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fw - the unknown factorThe knowledge and tools to realistically determine the “unknown weather factor”. Involved in developing guidelines.
Highlights.Issue 64/2017
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Virtual Captive TestsSorting out the manoeuvringissues before too much time hasbeen spent optimising the hulllines will save time and money.
Battery hybrid applied to marine propulsionIncreased interest gives a number of projects evaluating different alternatives.
Demonstrating the use of urban and inland waterwaysFor densely populated cities and more sustainable transport.
PAGE8 – 11
Page 8 – 11
Demonstrating the use of urban and inland waterwaysTwo large collaboration projects: DenCity and NÖKS II.
Investigating maritime accidentsInsights and a deeper understanding from both a human and technical perspective.Page 12 – 13
Page 6 – 7
Advanced maritimeoperations in civilengineeringSupporting our client to ensure a much better understanding.
2 Highlights 64 / 2017 – Virtual Captive Tests (VCT), a tool for investigating manoeuvring performance
In order to generate business success, opportunities have to be explored and obstacles overcome. Before launching new services onto the market, demonstrations of the concept can be a valuable way of gaining insights into market readiness and identifying hurdles that still need to be overcome.
We have recently demonstrated how urban and inland waterways can be used, as part of two large collaboration projects, ‘DenCity’ and ‘NÖKS II’. Demonstrating new logistics solutions is an important step in gaining an understanding of the system prerequisites for commercialisation, not only with regard to technical issues, such as vessel design characteristics and cargo handling equipment, but also social matters, such as the importance of practitioner involvement and the evaluation of performance criteria. This is a promising path for the future, both in terms of managing the trend towards more densely populated cities, and using more sustainable transport solutions.
The BB GREEN project is another example of a demonstration project where SSPA has been a partner. A fullscale demo vessel has been constructed to prove the feasibility of new fast ferries that enable environmentally friendly public transport in cities. The fast airsupported vessel (ASV), ‘Airi El’, is being used to promote and demonstrate how the new ASV fast commuter ferry technology can be commercialised.
At SSPA, we ensure that our clients can address their future challenges and contribute to innovative solutions and new ways to enable sustainable development. Through commitment, integrity, insight and expertise, we facilitate our clients’ path to success.
Do not hesitate to contact us with feedback, comments or questions. We hope you enjoy this issue of SSPA Highlights.
Susanne AbrahamssonPresident
Highlights.
Manoeuvring performance generally features too late in the design process in SSPA’s experience. Sometimes shipyards have to face costly and timeconsuming lastminute changes to the design (when the IMO standards for ship manoeuvrability are not met). And what if the manoeuvring performance is “too good”? Is the rudder too big? (Resulting in resistance that is too high). The use of a new method of CFD calculations enables SSPA to offer earlystage manoeuvring pre dictions with much higher accuracy than before. By sorting out the manoeuvring issues before too much time has been spent optimising the hull lines, the new build project will save time and money in the design stage. SSPA’s experts also believe that this approach will lead to safer, better and more sustainable ship design. Virtual Captive Tests (VCT) is one of SSPA’s “manoeuvring tools”.
VCT, a tool for investigatingmanoeuvring performance
The VCT method is briefly explained in this article and discussed in the context of the rest of the tools available for manoeuvring investigation. VCT can be incorporated in various stages of the design process, offering a very cost-efficient method of ensuring good manoeuvring performance with the aim of meeting the International Maritime Organization’s (IMO) standards for ship manoeuvrability.
What is VCT?Virtual Captive Tests (VCT) are a cost and time-efficient method of investigating manoeuvring performance at an early stage of the design of a vessel. Captive model tests have been used for many years to measure hydrodynamic forces for input into a manoeuvring simulation model.
The VCT manoeuvring tool is a combination of Computational Fluid Dynamics (CFD) calculations (similar to Captive Model Tests) and manoeuvring simulations based on forces
Flow visualisation at the stern of a twin-screw vessel with operating propellers and large rudder angles. Pressure distribution on the hull and appendages streamlines passing through the propeller disc, and axial velocities around the rudders can be observed.
from the CFD calculations. You may wonder: why not just use CFD? The answer to this question is that this option is considered too advanced, too timeconsuming and too expensive.
However, CFD calculations similar to model tests with a free model would probably give the most accurate prediction, since manoeuvring tests with a free model are the most accurate way of investigating manoeuvring performance. In the meantime, while we are all waiting for faster computers, the VCT method represents a more feasible option.
