Ship Design Research Articles

Risk assessment of maritime autonomous surface ships collisions using an FTA-FBN model

Maritime autonomous surface ships (MASS), presenting the future of maritime transport, are attracting increasing attention from the international maritime community. The collision risk analysis of MASS reveals unsolved challenges, which without appropriate solutions, will result in the error prone development of the relevant risk control measures and policies. Among the challenges, two significant ones in the existing literature are the lack of historical failure data to realise quantitative risk assessment, and 2) the complex causal relationship among the relevant risk factors. This paper aims to develop a new Fault Tree Analysis-Fuzzy Bayesian Network (FTA-FBN) model to conduct the collision risk assessment of MASS with uncertainty in data. First, it establishes a causal relationship among the risk factors through an FTA. Secondly, mapping the obtained FTA diagram into a BN allows fault diagnosis and the identification of the most important factors influencing MASS collisions. In this process, a survey is conducted to collect the primary data for configuring the conditional probabilities of the relevant influential factors and quantifying the developed BN for risk diagnosis and prediction. Finally, the new model is verified by using sensitivity analysis and three axioms and then applied to conduct scenario-based risk prediction and diagnosis to generate insightful findings to guide MASS navigation safety. The results demonstrate that the FTA-FBN model realizes the simplification of the expert scoring process, reduces computational complexity, and addresses the challenge of constructing causal relationships between MASS collisions and their risk factors due to the scarcity of historical accident data. Additionally, the BN backward reasoning identifies key collision risks, including external physical attacks, inadequate training of shore-based operators, insufficient maintenance of ship equipment and systems, and cyber-security threats. The new model when being adapted, can provide a reference for the formulation of safe navigation policies and provide important insights for shipping companies to ensure the safe navigation of their ships and shipbuilders to optimise ship design.

Prediction of cavity inception speed and underwater radiated noise of a full-scale marine propeller based on a cavitation tunnel model test

Propeller cavitation is a dominant source of underwater radiated noise (URN) from shipping, and the appropriate evaluation of propeller noise mitigation measures is important for ecological ship design. In this study, a model test procedure and scaling method to predict the full-scale URN level from hydrodynamic noise sources were introduced. The cavity size based on the empirical vortex model was considered in the proposed scaling method for a quiet cruise condition with isolated tip vortex cavitation. This relation provides information on the equivalent cavitation number for the model test to have the same relative radius as that of the full-scale tip vortex cavitation. The alternative test cavitation number can also be chosen as close as possible to the point that gives the equivalent tip vortex cavity size if sheet cavitation exists in the condition for the equivalent cavity size. In this case, additional noise scaling should be performed using the ratio of the tip vortex cavity radii. The new scaling exponent introduced in this study varies according to the distance from the cavitation inception condition and shows a decreasing trend from the value at the inception condition as the equivalent cavitation number for the model test decreases. The scaled URN levels based on the proposed method showed reasonable agreement with the measurement results of a full-scale ship. Finally, the noise reduction effect of the specially designed wake control fin and propeller was investigated through a comparative model test following the proposed scaling strategy, and significant noise reductions were observed with changes in the design configuration.

RANS study of surface roughness effects on ship resistance

Abstract In marine engineering, optimizing the performance of vessels is a key issue, particularly in increasing fuel efficiency, reducing operating costs, and minimizing environmental impact. One of the most critical determinants of vessel efficiency is hull resistance, which directly affects fuel consumption, power requirements, and cruising speed. We aim to investigate how surface roughness affects hull flow resistance, to quantify the drag variation at different surface roughness levels using special wall functions that reproduce boundary layer dynamics. This approach involves the complex interaction between the intricate complexity of roughness and the nonlinear pressure drag effects on the hull. The KVLCC2 ship model is used as a representative prototype in the CFD analysis based on the RANS equations and the k-omega SST model to independently evaluate the roughness effects on individual ship sections. The comparative analysis with empirical data reveals the complex relationship between surface roughness and ship resistance and provides insights for ship design and operational improvement. The study investigates the interaction between drag coefficient and vessel performance to improve hydrodynamic efficiency.

