In the face of escalating global emissions and rising awareness of the dangers of climate change, there is a need for sustainability initiatives across all industry sectors. Within the shipping industry, this is leading to a resurgence of interest in wind-assisted propulsion systems. This research investigates the hydrodynamic design of a wind-assisted cruise ship, aiming to redefine the image of the historically very polluting cruise industry by designing a vessel aimed at achieving 50% propulsive fuel savings through wind-assisted propulsion. The literature review provides the broad theoretical and computational background necessary for the design evaluation. The description of the historical evolution of wind propulsion, as well as state-of-the- art wind-assisted vessels and emerging concepts, provides the inspiration for the design investigation. A detailed hydrodynamic analysis was conducted, focusing on variations in hull design (B/T ratio, dead- rise angle) and appendage design (skegs, passive and active anti-drift fins). The efficacy of the mod- ifications was evaluated on an operational level using power prediction programs, allowing for perfor- mance assessments in varying conditions. A semi-empirical approach for the prediction of hydrodynamic forces and moments under drift using the maneuvering tool SURSIM is hypothesized as a computationally light alternative to numerical methods. However, SURSIM was found not to have the required fidelity to accurately predict the lift coefficient of the hull at small drift angles. Therefore, a computational fluid dynamics (CFD) approach was adopted for the determination of the hydrodynamic loads. The optimal unappended cruise ship design resulted in fuel savings of 34.5%. Optimal hydrodynamic efficiency favors a hull optimized for minimal resistance, and a retractable, active angle-of-attack fin for improved side force and yaw moment balance. The introduction of the fin led to an increase in fuel savings to 37.3%. Notable improvements in ship maneuverability can also be expected based on significantly reduced rudder actuation in sailing conditions. Operational variations have a large impact on fuel savings. Using the wind statistics of the N. Atlantic Holland America Line increased fuel savings to 48%, compared to the MEPC.1/Circ.896 standard. Con- siderable further gains can be achieved through the efficient handling of surplus wind power. Allowing a variable operational speed between 10.6kn and 20kn instead of a fixed speed of 12kn increased the fuel savings on the N. Atlantic route to 56.7%. Wind-assisted propulsion can be a viable strategy for significant fuel savings beyond 50%, and efficient appendage design can meaningfully improve the ship’s performance. Accurate prediction of fuel sav- ings requires clear knowledge of the operational conditions and control strategies. Further investigation of the detailed appendage design, and comparison of variable speed operation to the employment of a regenerative propeller mode is recommended. This thesis contributes to the evolving discourse on sustainable maritime transport, specifically within the cruise ship sector, by providing a comprehensive analysis of wind-assisted propulsion’s potential benefits.

The offshore wind energy sector is rapidly growing with an increase in the capacity of offshore wind turbines, resulting in increasing dimensions of offshore wind turbines and their foundations. Additionally, there is a tendency to locate offshore wind farms more offshore because of more consistent wind speeds and more space. Sites with a water depth less than 70 metres are suitable for fixed-bottom foundations. A commonly applied fixed-bottom foundation is the monopile due their simplicity, ease of installation, and relatively low costs. Over the past years, the diameter of the monopile increased from an average of 5 metres tot 10-12 metres. These ever-growing monopiles need to be installed from floating vessels, such as heavy lift crane vessels, which are not dependent on water depth, instead of jack-up vessels. During installation, heavy lift crane vessels form a multi-body system with the crane and monopile and pile gripper ring, inducing coupled dynamic behaviour, resulting in resonance behaviour.

Currently, monopiles are installed at the side of a heavy lift crane vessel. However, a new technology is in development to install monopiles in a recess at the stern of the vessel. The upending and lowering of stage of monopile installation are considered as critical events and it is obligatory to assess the operational limits of these stages during the planning phase. The purpose of this thesis is to compare side and stern installation of 2XL monopiles from a heavy lift crane vessel during the upending and lowering phase in terms of operational limits. Therefore, a case study is performed, using Hornsea Offshore Wind Farm on the North Sea as a reference project. Time-domain simulations are conducted in OrcaFlex for various significant wave heights and spectral peak periods for both side and stern installation. The operability of the mission equipment is assessed, resulting in a comparison for side and stern installation. It is found that during upending stage, stern installation provides a larger operability window compared to side installation. During the lowering stage, side and stern installation have a comparable operability window. In conclusion, stern installation shows promising results to further develop this installation method.

