Marie Jonas’ research at Conoship reveals that using logarithmic wind in simulations gives more realistic predictions of wind-ship interactions, helping optimize wind-assisted propulsion systems for greener maritime transport.
Insights from a graduate study by Hotze van Doorn
Innovation in ship design goes hand in hand with structural integrity and efficiency. At Conoship International, pushing the boundaries of design requires advanced tools, and Finite Element Method (FEM) analysis is one such tool. Recent graduate research at Conoship explored how FEM can be applied more effectively during the early design stages, by delivering faster, smarter insights for safer and more sustainable vessels.
The goal: To develop methods for applying FEM effectively, even when limited design information is available.
Core theme: How ship designers can use FEM effectively in early design to optimize structural dimensioning.
Key insight: FEM is especially valuable for buckling checks in thin plate fields amidships, due to modern high-strength steel and larger span distances.
“My journey with Conoship began during the company fair at my university,” recalls Hotze van Doorn. “I was studying Maritime Technology in Leeuwarden when I met Klaas Visser (Manger Design & Engineering, and Naval Architect) at the Conoship stand. He offered me an internship, which turned out to be a perfect match.”
During his third year at university, he joined Conoship as an intern for his office placement. “I developed my skills as a structural designer and learned a lot from the team,” he says. After the internship, he continued working part-time every Thursday: “It was always a great experience, especially because every other Thursday ended with a team drink!”
What stood out most was Conoship’s commitment to supporting his academic development. “Whether I needed information for a project or real-world assignments to earn credits, the team was always willing to help. So when it came time to choose where to do my graduation thesis, the decision was obvious.”
“Early FEM analysis enables better decisions and stronger designs, without slowing down the creative process.”
The graduation project focused on a pressing challenge in contemporary shipbuilding: buckling in the open plate fields of a ship’s midsection. As vessels increasingly use high-strength steel to enable lighter and more efficient structures, designers adopt larger frame spacings and thinner plating. The downside? Greater susceptibility to compressive stresses and buckling.
Using Finite Element Analysis (FEA), Hotze developed a method to identify vulnerable plate fields early in the structural design process, even when limited input data is available. “This approach helps designers make better decisions from the start, preventing buckling issues later on,” he explains.
The research demonstrated that full-ship FEM in the concept phase is rarely practical, but selective modeling can deliver high value. By focusing on critical areas such as the cargo hold and applying targeted FEM checks for buckling, designers can strike the right balance between speed and accuracy. The study also provided practical guidelines and time-saving strategies for integrating FEM into Conoship’s existing processes.
“By refining how FEM is used, we can reduce modeling time while gaining key insights into structural performance. Ultimately, this contributes to safer, stronger, and more efficient vessels.”
For Conoship, this project reflects the company’s commitment to innovation and collaboration with future maritime engineers. The research of graduation students not only adds value to our design processes but also strengthens the bridge between academia and industry.
As Conoship continues to pioneer sustainable ship concepts and structural solutions, methods like FEM could play an increasingly important role. By making these tools faster and more effective, Conoship ensures its designs stay ahead in safety, efficiency, and sustainability.
If you are curious about this topic and would like to know more. Feel free to leave us a message on our contact page or contact Hotze directly.
Conoship studied rigging safety for the bruine vloot, proposing updates to ES-TRIN standards to improve safety and usability.
Redox flow batteries (RFB) are already widespread for stationary energy reserves, but in the maritime industry their potential remains largely unexplored. Former graduation student and now full-time employee, Piet Visser, delved into the feasibility of redox flow battery for ships on board short-sea operating vessels. At Conoship, we consider full– or partly electric propulsion a crucial element for reaching the 2050 sustainability goals.
Over the last academic semester, Piet has been conducting his research and integrating at the Conoship office in Groningen. He has done so with remarkable success as his degree in Maritime Technology has been concluded and he has since begun as a full-time employee.
‘It was a wonderful experience working for Conoship due to the comfortable working environment and exciting graduation assignment. During the project I learned a lot, but I am happy to be a full-time employee right now.’
Studying at NHL Stenden was a resourceful experience to help delve into the fundamentals of maritime technology. However, doing a theoretical research project with clear practical implications has allowed Piet to delve into something truly unique.
Redox flow batteries are an innovative energy storage solution that has already gained traction in stationary applications worldwide. Unlike conventional battery systems, RFBs store energy in a liquid electrolyte and release it through electrochemical reactions. The major advantage, compared to traditional batteries, is their energy efficiency, long cycle life, and scalability. Additionally, RFBs do not run the risk of combusting like lithium batteries, providing a major safety boost for sailors.
At the core of an RFB is an electrochemical cell divided into two chambers: one positive and one negative, separated by a membrane. The electrolyte, which contains active chemical species, is pumped through these chambers, where energy is stored or released based on the reaction taking place. The choice of electrolyte is crucial, as it determines the battery’s energy density, efficiency, and overall feasibility for marine applications.