What does VCT add?The advantage of CFD compared to physical model testing is a better understanding of the flow around the vessel because the calculations can be paused and the pressures, velocities, etc. can be studied thoroughly. This provides the naval architect with a unique opportunity to improve details based on information that
Demonstrating future capabilities supporting sustainable developments
cannot be obtained through physical model testing.
VCT in the design spiralA general design spiral for manoeuvring was presented in previous issue of Highlights (63/2017). The VCT can be placed in this spiral either to make better Concept simulations or to make better Testsupported simulations.
Manoeuvring performance at speedOverall manoeuvring performance at speed can be categorised by dynamic stability, turning ability and yawchecking ability. A ship is dynamically stable on a straight course if it after a small disturbance soon settles on a new straight course without any corrective rudder. Turning ability is the ability to initialise and complete a turning manoeuvre. Yaw checking is the ability to counteract a turn, which is
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Test supported simulations (IMO Criteria)Test supported simulations (IMO Criteria)Test supported simulations (IMO Criteria)
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General design spiral for manoeuvring. The idea is to start the design process in the outer parts of this spiral and work our way into the centre, where various design decisions have converged into the final design. We have divided our spiral into four quadrants: manoeuvring, seakeeping, calm water and cavitation. MDL, Maritime Dynamics Laboratory, SSPA’s basin for manoeuvring and seakeeping. TT, Towing Tank, SSPA´s towing tank.
Magnus WikanderMarketing & Sales Manager, Ship Design.Magnus graduated with an MSc in Naval Architecture from Chalmers University of Technology in 2004. Prior
to joining SSPA, he held various positions within ship design consultancy as well as working as a project manager for a ship repair yard working within the main focus areas of energy efficiency, newbuilding and environmental solutions. Since joining SSPA in 2013, Magnus has held the position of Marketing & Sales Manager, Ship Design.
Contact information E-mail: [email protected]
Martin AlexanderssonProject Manager. Martin has an MSc (2009) in Naval Architecture from the Royal Institute of Technology and has
been employed at SSPA since 2011. At SSPA, he is involved in various research and consultancy projects in the fields of seakeeping and manoeuvring. His projects usually involve manoeuvring simulations and the development of computer software.
Contact information E-mail: [email protected]
Simulations By simulations we mean simulations in SSPA software SEAMAN, which is an implementa-tion of Nils Norrbin’s slowmotion derivatives model. This approach does not attempt to model the physics of the complicated flow over the manoeuvring hull. It is simply assu-med that the forces are dependent upon the motion variables, their time derivatives, hull geometry and the rudder angle. The Taylor series expansion of forces is used.
Captive model tests The ship model is held captive, which means
that it is not free to move. Instead the model is forced to move in simple, predefined motions and resulting hydrodynamic forces are measured by a captive balance. The results from captive tests can be used to derive a mathematical model that can be used in simulations. These types of tests are also known as Planar Motion Mechanism (PMM) tests.
Model tests with a free model Model tests with a free model are the com-plete opposite of captive model tests. Here the model is free to move in all directions.
Forces and moments are applied to the model using propellers, and rudders and the resulting motions are measured. Model tests with a free model in the Maritime Dynamics Laboratory (MDL) are the most accurate manoeuvring test that SSPA can offer.
SSPA manoeuvring database Manoeuvring model tests with a free model conducted over the years in the Maritime Dynamics Laboratory (MDL) have been stored in a database. Regression on this database can be used to develop generic simulation models in ShipGen.
usually characterised by zigzag tests. Poor manoeuvring performance is of course a safety risk.
Furthermore, poor manoeuvring characteristics might also have economic implications. Low course stability may lead to excessive use of the rudder to maintain a straight course, which in turn will decrease ship speed or increase fuel consumption.
Accuracy CFD calculations for manoeuvring seems to be a rapidly evolving field at the moment. SSPA believes that the calculations still need to be benchmarked to a database of already tested vessels and validated using model tests to ensure accuracy. SSPA’s facilities, especially the Maritime Dynamics Laboratory (MDL), have very good capabilities for this validation. The capability to run all possible captive tests, both rotational and sinus tests, and to run tests
using a free model, offers more or less all pieces of the puzzle.
