Early-stage design exploration is crucial since most of the major design decision are locked-in and only small design modifications are possible at later stages. To assess the performance of the various design candidates while performing design exploration, there are available methods and tools of various fidelities. These methods can be combined to form a multi-fidelity (MF) framework that guarantees accuracy through the high-fidelity model and achieves faster computational speeds through low-fidelity models. The present study proposes the adoption of information-theoretic entropy to improve a MF design framework based on Gaussian Processes (GPs). Entropy quantifies the uncertainty associated with the prediction of the design space. We propose using this uncertainty metric both as a criterion to determine whether further designs should be sampled to construct a reliable approximation of the design space and as a criterion to establish in which optimization step the optimization of the covariance matrix for the MF-GPs should be performed. The approach was tested to benchmark analytical functions and to a ship design problem of an AXEfrigate. The approach holds potential in practical applications, as it aids in the determination of whether additional resources should be allocated for high-fidelity analysis to support early-stage exploration.@en

The development of the global COVID-19 pandemic from 2020 onward has had significant impact on the world and specifically the maritime industry. Striking examples were COVID-19 outbreaks onboard the Diamond Princess cruise vessel and the U.S.S. Theodore Roosevelt aircraft carrier at the start of the pandemic. Contagious disease management onboard large passenger ships remains a complex issue, amplified by the international character of the industry, confined environment and shared facilities. This paper therefore presents an integrated infection and crowd behavior model used to calculate agent-specific infection risk, incorporating guest and crew circulation through a passenger ship layout. The integrated model is used to investigate the effect of ship layout design, capacity reduction and mask wearing on COVID-19 airborne infection risk onboard large passenger vessels.@en

Reducing the use of fossil fuels in shipping requires new, alternative maritime fuels. Hydrogen carriers offer a safe and energy-dense solution for storing hydrogen, a zero-emission alternative fuel. This research focuses on ammonia borane, NaBH4, n-ethylcarbazole and dibenzyltoluene. Applying hydrogen carriers influences ship design significantly, as they require additional specialised equipment to remove hydrogen from the hydrogen carrier. This research estimates the size of the equipment. As this equipment will need to be stored and maintained on the ship, the exact sizing and sequence of the additional equipment will likely influence ship design. Results show that the reactor size is significant for all hydrogen carriers. The mixing tank is considerably sized for NaBH4 and ammonia borane, while the heat exchangers are large for dibenzyltoluene and n-ethylcarbazole.@en

This paper addresses the growing offshore wind market's demand for larger turbines in deeper waters by highlighting limitations in existing installation solutions and proposing a new concept with a floating monohull, named Moonshot, which will thus be different than traditional jack-up or semi-submersible crane installation vessel options. This paper discusses the design process, which combines Ulstein Rotterdam’s Controlled Innovation and Blended Design to develop the concept. This process is used to explore various market scenarios to determine optimal vessel parameters. Results demonstrate how optimizing for financial performance or seakeeping behavior impacts the design. Moonshot's initial parameters are established, and its performance is compared to existing installation solutions.@en

The ongoing technological development of methanol energy converters (EC) towards decarbonization means that their dimensions and performance characteristics will be continually updated during the lifecycle of vessels currently designed. These advancements influence the ease of EC integration within the general arrangement of the vessel. The decision to switch from an internal combustion engine to a fuel cell or a hybrid configuration depends both (1) the technology adoption costs (i.e. CAPEX, OPEX) of the EC and (2)
on the effect of EC on the actual engine room layout. The state-of-the-art literature has typically addressed these two challenges separately. This study proposes a design method to bridge these two fields by combining the use of (1) Markov decision processes to assess uncertain future methanol EC developments during the vessel lifecycle and (2) a generative probabilistic layout algorithm to quantify the risks associated with the EC systems layout integration. The case study identifies the drivers behind the EC technology choice during the lifecycle of a notional yacht vessel.@en

