Understanding the failure behavior of thin-walled steel structures under large-deformation plasticity and fracture is crucial for assessment of accidental loading conditions. This thesis will experimentally determine the crack propagation direction in a thin steel sheet under different combinations of in-plane strain, which is essential for improving simulations. Necking and crack angles in a commercially available ductile steel sheet (DC01) are determined under various stress conditions, ranging from uniaxial to equi-biaxial tension. A state-of-the-art formability testing method (Marciniak) is adapted to meet the specific needs of this project. Through tensile testing, the Lankford Parameters of DC01 steel are determined, with which a theoretical assumption of the crack angle can be made using Hills theory (1952). By varying the specimen and carrier dimensions, the strain ratio range of −1/2 to near 1 is tested. A Digital Image Correlation (DIC) system is used to measure deformations and strains during the whole deforming process. Pictures taken from the DIC system and post-mortem section cuts allow for the determination of the crack angle with respect to the in-plane and through-thickness directions. The resulting crack angles agree with the theoretical angles determined by Hill (1952) when the frame of reference of determining the crack angles are rotated.

To more effectively reduce carbon emissions from ships during op- eration, utilizing hydrogen as a fuel for ship engines has emerged as a promising direction. Given the unique physical properties of hydrogen, targeted modifications to existing engines are necessary for adaptation. In hydrogen-fueled engines, the injection system is a critical component. This study aims to adjust the design parameters of a novel injector to match large two-stroke ship engines and to theoretically demonstrate the feasibility of this novel injector for use in large two-stroke engines fueled by hydrogen.Currently, the ma- jority of hydrogen-fueled engines are four-stroke engines, typically employing high-pressure injection. However, high-pressure injection tends to shorten the lifespan of the injection system, consequently reducing the overall lifespan of the engine. Therefore, this study proposes a low-pressure injection scheme, combined with in-cylinder direct injection, to mitigate the risk of unintended ignition. Given the high autoignition temperature of hydrogen, spark ignition is employed to facilitate ignition. A critical step in evaluating feasibility is determining the appropriate injection timing.Initially, it was es- tablished that hydrogen should be injected after the commencement of the compression stroke to achieve optimal mixing. Subsequently, the study analyzed the in-cylinder pressure variations during the compression stroke to identify the feasible injection window. Finally, the design parameters of the injector were configured to align with these conditions. The findings theoretically demonstrate that this injector can achieve low-pressure direct injection in large two-stroke hydrogen engines.Due to time constraints, the study did not inves- tigate the effects of different injection angles and positions on the engine. Nonetheless, the theoretical analysis confirms the feasibil- ity of employing low-pressure direct injection in large two-stroke hydrogen engines.

This graduation thesis studies the CI combustion of ammonia and hydrogen in an ICE. It contains a review of the literature and a modeling study of the ignition and cylinder performance of the AmmoniaDrive test engine. AmmoniaDrive is a NWO-funded research project that aims to decarbonize shipping by introducing an ammonia-fuelled SOFC-ICE power plant for ships and other heavy-duty applications.
Ammonia (NH3) has unfavorable properties for combustion, such as a high heat of vaporization, narrow flammability limits, a high flame quenching distance, low flame speed, and most important: a high resistance to autoignition. Those properties have to be overcome and hydrogen (H2) is known to be capable of playing a role. As the properties of hydrogen are extremely high combustion speed, very wide flammability limits and a very short flame quenching distance. Unfortunately, both ammonia and hydrogen have a high resistance to autoignition, while CI engines need a fuel with low resistance to auto-ignition. For this reason, a carbon-based fuel, like DME or HVO, is considered necessary to achieve ignition.
The state-of-the-art experimentally achieved combustion concepts are an homogeneous charge compression ignition (HCCI) combustion concept of Pochet et al. [2020a] and an reactivity controlled compression ignition (RCCI) combustion concept of Chiera et al. [2022]. The HCCI combustion concept is fueled by NH3 and H2, without a carbon-based fuel. However, it requires a compression ratio (CR) of 22, a high intake temperature, and is limited by the maximum pressure rise rate (MPRR). The RCCI combustion concept is fueled by NH3 and diesel. This concept can achieve up to 81%e NH3, but still requires 19%e diesel.
A modeling study is done to investigate how to improve the CI combustion strategies, taking into consideration the context of AmmoniaDrive. The modeling study consists of two closed volume single-zone thermodynamic reactor models: the ignition model and the engine cylinder model. The ignition model is a constant volume model, resembling top dead center (TDC) conditions. The engine cylinder model simulates a closed volume from bottom dead center (BDC) to 90 CAD after TDC and incorporates volume change and the heat loss. Bothmodels make use of the chemical kinetic mechanism of Shrestha et al. [2018] to incorporate the combustion reaction. Due to the limitation imposed by the available species in chemical kinetic mechanisms, the carbon-based fuel in the modeling study is DME. For the future, hydrotreated vegetable oil (HVO) seems a more favorable carbon-based fuel, based on experimental results in a constant volume combustion chamber (CVCC) of Hernandez et al. [2023].
The results of the two models indicate that an HCCI combustion concept of ammonia and hydrogen, without a carbon-based fuel, will not ignite within the engine limits of the AmmoniaDrive test engine. An HCCI combustion concept of ammonia, hydrogen, with DME will ignite, but has a limited power output due to the MPRR. An RCCI combustion concept with stratification of DME throughout the cylinder looks promising based on the engine cylinder model results. Stratifying DME concentration, and with that the fuel reactivity, is likely to reduce the MPRR. This would allow for a higher power output due to the possibility to injectmore fuel energy without exceeding the engine limits.
Combining the literature and modeling results, it is likely that an RCCI combustion concept with ammonia, hydrogen, and HVO will lead to a higher power output and a decreased required amount of carbon-based fuel, whilst staying within engine limits.