This thesis investigates the implementation of modularity in the early-stage design process of custom luxury yachts, specifically targeting the Feadship fleet between 75 and 110 meters. The research aims to determine whether modular design methods can optimize efficiency and creativity while maintaining the high degree of customization demanded by clients. To address this, the thesis introduces Modular Function Deployment (MFD) as a structured framework for identifying and evaluating yacht systems suitable for modularization.

Key insights from the study demonstrate that MFD, coupled with innovative tools such as the Area Prediction tool and the Arrangement Generator tool, can enhance both design creativity and efficiency. Contrary to concerns that modularity might restrict creativity, these tools offer designers a structured yet flexible platform for exploring numerous configurations. This encourages the exploration of innovative design arrangements that push the boundaries of conventional yacht architecture.

The study also focuses on evaluating how designers can benefit from modular principles. The Area Prediction tool, based on the Random Forest regression model, predicts the surface areas of different yacht modules. The Arrangement Generator tool allows designers to visualize potential layouts, iterating through various combinations rapidly. These tools support designers in generating new, optimized arrangements that maintain high levels of customization. A case study with Feadship designers highlights the fact that modularity offers substantial benefits, although challenges remain in terms of integrating these tools fully into the creative process.

Future research is suggested to explore whether yacht clients will accept modularity without perceiving the designs as less bespoke, how designers can shift from traditional bespoke methods to modular approaches, and how regulatory challenges may be navigated. But more important, the impact of the ongoing energy transition on future yacht designs is considered significant, necessitating future updates to the prediction tools as yacht specifications evolve.

With the increasing water depths of the new offshore wind farms, the challenging soil conditions, the availability of assets, and other factors, jack-up installation vessels may no longer be suitable to complete the installation scope of work for the new wind farms. Therefore, installation methods and techniques using floating vessels must be further developed to allow safe and efficient installation of wind turbines.

Due to the response of floating installation vessels, excessive motions can be transmitted to the lifted object, making the installation operation very weather sensitive. To increase workability, Heerema Marine Contractors (HMC) has developed the RNA method for wind turbine installation using a semi-submersible crane vessel. This method uses a temporary support structure on the vessel deck (installation tower) where the RNA is fully assembled with the assistance of the GREP (Guided Root End Positioning) tool to constrain the blade root to the top of the installation tower and consequently the hub. Finally, the RNA is installed in a single lift on the WTG permanent support structure. However, the GREP tool is compatible only with a specific range of wind turbine blade dimensions; therefore, for a different-size wind turbine blade a new GREP tool must be designed, fabricated, and mobilised.

This project proposes an improvement to the HMC's RNA method to eliminate the necessity of the GREP tool. That is, a motion-compensated Stewart platform attached to the crane boom, where the blade is fixed to be installed in the hub on top of the installation tower. The project is developed by investigating the initial assumptions; those are crane boom stiffness, blade deflection, installation tower motions and their influence on the vessel's response, and aerodynamic loads acting on the blade during installation. The kinematics (inverse and forward) and dynamics of a Stewart platform are formulated, as well as the mechanical concept of the proposed system and the blade installation process using a Stewart platform attached to the crane boom.

Furthermore, to eliminate the requirement of the GREP tool, a control system is developed to compensate for the blade root motions relative to the hub. The motion control system uses sensors to measure the hub's motions and generate the Stewart platform actuators' set points. Different possible sensor set-ups are evaluated, and a filter is designed to reduce the influence of the sensors' noise. The control system is developed on the basis of feedback PI (Proportional and Integral) and adaptive feedforward control to the actuators (hydraulic cylinders).

It is concluded that it is technically feasible to use a motion- compensated Stewart platform for blade installation in the RNA method. However, the economic aspects of the proposed solution must be investigated.

The accessibility in far offshore wind farms during unplanned maintenance is reported to be insufficient. This system largely consists of daughter craft, small vessels that increase the multitasking capabilities of an SOV. The goal of this research is to improve the accessibility to ultimately increase turbine availability, which is proven in this work to be necessary. The research is carried out in cooperation with Siemens Gamesa, a major wind turbine supplier. This research builds off the basis laid by Brans et al., who applied a needs analysis on the daughter craft system. This research applies the next step in the systems engineering sequence: concept exploration. The scope of this research extends beyond that of the daughter craft to any system that can improve the unplanned maintenance of far offshore wind farms.

