The people that make HES

HES takes care of having the right people in the right place. We believe each and every team member has to perfectly fit in the team and in their role. They are the organization and bring the right mindset to the table. 

"First the who and then the what."

Management Team

Ivan van Winsen

Managing Director

Ivan has nearly 10 years of experience in the offshore sector. Graduated from Delft University of Technology with a master's degree in ship hydrodynamics he started his career with Heerema Marine Contractors as marine engineer. He has worked on several commercial and innovation projects worldwide, as well as leading the Heerema Simulation Center.

He loves technical challenges and working with a group of enthusiastic people that all bring their individual expertise to the table, resulting in the best possible solutions! Over the last years he led the internal development of the Motion Compensated Gripper Frame and led the development team within HES. As per August 1st he has been appointed as Managing Director.

In his free time he loves sailing with his wife and two sons, reading and cooking.

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Henk Smienk

Engineering Manager

Henk has over 20 years of experience in offshore installation engineering. At HES, he is the Manager Engineering. His main knowledge and experience are in offshore wind installation engineering and pipeline, riser and cable installation engineering. He has a pragmatic view of engineering, understands the interfaces between different competencies within offshore engineering and is able to steer on reducing risks for offshore projects. Henk has a master's degree in river engineering and graduated from the Delft University of Technology.
Outside the office he spends his time with his girlfriend, three boys and one little girl, and likes to be outdoors, skiing and running long distances as he finds it relaxing.
Silvan Slijpen

Commercial Manager

Silvan has nine years of experience in the offshore industry ranging from dynamic riser system analysis to leading a team in the construction of subsea tie-in spools. This enables him to manage a team while also having a profound understanding of the technologies involved.
Silvan is service minded, his ability to understand the technical issues of the client allows him to propose an effective and cut-to-suit engineering solution. His aim is to maintain this service minded approach from project kickoff until project close out to ensure every project is finalized with a satisfactory outcome for the client and for HES.

Management Update

"The core focus will be to maintain the company culture of a young and energetic scale-up, building on our company brand and use 60 years of Heerema experience to become the engineering consultancy firm for offshore renewable projects. " 

Alessio Pistidda

Sr. Specialist Marine Engineer

Alessio has over 10 years of experience in marine engineering and CFD applications.
He graduated cum laude in Mechanical Engineering in Italy. After a PhD in fluid dynamics he joined HMC to work on various projects, such as subsea, windfarms, floating units, and yacht design.
Alessio has a strong understanding of physics and good communication skills. He is an out-of-the-box analytical thinker, who loves to invent solutions for challenges that cannot be solved in the common way.
He enjoys fishing, cooking and spending time with his family.
Andres Yepez Calderon

Structural Engineer

Andrés is a passionate and creative engineer. He obtained his MSc from the Delft University of Technology and his BSc from the University of Washington, both in Civil Engineering with specialisation in structural engineering. He gained strong experience in FEM, structural mechanics, and programming from the year that he worked in structural analysis and automation for the building industry and from his MSc thesis in computational mechanics. At HES Andrés mainly works in structural analysis and design, automation, and software tooling for the offshore engineering industry. 
In his free time Andrés enjoys bouldering, playing squash, and reading about topics that make him passionate. 
Arjen Franken

Specialist Structural Engineer

Arjen holds a master of science in Aerospace Engineering and spent the first 8 years of his career in the Aerospace Industry as a structural engineer working on Finite Element Analyses.
In 2011 he started working for Heerema Marine Contractors and became the lead of the Finite element analyses group responsible for the pipeline spooling and reeling analyses as well as pipeline integrity analyses for the friction equipment (Hang off clamp, tensioners).
Arjen has a strong focus on quality and details, good communication skills and enjoys working together in a team.
In his personal time he enjoys sports, dance, travel and construction work on his house.
Arthaud Adriaenssens

