Wind Propulsion 2024

Wind Assisted Propulsion Systems (WAPS) in the light of the regulatory framework
Alexandra Maciolowska, DNV AS

Wind Assisted Propulsion Systems (WAPS) have gained significant attention in the shipping industry as a means of reducing fuel consumption and emissions. Integrating WAPS into a vessel design presents challenges that impact navigational safety and regulatory compliance such as reduced visibility, obstructed navigation lights and radar blind sectors.
Designing vessels with WAPS requires a holistic approach that balances energy efficiency gains with navigational safety.
Wind-assisted propulsion systems present significant challenges for navigators. Some of the challenges can be addressed through design improvements, others necessitate equivalent solutions, thereby raising concerns. Additionally, in certain cases, the existing regulatory frameworks fail to adequately account for the implications introduced by these systems.
Collaboration among industry stakeholders, innovative design practices, and regulatory updates will have to be implemented to pave the way for successful WAPS adoption in the maritime sector.

Wind propulsion and classification approach - Evolvement of rules based on experiences gained
Aude Leblanc, Bureau Veritas

The maritime industry is witnessing a growing interest in integrating wind propulsion systems to enhance sustainability efforts and reduce environmental impact. As the world intensifies its focus on environmental sustainability, the integration of wind propulsion technologies has emerged as one of the key solutions to reduce propulsion power and consequently carbon emissions.
As a response, BV as classification society is actively working on further developing and refining class rules to ensure the safe integration of wind propulsion technologies into vessel designs.

The first part of the paper will present a comprehensive overview of BV class rules, highlighting key considerations while considering the broader technological outlook and its significance in addressing sustainability challenges in the maritime sector. Special attention will be given to the adaptations made to address challenges associated with wind propulsion, with a specific focus on stability aspects.

The second part of the paper will illustrate the application of BV class rules on particular projects: the newbuilding for Orient Express and Ponant’s S2Z project. By exploring this project, the paper explores the specific challenges encountered and details the bespoke solutions planned to be implemented to ensure compliance with class rules while optimizing the integration and performance of wind propulsion technologies.

Prediction of Fuel Savings and HAZID/HAZOP Workshops – Essential actions for every WAPS project
Lefteris Karaminas, American Bureau of Shipping (ABS)

In the past decade, the ongoing need for improving a vessel’s operational efficiency and reduction of fuel consumption and emissions, has taken center stage. Wind Assisted Propulsion Systems (WAPS) are continuously evolving as they are a potential energy saving solution for many vessels.

From a project management perspective, unlike other retrofit improvement projects, a WAPS project will pose more challenges in the sense of (a) prediction of propulsion fuel consumption savings as that influences cost-benefit analysis; and (b) Identification of risk as retrofit can pose some challenge due to WAPS in operation and management.

The paper consists of two parts.

The first part provides a transparent methodology to estimate the net fuel consumption saved from propulsion when using specific WAPS for a defined vessel route, for a given time-period, vessel draft and service speed. The net savings are calculated by simulations of vessel performance on the orthodrome between the departure and arrival ports. This methodology is applicable to rotor sails, hard sails, soft sails and suction wings.

The second part describes the elements of a HAZID/HAZOP workshop to identify, evaluate, and control hazards and risks to determine potential problems that may be uncovered by reviewing the safety of WAPS design and revisiting existing processes and ship operations. These workshops are to be applied to identify situations where a combination or sequence of events could lead to undesirable consequences (property damage, personnel safety, and environmental damage), with consideration given to all reasonably foreseeable causes. Prerequisites, methodology and example findings are provided.

Wind Propulsion for Hurtigruten's future Zero Emission Cruise Vessels (Project Sea Zero).
Anders Alterskjær, SINTEF Ocean

The present paper examines the application of wind propulsion technology on Hurtigruten’s coastal cruise vessels, as one of the enabling technologies for realizing a zero-emission battery electric concept which is the goal of the project "Sea Zero". We have conducted several route simulations using models of different levels of fidelity as the project progressed to understand the potential benefits and challenges of integrating sails on this type of vessels also considering operational constraints. Our focus has been on finding the optimum sail type, size and configuration while taking into account multiple aspects such as the vessel's route, speeds, weather data, stability requirements, interactions between sails, and the interaction with the hydrodynamic performance. Furthermore, wind measurements from onboard one of Hurtigruten's existing vessels were compared to the hindcast data sources used for route simulations to examine any effects on predictions.