Because the subject matter is relatively little covered in the scientific field, this research lays great emphasis on the context of the problem. The status quo of the sector is described in terms of equipment, operations, regulations, forms of limitations, financial context, trends, and different stages performed in unplanned maintenance. By performing an analysis of alternatives a high potential for system improvement is found.

A set of performance requirements for the accessibility system is developed to structurally assess the system and possible improvements. These performance requirements are used to determine which alternative system holds the most potential for accessibility improvement. Increasing daughter craft dimensions is chosen as the most potent alternative. A feasibility study is performed on deploying CTV-sized vessels far-offshore for two weeks thereby significantly reducing transfer time and distance. These vessels are called far-offshore transfer vessels (FOTV).
Different configurations are tested for storing the FOTVs far-offshore when not in operation and interfacing with the SOV. Two principal concepts are identified: Enlarged daughter craft, where the FOTV is stored on the SOV, and the exposed principals, where the FOTV remains in the water. One configuration of the enlarged daughter craft principal is deemed feasible: The lifting launch configuration. Two configurations of the exposed principal are deemed feasible: The connected to the SOV configuration and the moored to designated platform configuration. Furthermore, a model is constructed to assess the logistic and economic merit of different combinations of FOTV, wind farm, and configuration.

This research concludes that the deployment of a FOTV combined with a lifting launch configuration is most profitable for any wind farm. Nonetheless, the exposed principal concepts outperform the current system significantly. The choice of FOTV depends mainly on the accessibility performance and day rate of the vessel but also on the wind farm. The model predicts that in the current market, the highest-performing CTVs are the most profitable options for FOTV deployment. Finally, the results show that the effects of improving accessibility vessel performance relates inverse exponentially to profit performance.

Superyachts are expected to be perfect since the owner pays millions for them, and the worst that could happen is tilting the ship once it floats. The lightweight, including the center of gravity, is essential to know with a high degree of certainty to prevent this. However, the lightweight is already expected in an early design phase, when still a lot is uncertain. When the weight deviates from the initial estimations, it would predominantly lead to unwanted changes in speed and stability.
The objective is to research a standardized way of estimating the weight of a superyacht in different stages of the project, including validating the current, improved, and new methods and combining this in a single tool. In the design phase, at the beginning of the project, most weight items or groups are based on comparisons with another yacht. Currently, this is done based on a single ship similar to the new design. Still, a significant improvement will be to compare the new design with multiple yachts, with the possibility for the designer to choose the comparison vessels.
The margins can also be researched. Currently, only the starting margin and the production margin at the end are set, but not in between. A guideline should be provided to indicate what margin is expected during each project stage. Also, the complexity level can influence the expected margin, which can all be placed in a table for a clear overview.
The center of gravity estimation of the items is done similarly to the weights. The weight distribution of the yacht is currently not included in the weight estimations, but it will be included in the new weight estimation tool. To achieve this, besides the CoG, the length of the items also needs to be noted for the longitudinal weight distribution. With this information, distribution along the ship in the length direction can be calculated per meter. The model can be validated by comparing these early design stage estimation methods with the more detailed estimates at the end of the engineering stage.
Finally, the research question can be answered, concluding the research. The weights and centers of mass of a superyacht can be predicted in the design phase by comparing the new ship to a database of existing yachts. These estimations can indicate the calculations’ completeness and accuracy at the engineering phase. The weight list includes margins based on the project’s stage and complexity. This way, the estimations and calculation accuracy are transparent and explainable. Also, the longitudinal weight distribution is added to complete and track the center of gravity estimations. Both the design and engineering department can present their findings and estimations next to each other, resulting in a clear overview of development during the project.

The current global fleet is still dependent on conventional fuels as energy source to transport goods to various places in the world. These conventional fuels, such as MGO or HFO, emit large amounts of greenhouse gasses and other pollutant emissions. Regulation concerning these emissions becomes stricter every day, therefore institutions and governments have established reduction targets. To accomplish these reductions, net zero alternative fuels are serious candidates to investigate. As a result of these developments, Thecla Bodewes Shipyards is interested in solutions to reduce these emissions for their general cargo vessel series.