For this research, a vanadium-based electrolyte using hydrochloric acid (HCl) as a solvent was selected due to its high energy density of 43 Wh/l (27 Wh/kg) and stable electrochemical properties. Vanadium redox flow batteries (VRFBs) are particularly attractive because they enable full charge-discharge reversibility, have a long lifespan, and are considered safer than conventional lithium-ion batteries due to their non-flammable nature.
The study focused on the feasibility of implementing RFB technology onboard ships, identifying key challenges such as system integration, operational risks, and safety requirements. A risk-based design approach was used to assess potential hazards, including electrolyte leakage, membrane failures, and material corrosion. To mitigate these risks, design measures such as compartmentalized storage, reinforced piping, and automated leak detection were evaluated to ensure safe and reliable operation at sea.
While the research confirms the technical viability of RFBs for maritime use, further refinement is needed to optimize efficiency and scalability. These findings provide a foundation for future development, paving the way for broader discussions on how this technology can contribute to sustainable shipping solutions.
Implementing redox flow batteries onboard ships presents key challenges, particularly in integrating storage tanks, pumps and piping while ensuring safety and reliability. The corrosive nature of the electrolyte demands strict containment measures to prevent leaks and maintain operational safety.
RFBs also require significant storage volume, making them less suitable for vessels with tight space constraints. While setup costs are high, their long lifespan and cycle stability offer long-term value.
Currently, RFBs are most viable for short-sea vessels – an area where Conoship specializes, positioning us at the forefront of this innovation. However, further design work is needed before large-scale adoption becomes feasible.
At Conoship, we continuously refine ideas to develop the most sustainable and efficient solutions for the maritime industry. Our CIP-series is a prime example—standardized short-sea vessels weren’t common in the market, yet we saw the potential. By focusing on modular, future-proof designs, we created ships that save time, reduce costs, and allow for easy adaptation to new technologies.
The same mindset applies to Redox Flow Batteries (RFBs). While they have yet to be adopted in shipping, their long lifespan, scalability, and safety advantages make them a compelling option. We are actively exploring how RFB technology can be integrated into our designs, particularly for future-fuel-ready vessels like the CIP-series.
To bring this innovation to life, collaboration is key. We are looking for partners in energy storage, shipbuilding, and regulation to develop practical applications for RFBs at sea. Interested in working with us? Let’s shape the future of short-sea shipping together.
Holland Shipyard Group has successfully delivered the cable recovery vessel Maasvliet, the first of five CIP3800 vessels, for Hudig & Veder. The first three of these will be operated by Hartel Shipping. This delivery introduces a new generation of fuel-efficient vessels to the European short-sea market, with the Maasvliet specifically designed for cable recovery operations.
The Maasvliet was launched on January 11th, 2024, at the shipyard facilities in Nantong, China. Following the launch, the vessel was transported to Rotterdam alongside her sister vessel Rijnvliet. At Hardinxveld, Giesendam, Holland Shipyard Group completed the final outfitting and commissioning work before delivery to Hartel Shipping in January 2024.
Designed as a cable recovery vessel, the Maasvliet is specifically equipped to retrieve and transport subsea cables, playing a crucial role in cable decommissioning and repurposing projects. With its fuel-efficient design and optimized cargo handling capabilities, the vessel enhances the sustainability of offshore and maritime infrastructure by facilitating the responsible removal and recycling of cables.
The vessel features an advanced diesel-electric propulsion system, designed for optimal fuel efficiency and reduced environmental impact:
In addition to its role in cable recovery, the Maasvliet benefits from the Vliet series’ advanced environmental features, which focus on fuel efficiency, emission reduction, and adaptability to future propulsion technologies.
The CIP3800 series demonstrates forward-thinking design principles with its future-fuel ready capabilities, allowing for potential conversion to alternative fuels. The vessel can also be prepared for battery hybrid installation, showcasing its adaptability to emerging maritime propulsion technologies. This standardized design approach offers the advantages of reduced delivery time while maintaining cost-effectiveness, making it an attractive solution for operators looking to modernize their fleet.
This delivery is part of Hartel Shipping’s fleet modernization program. The next two vessels in the series are scheduled for delivery throughout 2024, with the second vessel, Rijnvliet, expected to join the fleet in Q2 2024. Upon completion, this series will strengthen Hartel Shipping’s position in the European coastal shipping market while significantly reducing their environmental footprint.
With its specialized role in cable recovery and its future-proof design, the Maasvliet is not just the first in the Vliet series—it represents a step forward in sustainable maritime solutions. We congratulate Hartel Shipping and Hudig & Veder Group on this significant milestone and look forward to the successful delivery of the complete Vliet series.
Following two extensive research projects on the ‘Stability of beam trawlers’ and ‘Improving the safety of beam trawlers’ (please reach out to us to request the research papers), we visited the MARIN model testing facility last October. Our appreciation goes to MARIN for their hospitality, expertise and professionalism, the results of the testing days are invaluable to the fishing industry.