We have also explored how the hull design could be optimized as the heeling moments from the wind propulsion system challenged stability requirements, and how the wind propulsion system may interact with other energy-saving technologies like air lubrication and innovative propulsion designs. Countermeasures for heel were also explored.
The paper discusses the technical considerations necessary for integrating wind propulsion systems, providing insights for ship designers, shipbuilders and operators interested in adopting this technology. It highlights the potential for wind propulsion to work alongside existing energy-saving measures, contributing to the maritime industry's efforts to reduce its environmental impact. Contributors: Hurtigruten, SINTEF Ocean, Vard Design & Solutions, Brunvoll

Energy Balancing of Windships with Hydrogeneration
Annika Fitz, DLR Institute of Maritime Energy Systems

Recent advancements in windship designs have introduced innovative vessel concepts featuring increasingly larger sail sizes. This trend facilitates the effective harvesting of renewable energy during maritime voyages. In optimal wind conditions, wind power may not only used for propulsion but also sophisticated conversion methods may be employed to meet additional energy demands, reducing reliance on conventional fuels.
This paper explores the potential of harnessing electric energy through hydroturbines submerged on the ship hull. The goal is to evaluate their efficacy in generating additional power to meet onboard hoteling loads and support propulsion during periods of low wind energy yield. To achieve this, varying weather conditions along the journey are considered to analyze the feasibility of energy balancing through hydrogeneration.
A comprehensive voyage plan is developed, taking into account varying weather conditions and optimizing energy harvest along the route. The plan adheres to specified boundary conditions, such as the desired time of arrival at the destination port. Additionally, a buffer storage system is modeled to support effective energy balancing. This investigation includes the determination of appropriate system sizes and explores cost implications, providing valuable insights for the practical implementation of these sustainable windship concepts.

Fluid-Structural Sail Optimization for Wind Assisted Ship Propulsion
Margarita Riera, Dassault Systemes

In response to the growing need for reduced energy consumption and minimize carbon emissions, there has been a surge in the development of numerous energy-saving ideas, and Wind Propulsion is postulated to lead the change.
Align with the IMO, in January 2024 Bureau Veritas published the Wind Propulsion Systems rule, NR206 R02, which explicitly mentions how the wind force of the wind propulsion system can be calculated by employing Computational Fluid Dynamics (CFD) solutions.
This presents an opportunity to conduct fluid-structure interaction (FSI) optimizations for parametric hard sails and their integration onto a cargo ship, all through a fully automated process spanning Computer Aided Design (CAD), CFD simulation, and Finite Element Analysis (FEA) onto the 3DEXPERIENCE platform.
The initial phase involves the generation of a parametric modeled sail. Following this process, the designer computes a sequential FSI starting with the steady aerodynamic performance of the isolated sail. This is a single-phase and steady-state Navier-Stokes simulation, extracting the pressure distribution along the sail. This will be automatically mapped into the a FEA simulation to evaluate stresses and displacements, powered by the Abaqus solver.
To handle the limited deck space available on a cargo ship, the second loop of this workflow is used to optimize the placement of the sail and its installation. This system simulation provides a high-accuracy unsteady CFD based on the Lattice Boltzman Method (LBM), where the cross flow and the impact of the sails over the entire cargo ship are analyzed. This allows the engineer to define the proper placement on the deck and compare different configurations.

Development of Wind Propulsion System
Akihiko Masutani, Sumitomo Heavy Industries Marine & Engineering, Co., Ltd.

