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.