The project, which began in 2022, was commissioned by the Dutch Ministry of Infrastructure in response to the tragic capsizing incidents involving beam trawlers UK-165 ‘’Lummetje’’ and UK-171 ‘’Spes Salutis’’. We dedicate our ongoing work to the crewmembers of the beam trawlers that were lost at sea, aiming to establish new standards in vessel stability and crew safety.
Beam trawlers are a type of fishing vessel introduced shortly after the second world war. They operate by dragging two large nets (called fishing trawls) through the water along the bottom of the sea.
On November 28th, 2019, beam trawler UK-165 Lummetje capsized and sank, with the sad loss of two lives. While investigations by the Dutch Safety Board were still underway, in December 2020 the UK-171 Spes Salutis experienced a similar incident, fortunately the crew was rescued.
Following the results of the investigation, the Dutch Ministry of Infrastructure and Water Management was recommended to ‘Investigate the scale of the safety risk of the capsizing and sinking of trawlers as a result of dangerous asymmetric loading conditions within the entire Dutch trawler fleet. Include all fishing vessels in this investigation, irrespective of their length. Take measures to counter this safety risk’. Hence, Conoship was assigned by the ministry to follow up on the investigation and recommend the solutions necessary to improve vessel safety.
During the first project on the stability of beam trawlers Conoship carried out, all Dutch flag beam trawlers were included in the investigation .One of the main conclusions of this project was that it was necessary to narrow down the scope to beam trawlers with a length of 24 meters and less.
We are on the brink of revolutionary change in the industry. For the first time, major players from the entire Dutch fishing industry are coming together to address maritime safety and regulations for beam trawlers. By bringing together builders, fishermen and those who make the regulations we are finally looking at major breakthrough. While the project is commissioned by the Dutch Ministry of Infrastructure and Water Management and carried out by Conoship, local governments are also involved, together with:
The research is relevant for all European nations as many findings can also be applied to different types of vessels. The Belgium and Germany governments have been specifically informed, as there is also a sizeable beam trawler fleet in those countries as well. Furthermore, other countries that use these types of vessels are the UK and France.
As so often, tragedy is at the essence of regulatory breakthroughs. Right now is the time to ensure we keep moving forward. As the various stakeholders of the (beam trawler) fishing industry come together we are close to pushing new national policies that will drastically reduce the risks Dutch fishermen face.
Looking at the second research project, it resulted in three proposals to stabilize the future of beam trawlers:
General stability rules apply also on beam trawlers, but adding requirements for fishing conditions with additional safety margin makes sure vessels can handle these tough situations better. The new rules focus on required vessel stability under heel at different angles and stability requirements while pulling fishing nets.
Based on the proposed new criteria, a stability module can be developed. Based on this module a warning system can be developed, to assist the crew with timely detecting of stability risks while fishing.
More practical education on vessel stability is essential to prepare skippers for tricky real-life scenarios. The conclusion of the research is to use an operational ship’s model to demonstrate and experience the effects of moving booms, rigging and other weights on stability. Additionally, the use of beam trawler simulators is also recommended. In particular, the 24-meter simulator at MARIN and the 40-meter simulator at VDAB.
The model testing was done based on the results of Conoship’s second research project and was executed by MARIN and commissioned by the Dutch Ministry in collaboration with MARIN. The first impression seems to confirm our findings.
MARIN simulated realistic fishing scenarios, such as the effects of fishing gear weight and derrick positions. Testing verified that these conditions ensure a more realistic evaluation of a vessel’s stability compared to traditional free-sailing criteria. Even minor design improvements for newbuilt beam trawlers and retrofitting existing ones can already play a major role in improving safety and stability.
MARIN will process the results of the testing, with which Conoship will assist in any way possible. At first glance, the results seem to align with the second research project, but we must eagerly await the definitive conclusion.
Working out the module upon which the warning systems can be designed. Implementation of the to-be designed warning system on new beam trawlers will be easy. On the other hand, retrofitting existing beam trawlers will likely be more challenging in the upcoming years.
Further develop the beam trawler simulations systems for the education of fishermen in close collaboration with MARIN.
Finally, the proposal to the Dutch Ministry will give national policy makers the opportunity to stabilize the future of beam trawlers. These steps mark the beginning of a safer future for the Dutch fishing industry. By addressing the challenges head-on, we aim to reduce risks at sea, protect the lives of fishermen, and ensure that beam trawlers remain a vital and viable part of our maritime heritage.
By taking decisive action today, we ensure that tragedies like those of the recent past become a thing of history. This journey is one that requires commitment from everyone in the industry. Together, we can implement these solutions, create safer vessels, and set a global standard for fishing vessel safety. We are proud to be a part of this process!
Do you want to know more about this topic or want to know about how you or your organization can contribute to stabilizing the future of beam trawlers? Feel free to reach out to us through the form on our website or call us directly at +31 (0)50 526 88 22.
Heerma Marine Contractors