Therefore, the objective of this research is to select the most suitable alternative fuel power- and energy system for a 7000 DWT general cargo vessel. In order to accomplish this objective, a literature review concerning potential alternative fuels is performed. After the selection of methanol as alternative fuel, the object of study is defined with specific boundaries and assumptions of the model. For the comparison of the current power- and energy system with future power- and energy systems, performance indicators are established and calculated. Subsequently, a case study is performed in which three concept designs for storage of methanol and two power plant configurations are proposed based on suitable
energy converters on methanol and electrical load balance of the vessel. This research concludes that the fuel consumption of the vessel increased by a factor 2.1-2.4, range decreased by respectively 35% and 45% and payload decreased by 70 tonnes. Concerning the application of a methanol power- and energy system on board of a 7000 DWT general cargo vessel, a SI-ICE power plant with methanol as main fuel seemed most feasible.

The diffuser stern is part of a design concept from Damen and the TU delft: the interceptor diffuser. This concept aims to improve the seakeeping behavior of fast ships in waves. With PIV measurements, a contribution to the development of the diffuser stern is made. The flow acceleration and detachment are studied, and a comparison with a CFD pre-study from Damen is made.

This study aims to provide a proof of concept of a plug-in hybrid electric superyacht. In this way, the yachting industry can help reduce carbon emissions worldwide and potentially increase comfort levels. The concept takes advantage of the typical operating profile of a yacht. A statistical analysis is performed to discretise this and obtain parameters for the all-electric design range at design speed. The available shore power is examined by means of a questionnaire. Three options to compensate the battery weight are presented to minimise impact on design. The resulting concept versions are checked for their potential impacts on four aspects: Design, Sustainability, Comfort and Operation. This includes a life-cycle assessment that results in serious impacts on sustainability at an all-electric range of 2% to 3% of the full range capability. Finally, the concept is tested by means of a test cruise.

The global temperature is rising as a consequence of the climate change. In order to stop the further increase of the global temperature, the international community has decided to aim at reducing global greenhouse gas (GHG) emissions in the near future. To achieve this ambition, various alternatives in shipping need to be explored including sailing on alternative fuels.
This study investigates the consequences of sailing on alternative fuels. It is investigated which problems might occur when sailing on alternative fuels, which rules are mandatory when sailing on alternative fuels and as a consequence what the effects are on the cargo transport costs.
The problems occurring when sailing on alternative fuels are caused by the lower energy densities of these fuels, the rules and requirements with regard to the storage of some of these fuels and the shape of the storage tanks for some specific fuels. The shape and requirements regarding the fuel storage tanks can make it necessary to replace cargo for storage tanks, which will result in increased transports costs. Furthermore, the lower energy density of alternative fuels result in more fuel weight, or volume as compared to conventional fuels. In order to transport the same amount of cargo, an extra bunker stop, or taking less fuel and reducing the sailing speed, can be an option. Another option to compensate for the increased weight, or volume of the alternative fuels, is to reduce the cargo taken on board. All options will result in higher transports costs as compared to sailing on conventional fuels. To investigate how these extra costs are composed a main question has been formulated: "In a situation where the transport costs are minimized, how do the transport costs compare when sailing on various fuels with different energy densities than conventional fuels?".
To answer this main question, a model was developed. The model is suitable to calculate the transport costs in various situations. For this research, three vessel types on three operations, using seven fuel types have been analyzed.
The analyzed vessels were a container vessel, an oil tanker and an ore carrier. The chosen voyages are common voyages. The analyzed fuels are fuels which are able to achieve the goal of reducing the CO2 emission with 70% per transport work in 2050 as compared to 2008. Heavy fuel oil was used as benchmark. Based on the simulations used in the developed model it was found that: the costs of alternative fuels are higher than those of conventional fuels. Batteries are too heavy, too large and too expensive to be considered as an option, for the researched vessels and operations. The capital costs of fuel cells make that the use of fuels in combination with a fuel cell is currently expensive at higher speeds. High fuel storage costs make hydrogen currently not competitive with conventional fuels. The transport using an oil tanker are the lowest for hydrotreated vegetable oil, second lowest for ammonia in combination with an internal combustion engine and the highest for battery electric.