The continuous improvement of naval architectural methods is vital for the develop ment of more efficient and sustainable vessel designs. The VCT method is taking us forward, with the hope that ships will be safer and greener in the future.
4 Highlights 64 / 2017 – Battery hybrid applied to marine propulsion
Battery hybrid applied to marine propulsionThe maritime industry is currently experiencing a significant increase of interest in battery hybrid installations for new buildings and retrofits. The driving forces include the current development in battery technology, potential for lowering operational costs, increased capacity of drivetrain and reduction of greenhouse gas emissions. Battery and hybrid propulsion have been suitable for some routes for a long time. Yet for a number of applications, other propulsion systems offer better possibilities for obtaining current design objectives, e.g. the correct capacity of drivetrain and reduction of greenhouse gas emissions. One of the crucial aspects is finding out when battery and hybrid propulsion is a feasible way of meeting the targets for a specific ship, including its operational profile. A number of recent projects show that SSPA has the tools and knowledge to answer these questions and to evaluate different alternatives for propulsion, from batteries and fuel tanks to propellers.
Increased interest in battery and hybrid propulsionBattery applications have recently become interesting in relation to some largescale marine applications. This is due to a combination of factors such as development within the field of lithiumion batteries, giving improved capacity, reliability and reduced battery prices. Aside from technical factors, concurrent development can be noted regarding uncertainties in relation to future fuel costs and fuel supply, stricter emission legislation and greater environmental ambitions.
At SSPA, increased activity within the area of battery and hybrid propulsion can be seen in an increasing number of projects within this area. Examples include “Greener yellow ferries”, a project for the Swedish Transport Agency involving environmentally friendly road ferries, described in an earlier issue of Highlights (62/2016), as well as technical project support for batterypowered sightseeing boats on behalf of shipowner Strömma Kanal and the fast, air supported commuter ferry “Airi El” in the project BB GREEN.
In the following, a couple of other projects from SSPA’s project portfolio within the relevant area are summarised to give examples of how SSPA’s tools and knowledge can be utilised to choose from a number of drivetrains.
Hybrid work boatSSPA was appointed early in the project to conduct the technical and economic feasibility study for designing a vessel with battery hybrid propulsion. The study also involved the conceptual design of drivetrains suitable for the ship’s operational profile.
The work group consisted of a small team utili sing expertise within Ship Design, Internal Combustion Engines, Life Cycle Cost Calculation,
At SSPA, increased activity within the area of battery and hybrid propulsion can be seen in an increasing number of projects within this area. One example is the fast, air-supported commuter ferry “Airi El” in the project BB GREEN. Photo: Anders Mikaelsson, SSPA.
Different drivetrain concepts and their cost per saved kg CO2. Illustration: SSPA.
supplier A supplier B supplier C low poss0
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STA proposed value
Proposed 2030 CO2 tax
Current CO2 tax
Operational Cycle Emissions and Onboard Systems.Significant activities in this project include:• Inquiries and interviews with the shipowner
and ship crew including data analysis to define an operational profile
• Definition of battery/drivetrain concepts suitable for the ship’s operational profile
• Calculation of life cycle costs for the drivetrain (from diesel engine/batteries to propeller shaft)
• Reduction of emissions of GHG (Greenhouse gas), NOX, HC
• Comparison of the different drivetrain concepts with regard to cost, emissions, functionality
• Optimisation with respect to the operational profile of significant aspects of the ship such as main dimensions, drivetrain type, size of battery bank, type of battery chemistry.
Before the basis for the specification was esta- blished, a number of intermediate results were
put forward to facilitate balancing of the ship owner’s functional requirements. One such result is shown in the figure below. This figure shows the cost per saved kg CO2 for different hybrid drivetrain concepts. The base value (zero cost/kg
Philippe GhawiProject Manager. Philippe received his MSc in Naval Architecture from the Royal Institute of Technology in 2012. At SSPA, Philippe works with
alternative fuels, energy efficiency and battery hybrid vessels as well as undertaking tra- ditional naval architecture-related duties such as ship stability and weight calculations.
Contact information E-mail: [email protected]
Olov LundbäckProject Manager. Since joining SSPA in 2016, Olov has been in- volved in projects in the areas of ship-motion simul- ations, battery hybrid
propulsion, effect of ship propulsion on the seabed, propulsion machinery and marine operations. Prior to joining SSPA, he worked with subsea infrastructure for the oil and gas industry, engine development at Scania and marine operations at Westcon Group. He has a PhD within ship dynamics from Chalmers University of Technology and an MSc in Naval Architecture from the Royal Institute of Technology.