FEM Engineer

Arthaud achieved a MEng in Structural Engineering from the University of Cambridge, shortly after he created a start-up that designs and engineers stage tents for festivals. Alongside the start-up he gained good engineering and FEM experience working on the analysis of sensitive houses and buildings in earthquake zones. Arthaud then made the transition in the offshore world to continue work as a Structural Engineer at HES.
Outside of work Arthaud enjoys taking part in a range of sports such as bouldering, running and cycling. Other hobbies include but are not limited to DIY projects, trivia nights and constantly being on the lookout for the next best coffee spot in town!
Casper van Lynden

Marine Engineer

In 2020 Casper joined Heerema Engineering Solutions for his graduation research about offshore wind installation vessels. After receiving his master in marine engineering at Delft University of Technology in 2021, Casper continued at HES as a marine engineer to work with a skilled and enthusiastic team to further accelerate the developments in the offshore wind industry.
In his time at HES he has performed work on various marine engineering and automation topics. In addition Casper gained offshore experience during the Greater Changhua and Fécamp offshore wind projects.
Being outside playing sports and meeting friends is something Casper enjoys a lot in his free time.
Christof Westland
Christof Westland

Specialist Engineer

Christof started his career at HMC after obtaining the MSc-title in Offshore Engineering at the TU Delft. At the subsea-department he was responsible for structural integrity analyses for pipeline-installations as well as giving offshore support during project execution. After suspension of HMC’s pipelay activities, he continued working for HMC at the marine department. Although supporting all departments, he mainly worked on the decommissioning analyses. Throughout his engineering activities he has a strong focus on automating and improving efficiency, which is exactly the reason why he joined HES.
For leisure he loves kiteboarding, playing the piano and making good food.
Daan Koetzier

Graduate student

Daan completed the double degree ‘European Wind Energy Master’, which took him from the Netherlands to Norway and Denmark to study the different scientific disciplines that come together in the field of offshore wind. He has an affinity for marine engineering and dynamics, which come together in the installation of offshore wind turbines.

As an engineer, Daan likes to work on newly emerging problems and solutions in the growing renewable energy market. Daan likes applying his theoretical background to find creative solutions that solve practical problems.

Outside of work, Daan can often be found surfing the waves of Scheveningen, making music, climbing and playing padel or tennis.

Dennis Dane

Software Engineer

Dennis joined Heerema Engineering Solutions after his graduation in Coastal Engineering. Dennis enjoys to work with water and objects that interact with water. His passion lays in combining engineering with programming. He believes that programming is an important skill in engineering which allows for problems to be solved faster. Being part of the core development team for Metis he merges his offshore wind knowledge and  programming enthusiasm.

In his spare time he likes to develop his website, 3d-printing, Arduino projects, skiing and water sports.

Dieuwer Keunen

Working Student

Dieuwer has had a keen interest in sailing and other water sports since he was younger, which sparked his initial motivation to study the wind energy field. He also believes that the energy transition is one of our generation's great challenges and is interested in finding solutions.
He is studying the European Wind Energy MSc program, including study periods in the Netherlands, Denmark, and Norway. Through a company day at HES, Dieuwer got to know the company and is now working on his graduation thesis that looks at the wet storage of floating offshore wind turbines while learning more about HES and the team.
Dimitrios Tsiropoulos
Dimitrios Tsiropoulos

Specialist Engineer

Being in the Energy industry for seven years, Dimitrios had the chance to work in some of the most fascinating projects in the offshore Oil & Gas and Wind industry.
Following his graduation with an MEng Ship Science from the University of Southampton, he has built a strong background in vessel and mooring hydrodynamics while working with some of the most skillful teams of Naval Architects and Marine Engineers across the globe.
“In HES, I found the people and the environment where I can transform my genuine passion for Engineering into industry-leading achievements through realization of some of the most challenging projects out there!”
Eelco van Vliet

Specialist Engineer

Starting his career as a maritime officer, Eelco’s interest in science and engineering led him to pursue a MSc degree in Maritime Technology. Nowadays, his ambition is to combine his practical/ theoretical knowledge of engineering with his understanding of software development and digitalization. He enjoys digging to the core of any problem in order to come up with a generic and automated solution. When he is not working, Eelco is either sailing, snowboarding, hiking, brewing beer, 3d-printing or playing guitar or football. 
Elisa Romero Pascual
Elisa Romero Pascual