Numerical and Experimental Analysis of Lifting Forces of Fin Stabilizers with Fin–Hull Interaction

A fin stabilizer is one of the most effective and frequently used anti-roll devices for maintaining a ship’s operational safety and passengers’ comfort. However, the discrepancy between theoretical hydrofoil-based predictions and the actual dynamic lift force of fin stabilizers due to fin–hull interactions requires more research attention. This study investigates the effect of fin stabilizers on mitigating roll motion through the performance of extensive computational fluid dynamic (CFD) simulations over a range of fin angles and ship speeds. Model tests were carried out to validate the drag and motion results obtained from numerical analyses. The results show that fin stabilizers significantly reduce the roll motion, with the lift coefficient values influenced by the Reynolds number, leading to differences between the theoretical and Reynolds-averaged Navier–Stokes (RANS) calculations. At a high Froude number (Fr), the actual fin lift is about half of the theoretical value. These findings highlight the requirement of selecting an adequate fin area at the predominant ship speeds and ensuring an effective anti-roll effect with fin–hull interaction. This study provides a significant reference for ship design, as well as stabilization system control and optimization.

Artificial Intelligence (AI) and Knowledge-Based Engineering (KBE) in Ship Design: Bridging Tradition and Technology Through ACQUAINT

_ Despite the limited use of artificial intelligence/knowledge-based engineering (AI/KBE) in industries with small series or one-off designs, our study demonstrates the technical feasibility and potential benefits of implementing AI/KBE in ship design processes. This research presents the development of “ACQUAINT,” uniquely designed to address the complexities inherent in bespoke shipbuilding. Central to this module is a robust AI-driven inference engine, integrated seamlessly with AutoCAD through a Python-based interface, facilitating a novel approach in shipbuilding’s detail and production design phases. The module’s capability to generate optimal designs autonomously—grounded in a deep understanding of design rules, constraints, and requirements—substantially reduces the reliance on human interaction. Our initial proof of concept with “ACQUAINT” showcases measurable advancements in ship design accuracy and efficiency, highlighting AI KBE’s transformative impact in shipbuilding and setting a foundation for future research and practical applications. Keywords ship design; artificial intelligence; knowledge-based engineering; self-learning system; software development; ACQUAINT; CAD/CAM software; computers in construction; computers in design; modernization; ship structure

Modelling environmental life cycle performance of alternative marine power configurations with an integrated experimental assessment approach: A case study of an inland passenger barge

There is pressure on the global shipping industry to move towards greener propulsion and fuel technologies to reduce greenhouse gas emissions. Hydrogen and electricity are both recognised as pathways to achieve a net-zero. However, in the evaluation of the environmental performance of these alternative marine power configurations, conventional life cycle assessment (LCA) methods have limitations reflecting the varied nature of ship design and operational modes. The integration of LCA with experimental assessment could remedy the shortcoming of conventional approaches to data generation. The system energy demand data in this study was generated based on specific ship design and directly fed into life cycle assessment. To demonstrate the effectiveness and potential the approach was applied to a case study of inland waterway vessel. Suitable hybrid PV/electricity/diesel and hydrogen powered fuel cell systems for the case vessel were modelled; and hydrodynamic testing and dynamic system simulation was undertaken to provide ship performance data under various operational/environmental profiles. Lifecycle assessment (LCA) indicated hydrogen and electrical propulsion technologies have the potential for 85.7 % and 56.2 % emissions reduction against an MGO base case, respectively. The results highlight that implementation of both technologies is highly dependent on energy production pathways. Hydrogen systems reliant on fossil feedstocks risk an increase in emissions of up to 6.3 % against the MGO base case. Sensitivity analysis indicated an electrical system with electricity production from 79.5 % renewables could achieve savings of 82.2 % in GHG emissions compared to the MGO base case. Crucially, the results demonstrate a further development of the LCA approach which can enable a more accurate environmental performance evaluation of alternative marine power configurations considering specific ship design and operational characteristics. Ultimately this addition makes the results more meaningful for commercial operations and decision making in the selection of alternative marine power systems to support the transition to net-zero.