Contact information E-mail: [email protected]
The figure shows total propulsion power along with the available power for an icebreaker during a typical icebreaking mission. Illustration: SSPA.
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There are examples of routes for which battery-powered ships have been suitable for a long time. One of these is the short route between the island of Koön and the island of Marstrand in Kungälv Municipality in Sweden. The first electric ferry (Hamnfärjan I) on this route was delivered in July 1913. The second electric ferry on this route (Hamn färjan II) was built in 1948 and had transported about 8 million passengers when it was decommis-sioned in 1985.
Today, this ship is operated as a historic vessel by a non-profit organisation. It has an 8hp ASEA motor powered by 40 battery cells of 2 volts each. The batteries are charged automatically on both stops of the route.
Hamnfärjan I (1913) and Hamnfärjan II (1948)
The electric ferry Hamnfärjan II (Courtesy of Färjans Vänner Marstrand).
CO2) represents a traditional diesel powertrain. The costs for the different hybrid drivetrain concepts were obtained by comparing different system solutions from different suppliers (denoted “supplier A–C”).
The alternative denoted “Lowest Poss” was built using compatible parts from the three suppliers, which resulted in lowest cost per saved kg CO2. As a comparison and indication of what the permitted cost of CO2 reduction might be, the horizontal bars in the figure show current and proposed future CO2 tax in Sweden.
Such results were utilised in combination with functional requirements to balance requirements and costs.
Battery hybrid icebreakersFor vessels with dynamic positioning, battery hybrid installations have become a competitive alternative for new-builds as well as retrofits. High demands on system redundancy for dynamic positioning applications require multiple engines running.This results in low engine loads and many engine hours, hence less efficient operation and high maintenance costs. When such a system is fitted with a battery bank, the battery bank enables one or more engines to be switched off while redundancy demands are still fulfilled. This leads to increased efficiency for vessel operation.
A somewhat similar type of battery hybrid appli cation has been identified for Swedish icebreakers. During assistance and towing in ice, icebreakers need a high power reserve to be able to maintain speed in case they hit an ice ridge or the ice gets thicker. The figure above illustrates this with an example of power demand and available engine
power during an icebreaking operation. SSPA is conducting a study for the Swedish Maritime Administration to analyse the need for a battery hybrid installation, the feasibility and the life cycle cost. This project is planned to be completed later this year.
Hybrid drivetrain simulationsSSPA is continuously driving the development of simulation capabilities using a simulation tool for optimisation of hybrid propulsion, among other things.
The tool can be used to calculate the fuel consumption of a dieselelectric hybrid powertrain, an operational profile and drivetrain properties such as diesel engine startup time. Another example of use is the design of optimal control algorithms for a diesel electric drivetrain with known startup time for main engines for a given battery bank size.
Replacing an old bridge is never easy. But what if you are doing it in the heart of a large city where the transports cannot be permitted to disturb regular traffic too much? And what if one of the bridgeheads is located within metres of an 800yearold building? And what if you have a very short timeframe for completing the work? In such a case, you need to take the operation to a whole new level. So before the Swedish Transport Administration invited bids for the project with the help of SWECO, they both decided put some of their assumptions to the test.
Advanced maritime operations in civil engineering The railway bridges in Stockholm city centre are to be replaced. Needless to say, this is a very sensitive operation and the Swedish Transport Administration wanted to acquire as much information about the problem as possible, as early as possible. One way of managing the impact of the operation on traffic was to transport and install the bridges over water. SSPA used its knowhow of maritime operations and stateoftheart simulation tool SEAMAN to help our client save money and manage the risks involved in such an operation. After the project, our client felt that they had a much better understanding of the problem and could start the bidding process with more confidence.
6 Highlights 64 / 2017 – Advanced maritime operations in civil engineering
BackgroundThe Swedish Transport Administration was tasked with upgrading the rail bridges at Getingmidjan in the heart of Stockholm. The operation will effectively divide the rail network of central Sweden in two. Work is to be performed on and in the vicinity of the oldest part of Stockholm, Riddarholmen, with some buildings dating back to the 13th century. In short, this is a very sensitive situation. The Swedish Transport Administration asked SWECO to help them prepare the request for proposal. SWECO saw that one way of
meeting the tight deadlines without disturbing the city traffic is to transport all the heavy parts by water. But is that even possible? They contacted SSPA for help with the maritime parts of the project, and we got down to work.