This paper examines the technical and economic influence of CO2 reduction measures on the design and operation of Dutch beam trawlers. This is done by means of a parametric model used to assess the influence on the overall design of the vessel. Technical feasibility is determined by meeting operational effectiveness requirements, maximum added draught, maximum added length, and a reduction of CO2 emission by at least 40%. Secondly the model evaluates the new energy carrier and fish storage layout as a result of additional required volume. Additional volume is gained within the net store, fish hold, or by hull extension. Additionally, various propeller configurations, waste heat recovery, and regenerative braking systems are explored to reduce energy consumption. The economic performance is assessed using yearly operational requirements, capital expenses of configuration, and total cost of ownership.@en

This paper compares two 2XL monopile installation methods: at the leeward side of the heavy lift crane vessel and in the recess at the stern of the vessel. The multi-body system of the vessel, monopile, crane, and mission equipment induces interaction and resonance behaviour. Operational limits are assessed at the crane tip and pile gripper during upending and lowering of the monopile. Stern installation provides a larger operability window during upending compared to side installation. During the lowering stage, the operability depends on the monopile submergence: side and stern installation provide a comparable operability. Considering both stages, stern installation shows promising results.@en

This paper proposes a data-driven approach to reduce emissions in international shipping, aligning with the IMO's goal of achieving net-zero greenhouse gas emissions by around 2050. Digital twins (DTs) offer promise for maritime decarbonization due to their simulation and big data handling capabilities. However, fully realizing DTs for new-build is by definition challenging as it requires a real-time data connection. Thus, the research begins with retrofitting existing ships using operational data collected through Bunker Delivery Notes (BDNs), a mandatory method for larger ships since January 2019. The proposed framework constructs digital models to support the retrofit DT, that are tested on a 300m bulk carrier. A fuel consumption model is built using a gray box approach, while various wind-assisted ship propulsion systems are modeled using a white box approach. The study evaluates the design implications and emissions reduction potential of implementing these systems.@en

This paper investigates the feasibility of iron powder energy generation systems on board a semi-submersible crane vessel. This is done using a design model that integrates design information and a simulated mission profile to determine a hybrid iron powder setup split. This setup is then placed within a set of vessel designs to calculate a base level feasibility looking at the draft, stability, and emissions decrease. For those concepts that were technically feasible, the new hybrid iron powder setup contributed to a reduction of CO2 up to 25-50% and a reduction of NOx emissions between 15-50%, depending on the mission profile.@en

Keynote. The evolution of ship design from a manual toward a computer-aided, digital approach has been drastic after the 1970s, with the explosive development of computer hardware and software systems. In today’s era of smart digitalization in the frame of Industry 4.0, recently introduced digital/software tools and systems increase the efficiency and quality of the life-cycle ship design process, but also the operational complexity and the demand for proper training of users of software platforms. Parametric optimisation and simulation-driven design, product lifecycle management, digital twins and artificial intelligence are nowadays frequently used by the maritime industry during the commissioning/quality control activities and in the various phases of ship design, ship operation and ship production. This paper presents an overview of notable developments in the above areas and the way ahead to respond to present and future challenges of the maritime industry.@en

Perceptions of feasibility in design spaces are susceptible to change if new and conflicting information becomes available later. Design space reduction decisions made in set-based design can amplify vulnerability to new information if remaining design spaces and present perceptions are unable to adapt. This paper considers different ways new information can alter perceptions of feasibility for complex design problems and introduces an early, probabilistic strategy for quantifying the risk of eliminating potential design solutions based on the vulnerability of remaining design spaces to new information. Emergent designs of a set-based design process gauging this risk are evaluated against one neglecting it for an analogous design problem. Early results indicate that the probabilistic model is able to effectively delay design decisions and prevent lock-in while design space understanding is still growing.@en