To keep the global warming of the Earth to a minimum, the greenhouse gas emissions need to be reduced. Van Oord aims to be carbon neutral by 2050; therefore, Van Oord is exploring alternative fuels. Ammonia is a promising option to use as a fuel due to the forty times lower well-to-wake emissions than MGO when it is produced with green energy. There is no carbon content in ammonia. Furthermore, the expected cost of using ammonia as a fuel is lower than other competitive 'green' fuels, such as hydrogen or methanol, due to the lower storage or fuel fabrication cost of ammonia. The goal of this research is to determine if and when it is economically viable to use ammonia as a fuel to decarbonize a trailing suction hopper dredger (TSHD). This is expressed in cost per dredged material [€/m^3].
Ammonia needs to be handled, stored and consumed taking into account safety precautions to have a safe operable ship. Additionally, ammonia has poor combustion characteristics, and therefore a promoter such as hydrogen (7-11%) or MGO (40-60%) is necessary to initiate the combustion. Additionally, internal combustion engines (ICE) using ammonia as a fuel are expected to have a low transient load capability. Therefore, if there is no MGO present, the dynamic loading capability of the ICE with the load variation of the dredging process is a challenge. The same challenge applies for a Solid oxide fuel cell (SOFC), where the SOFC does hardly have transient load capabilities.
A TSHD currently has an ICE capable of dynamic loading, and the main reasons for this transient load is the change in propulsion power, which is dependent on the friction of the draghead and the sailing speed of the vessel. Furthermore, a sudden change in mixture density in the dredging tube during dredging will result in a sudden transient load. To cope with these transient loads, the energy supply on board of a TSHD must have transient load capabilities.
A fuel consumption model has been developed to compare five drive train configurations for the dredging project Kustlijnzorg with an operational profile of 30 days with respect to the original drivetrain. The total power demand [kW] and the transient load [kW/s] was included on a boolean way in this model. When the power demand or the transient load was too high then the model would stop. By means of this model, the main particulars of the engines, fuel cells and batteries regarding power and energy were determined. The output of this model was the amount of fuel consumed during 30 days. This fuel consumption model was validated with another project.
The Construction Industry Research and Information Association (CIRIA) has developed a method to valuate a TSHD. With this CIRIA methods, the value of a conventional TSHD is determined and compared with the value of the ammonia driven configurations. The value of a new vessel that operates on ammonia can be estimated with the help of a sustainability factor. It is found that the weekly cost of the vessel is mainly dependent on; the value of the vessel, which is dependent on the installed power and cost of technology, the fuel consumption, the cost of fuel and the carbon tax.
Currently, it is not economically feasible to use ammonia as a fuel to decarbonize a TSHD. So, not with an ICE or SOFC. However, when green ammonia is used in combination with a SOFC, then a TSHD can be fully decarbonized. In order to make ammonia an economically feasible option for a TSHD, the price of MGO and carbon has to increase, or the price of the SOFC and ammonia (grey and green) has to decrease significantly.
Currently it is unclear if the carbon tax in the future applies to tank-to-wake (TTW) or well-to-wake (WTW) emissions. If the WTW emissions are taxed, then grey ammonia is never a better choice than MGO in terms of cost. Which is also the case when considering the CO2 equivalent emissions.
To conclude, it is currently not economically feasible to decarbonize a TSHD using ammonia as a fuel based on the cost per dredged material [€/m^3]. The limited transient load capabilities of drive train configurations on ammonia, need a battery or MGO to cope with the transient load of a TSHD. Future progress in the technology or developments in the reduction of transient loads could make ammonia as a fuel for a TSHD a better option. Finally, future developments in the price of: carbon, ammonia and MGO can make it economically feasible to decarbonize a TSHD.