Product Lead Floating Wind

After finishing her Civil Engineering MSc, Elisa joined HMC as a Marine Engineer, where she worked for several Installation and Decommissioning projects for 5 years. During her last year at HMC she worked at the Simulation Centre, where she could be part of innovative and out of the box offshore projects. After that she joined a maritime simulation software company where she lead the product team.
At HES, Elisa is working on floating wind, leading the technical developments and looking for commercial opportunities.
In her free time, she likes to cycle, practice yoga, read and spend time with family and friends.

Ellemijn Rog

Sr. Installation Engineer

Ellemijn started at HES with 5 years of experience in the offshore renewable industry. With a master’s degree in marine engineering, she has developed a wide perspective on the offshore wind market in the last years. She has experience as an installation and cost engineer, an integral role in multidisciplinary and international teams. She enjoys to participate in the newest developments of the offshore wind market. Within HES, Ellemijn uses her experience to strengthen the fixed and floating wind developments. In her spare time Ellemijn enjoys to play field hockey, running, cycling and hiking.

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Ethan Nigel

Marine Engineer

Ethan is a member of the marine engineering department at HES, where he brings extensive knowledge from his studies. His dissertation analysed the dynamic performance of a semi-submersible floating wind turbine, and now his focus at HES is on motion-compensated gripper frame technology.

He enjoys problem solving and working at the forefront of engineering technology. In his free time, Ethan likes to go to the gym, running, and meeting up with friends. 
Farkas Beothy
Farkas Beothy

Marine Engineer

Farkas did his BSc in Mechanical Engineering in Hungary, then came to the Netherlands for his Masters. After graduating cum laude from his MSc Marine Technology in Delft, Farkas started Heerema Engineering Solutions. In his work, he tackles problems in both abstract and practical ways to gain in-depth insight into the subject and find feasible solutions to the problem. His main focus at HES is doing marine engineering tasks within the floating wind development team. In addition, he also participates in projects that involve CFD, motion analysis, and internal development works.

In his free time Farkas plays Ultimate Frisbee at a high level. He likes cooking, go on bike rides, and recently picked up Kitesurfing.

Gino Parisella
Gino Parisella

Sr. Marine Engineer

Gino has over 8 years of work experience in the offshore and oil & gas sector. He has worked as Marine Engineer at a number of leading companies including Heerema Marine Contractors and InterMoor.
As an engineer, he has developed effective skills, and he is always eager to build knowledge aiming to deliver effective solutions on hydrodynamics, offshore installations, and mooring projects. In his career, Gino has done work for a range of vessels and structures, as well as engineering designs for large offshore transports and installations.
Gino is currently extending his qualifications with a PhD in Mechanical Engineering studying wave energy devices. In his spare time, he loves to travel, surf waves, and spend time with his family close to the ocean.
Giulia Rossi

Marine Engineer

Giulia has a BSc in mechanical engineering from Canada, and an MSc in sustainable energy technology from TU Delft that she finished in Sept 2023.
Since her Bachelor degree, Giulia has been interested in wind energy systems, her thesis looked at ice detection on wind turbine blades, which influenced her decision to move to the Netherlands to focus more on renewable energy technologies (wind, solar & storage systems).
Her MSc thesis focused on floating offshore wind, which eventually led to the interest and application to work for HES. 
In Giulia's free time she enjoys organising and taking part in hiking expeditions, running outdoors, and recently started bouldering!
Harald Ottens

Technical Project Manager

Harald has more than two decades of experience in engineering across the offshore, petrochemical, and space industries. He has experience as a project lead, ensuring timely completion and maintaining high-quality standards for consultancy projects.

He thrives in collaborative, cross-disciplinary environments, leveraging his profound knowledge of physics, engineering, and software to develop sustainable solutions for clients.

Harald has an MSc in aerospace engineering and a BSc in economics and business. He finds joy in biking, running, and spending time with his family.