Applications of encoding-decoding network on numerical simulation mapping for propeller wake

Numerical Simulation methods of RANS and LES have been widely used to simulate the velocity field induced by propellers. In order to combine advantages of quick computation time from RANS and detailed information from LES, this paper innovatively proposed a customized data-driven encoding-decoding network to achieve mapping from RANS results to LES results. Firstly, an encoding-decoding neural network model was constructed to extract features from RANS/LES for propeller wake. The extracted features with additional information concatenation during the encoding steps were then used to reconstruct the original samples and got a reconstruction error of 1%, which proved the effectiveness of feature extraction ability of the proposed model. The proposed model was then used to map directly from RANS to LES data with a better performance compared to traditional PCA feature extraction and mapping method. Afterwards, the proposed network was applied to two more RANS to LES mapping scenarios to validate the generalization ability. The model could map a coarse-grid RANS to LES of ship propeller with less than 9% MSE error. Similarly, mapped LES of nominal wake was 98% more alike the original LES samples than the RANS samples. As a result, the proposed model could be used either to extract features for potential feature-based performance prediction, or as a quicker method for detailed simulation for propeller wake and nominal wake, thus expedites the design process of ship design.

Posters of All Participant Designs

12th National Ship and Yacht Design Competition Posters of all participants

Multi-Parametric Methodology for the Feasibility Assessment of Alternative-Fuelled Ships

The shipping industry significantly influences global greenhouse gas emissions through a predominant fossil fuel-based fleet. Regulating bodies are continuously developing rules to reduce the shipping carbon footprint. Adopting low-carbon fuels is considered a step toward achieving the Paris Agreement’s goals; however, it represents a significant paradigm shift in ship design. This work aims to illustrate a methodology for the feasibility assessment of alternative-fuelled vessels considering technical, environmental, and economic perspectives. The technical feasibility focuses on ship propulsion, fuel system safety, and design parameters. The environmental impact evaluation is based on the Tank-to-Wake and the Well-to-Wake approaches. The cost assessment is performed by estimating capital and operational expenditures, considering only the modifications required by the new fuel. The methodology addresses new-building and retrofit solutions, and can be used as a decision support tool for selecting the best strategy. A key output of the methodology is the cargo emission footprint, expressed in equivalent carbon dioxide per cargo unit. Using a handysize bulk carrier as a case study, this work points out the effects of using methanol as an alternative fuel, highlighting its impact on market and transport strategies in a sector evolving towards Eco-Delivery services.

12th National Ship and Yacht Design Competition Concluded

12th National Ship and Yacht Design Competition Concluded

Developed Status and Forecast of Intelligent Ship Application

The concept of smart ships is not limited to ship autonomous driving, it covers a broader scope, including the full life cycle of ship design, construction, operation and maintenance. By integrating advanced sensors, navigation systems and data analysis platforms, smart ships are able to monitor ship status and the Marine environment in real time, optimize route planning and improve fuel efficiency, thereby reducing energy consumption and greenhouse gas emissions. In addition, smart ships can revolutionize the shipping industry by improving maritime safety and reducing human error through remote control and autonomous decision-making. In recent years, smart ship technology has gradually moved from the theoretical research stage to practical application, and has attracted wide attention from the global shipping industry. A number of international cooperation and research projects have been launched to explore the practical application potential and promotion paths of smart ships. However, the development of smart ships also faces many challenges, including technical difficulties, legal and regulatory restrictions, and public acceptance issues. This paper will deeply discuss the current development status of smart ships, analyze the main challenges it faces, and forecast the future development trend, in order to provide reference and inspiration for the innovative development of the shipping industry.

What is a ship design firm, really?

What is a ship design firm, really?

Special ship design and ocean space multi-use synergies

This paper introduces the concept of synergistic multi-use between offshore wind and other sectors in the ocean space, to the ship design audience. We study the opportunities that arise when using special ships to service several ocean sectors, thereby realizing some of the synergies for multi-use. Multi-use of the ocean space becomes desirable due to the increasing demand for marine area by growth sectors like offshore wind and offshore aquaculture. We find that the primary opportunities to realizing multi-use synergies from vessels lie in the operational phase. Logistical support, crew transfer, emergency response, accommodation, and some inspection and repair tasks are sufficiently similar across offshore wind and fish farming that multi-use should be considered. The application of the synergistic multi-use concept also extends to other special ship types, such as offshore support vessels serving oil and gas production.