With the increasing concerns of the emission of greenhouse gases and other pollutants and the push towards sustainable and greener means of transportation, there is a need for new drive systems running on alternative fuels. One fuel that holds significant potential as a marine fuel for the future is methanol. When produced utilising carbon capture methods and green energy, it has the potential to be a net zero fuel. Among other high-potential future fuels, methanol has the added benefit of being liquid at room temperature. Additionally, methanol has the potential to be utilised in novel drive systems, such as the combination of a solid oxide fuel cell (SOFC) and a reciprocating internal combustion engine (ICE). This concept utilises the high efficiency and negligible NOx formation of the SOFC, while the ICE provides dynamic load capabilities. This study concentrates on the electrical efficiency of this type of plant for maritime applications.
This work presents an in MATLAB & Simulink constructed first principles based model of a methanol fuelled SOFC-ICE combined cycle. The zero-dimensional SOFC model consists of a temperature controlled methanator which maintains an external reforming ratio of 0.5; a cell mass balance; a cell energy balance, and an electrochemical model. The ICE model core consists of a turbocharged five-state Seiliger cycle. It simulates Wärtsilä 12V31DF fuelled with methanol and dehydrated hydrogen-rich anode of gas (AOG). The SOFC efficiency and its separate losses are evaluated for different temperatures, current densities, fuel utilisation factors UF and steam-to-fuel ratio’s in combined cycle operations. Additionally, the standalone SOFC performance, without the use of waste heat from the ICE and disuse of residual fuel in the AOG, is evaluated, but only for the nominal condition. The ICE efficiency and losses are evaluated for a power range between 1% and 100%. By varying the ammount of cells, the following power splits PSOFC/PICE have been evaluated: 0/100 25/75; 50/50; 75/25 and 100/0. The combined cycle performance is evaluated for different temperatures and current densities.
This study found that while varying the steam-to-fuel ratio and fuel utilisation factor (UF) have minimal impact on the electrical efficiency of the SOFC in combined cycle operations, temperature and current density have a significant effect on the efficiency of the SOFC. For a steam-to-fuel ratio of 1:1, a UF of 0.8, a current density of 5000 A · m−2 and a mean cell temperature of 1073K an efficiency of 58.6% was obtained. The standalone SOFC, or 100/0 power split, obtained an efficiency of 48.4%. The stand-alone ICE genset, or 0/100 power split, operates at a nominal efficiency of 42.3%. When the ICE is used in a direct drive configuration, it corresponds to an efficiency of 43.6%. The combined cycle obtained efficiencies of 45.4%, 49.1% and 53.4% for 25/75, 50/50 and 75/25 power splits, respectively. These results are compared to the results of a similar study investigating an ammonia-fuelled SOFCICE combined cycle for maritime applications, which reported efficiencies of 47%, 50% and 52% for 25/75, 50/50 and 75/25 power splits, respectively, under similar operating conditions.
The efficiency gain of the methanol-fuelled 75/25 configuration compared to the direct drive is limited. This raises the questions about whether the added complexity of introducing an SOFC is justified for the limited efficiency gain. The highest efficiency was obtained with the methanol-fuelled 75/25 power split, but due to the large proportion of SOFC power, it is less tolerant to dynamics in the load, making it questionable whether it can fully meet the dynamic power demand of a ship. Therefore, the 50/50 power split configuration is expected to be the most viable option in terms of both technological feasibility and efficiency gain. A change in the power split to 100/0 results in a decrease in system efficiency due to the lack of waste heat from the ICE and the inability to utilise residual fuel in the exhaust. When considering efficiency, the values for the ammonia fuelled and methanol fuelled plant are similar.
The 50/50 powersplit configuration is 5.6 percentpoints more efficient than the methanol fuelled direct drive ICE and 1.2 percentpoints more efficient than the methanol-fuelled standalone SOFC. This clearly shows the synergistic benefits of combining a methanol-fuelled SOFC with an ICE. However, when compared to the ammonia fuelled combined cycle with 50/50 power split, it is 0.9 percentpoints less efficient. Nevertheless, it is important to exercise caution when drawing further conclusions from this last figure as the model has been constructed at a system level and no thorough uncertainty analysis has been conducted. Furthermore, the requirements regarding the power and energy density are strongly dependent on the type of ship and its operational profile. Therefore, future research should include the implementation of dynamic load capabilities in the model to evaluate its technological feasibility and overall net efficiency gain in various operational profiles of ships. Also, further research is required on the methanol-fuelled ICE cylinder process and the heat integration of the combined cycle.

New vessels need to remain fuel flexible in order to handle the uncertainties of the future regarding the available alternative fuels aiming to lower their environmental impact. On the other hand, it is even more challenging for existing vessels that are not fuel flexible to successfully improve their carbon impact. The current study examines the combustion characteristics of alternative maritime fuels including methanol and hydrogen in the compression-ignited internal combustion engines of Bravenes that burn diesel fuel, as well as the implications these fuels have on the environment and on safety when used onboard ships. The diesel fuel still acts as the main fuel but also as the ignition fuel for the injected additives. The purpose of the additives is for the substitution of diesel and to offer more complete combustion in the cylinders. Van Oord is already implementing the Fuelsave Marine+ technology on board Bravenes. This technology aims to reduce harmful emissions like ABe and greenhouse gases while also increasing engine efficiency in order to contribute to the overall energy transition effectively. Therefore, the primary goal of this research is to examine if there are any potential impacts of the technology on the efficiency, emissions, and fuel consumption of Bravenes engines.