Ian Mullens
Ian Mullens


Ian has graduated his double MSc track degree at TU Delft in 2021 and has a drive for learning and working with new concepts. He is an adapt programmer and especially intrigued by opportunities regarding automation and optimization within the offshore sector. He started his professional career at Heerema Engineering Solutions with the development of a logistical analysis software package Metis, whilst also executing analysis for various projects. 
In his free time Ian enjoys travelling, hiking and playing around with various bits of software.
Jelle ter Braak
Jelle ter Braak

Specialist Engineer

Jelle’s journey in the offshore industry started by finishing his MSc Offshore Engineering at the TU Delft. After working in the structural department at HMC where he co-developed a purpose built Finite Element Package he moved to HES. For three years Jelle has worked with several clients and has been involved in multiple interesting innovation projects related to the XL monopile installation market. The projects include but are not limited to subsea monopile templates and motion compensated gripper frames where he is working on hydrodynamic, control and simulation topics.
In his free time Jelle enjoys food, reading, making music and photography.

Jim Zwartveld
Jim Zwartveld

Specialist Engineer

Jim graduated cum laude in the field of Structural Dynamics of Offshore Constructions at Delft University of Technology. He started scripting during his graduation thesis at HMC and continued filling his toolbox during his employment period. Jim has worked as a Structural Engineer on Decommissioning projects and tenders for HMC, and contributed to the development of engineering tools.
He enjoys mountains and nature; cycling, hiking, snowboarding, travelling.
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Joep van der Spek

Marine Engineer

Joep joined HES as a working student in 2019 and stayed for almost 2 years while pursuing his MSc degree in Marine Technology, specializing in Ship & Offshore Structures. He worked on smart solutions for wind installation and automation of hydrodynamic analysis. 
He graduated on the initial load assessment of semi-submersible floating offshore wind turbines under wind/wave misalignment with a major turbine supplier. After his graduation, he returned to HES to strengthen the floating wind development team. Among other topics, he focusses on floating wind developments for internal and external projects.  
In his free time, he enjoys backpacking and can be found around Delft road cycling or playing basketball.

Karin Leijs

Offshore Engineer

Karin started working for HES directly after finishing her MSc Offshore & Dredging engineering in 2021. Next to offshore engineering, she has an interest in coding and is able to write up software for dedicated engineering tools. She showed this especially when working on our inhouse software Metis.
In her free time, Karin enjoys playing football, giving training to junior teams, cooking comfort food and dancing in her living room.
Kathryn McPherson

Software Engineer

With 12 years of engineering experience in the oil and gas industry, Kathryn has experience in every phase of a project, from concept studies to design, interface engineering, integration testing, offshore installation analysis, pre-commissioning, and decommissioning. Her main area of expertise is the design and installation of subsea pipelines. She also has a background in mathematics and a master's degree in space science. In 2023, Kathryn joined HES and has been working on the Metis logistics tool. She approaches challenges systematically, ensuring technical accuracy, and enjoys working in a team. In her spare time, she likes to spend time with her family, go running and cycling, and occasionally take part in triathlons.

Lisa van Calsteren

Office Manager

Lisa looks after anything and everything around the office, such as travel arrangements for conferences and meetings, event organising, administration, onboarding, and many other items. 

Before working at HES, Lisa had experience working with an oil company, real estate, and also in the casino. She enjoys spending time with her friends, cooking, travelling around the world, and enjoying all that life has to offer. 