International shipping needs to aim for carbon neutrality by 2050, however on the other hand, the price of green fuel is expected to remain high for a long time. Therefore, use of inexpensive wind power is desired by the
industry. The use of wind power for the ship propulsion is gradually progressing, and many wind-assisted propulsion ships are
beginning to enter service. Challenges when using wind power as the coming main
propulsion method has not yet come to light, however, past research has shown that control of weather helm
(yaw-moment) is an essential factor for course keeping under full sail condition. This is because a yaw-moment is generated when wind speed increases and the thrust of sail increases, and it becomes difficult to maintain course stability using the rudder only. Therefore, in this research, a concept in which the yaw-moment can be controlled by the independently controlled rotor sails in place of the rudder. For evaluating feasibility of the concept, CFD simulations and extensive experiments in circular tunnel and at free running under the wind
have been conducted. During the experiments it was confirmed that this control concept is effective even in unsteady conditions where wind direction and speed fluctuate. As a result of this research, we believe that this concept will greatly contribute to the spread of wind propulsion system.

Concept Study for a 4,500 TEU Container Ship with Wind-assisted Propulsion
Christoph Thiem, Hapag-Lloyd AG

Hapag-Lloyd, a leading global container liner shipping company, aims to achieve net-zero greenhouse gas emissions for the entire fleet until 2045. Wind-assisted propulsion is considered as one potential option to reach this target. A dedicated research project has been initiated to better understand challenges resulting from wind-assisted propulsion onboard container vessels, to work on solutions and to increase the fuel saving potential. Together with partners such as the sail technology provider AYRO/OCEANWINGS and the engineering and consultant company TECHNOLOG, a newbuilding concept with extensive usage of wind power has been developed.
The paper provides an overview on benefits and challenges of wind-assisted propulsion from a container liner shipping company point of view. It presents a newbuilding concept for a 4,500 TEU container ship with wind-assisted propulsion. The results of an advanced performance analysis are described which includes CFD analysis of the sail system, VPP (velocity prediction programming) calculations and weather-routing.

Leveraging Wind Propulsion Systems for New Build Vessels via Generative Design
Simon Schofield, BAR Technologies

In recent years, Wind-Assisted Propulsion Systems (WAPS) have emerged as effective energy-saving devices, offering significant emission reductions for ships. A notable example of this is BAR Technologies' WindWings®, which have been developed through a distinctive design approach and extensively validated with data from real retrofits, demonstrating quantitative benefits under diverse operational conditions. Our recent research has shown that the advantages of WAPS, such as WindWings®, can be further amplified when vessels are optimised and designed to incorporate these systems from the preliminary design stage. This approach contrasts with retrofitting existing vessels, which were not originally conceived with WAPS in mind, thereby limiting the potential for maximum savings. Additionally, even with modern simulation-driven tools, there remains a challenge in efficiently producing innovative and truly optimal designs. This challenge stems largely from the concurrent use of these tools with complex and time-intensive physical simulations.
Therefore, we have develop a WAPS-centered and generative ship design tool that uses WAPS as the core to evolve vessel designs. To this end, our tool is driven by Industry 4.0 and 5.0 trends, aiming to propel initiatives for the transfer and customisation of a range of novel AI technologies that cover the full spectrum of combined simulation-driven hull form and WAPS use optimisation. These include state-of-the-art data-driven approaches and generative design techniques coupled with disruptive hydrodynamic simulation paradigms to: i) improve the efficiency of design space exploration, ii) reduce the overall computational cost, iii) develop versatile design parameterisation, and iv) integrate WAPS in the preliminary design process.

Intellectual Property in the Marine Sector - Practical and Strategic Tips and Examples in Wind Propulsion
Tim Wilson, Withers & Rogers LLP

Wind propulsion may be one of the oldest means for propelling ships, but the sector has recently seen renewed, perhaps even unprecedented, levels of innovation. Driven by policy changes around emissions and owners’ and operators’ demands for greener fleets, marine industry innovators are seeking to refine & adapt the oldest marine energy source to the demands of modern industry. Growth in Intellectual Property (IP) rights in the sector is significant. How can innovators in the sector protect their innovations and what are the benefits? What is the impact on competitors and how can they monitor others’ innovation and IP activity? Here, we will go over the core facets of the Intellectual Property system as it applies to this area of technology, analyse trends in Intellectual Property in the wind propulsion sector, and advise on how players can protect wind propulsion innovations to help to secure funding, contracts, gain tax efficiencies and protect market share.