The model used is able to characterize the combustion of the engine using the Seiliger combustion shape parameters a, b and c. These parameters consider the combustion efficiency, the ignition delay, and the heat fractions of the potential heat for the appropriate stages. The effects of the additives in small quantities can be seen in the combustion duration and the ignition delay of the combustion. In order to properly model the additional fuels effects some of the diesel mass needed to be substituted with methanol mass to provide the same energy content in the cylinder. Attention was also given to the proper selection of the KN&𝑋𝑏 parameters impacting the combustion shape parameters, and as a result the pressures and temperatures in the engine.

The results of the model for the diesel and diesel with additives operation predict a decrease in diesel fuel consumption which is a good indication of 𝐶𝑂2 emissions reduction. The peak cylinder pressures have increased with the additives injection and the peak temperatures as well which indicate an increase of 𝑁𝑂𝑥 emissions. The increase in the temperatures is not something expected in reality and could be due to a modeling effect. The indicated work of the engine combustion cycle also improved for the Fuelsave technology but due to the increase in peak pressures the mechanical efficiency decreased resulting in reduced effective efficiency. The selection of the Seiliger settings, which allowed
for a higher heat loss efficiency than was realistically anticipated, is another factor contributing to the decrease in effective efficiency. All in all, proper measurement campaign needs to be performed to show the clear effects of the technology as a retrofit solution on board existing vessels for efficiency and emission reduction.

Progressing targets on GHG emission reduction urge the the Netherlands Ministry of Defense (NL MoD) to reduce the use of fossil fuels, as they announced to contribute to the Paris agreement by reducing its dependency on fossil fuels by at least 70% by the year 2050. However, without sacrificing striking power, because future naval combatants need to perform their operations on the highest end of the violence spectrum and need to have sufficient autonomy to perform their operations at sea independent of logistic supply lines. The Royal Netherlands Navy (RNLN) is investigating the replacement of the Air Defense and Command Frigate (LCF) between 2030 and 2040 by a Large Surface Combatant. As it will be impossible to achieve substantial reduction of GHG emissions through energy-saving technologies, sustainable fuels need to be implemented in the design. In this thesis, the impact of sustainable fuel choice on the design of Large Surface Combatants with a displacement of around 6000 tonnes is assessed. In particular, the current and future developments of sustainable methanol and diesel have been reviewed from existing literature and are examined on the replacement Large Surface Combatant: specifically their advantages, disadvantages, production routes, future production cost estimates and availability to give an understanding which pathways can help the NL MoD to achieve their stated GHG emissions reduction goals. Furthermore, three different design concepts are presented with respect to fuel composition from which the impact of the established fuels is quantitatively examined. First, sustainable diesel is a drop-in fuel, which makes blending of sustainable diesel with fossil diesel possible in the existing infrastructure allowing a gradual transfer from fossil diesel to sustainable diesel. However, the production is less efficient in a well-to-wake approach and the cost of Bio-diesel and E-diesel is 5% to 30% more expensive with a mean estimated additional cost of 6 €/GJ compared to methanol. Secondly, operating on methanol has a significant impact on the design of a large surface combatant: the specific energy of methanol is more than twice as low as diesel and the ship needs a longer machinery space to allow for a diesel engine propulsion configuration. This results in a increase in displacement of 20%. Finally, navies could consider a two-fuel strategy: sail on methanol during operations with limited autonomy, typically in peace time, and operate on diesel during operations with high autonomy, during war time operations. In this case the design needs to include both diesel and methanol fuel systems and additional space for methanol safety measures. This results in a increase in displacement of 4%. However, the range when operating on methanol is reduced to 2187 nm compared to a 5000 nm baseline range. Assessing the impact of sustainable methanol and diesel for Large Surface Combatants at this level of detail and considering a two-fuel strategy is novel for the field. The results can be used by the Royal Netherlands Navy to compare the different concepts and serve as an indicative substantiation in the acquisition of a new Large Surface Combatant. Moreover, it can help in forming the strategy to migrate future naval combatants from current fossil fuels to future sustainable fuels.

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.

With the introduction of the Energy Efficiency Design Index, concerns have been raised to the survivability of ships with small engine power to maintain manoeuvring capabilities in adverse weather conditions. Therefore, Sui (2021) developed a simulation model from ‘tank to wake’ of a manoeuvring ship in irregular waves to advice a minimum power limit for regulation purposes. The original model consists of the Kijima model extended with the mean second order wave drift forces of a VLCC tanker published by (Yasukawa et al., 2019).
The research reported in this thesis is conducted as part of this work. Therefore, the aim is to improve the fidelity of hydrodynamics. Therefore, a modular unified model is established where the manoeuvring forces of Kijima model are included as non-linear damping in the Cummings equation. Whereas only the mean second order wave drift forces were included in the original model, the first and second order wave excitation forces, the radiation forces, and the restoring forces are included in the new model. The convolution integrals of the radiation damping forces are circumvented with state space models with the identification method of Perez & Fossen (2009). The input of the forces are the force response amplitude operators, the quadratic transfer functions, and the added mass and damping coefficients in the frequency domain obtained from the diffraction analysis performed on a barge in Ansys Aqwa, because the hull geometry of the benchmark ship is unknown.
Moreover, a wave generation model is included capable of generating sea surface realizations for irregular waves from multiple wave spectra. In this study, irregular long crested wind generated waves are generated from a JONSWAP spectrum. The JONSWAP spectrum is generated based on the wind growth curves and thus depend on the wind speed. Consequently, the significant wave height and the peak period of the spectrum are consistent.
The model is validated against the measurements of the benchmark turning trail and compared to the original model. The original model is slightly more accurate. Nevertheless, both results are considered acceptable, and, it is concluded that that the fidelity of the models is similar.
Thereof, the model is used to simulate a ship escaping an increasing storm based on the case of the Pasha Bulker. Therefore, a turn from beam to head waves starting at a low velocity is simulated in sea state 7, 8, and 9. In the original simulation, the ship failed in sea state 9. With the new model, the ship is able to perform all turns. Therefore, it is concluded that the ship is not underpowered. Consequently, the engine power is reduced. With half installed power the ship fails to escape the storm and it is endangered.