Superyachts are large emitters of greenhouse gases, as well as other emissions such as NO_x, SO_x and PM. In order to meet the climate goals set by the IMO, to reduce GHG emissions by 50% in 2050, alternative fuels are being investigated. Methanol is an alternative fuels with great potential. Methanol can be produced completely carbon neutral from biomass or captured CO₂, contains no sulphur, can be stored in liquid form at atmospheric pressure and temperature and can be used in both fuel cells and combustion engines. There are currently no yachts sailing on methanol but methanol has already been implemented in several other ships. Both yacht builders and owners show interest in the implementation of methanol. Since it is unclear which alternative fuel will become the standard on the long term in the yachting industry, it is of interest to also investigate the impact over a longer period of time or of several pathways. Previous research is limited to emissions and costs related to alternative fuels on a limited range of ship types which do not include yachts. The impact of methanol on the design, emissions and costs is still largely unknown for yachts. In order to determine this impact, the properties of methanol, rules & regulations regarding methanol, design impact of the storage of methanol, environmental impact of using methanol and the impact on costs are investigated. To determine this impact for several yachts, a tool has been developed which can be used from the early design stages. The tool uses the properties of a yacht to determine power and fuel volume requirements for the implementation of methanol. It also determines the available volume in the yacht for methanol storage in a basic tank arrangement. Together these form the properties of the yacht with the implementation of methanol. From these properties, the emissions and costs are determined and then combined in a pathway analysis to determine differences in impact of several future pathways. The results show that using methanol generally has a positive impact on emissions, compared to a diesel yacht. Methanol offers SO_x free emissions, a reduction of PM emissions and NO_x emissions equal to that of diesel without the necessity of after treatment. CO₂ emissions slightly increase with fossil methanol but can be net zero with renewable methanol. The impact of methanol on converter and storage costs is considered negligible compared to a diesel yacht. Fuel costs of fossil methanol are slightly higher than fossil diesel, renewable methanol fuel costs are lower than renewable diesel and 5 times higher than fossil methanol. The impact of methanol on the design is relatively large. Compared to diesel, approximately 2.3 times the amount of fuel is required for an equal range. The double bottom is not a feasible location for methanol tanks. A significant amount of interior area is occupied by the fuel tanks and the surrounding cofferdams. Therefore retrofitting existing yachts with methanol is not considered feasible. For new designs, methanol is considered a feasible option.

Distribution system robustness estimation is crucial in performing a substantiated trade-off in early-stage ship design. To improve the current robustness estimation, a maritime robustness approach (de Vos, 2018) is compared to and verified by a general network robustness approach (Van Mieghem, 2010). The first studied approach is verified by the second approach. However, the applicability of the robustness measure remains limited due to the graph requirements generally accepted within the field of graph theory.

The urgent development of green energy has become a worldwide trend in the war against the threat of global warming and the impact of extreme weather. The offshore wind farm is one of the solutions that are able to harvest energy sustainably from the environment. To erect these offshore windfarms, the debate about whether a new fleet should be designed and built or make the existed offshore fleet go under retrofitting has been raised. The stakeholder group involved in this issue is formed by the ship designers, ship operators, and market analysts. The difference between the existed offshore support vessel fleet and the offshore wind farm support fleet is the former is built to perform a certain operation and will require another considerable investment to be retrofitted while the latter is looking for solutions to switch from different equipment thus to keep the flexibility between different operation.
The main objective of this research is to propose a ship design methodology to enable the offshore wind farm's request in mission flexibility by improving the design process in the preliminary design phase. Modularity and Knowledge Based Engineering (KBE) are chosen to be the two main topics to support the research objective. To narrow down the research scope, the research object is limited to a small Offshore support Vessel fleet that is able to perform service throughout the lifecycle of an offshore windfarm.
The application of the modularity concept is to break down the vessel system into smaller subsystem or function blocks then reassemble them to be self-sufficient modules. Modules are the basic elements for forming a modular platform to provide a basic model that is able to perform various operations by mounting different equipment. In the former research done in NTNU, a methodology for manipulating the modularity to assemble a product platform by processing previous configuration scripts has been developed. It has greatly reduced the repetitive and iterative works in the design of similar vessels, especially the design for OSVs. Though the configuration scenarios are flexible to change, the pre-designed modules' properties are limited by the based configuration. On the other hand, the configurations are closely tight to the hull shape thus limited the freedom from both the hull design and configuration design. In this research, an improved configuration generator is developed to separate the configuration design and the hull design. The proposed methodology will also keep the flexibility in importing new configurations and the latest hull shapes without conflicts.
Knowledge based engineering is another topic included in this research. It has been proved and widely used in the aerospace industry. As for the ship design industry, the application is limited to local structure design. KBE is a bridge to bring the user and the designer together in the design project. It consists of a programming stage, Knowledge Based System (KBS), to process the selection of suitable design cases and a visualization stage, Computer-Aided Design (CAD) ,to give a direct review on the whole design project. The fundamental drivers for each KBE system are called "High Level Primitive" (HLP). They are the basic units for the knowledge stored in the database. KBS picks out suitable HLPs from the database and assigned them in a configuration script thus forming a design result stored in the digital world. CAD will take over the result and visualize it in the drawing window. This is the proposed methodology to fill the gap between the modularity re-configuration and the diversity of modules.
A Multi-Model-Generator (MMG) will become the final output of this research. It is designed to be able to reproduce several vessels in the OSV market. A further demonstration of the ability to generate a modular OSV product family at the end of the research. Though the modeling output has been proved to meet the index set for the research object, the MMG has the potential to be improved in the future by importing a well-constructed database from the industry.

