabar ports, respectively. It is recommended that Port Authorities and Terminal operators, in collaboration with the Nigerian Shippers Council, should develop delay reduction policies and strategies in the ports, in order to ensure that trade processing and ship turnaround time operations in Nigerian ports comply with the global benchmark of 1.20 days for ship turnaround time and 4.00 days for shipping trade.

Highlights

Nigerian ports have been battling issues of port delays which made the ports less attractive with less patronage as prospective port users are made to spend more time and finance in transacting business with Nigerian ports.
These delays are mostly evident in the Ship Turnaround time (STRT)and Cargo dwell time (CDWT) in Nigerian Ports which are major factors in determining Port Performance globally.
The study conducted an evaluation of these delay causing factors and was able to estimate the number of extra days ships in Nigerian ports as against global benchmarks of other ports using STRT and CDWT as basic parameters of Port Performance.
The Apapa Port in Lagos State was deduced to be the Port with highest rate of delay while the Onne Port Complex in Rivers State was deduced to have the least delay in number of days.
Recommendations were also proffered as to mitigate these delays to make Nigerian ports competitive and more attractive to prospective port users.

Situation awareness information requirement for marine engine room monitoring at the future shore control center

Changhun Han — 2024-07-04

Information integration for explicit comprehension can be highly challenging in a large-scale system with interconnected equipment under the influence of the environment. This presents a great challenge in acquiring and maintaining situation awareness during the transition from traditional to remote and, eventually, to autonomous operation. However, the maritime industry appears to approach situation awareness in a highly restricted manner that focuses on visual and navigational awareness only, resulting in no support system for engine room monitoring. This research conducted a goal-directed task analysis with thirty-one subject matter experts, with an average sea experience of 9.78 years, to investigate situation awareness in the engine room. As a result, the situation awareness information requirements for nine machineries and twelve systems are developed. The findings reveal that numerous perception elements, and their complex combinations, for higher-level awareness comprise situation awareness, and situation awareness deterioration is highly likely, due to the replication or reproduction of ship sense and expanded system coverage to compensate for the lack of marine engineers on ships. This research proposes that presenting higher-level situation awareness information in consideration of schema instantiation could be a promising alternative to developing and optimising the situation awareness support system for engine room monitoring at the future shore control center.

Highlights

The replication of conventional monitoring systems for remote operation results in a loss of situation awareness information as the conventional systems are designed to collaborate with human operators onsite
The relocation of humans from ships to shore must incorporate the transfer of information that human operators generate
Situation awareness in the engine room comprises numerous information elements and requires a high level of information integration skills for comprehension and projection
Situation awareness support systems must facilitate information integration while maintaining a balance between system explainability and simplicity
Cue strength differences in comprising comprehension and projection might effectively address system complexity and situation awareness

A correlation of port users’ patronage and tariff structure of Nigerian seaports: A study of Lagos Apapa port

Mohammad Sanusi Abubakar — 2024-07-30

The study evaluated the relationship between port tariff structure and user patronage of Apapa port from 1977 - 2021. Data sourced were secondary data from the Nigerian Ports Authority (NPA) annual reports and NPA simplified tariff structure 2021 providing time series data on ship dues, ship traffic volume, vessel gross registered tonnage, pilotage charge and harbor dues. Six hypotheses were formulated from the objectives of the study to answer the research questions and provide empirical evidence for the statistical results of the study. The study employed Pearson correlation and Simple Linear Regression Analysis to evaluate the relationship between variables. Models were developed which determined the relationships between each of the independent and dependent variables. The study revealed that user patronage of Apapa port has significant relationships with port tariff in terms of the ship dues, harbor dues, and pilotage charges paid to the NPA by ship-owners and/or their agents, accounting for the increasing number of ships regularly visiting the port. In conclusion, the study infers that there is significant relationship between port tariff and user patronage of Apapa port, Nigeria. The study recommends that tariff is an instrument of port pricing which also contributes to overall transport cost, therefore, designed and billed to encourage patronage of the port industry. It is noted that maritime trade competitiveness and the tariff system of a port are considerable factors for ship-owner in patronizing a local port industry.

Highlights

The study reveals a significant relationship between port tariff structures (ship dues, harbor dues, and pilotage charges) and user patronage at Apapa port, Nigeria, from 1977 to 2021.
Moderate and competitive port pricing is identified as a critical factor that increases port patronage, leading to higher revenues for the port industry.
The study provides empirical evidence supporting the relationship between independent variables (tariff structures) and dependent variables (ship traffic volume and tonnage).
The study underlines the importance of maintaining competitive tariff structures to attract more ships and increase port revenues, informing policy decisions on port management and pricing strategies in Nigeria.

Utility of 3D printing in ship repairs

Nitin Agarwala — 2024-07-17

With a growing focus on Sustainable Development Goals 2030, sustainability has become crucial in the shipping industry. Disruptive technologies like 3D printing can reduce manufacturing and operating costs, ensuring a robust spare supply chain for ships and offshore platforms. This technology can manufacture complex shapes, aiding in repairs and maintenance without requiring extensive cutting and welding. However, the unique and non-repetitive nature of ship repairs has hindered automation in this sector. This paper examines the utility of 3D printing in ship repairs, aiming to reduce repair costs and time while enhancing sustainability. The study shows that numerous advantages exist in using this technology in the shipping industry. However, its usage needs to be facilitated with adequate public awareness, preparation of procedures for manufacturing 3D printed parts, and standardization of 3D printers.

Highlights

Sustainability has become an important aspect in the shipping industry
Disruptive technologies like 3-D printing can help achieve the desired sustainability
Use of 3D printers for ship repairs can improve availability of ships
Use of 3D printing for ship spares requires manufacturing procedures to be specified by the classification societies

Sea clutter suppression using neural network

Ravi Kumar Kandagatla — 2024-07-09

Sea clutter suppression is a critical task in radar systems to enhance target detection performance in complex naval environments and at coastlines. This paper discusses the use of neural networks for marine clutter suppression and coastal surveillance radar clutter suppression. Effective maritime clutter suppression is made possible by the Feed Forward Neural Network (FFNN) and Principal Component Analysis (PCA) based clutter reduction method, which uses neural network deep learning capabilities to automatically identify and extract features and patterns from raw radar data. Support Vector Machine (SVM) is utilized for clutter suppression along the shoreline. To train and test the network model, a sizable collection of radar measurements, including clutter and target echoes, is gathered. After pre-processing, the gathered data is used in a specially created model, which uses its underlying patterns to distinguish between target echoes and clutter. Then, clutter in real-time radar signals is suppressed using the learned neural network models, improving the detection of targets on the sea and at the coastline. Performance measures Structural Similarity (SSIM) and Signal to Noise Ratio (SNR) shows that the proposed method provides improved clutter reduction.

Highlights

Maritime clutter suppression is required for better visibility of targets
Neural Networks provides better clutter suppression
Clutter reduction using PPI images helps in Surveillance applications
Objective performance measures SNR and SSI are used for performance analysis
Better training and good dataset helps in improved clutter reduction for neural network approaches