In the modern world, environmental concerns arise due to an increase in the green house gas (GHG) emissions of the shipping industry; in 2015, 2,5% of global GHG emissions came from the shipping industry alone. Measures must be set in place to reduce the future emissions. One way to reduce emissions is by imposing the Energy Efficiency Design Index (EEDI). This is a measure to define the ratio between the CO2-production and the cargo capacity and speed of a ship. In other words, this ratio defines the environmental cost over societal benefit of a ship. The International Maritime Organisation wants to have a set requirement on the EEDI of new ships and preferably reduce this for existing ships. One way to reduce the EEDI is by reducing the installed engine power of the ship. One risk is that the ship might then become underpowered when it sails in adverse weather. The underpowering of ships could lead to safety hazards for the passengers and crew. For that matter, this thesis will investigate whether the ocean-going chemical tanker 'Castillo de Tebra' is underpowered when sailing in large waves. Specifically, the effect of the waves on the inflow velocity of the propeller will be looked at and how this affects the propulsive performance of the vessel.
An extensive literature review was carried out in order to find out what the state-of-the-art is within the determination of ship propulsion in waves. This has been divided into three separate subjects, namely wave excitation, propeller and engine operating in waves and finally manoeuvring and seakeeping. When determining the forces that occur on a ship when it advances in waves, most methods use potential flow as the results are reliable and have low time effort. Determining propeller performance when the full wake distribution is known can also be done using potential flow methods. Basic open-water characteristics are a valid alternative as well. CFD can be used for both wave excitation and propeller performance calculations, but this is time consuming and computationally complex. When simulating manoeuvring and seakeeping behaviour of ships, two-time scale methods or unified methods are mainly used.
For the research part of this thesis, numerical simulations were performed to determine the change of inflow velocity at the propeller plane for a large range of wave frequencies and wave directions, for a vessel having a forward speed. This velocity change was used to determine what the thrust and torque generation of the propeller is in waves. The engine operating envelope and ship thrust envelope were used to check whether the engine has enough power to provide the torque that the propeller generates and whether the ship has enough thrust availability. Frequency-domain results were transformed into time records for irregular waves using the JONSWAP wave spectrum and a cosine funtion. It was concluded that the ship was underpowered in adverse weather conditions, when an instant control system was assumed that inject enough fuel instantly to keep the engine at the rated speed when it needs to deliver more power. It was also assumed that the ship speed was kept at the design speed. In reality, voluntary and involuntary speed loss will occur when a ship sails in bad weather. Voluntary in the form of manual speed decrease by the captain and involuntary in the form of added resistance causing the ship to reduce in speed. A number of solutions are finally presented in this thesis to omit engine overloading in adverse weather.

Often, vessels have multiple operation modes that are specialised for a certain task. If a vessel is employed with a controllable pitch propeller(CPP), the blade pitch can be adjusted, adding a degree of freedom to the system. This advantage creates the possibility to increase the diversity of operation modes of the vessel and allows for flexibility, precision and specialisation for a certain task. Additionally, CPPs can be controlled such, that operational limits of the driving machinery are not exceeded.

As vessels have become increasingly diverse with respect to their functional abilities, and complex with respect to their propulsion configurations, design of combinator curves becomes increasingly labour intensive. Earlier developed software applications, that aim to support the matching process or combinator settings, lack clear insight of important performance indicators and their impact on the combinator curve design.

In this thesis, a Combinator Curve Generator(CCG) is developed to support the design of combinator curves for vessels that employ CPPs, in order to decrease the labour intensity of the combinator design process. Further, approaches are developed to optimise combinator curves for operation modes of a vessel in terms of four performance indicators; propeller efficiency, cavitation inception, engine efficiency and fuel consumption. The approaches are implemented in the CCG such that a combinator curve can be designed, optimised and evaluated. Additionally, a trip simulation tool is developed and added to the CCG, in order to determine and evaluate the total fuel consumption of a trip for different cruise speeds and a certain time duration, whilst taking into account the distance, the operational profile of the vessel, the combinator settings and the hotel load.