The ideaOne way of replacing the bridge segments is to transport them from the Baltic Sea through the locks at Södertälje and onto Lake Mälaren. The bridge segments will then be assembled into complete bridges in a suitable location on the lake. These bridges will in turn be loaded onto barges, manoeuvred through the archipelago into Stockholm and put into the correct position. Does this sound complicated? SWECO wanted to know exactly how complicated it was, or indeed whether it was even possible. The whole operation was to be set up in a simulated world where it would be carried out repeatedly to find an answer.
Is it possible?To check whether the proposed idea was feasible, SWECO turned to SSPA. The operation was analysed and divided into several phases:1. Transport the bridge segments through the
locks and canals at Södertälje.2. Assemble and prepare the bridge segments
for final transportation.3. Transport the assembled segments to the
mounting area of the bridge4. Manoeuvre the barges into position and
lower the bridge onto its supports.
SSPA did research on what barges and tugboats could be used for the transportation through to the assembly area and from the assembly area to the bridge mounting area. These vessels were then used in simulations. In addition to the mathematical simulations
In these simulations, it was assumed that the barge will be using winches connected to the shore-line and anchors for positioning. The tugs will be disconnected from the barges before this critical section. Illustration: SSPA
cations to make them possible. At the end, our clients SWECO and the Swedish Transport Administration felt that they had a much better understanding of the problems inherent in this type of solution. And the more you know, the better you can handle the RFP, Request for proposals. You can save money and manage the risk better. With that knowledge, they felt comfortable putting out a request for proposals for replacing the bridges.
What methods will the bids propose? We don’t know yet. But we do know that transporting the bridges on water is one way to do it.
Linus AldebjerProject Manager. Linus has a degree in Engineering Physics from the Chalmers University of Technology. He has a background in
mathe matical modelling, control algorithms and simulations applied to the maritime domain. He is currently leading the development of SSPA’s simulation tool SEAMAN and was project manager for SSPA’s part of the Getingmidjan project.
Contact informationE-mail: [email protected]
in each phase, a 3D model was created for the final positioning of the bridge.
1. Transportation through the locksA geometric analysis was carried out for how the barges, bridge segments and tugboats would make it through the locks in Södertälje. In addition to lock passage, fasttime simula tions of the entire passage were also run using SEAMAN. It is not the first time that this tool has been used for simulations of lock operations. For example, it has been used for simulations of ships transiting the Panama Canal, and for ships in Södertälje as well. This time the simulations showed that passing the locks is possible under the assumptions of this project.
Simulations are an efficient tool for maritime infrastructure development projects. The output will directly support clients in their decisions on alternative layouts of ports, fairways and terminals. SSPA has decades of experience and records supporting clients worldwide. For each simulation assignment, SSPA communicates with the client to ensure
that the simulation has the right level of detail with regard to both accuracy and cost-efficiency. To reach the appropriate level, there are a number of areas that SSPA tailors to the client’s needs: Ship Dynamics, Modelling, Instrumentation, Visualisation and Analysis.
we will manoeuvre two barges and a large bridge with two tugs. This means that any route chosen for the transportation had to be evaluated with diligence. Simulations were run using various wind conditions to find out whether the transport is feasible. The height of bridges along the route is a limiting factor, as well as the width of the fairway. One example of a difficult manoeuvre is when the bridge and barges are moved around the island of Stora Essingen.
4. Positioning the bridge at the bridge siteDuring the final phase of the operation, the barge carrying a bridge will be positioned so that the bridge can be lowered directly into its final position. This is high-precision manoeuvring of a very heavy vessel with a very narrow margin for error. In these simulations, it was assumed that the barge will be using winches connected to the shoreline and anchors for positioning. The tugs will be disconnected from the barges before this critical section.
How do you control up to eight winches that are to pull with different forces to control not only the heading of the barge, but also its position at the same time? Is it possible to do it automatically so that a large number of simulations can be performed quickly? In this case, SSPA created an autopilot function based on the same principles used to control thruster allocation in spaceships. But instead of a thruster creating the force, a constanttension winch does. The control algorithm will move the barge into position at the bridge site. When the barge is accurately positioned, the bridge will be lowered slowly into its final resting position. The eagle has landed.