A New Experimental Set-Up To Test The Influence Of Wind Propulsion On Manoeuvring And Seakeeping
Anton Kisjes, Maritime Research Institute Netherlands (MARIN)

With the rapid growth in wind propulsion installations within the market, it becomes increasingly relevant to facilitate reliable test procedures to validate whether the ship is still capable to show sufficient manoeuvring and seakeeping behaviour. Depending on the specific case and wind condition, wind propulsion can have significant impact on a ship’s response. Earlier research [1] showed that a test set-up with a “real wind field” on a moving carriage, was capable to indicate a certain ship response, but also had its limitations. Therefore, a new test set up was developed within the EU Optiwise project (https://www.optiwise-project.eu), coping with the lessons learned from earlier investigations. The approach extends on gained experience from tests conducted on a Volvo Ocean yacht [2] that used two winches to apply the wind loads. The proposed test set-up expands the number of winches to five, enabling to independently apply a yawing wind moment and making it possible for the ship model to complete a turning circle without the implication that the lines become restricted. In collaboration with our Optiwise partner Chantiers de l’ Atlantique, their cruise vessel was selected to investigate how wind propulsion changes the manoeuvring and seakeeping performance using the new test set-up. The results indicate that the set-up proved to be successful and will be further standardised to ensure that ships remain safe in operation and compliant to current and developing regulations on wind propulsion. This paper presents a detailed description of the test set up and elaborates on the test results.

Aerodynamics of the Rotor Flettner Sail at high Reynolds number
Frederic Deybach, Total Energies S.E.

This paper presents original experimental results on the aerodynamic characteristics of several Flettner rotor configurations at high Reynolds number. The configurations examined are three-dimensional, which have been the subject of very few studies. This study examines the influence of geometrical aspect ratio and end plates size at different Reynolds number.
The wind tunnel test campaign carried out at Institut Aerotechnique Saint Cyr l’Ecole, France provided the C_L ,C_D aerodynamic coefficients for each configuration, as a function of k, ratio of the peripheral speed to the relative wind speed, over a range of 0 to 6, and as a function of Reynolds number in the range between 100,000 and 1 million. The results presented are accompanied by a detailed comparison with previous tests, from Buseman, Charrier, Baladamenti and Bordogna.
The study highlighted the influence of the end plates, whether they are stationary or attached to the rotor. In this regard, the results show the effectiveness - on the level of C_Lin particular - of attached plates of significant diameter placed at both ends. More essential, the study shows the low sensitivity of the aerodynamic results, C_L ,C_D to the Reynolds number between 100 000 to 1 million as soon as the k parameter exceeds 1, There is even independence to Reynolds number over the most useful range of k (2 to 4) over the range of Reynolds number tested during the campaign.

Boosting Wind-Assisted Ship Propulsion Performance Through Accurate Wind Sensing Techniques
Konstantinos Fakiolas, FINOCEAN LTD

Any performance prediction assessment and even a commercial supply contract made for a WASP application on a given ship are based on methodologies that take into account the force components of a WASP system as applied and developed through each encountered wind angular direction and intensity, usually to an accuracy of 5o.
Hence, the basic assumption made is that the WASP unit will always respond accurately during the dynamically altering incoming wind conditions to optimally adjust its operational parameters (i.e. Angle of Attack, RPM or Fan speed) against these specific measured values.
An important question though, is How these - incoming to the ship and WASP systems - Wind properties are measured, which instruments are used for this purpose and how accurate are they for the intended WASP application.
This paper will present the issues associated with only relying on the typical standard ship Anemometers, the complexity of operating conditions with which Mechanical Sails of WASP systems are required to function on a ship, and which alternative equipment and methods can be used to boost performance of these WASP systems, so that they will be able to deliver their fully promised performance potential, as predicted.
Specific mention will be made on how fibre optic sensors can be one such a reliable solution, since they have been already used on board WASP fitted ship applications and it will be demonstrated how they can become an effective component of a WASP installation, among other complementary performance enhancement equipment.