Lizette Dittmar - van Halewijn
Lizette Dittmar - van Halewijn

Sr. Administrator

Lizette is the Senior Administrator at HES. She has been working for different Heerema companies for over an extensive period, including working as an area accountant for HMC. In this role she was responsible for the financial administrations of foreign offices like Brazil, Mexico and Singapore.
Before Heerema Lizette worked for an insurance company and accounting offices. In her spare time she likes horse riding, cooking, drinking nice wines, walking, visiting concerts and whenever possible motorcycling.
Mark Hoorn

Structural Engineer

Mark is a structural engineer who joined HES in 2023, bringing with him two years of experience in decommissioning projects. In 2020, he obtained his master's degree in Offshore and Dredging Engineering in Delft, which gave him a strong foundation in offshore structures and construction.  Mark is passionate about using technology to increase efficiency and enjoys coding to automate parts of his work.
In addition to his work, Mark enjoys cooking, baking, and hiking in his free time. Cooking allows him to unwind and express his creativity in the kitchen, while baking allows him to experiment with new techniques and flavors.
Nicolas Moscoso

Geotechnical Engineer

Nicolas has over 7 years of experience in the offshore industry as a geotechnical engineer. He specializes in soil modelling and interpretation, impact and vibro-drivability analysis, lateral stability, anchors design and automation.
With his fair share onboard offshore projects, he also specializes in pile instrumentation and monitoring. With this combined experience and critical mindset he aims at finding a theoretically backed-up practical solution, while always keeping the project timeframe in sight. He gets energized in technical meetings discussing angles that fit all parties involved. 

In his free time, he loves playing squash, kitesurfing and walking his dog.
Patrick Symes
Patrick Symes

Installation Engineer

Patrick started working for HES after his obtaining his MSc title in Offshore Engineering from TU Delft in late 2020. Patrick started programming during his studies which was key to his thesis on the topic of buckling stability of cranes. He recognises the importance that automation brings to the future of engineering and continues to learn how to implement this into the everyday life of an engineer.
Patrick chooses to spend his free time on hobbies like woodwork, adventure hiking and learning new recipes.
Quint van Suijlen

Installation Engineer

Quint joined Heerema Engineering Solutions in the spring of 2022 to complete his master's thesis regarding the floating to floating installation of offshore wind turbines. After completing the Offshore and Dredging Engineering Master at the TU Delft, he continued at HES as an installation engineer. With his background in Mechanical Engineering, he likes to solve engineering challenges from both practical and theoretical points of view. This to find the most convenient engineering solution for a given problem.  
Riding his motorcycle, sailing, football, DIY and spending time with his friends and family keep him busy during non-business hours.  
Reinier van Rossum
Reinier van Rossum

Technical Authority Wind Installation

After graduating in mechanical engineering on the University Twente Reinier spent 3 years of designing amusement rides (roller coasters, Ferris wheels and freefall towers) before he transferred to the offshore industry at Heerema Marine Contractors in 2001. In his first 7 years with HMC he has developed from structural engineer to project engineer, the role he fulfilled the remaining time with the company. In his role as project engineer Reinier had the technical responsibility over several installation and decommissioning projects, where he supervised and guided multidisciplinary teams. 
He is fan of a broad range of sports, mainly as spectator. Actively he likes to go running, ride his racing bike, play golf or ride his motorcycle.
Robert Weegenaar
Robert Weegenaar

Sr. Installation Engineer

After finishing his MSc Offshore Engineering in Delft, Robert started as a Pipelay Installation Analyst at the HMC Subsea Department. In addition to working on theoretical computer models he soon gained ‘outdoor’ experience offshore and on fabrication yards in Batam, Indonesia and Avilés in Spain for a period of 1.5 years. At HES he is mainly working on offshore wind installation engineering & logistical analysis, removal engineering and software tool development.
In his free time Robert enjoys his family life, welding, restoring his classic Moto Guzzi motorcycle and kitesurfing.
Sam de Bode
Sam de Bode

Installation Engineer

Sam has a background in Maritime Engineering. In his work he is passionate about switching from conceptual theories to practical solutions. After working half a year at the office, he has joined an offshore installation campaign on the vessel Aegir of Heerema Marine Contractors, a very nice perk of working for HES.
He is currently involved in Installation and Marine Engineering for Floating Offshore Wind Installations. In addition, he set up the bi-weekly technology sessions at HES, in which speakers from external companies are invited to present their innovation or technology at HES.
In his free time he enjoys boxing, gardening, listening to African music and hanging out with his dog.
Sanjeet Desai

Automation Engineer

After finishing his BSc in Mechanical Engineering in India, Sanjeet came to the Netherlands to pursue an MSc in Aerospace Engineering. After graduation, he joined a simulation software company where he worked with numerical models for ship performance and hydrodynamics. He also helped with the development of a digital twin platform and CFD simulations.