Wind turbine industry is growing and future predictions are promising. However, a shortage of installation vessels could influence this growth in offshore wind industry. Commonly, wind turbines are installed in components using a jack-up vessel. Occasionally, wind turbines are installed fully assembled. The center of gravity of a fully assembled wind turbine is relatively low and thus lifting above the wind turbine is not necessarily for fully assembled wind turbine installation. Wind turbines can be installed fully assembled using cranes in twin lift configuration to reduce required lifting capacities. The flexibility and scalability of the vessel depends on the location of the cranes on the vessel. Different vessels can install wind turbines with their advantages and disadvantages. To identify these solutions, principles are proposed and compared with state-of-the-art vessels for wind turbine installations. A morphological analysis is used to identify promising solutions for fully assembled wind turbine installation. Eight concepts are compared in a scenario comparison with varying distance between nearby marshalling ports and the wind turbine park location. Several solutions show subsequent improvement in installation rates. One new concept, the PWT installation vessel, shows overall improvement in installation rates. This solution, developed by the author of this report, is proposed for flexible and scalable fully assembled wind turbine installation.

This thesis is done in cooperation with Sime Darby Oils Zwijndrecht (SDOZ). SDOZ is a refinery of vegetable based oils. The goal of this thesis is to optimize the scheduling of the Refined Oil Storage (ROS) of the refinery. This is done because within the company it is suspected that the current way of assigning the tanks, that is reactively by hand, is severely limiting the amount of usable free storage volume within the ROS. By increasing the amount of usable volume within the ROS, the production in the refinery, and therefore its profits, could be increased. This thesis starts out by analysing the exact scheduling problem at SDOZ. This information was then used to compare multiple scheduling optimisation methods from the literature in order to find the best applicable method. This was "A novel network-based continuous-time representation for process scheduling". The report continues by verifying this method, by reproducing example cases included in the literature. During these reproductions some issues were found, which were resolved by making modifications to the method. The next step was to improve the method to better suit the method to be used to schedule the SDOZ ROS. This was done by creating additions, which included the use of loading spots, the use of preloaders, and the need for quality checks. The complete method, including all features of the literature, and the additions made in this thesis, was verified after which it was validated. In the validation the developed method was compared to the current situation at SDOZ. This comparison showed that using the method developed in this thesis can improve the amount of usable free storage volume within the ROS significantly. It is therefore recommended for the company to implement the developed method. In this thesis the first steps needed in order to apply the method to the ROS of SDOZ are taken. In future research this could be used to completely optimise the scheduling of the ROS, something that was due to calculation power limitations, not yet possible in this research.

The current operational cost estimate applied by shipping management companies is insufficiently valid and accurate for determining the operational budget. Most shipping management companies include scheduled maintenance jobs in the operational cost calculation. Scheduled maintenance does not take unforeseen maintenance into account. In retrospect, unforeseen maintenance makes up approximately 8\% of the total operational costs. The estimation of the operational costs can be improved by including the unforeseen maintenance costs. Improved operational cost calculations lead to better substantiated maintenance policy decision-making. Therefore, the (unforeseen) maintenance costs over the lifetime of a vessel are modelled. This research focuses on maintenance cost calculations, based on failure behaviour. First, it is explained how the Maintenance Cost Model calculates and compares the costs of different maintenance policies. Thereafter, the model is validated in a case study. The achieved cost reductions resulting from the case study varied from 0\% to 70\%, with a conservative average of 16\%. Next, the case study conclusions are assessed in a sensitivity analysis. The model generates a, system specific, cost based ranking of the maintenance policies. The ranking can be used by shipping management companies, to obtain a better substantiated system specific maintenance policy. The developed model in this research is generally applicable and proves the concept. The research concludes with recommendations for future research, which includes further expansion of the Maintenance Cost Model and the possibilities to increase the likelihood of the number of replacements.