“Advancing the Wind Propulsion industry: ITTC Guidelines and Recommendations”
Sofia Werner, RISE

Authors: Sofia Werner, Anders Alterskjær, David Trodden, Rogier Eggers, Yeongyu Kim, Yuling Gao, Xinshu Zhang, Kenichi Kume

Wind propulsion technology for modern cargo vessels has rapidly evolved from non-existent to a viable industry within a few years. Anticipated growth in this field necessitates standardisation of methods and terminology. The International Towing Tank Conference (ITTC) Specialist Committee on Wind-Powered and Wind Assisted Ships has diligently worked over the past four years to establish guidelines for performance indicators, prediction methods, and sea trials. Their efforts include comprehensive reviews of wind propulsion technologies, hydrodynamic and aerodynamic methods, safety considerations, and regulations. This paper outlines the draft guidelines’ scope and methodology, along with recommended procedures. Additionally, it provides a summary of the committee’s investigations. Finally, the paper proposes potential research topics aimed at inspiring students and researchers.

Where should they POINT? eSAIL trimming optimization through a Potential Interference Tool
Marc Martí Arasa, Bound4blue SL

The implementation of Wind-Assisted Propulsion Systems (WAPS) is growing rapidly in an attempt to decarbonize the shipping industry. Maritime pollution has been on the focus of the International Maritime Organisation (IMO) for decades, and now a clear trend towards greener practices can be observed.
The need for higher emission reductions to comply with the stringent regulations requires charterers and shipowners to innovate, and the installation of WAPS on their vessels is the most promising one. The eSAIL, the solution provided by bound4blue, is a high-lift device (capable of achieving lift coefficients up to 8.3). All high-lift devices, such as eSAILs or Flettner Rotors, generate a large flow disturbance around them, and any object in the vicinity could cause a performance reduction. Being able to accurately model and predict the aerodynamic interaction is a key factor in maximizing the achievable savings of wind propulsion when installing multiple WAPS on a vessel.
The goal of this paper is to present the development of a rapid simulation tool (POtential INterference Tool - POINT) that allows to understand the interaction effects between multiple WAPS, which is crucial for selecting the configuration that best suits each vessel. The most common rapid simulation tools used are based on simple potential flow models, but these are best suited to streamlined bodies with smaller flow field perturbations, which is not the case for WAPS delivering very high-lift. Additionally, modelling the suction system, the working principle of the eSAIL, cannot be incorporated into these common models. Therefore, a mathematical model based on panel method, extensively used in the aeronautical industry, was developed to capture the complex aerodynamic phenomena of the eSAIL. Once calibrated against single-eSAIL wind tunnel test data and 3D CFD interference simulations, the tool can be extensively used to predict realistic performances of multiple eSAILs installed on vessels.

Experimental investigation of the impact of leeway and rudder angle on the yaw moment balance for wind propelled ships
Saeed Hosseinzadeh, University of Southampton

Wind-assisted propulsion systems are growing in popularity as a technology for decarbonizing maritime transport, due to their capability to lower ships' fuel consumption and mitigate greenhouse gas and other emissions. There is a need, however, to investigate the hydrodynamic implications of wind propulsion for these vessels, particularly the aerodynamic side force causing the hull to adopt a leeway angle to its heading. The study described in this paper is focused on assessing the hydrodynamic performance of wind-assisted ships under different leeway angle conditions. A set of self-propelled captive model tests is carried out on the single-screw KCS containership vessel in the University of Southampton’s Boldrewood towing tank. The experiments are conducted in an offloaded propeller condition to represent a proportion of the required thrust coming from the wind. A range of leeway angles between ±5° are tested along with a series of rudder angles, varying from -30° to +30° with 10-degree increments.

A detailed discussion is provided on how varying leeway and rudder angles affect both ship resistance and lateral forces. In addition, the effect of rudder and leeway angles on the yaw moment is studied. The results indicate that as the rudder angle increases, there is a corresponding increase in ship resistance, side force, and rudder induced yaw moment. For each leeway angle tested the required rudder angle to balance the hydrodynamic induced yaw moment is presented demonstrating that significant rudder angles may be required for wind propelled ships.

Optimizing Wing Sail Efficiency: A Computational Fluid Dynamic Approach to Understand Stall Recovery
Alexander Wright, Wolfson Unit M.T.I.A.