ResultSSPA was able to use its knowhow of maritime operations to identify a number of operations that were obviously not feasible. Using the simulator tool SEAMAN, we tested these operations thoroughly until we were convinced that they were possible, or suggested modifi
2. Preparing the bridge segmentsThe bridge segments will be arriving at Lake Mälaren on flat-top barges positioned in a way that is suitable for transport and passage through the lock. Before final positioning of the bridge, they will need to be assembled and reloaded onto barges in another configuration more suitable for the bridgepositioning operation. This could be done on shore, but also on water by moving them from one set of barges to another. To make sure that it is possible, SSPA performed simulations of this advanced bargetobarge operation.
3. Transportation to the bridge siteThere are a number of waterways into central Stockholm from Mälaren. But in this case,
One example of a difficult manoeuvre is when the bridge and barges are moved around the island of Stora Essingen. Illustration: SSPA
You can save money and manage the risk better.
With knowledge, our client felt comfortable putting out a
request for proposals.
Demonstrating the use of urban and inland waterways – for densely populated cities and more sustainable transport
8 Highlights 64 / 2017 – Demonstrating the use of urban and inland waterways – for densely populated cities and more sustainable transport
Demonstrating new logistics solutions is shown to be an important step for gaining understanding of system prerequisites for commercialisation, both with regard to technical issues such as vessel design characteristics and cargo handling equipment, and social matters such as the importance of practitioner involvement and the evaluation of performance criteria. SSPA demonstrated the use of urban and inland waterways as part of two large collaboration projects: DenCity and NÖKS II. This is a promising path for the future, both for managing the trend towards more densely populated cities and for using more sustainable transport solutions.
Transition towards a future and more sustainable transport systemThere is a need for significant changes to be made to the transport system in order to meet society’s longterm transport goals. Local and
national authorities are facing major challenges related to the freight transport sector, in parti cular concerning the increasing greenhouse gas emissions from freight transports. This unsustainable trend is largely due to a larger proportion
SSPA planned and coordinated the demonstration for the DenCity project. All data, such as time for transportation and cargo operations, deviations from the expected time, fuel consumption, noise and costs was collected and carefully monitored, analysed and evaluated.
1. The barge collected package freight every day from the DHL terminal a couple of kilometres
upstream from Gothenburg city centre.
2+3. The packages were then unloaded in the city centre
for further distribution on cargo bikes and in electric vehicles.
4. Waste was then loaded on-
to the vessel and transported from Lindholmen
5. To the waste- to-energy incinerator plant in Sävenäs for
production of electricity and heat.
This illustration shows the itinerary for the demonstration in the DenCity project.
Goods
Waste
The DenCity project aims to find innovative solutions and services to reduce over-crowding and environmental impact, and increase the quality of life for residents and workers in densely populated city districts. The key is to involve the general public in designing the solutions. DenCity is a collaborative project between industry, academia and society and is financed by the Swedish innovation agency VINNOVA and Västra Götalandsregionen.
Read more at the project website: https://closer.lindholmen.se/en/projects-closer/dencity
Demonstrating the use of urban and inland waterways – for densely populated cities and more sustainable transport
of goods being transported by road instead of other, more energy-efficient modes of transport such as sea transport.
In urban environments, and in addition to the transport sector’s greenhouse gas emissions, road freight distribution has other effects as well: congestion, noise and local emissions. Many urban areas are growing rapidly and local authorities are also facing challenges in relation to lack of available space. Also, many cities are located near and around waterways since historically, sea transportation was the main mode of transport. The proximity to water means that waterways are already an available part of the infrastructure with the potential to be a solution for more sustainable city logistics.
Furthermore, inland waterways are rarely used outside of city centres either. Swedish
statistics show only 3 per cent of domestic goods are transported by sea, with 0.7 per cent transported on inland waterways. The corres ponding percentage for inland waterways in the Netherlands, for example, is 18 per cent. Today, there is unexplored potential to be found in increasing sea transport by connecting inland waterways to large export or import ports, e.g. the Port of Gothenburg.
Therefore, one promising path for reducing the increase in road transport and the negative impact from such transport systems is a shift to transport on urban and inland waterways. However, implementing and designing urban and inland waterway systems is a complicated issue involving multiple actors within the transport system with potentially conflicting aims. By demonstrating the use of waterways
in both urban and inland environments, important knowledge can be obtained as a first step towards necessary longterm changes to the transport system.