The prediction of the statutory attained subdivision index is a challenging issue for the initial design of ships due to the design freedom offered by a probabilistic damage stability assessment. To this end, optimisation techniques integrated with a parametric model of the internal layout may generate a preliminary subdivision design, fulfilling damage stability regulations and cargo volume requirements. The present study explores using a multi-objective constrained optimisation algorithm coupled with a parametric model of a single hold cargo vessel, first investigating two design goal alternatives and secondly performing a global sensitivity analysis on the design variables for the most promising solution. The adoption, in parallel, of state-of-the-art practices shows the validity of the obtained solutions and the time benefits for designers. Nonetheless, the non-linear nature of probabilistic damage stability does not allow for clearly identifying the most impactful parameters on the attained survivability index.

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The adverse human contribution to global climate change has forced the yachting industry to acknowledge the need to reduce its environmental impact due to the client's increasing pressure and potential future regulations to limit the ecological effects. Unfortunately, current real-world data presents a significant disparity between predicted and actual gathered energy consumption results. Thus, this research aims to develop an approach to accurately predict total dynamic Energy Consumption (EC) using real operation voyage data for the improved early-stage design of future yachts. A Grey-Box Modelling (GBM) solution combines: physics-based White-Box Models (WBM); and Black-Box Model (BBM) artificial neural networks to provide estimations with high accuracy and improved extrapolation capacity. The study utilizes ten months of onboard continuous monitoring data, hindcasted weather, and voyage information from a Feadship fleet yacht. Upon applying a sequential modelling methodology, predictions are compared between the three model categories, indicating propulsion and auxiliary estimates fall within 3% and 7% error of operational conditions. The study is then continued using external range datasets to evaluate the extrapolation potential. While GBM improvements are seen over the BBM, limitations were directly related to the strength between dynamic WBM input-output correlations. Ultimately, GBM's have the potential to improve both accuracy and extrapolation ability over existing WBM and BBM's; however, much is dependent on the strength of the input-output relationships.

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Trim optimization improves the energy efficiency of ships, thus reducing operational costs and emissions; however, trim tables are only available for a limited number of ships. There is thus a desire to develop additional, more accurate trim tables without the need for expensive model testing. The objective of this research was to develop a method to decrease fuel consumption by trim optimization, by a dynamic shaft power estimation model based on available operational data. A method that uses noon report data and a grey-box modelling approach is proposed. The grey box model consists of a multi-layer feedforward neural network to estimate the required shaft power, using operational parameters and an initial estimate of the required shaft power. A case study is presented for a modern chemical tanker and sea trials have been conducted to validate the results. The method provides correct trim advice for full load conditions; however, the magnitude of the effect is smaller compared to sea trial results. The model is able to estimate the required power with an average accuracy of over 6% for a random subset of the noon report data. Due to challenges inherent to noon reports as a data source, the actual effect of trim and speed have a bigger magnitude than the extracted trend.

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This article examines the potential implications of using iron powder as an alternative fuel on the design and performance of container ships. Iron powder is a relatively new alternative energy carrier and one in which little research has been done into the application on-board vessels as part of the maritime energy transition. The key benefits of iron powder are that it is a circular energy carrier and the combustion process emits no greenhouse gases. Transitioning to iron powder is expected to have far reaching implications for the design and performance of ships. Thus, this paper aims to perform the first study assessing the potential of this concept applied to container ships. To do so, a preliminary design space was explored with a custom parametric design model developed to generate preliminary designs of iron fuelled container ships as a function of the operational profile. Using this parametric design model, it was identified that iron fuelled container ships are weight limited, unlike conventionally fuelled container vessels. Furthermore, iron fuelled container ships are best suited for short voyages at low cruising speed. For these voyages, it was concluded that iron fuelled ships are economically feasible; however, other alternative marine fuels are likely more profitable than iron due to the low efficiency of iron fuelled ships and the high cost of iron per unit energy.