For a wide range of conditions, optimising drive from wing sails requires operating close to peak lift. This results in increased chance of stall occurring with small perturbations in the environmental conditions (wind shift, change in wind speed , vessel movement etc). If the wing is not realigned the flow can easily stay stalled even after the initial conditions are regained, thus greatly lowering drive and overall system efficiency. A well refined control system will quickly identify stall, change the angle of incidence to re-attach flow and then move back to peak drive force and system efficiency.

This paper presents a computationally based approach for modelling stall recovery, using a current design of a single wing in isolation on board a ship to investigate the speed and size of wing realignment required for different scenarios, from which a control algorithm can be derived. The wing and ship will be simulated using unsteady RANS, utilising a dynamic mesh to capture the wing motion.

The effects of magnitude of loss of lift versus realignment required as well as speed of wing movement for typical conditions are presented, from which the design of both performance monitoring and wing control mechanisms can be specified.

Comprehensive Assessment of Bilge Keels and Fins for Enhancing Wind-Powered Vessel Performance: Bridging Laboratory Insights to Operational Efficiency
Gunnar Jacobi, Delft University of Technology

This study delves into the effectiveness of bilge keels and fins, exploring their impacts on the efficiency of wind-powered vessels. Employing Particle Image Velocimetry (PIV) in a towing tank configuration, the research systematically analyzes flow features generated by these keels and quantifies the hydrodynamic forces across various bilge and fin keel geometries. Building on prior research, this investigation extends its scope by tracking the path of shed vortices towards the propeller plane and evaluating the tested appendage configurations along global shipping routes. A comprehensive digital ship modeling is composed using the Pelican performance prediction software, incorporating laboratory measurements for hydrodynamic coefficients and vorticity induced effects. The impact of these appendages on ship performance in operation on select global routes is presented and discussed. Results from laboratory experiments reveal distinct mechanisms through which each appendage type enhances hydrodynamic performance while at the same time identifying certain damaging interaction effects, providing valuable insights for future design optimizations.

Seakeeping and manoeuvring simulations for wind powered vessels in the design stage.
Stavros Kontos, RISE

Wind propulsion systems (WPS) can contribute to achieving the IMO’s greenhouse gas emissions reduction targets. However, the additional transversal forces and yaw moments they produce can affect the manoeuvring and seakeeping performance of a ship. In this study we utilize time domain simulations to assess the manoeuvrability and safety of a wind powered vessel at an early design stage.
SHIPFLOW Motions, an unsteady 3D fully nonlinear potential flow hydrodynamic solver, will be used to investigate the effects of unsteady wind and waves on the ship’s sailing performance.
SEAMAN-Winds will be used to investigate how a WPS affects the manoeuvrability and safety of the vessel. Existing safety criteria will be examined (e.g., weather criterion, course and track keeping, zig-zag test) and we will discuss whether additional criteria for WPS equipped ships are needed.
Furthermore, we will demonstrate how real-time simulations can be used to train mariners on the WPS technology, assess the HMI design and increase the overall acceptance of the systems.

From theoretical performance prediction to operation and on board measurements ; review of a complete journey along Canopee project
Giorgio Provinciali, AYRO

Performance prediction has been central all along the design phase of Canopee, the world’s first wind assisted RORO ship, equipped with 4 OceanWings of 363m² each. From global ship equilibrium, to brake power reduction estimation and fuel consumption on a route, an overall review of what has been conducted during the design phase is detailed.
Then, now that the ship is in operation, a first comparison of real life consumption gains with initial theoretical predictions is proposed.
Finally, with increasing performance prediction capabilities, a discussion is opened on new physical modeling techniques of higher accuracy and their impact on final consumption predictions.

Long-term verification of WAPS systems using in-service measurements
Johanna Tranell, DNV

Wind Assisted Propulsion Systems (WAPS) installations are rapidly increasing in number, as a promising measure to reduce emissions for deep sea shipping. DNV is investing significantly in building knowledge about WAPS for the purpose of building trust in the performance and value of such systems, aiming at facilitating the uptake. Building on previously developed procedures for assessing the long-term performance of technologies that can be switched on and off during operation, this paper discusses advantages and challenges of the procedures, demonstrated by measured data. Topics discussed include test procedures, required filtering, different methods of quantifying the obtained energy saving and related uncertainty factors in the estimate. Strategies for reducing and quantifying the uncertainty are also discussed.