Important recommendations for further development include extension of the database of inception diagrams for propellers with different blade area ratios, and the broadening of the propulsion configuration scope, such that different main engines and power supply systems can be considered. Finally, it is recommended to research the possibility to calibrate the effective angle of attack method on the basis of the optimisation approach proposed in this thesis.

The goal of this thesis is to characterise diesel-ammonia combustion using a mean value first principle approach, and to implement this characterisation of diesel-ammonia combustion in a time domain two-stroke engine model. This model will be used to indicate the technical feasibility of diesel-ammonia as a marine fuel. The main research question of this project is: How does the performance of the main engine of a deep-sea cargo vessel fuelled with diesel-ammonia compare to one fuelled by diesel only? The TU Delft engine B model is chosen to model the behaviour of an engine of an ocean going cargo vessel. The model has been adapted to simulate the behaviour of diesel-ammonia engines. The adapted model is used to compare the performance of a diesel only engine with a diesel-ammonia engine. The main conclusion from this study is that diesel-ammonia engine compared to diesel only engines have a higher specific fuel consumption because of the lower heating value of ammonia. Newly designed diesel-ammonia engines can potentially be more power dense because of stoichiometric air-fuel ratio of ammonia. However, the combustion efficiency could be a limiting factor. The diesel-ammonia engine emits significantly less CO2 and SOx emissions. However, ammonia emissions, caused by incomplete combustion, and an increase in NOx emissions, caused by the nitrogen in ammonia, are a concern. Furthermore, diesel-ammonia engines operate at lower maximum pressures and temperatures, therefore the mechanical limits of the engine are not exceeded. Lastly, diesel-ammonia engines do not require a different turbo charger system.

Submarines face an ongoing (technical) battle to improve the operational effectiveness by increasing the submerged endurance and range. Installing lithium-ion batteries on new or refitted diesel-electric submarines has become increasingly interesting based on their relatively high energy density and specific energy. The characteristics compared to the currently implemented lead-acid batteries are known, meaning that the implementation of lithium-ion batteries on submarines can increase the submerged range and endurance based on their better specifications. Additionally, lithium-ion batteries require less maintenance and provide a relatively longer life expectancy compared to lead-acid batteries. However, lithium-ion batteries can develop a thermal runaway: a process which exponentially generates heat, leading to the risk of an explosion and fire. A thermal runaway can be initiated based on internal failure mechanisms and external causes, such as exceeding critical temperature limits. Understanding of the thermal behaviour of lithium-ion batteries is essential to reduce the probability of a thermal runaway. The probability of initiating a thermal runaway can be further reduced by auxiliary systems such as a cooling system and a battery management system. The main objective of this research is therefore to investigate the implications on preliminary submarine system design based on the thermal behaviour of lithium-ion batteries and to quantify the thermal behaviour and design implications. The relevance is that by quantifying the thermal behaviour, the cell temperatures can be estimated. As a consequence, awareness of the risk of a thermal runaway is established, while at the same time input for the dimensioning of a cooling system is provided. An analysis has been performed concerning the safety of lithium-ion batteries. The causes, the characteristics and the prevention methods regarding a thermal runaway have been studied in this research. The four stages of a thermal runaway are discussed, as well as the generation of toxic and flammable gasses. Moreover, the sources of heat generation in a lithium-ion cell have been described. The heat generation typically consists of reversible and irreversible heat components, of which the relative contributions have been described based on the charge or discharge rate. To support preliminary submarine design, a thermal model of a lithium-ion battery module has been created. The first model that has been created describes the electric behaviour of a lithium-ion battery cell that is typically implemented in marine applications. EST-Floattech has provided technical specifications of the lithium-ion pouch cell that is implemented in their modules. The second model determines the generated heat based on the electrical model and cell specific properties. The third model simulates a lithium-ion battery module, where heat is generated by multiple cells and heat transfer rates with the surroundings are modelled. A lumped thermal capacity approach has been implemented and cooling is modelled to provide insight in typical cooling rates regarding thermal management. Conclusions have been drawn regarding the temperatures of the cells in the module based on three operational profiles. Based on a submerged sprint, C-rates up to 1.0C can be sustained without cooling while remaining below the critical temperature limit of 55°C. For consecutive cycles during a covert transit or covert surveillance, cooling is typically necessary. Only at C-rates below 0.3C a covert transit can be sustained. Typical cooling rates vary between 60 W and 185 W, where the effects of cooling are most significant for covert transit and covert surveillance. Module optimisation provides increased cooling rates while increasing the energy density and specific energy. This results in a decreased mass and volume of the module, resulting in a significant amount of extra space in the entire battery system on board of a submarine. The largest improvement in thermal management can be realised by choosing the right conductive filler. Moreover, the cooling capacity has a significant influence on the cell temperatures. Cell temperatures remain relatively constant after the fourth cell in a row, meaning that modules are typically not limited by the number of cells.