The expanding scope of ship design practice

As the former International Chair of IMDC, the initiator of the continuing series of IMDC State of Art (SoA) Reports and the lead author of most IMDC SoA Reports on design methodology from 1997 to 2018, the author has both pioneered and observed an increasingly broader scope in the practice of the design of particularly complex vessels. The paper commences with reviewing some key publications, not just to recent IMDCs, that have tracked the manner in which “ship design” (in the broadest sense) has become more sophisticated – especially in the crucial early stages of design. The diversity of ship design practice, not just due to computer-based methods, is readily observable. Moreover, the impact of computer aided design in ship design has not just been to better analyse ship performance (e. g. in hydrodynamics, strength and ship infrastructure systems behaviour) but also in the increasing use of graphical tools and design methods to enable “better ship design”. In a growing number of, mainly, academic centres, but also in some government agencies and design consultancies, there is a clear desire to better understand how to design “ships” and to manage the ship design process, especially for the most complex and novel classes of vessels. In particular, the objectives being sought when conceptualising and synthesising a range of ship options (as part of the requirement elucidation approach) in an ever-increasing scoping of the relevant issues, amounts to developing a more holistic approach. This is not just due to an increasingly complex ship acquisition and ownership environment, but also due to environmental and socio-economic (especially system safety) concerns. Overlaying all this are the opportunities or the spectre of Artificial Intelligence (or perhaps more immediately those of Machine Learning) and its likely impact on engineering practice as well as those other professions in the “marine design enterprise”. The paper concludes by emphasising that while ship design has distinct differences, when compared with most other large scale engineering design practice, the lead ship design profession of the naval architect has somehow to deal with this expanding scope in the practice of “ship design”. This means the education and on the job development thrust must broaden if the ship design profession is not to be side-lined into acting as mere hull engineers. It is argued, such a specific role will be more vulnerable in an increasingly Machine Learning dominated future, than the holistic ship creating and systems architectural alternative. Finally an ambitious vision for future ship designers is given alongside a summary of the specific main contributions by the author to ship design methodology.

The impact of maritime decarbonization on ship design: State-of-the-Art Report

The maritime industry faces a critical challenge to decarbonize and meet the ambitious goal of net-zero emissions by 2050. This transition requires innovative ship design strategies to address the increasing complexity and multiplicity of technical solutions amidst dynamic regulatory, geopolitical, and market uncertainties. This paper examines the maritime decarbonization challenge's impact on ship design and decision-making under uncertainty, highlighting the necessity for collaboration between researchers and practitioners to tackle this emerging challenge. To navigate the uncertainty, stakeholders can integrate advanced design methods and decision-making processes considering the full lifecycle and fleet-level implications. This paper promotes taking a holistic approach that incorporates regulatory compliance, technological advancements, and commercial considerations, as well as a blend of methods to manage decision-making under uncertainty. Continued research in specific areas is essential to develop and refine frameworks that optimize design and operation for the industry's sustainable future.

The importance of first-principles tools for safety enhancement in the design of passenger ships in the case of flooding events

The design of a passenger ship is a complex process covering multiple aspects of naval architecture and marine engineering to address performance, functionality safety, and cost as primary objectives. Between them, safety is a key element focusing on the people on board. In this sense, ship safety in the case of flooding events needs proper estimation from the first stages of the design process employing an appropriate metric. To this end, safety can be evaluated as a risk by calculating the Potential Loss of Life. Thanks to a multi-level framework developed during project FLARE, it is possible to calculate the risk associated with an accident, increasing the level of reliability as the design process advances. The framework aims at employing first-principles tools from the early stages of the design process, abandoning static calculations and empirical formulae as soon as data is available to set up advanced calculation techniques. Then, the framework adopts rigid-body time-domain calculations for the flooding simulations, advanced evacuation analysis tools, and direct crash simulation to evaluate collision damages. The process allows for testing alternative design solutions for the ship to enhance safety. Investigating risk control options is also possible, considering active or passive systems such as fixed foam installations, deployable barriers, or crashworthiness. Such an approach allows for evaluating safer solutions, respecting other design constraints and cost-related aspects. The present work describes the risk assessment framework for the case of flooding events, together with the different levels of accuracy that can be achieved, showing the improvements that could be reached by employing alternative risk control options.