City logistics using urban waterways in GothenburgGothenburg is currently growing rapidly and the city has plans for developing several new districts in close proximity to the river, Göta älv, which cuts through the city. One of these areas is the former port, Frihamnen, which is located close to the city centre and will be developed to accommodate and provide work places for approximately 15,000 people. Local authorities have designated this area a place where innovative and sustainable solutions
The demonstration for the NÖKS II project was a one-time container trans-port from Gothenburg, at the mouth of Göta älv, to Vänersborg at the estuary of Göta älv. 12 (20”) containers were transported using a barge/pusher combi-nation operated by Sandinge transports. The unloading operation was demonstrated at the Port of Vänersborg. The containers were unloaded from the vessel and loaded
onto trucks for delivery to the final destination.
SSPA supported Avatar Logistics with technical preparations for the transport operation (e.g. a specification of the loading plan) and by evalu ating the transport efficiency and environmental performance of
the demonstration.
Gothenburg
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NÖKS II is a three-year EU-funded project (2015–2018) that is part of the Interreg ÖKS (Öresund-Kattegat-Skagerrak) pro-gramme with partners in Sweden, Norway and Denmark.
The project is coordinated by SSPA and aims to increase the use of sea transport solutions within the region and to contribute to a more environmentally friendly and low-carbon transport system. The project is financed by Interreg, Öresund-Kattegat- Skagerrak, the European Regional Deve-lopment Fund, Västra Götalandsregionen, Fyrbodal and Region Skåne.
Read more at the project website: http://noks2.com
10 Highlights 64 / 2017 – Demonstrating the use of urban and inland waterways – for densely populated cities and more sustainable transport
planned, coordinated and carefully monitored by SSPA and all collected data, such as time for transportation and cargo operations, deviations from the expected time, fuel consumption, noise and costs was analysed and evaluated.
Container transportation on Göta älvThe Port of Gothenburg is the largest port in Scandinavia and handles about 30 per cent of Swedish exports. Göta älv is an important link to the Port of Gothenburg from Sweden’s largest lake, Vänern. Existing shipping lines transport mainly bulk goods to and from ports in the Vänern region to and from other European ports, and there is no current waterway transport solution for containers to the Port of Gothenburg. Instead, businesses in the Vänern/Göta älv region use other transport options such as road or rail to transport con tainers to the Port of Gothenburg.
NÖKS II is a threeyear EUfunded project (2015–2018) that is part of the Interreg ÖKS (ÖresundKattegatSkagerrak) programme with partners in Sweden, Norway and Denmark. The project is coordinated by SSPA and aims to increase the use of sea transport solutions within the ÖKS region. SSPA is heading up a work package with a focus on studying and analysing short sea shipping solutions as a link to existing logistics nodes. One such link is Göta älv.
In March 2017, a logistics concept for container transport on Göta älv was demonstrated in cooperation with Avatar Logistics. Demonstrating this new logistics concept involved handling a number of issues such as what goods to transport, what vessel to use, what documentation would be needed to comply with existing laws and regulations, and how to gain access to ports and required equipment for unloading/loading. Consequently, several actors needed to be involved for such
within urban planning and mobility will be developed and tested. One such project is the large gov ernmentfunded project DenCity, which aims to find sustainable mobility solutions in order to eliminate the need for heavy trucks. SSPA is involved in this project and is responsible for exploring solutions and identifying drivers and barriers for an increased use of urban waterways to meet Frihamnen’s need for sustainable city logistics.
To demonstrate the environmental, technical and economic feasibility of transporting goods and waste on urban waterways, possibly using the same vessel, an actual waterborne transport system was designed and tested in Gothenburg. As the new area in Frihamnen is not yet built, the demonstration took place in other parts of the city with goods and waste transportation for two weeks using urban waterways.
Gothenburg’s waterways pose several challenges when it comes to choice of vessel. For example, there are many low bridges, narrow passages and shallow waters to be considered while also finding ways of maximising cargo capacity. The vessel used was a small barge, wellsuited for the desired route, with an accompanying tugboat. The waste was loaded using the truck’s container lifting devices and goods were rolled onto the barge using small ramps. This means that no additional landbased cargo handling equipment was needed.