This paper examines a case study to determine the effects on system performance of the power plant and ship operational capabilities, this case is a ship designed by the company DEKC. It is a small general cargo vessel of 2999 GrT (Gross Tonnage) called the Future Trader. The ship design is finished and the ship will be equipped with a modular power plant and fuel storage on the aft of the ship. In total four different power plants will be compared. The first is the base line system, this consists of a single internal combustion engine fuelled by Marine Diesel Oil (MDO). The three other systems will be modular systems. They all use the concept of distributed generation. There is looked into a system with three internal combustion engines fuelled by MDO. Besides this there are two fuel cell systems. Each consists of two separated fuel cells and one uses hydrogen and the second ammonia as fuel. For those systems mathematical models are created to compare three modular power plants to each other and to a base line. With those models the effects on the Future Trader's range, fuel costs (operational capabilities) and emissions are researched. A modular power plant is installed on the aft of the ship, constructed of four power packs each in a Twenty foot Equivalent Unit (TEU). The four systems will be simulated on four voyages and the results will be normalised with respect to the first setup. It can be concluded that a modular system with the concept of Distributed Generation (DG) will reduce the ships overall performance in comparison to the single engine diesel electric system (base line). When reviewing the fuel cell systems with respect to the base line system it is found that the ammonia fuel cell system has zero emissions and it still offers a sufficient range. The increases in fuel costs are lower than that of the hydrogen fuel cell system. Hydrogen will also reduce harmful emissions to zero but the reduction in range is more severe. The increase in fuel costs is also significantly higher than for the base line. Overall ammonia seems the most promising of the non hydrocarbon fuels. The DG system is also useful as long as emission regulations remain unchanged. The MDO DG system can be loaded for large distance voyages and hydrogen can be loaded for short voyages if desired.

The International Maritime Organisation (IMO) is a specialized agency responsible for the safety and security of shipping and the prevention of marine and atmospheric pollution by ships. Air pollution is one of the contributors, CO2 emission is recognised as the biggest contributor to the increasing temperature of the Earth. Global warming is a controversial topic and actions are taken to reduce further rising of the temperature on Earth. The IMO has set limits for vessels on the emission of NOx and SOx. Currently, the IMO is negotiating on how to limit the emissions of CO2 to reach a reduction of 50% in comparison to 2008. The purpose of this research is to provide an emission model for TSHDs showing an emission profile (CO2, SOx and NOx) per cycle of operations, and present emission reduction methods. Within the emission model there are eight main parts that are connected and create the results. The results are shown per cycle of operation and are calculated per phase. The six main phases of a cycle of operation are: Loading, transit loaded, connecting, discharge, disconnecting and transit empty. The first part of the emission model determines the hull resistance. The second part consist of the trailing resistance. This part is split up into three more detailed segments: the calculations for the cutting force, cutting depth and trailing force. The trailing and hull resistance together form the total resistance within the loading phase. For the transit phases, only the hull resistance is used for the total resistance. With the total resistance known, the propeller is matched to the main engine in the third part. The fuel consumption and emitted emissions are calculated in the fourth and fifth part. The power requirement for the other engines, pumps and auxiliary equipment are calculated in part 6th through 8th. For each job, specific input is required for the calculations. Combining this input and the calculation parts, the emissions, fuel consumption and fuel cost are given per dredged m3.
Five methods to reduce the emissions for TSHDs are researched. First, the type of power arrangement is researched. A mechanical power arrangement with a combined drive and a direct drive, an electrical power arrangement and a hybrid power arrangement are investigated. The variations of power arrangements are implemented on the Dodge Island. Second, the difference between a fixed (FPP) and controllable pitch propeller (CPP) is researched. Most modern day TSHDs use a CPP, as the efficiency during the wide variation of operating conditions is greater than a FPP. The third method to reduce the emissions is to find the optimal loading speed. The optimal speed is researched for a floating visor and a fixed visor. The most common solutions to comply to the limit of the SOx emission is using ultra low sulfur diesel or installing a scrubber. The fourth reduction method is focussed on the use of scrubbers. The most used types of scrubber are the dry, open loop, closed loop and hybrid scrubber. The last method to reduce the emissions is shutting off the engines when not in use. The trade-off is the wear of the engine. To verify the results of the emission model, the fuel consumption of multiple completed jobs is compared with the predictions of the emission model.

For many maritime applications Li-Ion batteries are foreseen as energy storage units that can improve the performance of the on-board power system in terms of continuity of service, fuel consumption, emissions and running hours of main engines. However, one of main limitations of battery application in on-board power systems is the aging of batteries. Applications of instantaneous power input/output such as propulsion dynamic assistance and heavy seas operation of ships, have an adverse effect on battery lifetime meaning that degradation of energy capacity over time is accelerated. Additionally, limited by their maximum current rating, batteries cannot deliver effectively high C-rates and therefore are not able to fully absorb the engine fluctuations. A typical solution for this problem is to over-size the battery system. By paralleling more batteries, the max. C-rate is lowered, and battery lifetime can be extended. On the other hand, an over-sized battery system will result in additional capital cost and weight. Therefore, it is evident that in conventional approaches there is an undesirable trade-off between battery aging and battery size. As an alternative practical approach into this problem, this thesis proposes an on-board hybrid energy storage system (HESS) that comprises of a battery and a supercapacitor component. By placing the supercapacitor in parallel to the battery and by using it for high peak currents, it is possible to reduce the stress on the battery and thus extend battery lifetime while improving the availability and the reliability of the power system. In addition, by taking advantage of the high specific power of the supercapacitor and the high specific energy of the battery it is possible to optimize sizing of the energy storage system for high power applications. In this thesis, a parametric approach of combined sizing and energy management for hybrid energy storage system is developed and integrated into a typical DC shipboard power system . Based on a case load profile, the HESS operation is simulated and benchmarked to battery-only installations. The static outputs of the sizing process and the dynamic outputs of the simulation are extracted in the form of design exploration maps and arrays that are used to correlate them to the key design variables. Finally, through this work, it is demonstrated that for high power applications with significant fluctuations, the proposed battery-supercapacitor HESS, can lead into smaller and more cost-effective installations, without compromising battery lifetime and while maintaining same levels of reliability performance.