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Design rationale is a promising way of capturing design decisions and considerations for later retrieval and traceability to improve collaborative design decision-making. To achieve these perceived benefits for early-stage complex ship design, this paper first elaborates on the development of a proof-of-concept design rationale method. The method aims to aid ship designers in the continuous capturing and reuse of design rationale during the collaborative concept design process. Second, the setup and results of an experiment conducted with marine design students and with experts are discussed. This experiment shows how the developed design rationale method benefits collaborative design decision-making such that it leads to improved insight into design issues across the design team during a single design session.@en

The adoption of alternative energy carriers is one of the key ways to meet the increasingly stricter emission regulations faced by shipping vessels from the international maritime organisation (IMO) and European Commission. To support this objective, this study examines the challenges and uncertainties associated with implementing a methanol power propulsion and energy (PPE) system on the design of a vessel. This paper argues that new fuels, such as methanol, should be treated as disruptive innovations due, in part, to the uncertainties surrounding their implementation. Their integration causes challenges regarding systems selection, layout design, and maintaining strict safety measures. In the case of methanol, current research treats the fuel as a system conversion based on diesel fuel. This paper provides a review of the state-of-the-art on the design of methanol fuelled vessels, and identifies a research gap related to the need for a new suitable design method for the design of ships integrating future alternatively fuelled PPE systems. A design approach inspired by model-based systems engineering integrating uncertainty modelling is proposed to examine the influence of uncertainty on the design of the vessels. The impact of uncertainty on the design is investigated through a case study of a simplified engine room layout utilizing a genetic algorithm to produce layouts for variable PPE systems dimensions within a Monte Carlo simulation.@en

This paper explores the design and feasibility of a 200-passenger, 30- to 40-knot emission-free ferry as a potential variant of the traditionally powered Coastal Cruiser 200 ferry currently operating in the Chinese Pearl River Delta. The Pearl River Delta is one of China’s most densely urbanized regions and faces numerous social, health, and economic issues due to air pollution. In addition, globally, there are no currently-operating zero-emission ferries that, at minimum, sail at 30 knots and carry 200 passengers. To assess the feasibility of the new ferry, a two step approach was followed. First, an evaluation of efficiency improving measures, energy carriers, and propulsion systems was performed to assess the tradeoffs and identify early design choices. Second, to quantify the most technically feasible design, a technical parametric model was developed specifically for this case study. Results showed that the ferry is technically feasible using batteries, compressed hydrogen fuel cells, or liquid hydrogen fuel cells; however, each has its distinct advantages and disadvantages which influence the potential final viability. Despite the regional focus of the case study, results are applicable to all ferries with similar design requirements.

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The focus on digitalisation in manufacturing is spreading to other industry fields, including large and complex objects like ships. Such interest introduces the concept of Digital Twins in supporting designers and operators through the whole ship-life cycle. However, the term Digital Twin is typically abused in the shipping industry, many times erroneously referring to any virtual version of a model-based system as a Digital Twin of the ship. The mutual data exchange between the physical and virtual environment, which is the basis of a true Digital Twin, is mostly missing, confusing a virtual model with a sophisticated living virtual environment. Few reviews are available in the literature for Digital Twins on ships. This systematic review proposes the identification of weaknesses and correlations between current Digital Twin applications in the maritime industry and other industry fields. Furthermore, the methodology applied here may be repeated in future studies to provide a fair and objective overview of the research advancements in the topic. The study highlighted how literature scarcely addresses the design and decommissioning phases, indicating that research should focus on these topics, especially concerning the design of future ships.

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This paper presents a new design rationale methodology to support collaborative design decision-making during early stage complex ship design. The nature of collaborative design is described and the need and key challenges of design rationale capturing and reuse are identified. Subsequently, the methodology is developed to overcome these key challenges. A primary characteristic of the methodology is it’s integration with design tools to reduce intrusiveness and enhance usefulness during collaborative design sessions. Finally, a case study was used to demonstrate the usefulness of the developed design rationale ontology, a critical step in providing designers an improved capability to capture and reuse design rationale during collaborative design decisionmaking.@en