Within HES, he is a part of the data engineering and automation team and will be helping with the development and preparation of Metis simulations.

In his free time, he enjoys cooking, photography, rowing, hiking, and occasionally mountain climbing.

Thiemen van Groeningen

Work student

After finishing his Bsc Marine Technology Thiemen started in September 2022 with his Msc Marine Technology, with as tracks of choice: Maritime Operations and Management and Ship Design. Besides studying he wanted to develop himself, get the first experience of working on real projects and gain some knowledge on what is out there after graduation. 
When this opportunity was given by HES, he took it with both hands and started as a working student in February 2023.  As he has really enjoyed it since, he hopes to stay part of and contribute to the HES team. In his free time, he plays in a football team, loves sailing and when there is a proper breeze he is probably out at sea kitesurfing.
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Thijs van Essen

Marine Engineer

Thijs graduated at HES on the motion-compensated gripper frame as part of the European Wind Energy Master and obtained both a MSc. Offshore and Dredging Engineering and an MSc. Technology – Wind Energy. After some adventurous years of teaching kite and wave surfing Thijs came back to work at HES. “I love the diversity at HES and the opportunity to work on many different projects with a great team.”  
As an engineer, Thijs enjoys solving challenging problems in the (wind) energy sector and working on innovative concepts, such as floating wind turbines and the motion-compensated gripper frame. In his work he mainly focuses on marine engineering.  Besides engineering, he loves water sports such as wave and kitesurfing, meaning you will often find him ‘offshore’ in Scheveningen when he’s not in the office. 
Thom Haafkes
Thom Haafkes

Marine Engineer

Thom graduated in May 2021 for his MSc Marine Technology in Delft and started working for HES since Sept 2021. He likes the combination of working on in-depth marine analyses, but also on more high-level topics, such as innovative installation techniques for the renewable offshore industry. He gained some offshore experience being a project team member for the installation of foundations for the Greater Changhua wind park in Taiwan.
In his spare time, Thom likes running, cycling, sailing, playing padel, cooking and photography.
Thomas Balder
Thomas Balder

Development Lead

Thomas has 14 years of experience in the offshore industry. With a background in physics, he is always looking for new ways to gain insight in complex matter and search for new solutions. Thomas built up experience in pipeline installation, friction clamps and tensioners, probabilistic design, monopile installation and decommissioning, and lots and lots of physical experiments.
After a short sidestep from the Heerema Group, Thomas joined Heerema Engineering Solutions lead new developments in the offshore wind. Outside the office Thomas loves to spend his time with his wife and 3 children or on his mountainbike.
Tieme Moens 1
Tieme Moens


Tieme joined HES in 2023 after finishing his Masters in High Tech Engineering, with a specialization in mechanics. After working on a microscopic hinge prototype for a year for his thesis, he decided to go back to the macroscale marine projects he studied for in his BSc Marine Engineering. With a passion for the environment and innovation, what better industry than offshore wind? Tieme is currently involved in grillage and seafastening design for installation vessels, and floating wind concept development.

In his work, Tieme enjoys a balance of modelling, programming, and designing. He also values an open, friendly and passionate workplace, which means he’s in the right place at HES. In his free time, Tieme can often be found at concerts and festivals, or at home reading.

Toon van der Linden

Geotechnical Engineer

Toon obtained his MSc from Delft University of Technology in civil engineering with specialization in geotechnical engineering. He has seven years of experience in the civil engineering industry as a geotechnical engineer, being involved in projects ranging from foundation and quay wall design to land reclamation and levee reinforcement design, geotechnical site investigation preparation and interpretation, seismic engineering and workflow automation. Within HES, Toon focuses on the geotechnical-related challenges HES is facing. In his free time he loves playing field hockey, going to the cinema and museum, reading and visiting football matches.