The shipping industry contributes significantly to the global greenhouse gas emissions due to the use of cheap fossil fuels. The booming cruise ship industry is forced to reduce the emitted greenhouse gases and emission of carbon dioxide to be able to access remote areas with higher restrictions and to comply with upcoming regulations. Fuel cells are a promising alternative to conventional diesel-powered systems to reduce the emissions. Next to the physical implementation, fuel cells have additional operational limiting factors, which have to be matched with the power demand. Compared to conventional combustion engines, longer start-up times and a lower dynamic response ability can be expected. Typically, the energy demand is estimated for all electric power consumers with the load balance approach in the conceptual design phase. The actual power demand is calculated based on the absorbed power and additional predefined factors for specific conditions. This conflicts with the dynamic power demand of cruise ships in various operational conditions. This thesis discusses the used bottom-up approach for such an improved prediction of the total power and energy demand of an expedition cruise vessel for the early design stages. The focus is on identifying the peak loads and load changes under consideration of the passenger behaviour, environmental and operational conditions on the basis of predefined typical days of operations. The dynamic power demand is predicted for the different propulsion, auxiliary and hotel systems, as identified and grouped in the system breakdown. This is done by using separate prediction models for the defined groups of systems and electrical components. The required energy per day is calculated directly from a time-domain integration of the power prediction. The demand for a whole operational profile is obtained by adding different typical operational days. The highest power is required by the main propulsion in sailing mode. However, expedition cruise ships often operate at lower speeds below the design conditions resulting in a considerably lower load. The maximum load of the hotel systems always appears in the morning, when all passengers are on board and several components ramp up from the lower night mode. Comparing the total power demand shows that the load changes caused by the hotel systems gets smaller in relation to the changes within the propulsion system as soon as the speed varies. In port condition, the relatively constant auxiliary load, including the hotel systems, remains and describes the baseload throughout the day. Generally, the dynamic prediction clearly shows the potential to better estimate the required power and energy, if varying operational conditions are considered. The method supports a well-founded decision on the power supply configuration, if it comes to hybrid systems including different power supply components and their operational characteristics. A multi-criteria decision analysis on the power supply side can build up on the required energy and power demand of a certain part load. The required fuel cell size can be quantified based on the estimated maximal load and the fuel tanks by considering the predicted energy demand of the specific group of systems.

The present research performed a design exploration of fast ferry catamarans with hard chined demihulls sailing in irregular head waves, to analyse the influence of the demihull shape (without appendages) on wet deck slamming, and identify the geometrical properties and their trends to reduce it. Wet deck slamming is a phenomenon known to cause passenger discomfort and seasickness, often a source of delay in the ferry's schedule and can even cause irreversible damages and endanger the crew. The research is carried out with numerical methods, where two main programs are used, namely the strip theory-based program for non-linear motions of high speed crafts FASTSHIP, and the design optimisation, parameter estimation and sensitivity analysis software, DAKOTA. To set up the experimental analysis, design and analysis of computer experiments (DACE) methods are used. The use of DACE involved the application of an in-house built parametric design tool for mass generation of hulls, coupled with a sampling-based method for the exploration of the design space. Because DACE methods require a large amount of data points (of the order of tens of thousands), it is deemed unfeasible to perform all the analysis with FASTSHIP. Therefore, a surrogate model is built instead, with the global approximation-based method known as Kriging. By considering the surrogate model in the study, mass production and evaluation of different hull forms were achieved, which led towards a brute force surrogate-based optimisation approach. Such approach enabled an in-depth exploration of both sub-optimal and Pareto-optimal regions of the multi-objective domain, thus not only showing the hull characteristics of the best hulls but also their trend of change from the sub-optimal to the Pareto-optimal region. Additionally, an alternative approach based on evolutionary algorithm is coupled to the surrogate model for a more direct and straightforward optimisation process, namely the multi-objective genetic algorithm (MOGA). Both approaches converged towards the same region, thus reinforcing the reached solution. The outcome of the research established a valid framework for performing hull design explorations on catamarans while addressing wet deck slamming. Furthermore, it showed that the demihulls should adopt bulkier forms. However, a trade-off existed between the various considered objective functions, hence the final decision should be based upon the user's criteria.