To improve the submerged time of diesel-electric submarines (SSK), air independent power (AIP) systems have been developed in the past. So far only submarines with AIP systemsin combination with one or more diesel generator (DG) sets are designed and built. The increased technological readiness level of modern fuel cells (FC) and the energy density of modern lithium-ion (li-ion) batteries trigger the possibility of a fully electric submarine. This concept of hybrid FC-battery energy storage and generation could eliminate the requirement for DG sets and a snort system to charge the batteries. The operational advantages in terms of improved indiscretion rate, reduced maintenance and smaller crew, silent energy conversion and reduced complexity of the ship systems design could have a great impact on conventional submarine design. In this thesis the design changes due to a switch to a fully AIP plant are described and a submarine concept design is created. The design should have the same submerged displacement and sprint capacity as a set reference design. The selected AIP plant uses a proton exchange membrane fuel cell (PEMFC), lithium iron phosphate (LFP) batteries and hydrogen stored in high pressure bottles. The design is based on a reference design from which the diesel related systems and batteries were removed. Since the new power plant requires less maintenance also the crew size was reduced, which resulted in a smaller accommodation. The removal of systems and the smaller accommodation resulted in a freed up volume for the new power plant. Using a matlab program that systematically generates power plant configurations within the available volume an ideal power plant is selected. The selection criteria is set to maximum
range, while still satifying the speed requirements. Subsequently, this power plant is integrated in the design. Other aspect that are considered during the design are the electric load balance, the heat balance, air quality and the type
of main electric motor. Also the trim and stability are considered. This results in a concept submarine design. Finally, the new concept design is compared with the reference design on the aspects mentioned earlier. For the range and endurance a fully battery powered submarine is also included in the comparison. The results show that the reference design has a three times higher maximum range and endurance than the concept design. However, when the indiscretion rate (IR) was taken into account the full potential of the concept design became clear. The IR of the concept design is 0%, which means it can operated underwater for the entire range and endurance. This is a large improvement over the reference design, which has to snort on regular intervals. When the concept is compared with the fully battery power submarine the maximum range and endurance are approximately doubled. As always, it all depends on the desired operational profile of the user whether the design is the most suitable option; however, it is expected that for most navies the created design is a significant
improvement over the diesel-electric alternatives. Considering all aspects above it can be concluded that the concept design with PEMFC, LFP batteries and compressed hydrogen is capable to perform short to middle long missions, while provided their operating navies with significant operational advantages like 0% IR, lower acoustic signature and smaller crews.

To achieve significant reduction in greenhouse gas emissions in shipping and enable ship owners to phase out fossil fuels entirely, renewable fuels, such as ammonia, play a crucial role. Ammonia is considered a balanced solution in terms of volumetric energy density and renewable synthetic production cost compared to other renewable fuels. However, many questions still need to be answered to determine if ammonia as a fuel for ships is a feasible option. Therefore, the purpose of this project is to investigate how ammonia can be applied safely and effectively as a marine fuel. An ammonia carrier will be used to study the concept of using ammonia as a marine fuel. To study effective use of ammonia as a marine fuel the following options for power generation are investigated: the steam turbine, gas turbine, internal combustion engine (both compression and spark ignition) and fuel cells (both proton exchange membrane, alkaline and solid oxide fuel cells). The results of effective use of ammonia as a marine fuel are used to develop an ammonia fuel system diagram. This diagram is studied by means of a qualitative risk assessment to gain insight in safety of using ammonia as a marine fuel.

This thesis aims at gaining insights into the operational principles of the diesel engine injection systems and reproducing the dynamic of fuel injection in the diesel engines. Two popular fuel injection systems are modeled in this thesis, including the mechanical injection system and the common-rail injection system.

The formation of NOx in diesel engines is heavily influenced by the amount of available oxygen and the combustion temperature. This thesis investigates the effects of the implementation of exhaust gas recirculation on the NOx emissions of a 4-stroke marine diesel engine. With EGR implemented a part of the fresh intake air is replaced by exhaust gas. The exhaust gas contains less oxygen and has a slightly higher specific heat. This should result in a lower oxygen concentration and a lower combustion temperature. A mean value simulation model is used to simulate the engine and predictions of the NOx emissions will be made by using emission fits and certain engine parameters.