For many years, ’het Loodswezen’ has relied on its tenders to transfer pilots to and from cargo vessels, with the primary focus on ensuring safety of both crew and pilots. In response to evolving emissions regulations and industry developments, the organisation launched the ’Tender of the future’ project. This initiative also provided an opportunity to enhance safety and comfort by redesigning the hulls of their tenders to address slamming, a significant issue observed in the latest tenders, the M-class. This challenge shaped the objective of this Master’s Thesis: "Delivering a new hull design for the tenders of ’het Loodswezen’ which will reduce the vertical accelerations caused by waves compared to the currently used L- and M-class tenders."

The first sub-question towards achieving the main objective is: "Which width is the optimal trade-off between a safe and efficient mode of operation and a high L/B-ratio?" This question was explored from two perspectives. From a safety standpoint, it involved examining the expertise of ’het Loodswezen’, relevant regulations, literature and consultations with Damen to identify the narrowest width that still ensures safety. From a practical perspective, simulations were conducted using Fastship (a tool designed for evaluating vertical accelerations of vessels by analysing cross-sections as falling wedges in the early design stages). These simulations were used to assess the impact of varying widths, achieved by scaling the Stan Pilot 2205, on
vertical accelerations. The combined results of these analyses identified the optimal breadth for a tender of ’het Loodswezen’ as 6.46 metres, a design that reduces the vertical accelerations with 10% compared to current tenders while maintaining safe and efficient operations.

In the subsequent phase, the bow and overall hull design were iteratively refined from a standardised planing hull towards the optimal design concept for a pilot tender of ’het Loodswezen’. Many iterations were performed and all simulated in Fastship in order to analyse its peak vertical accelerations. These peak values were used to define comfort, as the crew will base their actions on the highest impacts rather than on average vertical accelerations. The main focus of the iterations was on:
• Maintaining the required initial stability.
• Increasing the deadrise angle to 25 degrees.
• Introducing a twist by increasing the deadrise angle toward the bow.
• Implementing a spray rail to enhance hydrodynamic performance by ensuring that the water is separated from the hull.
• Raising the deck at the bow to increase the reserve buoyancy to prevent bow diving.
• Widening the deck at the bow to ensure that the same operational procedures can be applied.
These iterations culminated in the final bow and hull design, optimised for the tenders of ’het Loodswezen’. This design reduces peak vertical accelerations in the bow while maintaining resistance and operational efficiency, achieving a balance between performance and comfort for safe and effective pilot transfers.

Reducing the bow flare and narrowing the bow have proven to positively affect vertical accelerations but introduce potential challenges maintaining efficient operation with the current working methods. To address this issue, the next sub-question was posed: "Can the deck be shaped in such a way that the drawbacks to operational efficiency are minimised while the flare in the bow is significantly reduced?" Through several iterations, a deck design was developed that enhances operational performance without substantially increasing vertical accelerations. This was achieved by incorporating overhangs in strategic locations, enabling the tenders to operate effectively at an angle against cargo vessels.

A final design was developed that reduces vertical accelerations with 27.8% compared to a standardised planing hull while maintaining operational efficiency and considering resistance. However, the results should be interpreted with caution, as they are based on simulations using a basic version of Fastship with a limited number of input parameters. These simplifications enabled rapid evaluations but inherently affect the precision of the results.
It is important to note that this design represents a conceptual model. Further research and development are required to obtain reliable results for the actual design. For instance, the LCG plays a crucial role in performance but was, for simplicity, aligned with the LCB in this conceptual phase. In subsequent stages, the LCG should be carefully established to positively influence the results. Additionally, the hull fairing remains to be completed, a necessary step for generating a hull shape suitable for resistance calculations in simulations.
With these advancements, a comprehensive simulation can be conducted by Marin, for which budget has already been allocated. This simulation will provide a more accurate comparison of the new design with the existing L- and M-class tenders of ’het Loodswezen’, ensuring a robust evaluation of its performance.

This thesis investigates the yaw stability of wind-driven vessels using wingsails, addressing the urgent need for decarbonising global shipping. An analytical method is developed to assess directional stability based on aerodynamic and hydrodynamic characteristics, yielding a universal stability criterion validated with SEAMAN data. The study explores practical stability assessment approaches and evaluates the impact of varying hydrodynamic parameters, aerodynamic models, and surge coupling effects.

Results show that while stability diagnostics are invariant under different hydrodynamic models, significant variations occur in destabilised hulls. Including a boundary layer in the wind model has negligible effects on stability but increases computational effort. The closed-loop analysis assesses proportional and derivative feedback control strategies, demonstrating satisfactory stability for both human and autopilot control across all points of sail in the original hull configuration.

Time-domain responses to step rudder inputs indicate small steady errors and oscillatory components under human control, with autopilot control yielding even more robust outcomes. The study highlights the importance of surge coupling in stability analysis, often overlooked in previous models. The thesis concludes that wind-driven vessels can achieve directional stability under active control schemes, providing a foundation for future research on sustainable maritime transportation.

Due to the IMO regulations on emissions, Wind Assisted Propulsion Systems have become more and more interesting for shipowners. One of those Wind Assisted Propulsion Systems is the VentoFoil from Econowind. However, to enable the decision of the shipowner on whether and where to place VentoFoils on board, this research aimed to construct a VentoFoil Adoption model, assessing the environmental and financial consequences of specific VentoFoil placement options. With this, the main research question is: ‘What is the impact of VentoFoil placement on ships from a ship owner’s perspective?’ The VentoFoil Adoption Model for Econowind required a Technology Adoption Decision-support model that could operate within a short computational time while incorporating an adaptable weather matrix. During the literature study on the existing models regarding WASP models, a research gap was identified. The gap primarily lies in integrating low-fidelity force modelling with financial decision support.

The VentoFoil Adoption model was constructed with a baseline calculation in which no VentoFoils were placed onboard. This baseline included the hull resistance and the wind forces on the deckhouse for all possible wind directions and speeds. After that, the VentoFoils were placed on deck, for which the VentoFoil forces were added with respect to the baseline calculations. The VentoFoil forces were calculated including the interaction between the deck and the VentoFoils, using a turbulent separation layer. The interaction between the deckhouse and the VentoFoils was simulated using a triangle shape in which the wake is turbulent. Lastly, the interaction between the VentoFoils was included using a parametrized wakefield in which the apparent wind angle changed based on the distance between the VentoFoils. From the resulting polar plots, the financial and environmental benefits of VentoFoils are illustrated. Fuel savings are achieved when sailing at reference speed and lower power, and increased cargo yield is realized at higher speeds with reference power. This is dependent on the weather probability matrix.

To demonstrate the practical application and effectiveness of the model, a case study was performed using the VentoFoil Adoption Model on the Magritte, a bulk carrier currently sailing with two 16-meter VentoFoils. From a shipowner’s perspective, the conclusion was made that two 30-meter VentoFoils would in the long term be more cost-effective. For most combinations of fuel price and cargo yield, the payback time of the case at reference power and thus higher sailing speed was lower, making it the favourable operational decision.

A validation using the ‘validation square method’ was performed on the method used within the VentoFoil Adoption Model. The empirical performance validity was investigated by comparing the results from the sea trial data of the MV Sunnanvik and the results from the model. The results are within a reasonable range.

The answer to the main research question can be found with the model. Multiple placement options can be inserted, giving the benefits and costs for well-considered decision-making of the ship owner on whether and where to place VentoFoils on board.