The Impact of the new DMS-1030 Stability Standard on the Future Design of Navy Ships

In 2022, the German BAAINBw launched a revised issue of their 1030-1 stability regulations for Navy surface vessels. The improvements of the revised code concerned (inter alia) a new stability criterion for minimizing the effect of parametric rolling combined with pure loss of stability on the wave crest and revised damage stability calculation assumptions, which mainly focus on the submergence of openings and a special treatment of watertight doors. The improvements of the code were found to be necessary to keep track of recent developments in IMO for commercial ships and to update the safety level represented by the code. At the same time, the revised code gives more freedom to the ship designer, a fact which may allow novel and more cost effective concepts of Navy Ships in the near future, provided, the evaluation of the stability according to the code takes place immediately during the very early design phase of the ship. The present paper gives insight into the important updates of the code and it demonstrates at the same time how the design of Navy Ships may benefit from the revised code, if it is applied throughout the very first design phase of the ship. The paper will further present an improved design regime for the early design stage.

Seeing a Sea of Ships - Exploring the Ship Design Space in the Digital Domain

We tackle in this work aspects of the ship design space in the digital domain, with an overview of the current status and opportunities to shift from fixed arrangements towards open technologies, proposing a mix of open and proprietary databases. The discussion is focused on the visual domain and digital thread in ship design. Literature examples from the Brazilian case and the visualization of the ocean space are presented (Numerical Offshore Tank - TPN), followed by the Japanese services to design and optimize hull for specific missions (NMRI), and lastly the current open ship design library developed in Norway (Vessel.js, NTNU). We present the argument that seeing a sea of ships, that is, visualizing the behavior of many options is already a reality, accessible from a portable device, without the need a large cluster as in the past, exemplified by web-based cases. Our conclusion is that computer graphics approaches to Ship Design should be considered open and exchangeable. Naval architects should focus on what they do best: creating, analyzing, refining, storing and populating the database of the know-how from the institution (e.g. university, research institute or company).

Piping layout integrated in ship design and stability evaluation

Damage stability assessment in ship design is a well-established area of our trade. However, where originally only a limited number of aspects were involved, gradually more details are included. Notably compartment connections by pipes and ducts etcetera. Combined with a high number of damage cases, in practice this results in a set of computations which is not complex as such, yet complicated by its sheer size. Although in the PIAS ship design software suite quite some dedicated tools are available, those have never been designed to support the requirements from today. In this light the software has been extended with a new system to fully define shape and topology of compartments and their connections. This paper reports on the system design, its application in damage scenarios, and on complications.

Satisfaction of passengers - process comparison between three different cruise ship classes

In cruise ship design, a ship designer often focuses on the ship’s function, while a cruise operator’s focus is on the creation of a comfortable and enjoyable cruise experience for passengers. Today, these two viewpoints are strongly connected, and thus, the way the inside of a ship is designed can impact how satisfied passengers are on their cruise journey. Thus, we need to figure out the best way to design a passenger ship from the perspective of the passengers themselves. In this paper, we analyse the differences in the combination passenger ship environmental elements and overall consumer satisfaction in two different cruise ship classes from the same ship operator, but from different eras. First, we present a theoretical framework and model for the cruise ship environment that consist of ambient, layout/design, social, product/service and onboard enjoyment factors. Then, by using data collected from the public domain, we compare two types of cruise ships using open-source data (N=755). This allows us to identify the factors contributing to the discrepancy in expectations across cruise guests. Based on this limited data, we create several linear regression models which indicates a favourable and statistically significant link between environmental elements and passengers' conduct while on board. Information processed this manner can be utilised to make informed decisions on cruise ship layout and amenities. In addition, the developed innovative KPI proved instrumental in influencing decision-making processes related to cruise ship designs and operations. Therefore, the findings from our research show a positive link between the onboard environment and the overall happiness of passengers.