During the demonstration, the barge collected package freight every day from the DHL terminal a couple of kilometres upstream from Gothenburg city centre, which was then unloaded in the city centre for further distribution on cargo bikes and in electric vehicles. Waste was then loaded onto the vessel and transported from Lindholmen to the wastetoenergy incinerator plant in Sävenäs for production of electricity and heat. The entire operation was
an arrangement, including parties such as ports, container terminals, goods owners, vessel operators and authorities.
The demonstration was a onetime container transport from Gothenburg, at the mouth of Göta älv, to Vänersborg at the estuary of Göta älv. 12 (20”) containers were transported using a barge/pusher combination operated by Sandinge transports. The unloading operation was demonstrated at the Port of Vänersborg. The containers were unloaded from the vessel and loaded onto trucks for delivery to the final destination. SSPA supported Avatar Logistics with technical preparations of the transport operation (e.g. a specification of the loading plan) and by evaluating the transport efficiency and environmental performance of the demonstration.
Knowledge gained from demonstrating new logistics solutionsSSPA has identified drivers and challenges associated with an increased use of urban and inland waterways. The main drivers of this alternative mode of transport in city logistics are the associated sustainability and large capacity for transporting goods. A properly implemented system has the potential to substantially reduce air emissions, congestion and noise by reducing the number of trucks on highways and in urban areas. Actors also see potential in commercialising waterway logistics solutions as a natural part of future logistics concepts.
Challenges that must be overcome relate to the difficulties in competing with existing road transport solutions. Road transport solutions are often cheaper and more flexible compared to a waterway option, for example, with regards to pick up and delivery place and time. The diffi-culties in competing with road transportation due to cost issues are particularly evident for inland waterways, where tariffs related to fare charges, requirements for pilots and handling costs in ports increase transport costs.
Furthermore, waterway logistics solutions often involve extra handling steps compared to current road transport solutions, which in creases transport time. This was particularly evident in the urban environment where several handling steps in the logistics concept influenced the total transport time and costs to a great extent. However, development of new areas such as Frihamnen enables the incorporation of urban waterways and gives possibilities to design optimised systems that will reduce the number of handling steps.
The best technology available was used in the demonstrations. Based on the results of the
The barge “Helena” and towing vessel “Dragaren 6” transporting waste and goods on the urban waterways in Gothenburg. Photo: Christian Finnsgård
Vendela SanténProject Manager. Vendela has an MSc in Industrial Ecology and a PhD in Technology Management and Economics. She has a
background in research, primarily focusing on sustainable logistics and how companies can take action to reduce their transport emissions. Since joining SSPA in 2016, she has been involved in projects related to a modal shift to sea transport solutions (such as NÖKS II and DenCity) as well as traffic analysis using AIS data.
Contact information E-mail: [email protected]
Christian FinnsgårdVice President, Head of SSPA Research. Christian has an MSc in Mechanical Engineering/Management from Chalmers University of
Technology, an MSc in Business Admini- stration from the University of Gothenburg and a PhD in Technology Management and Economics from Chalmers University of Technology. He has a background in research, primarily focused on logistics. Since joining SSPA in 2014, Christian has been the project manager for the NÖKS project and has been involved in various projects ranging from logistics to sports research, heading international and national research projects.
Contact information E-mail: [email protected]
Viktor DaunProject Manager. With a BSc in Civil Engineering and experience from the construction industry, Viktor graduated with an
MSc in Naval Architecture from Chalmers University of Technology in 2014. After completing a trainee programme with rotations in several different companies in the maritime industry, Viktor joined SSPA in 2016. Since then he has worked on projects involving naval architecture, maritime infrastructure and logistics.
Contact information E-mail: [email protected]
demonstrations, it is possible to discuss and suggest possible improvements for a concept optimised for urban and inland waterways respectively. There are a number of different vessel concepts that are viable from either a financial, technical or an environmental perspective. Urban waterway vessels are believed to be good candidates for alternative fuels such as biogas, biomethanol or batteries since air emissions, noise and energy-efficiency
As in urban contexts, alternative fuels are of interest since Göta älv, like most inland waterways, passes through several cities and populated areas. Minimising emissions from the vessel is essential when competing with other modes of transport since environmental performance is becoming increasingly important.
To utilise the advantages of waterway logistics, it is important to design transport systems that benefit from scale, both economically and environmentally. This requires increased coordination among the actors involved to consolidate cargo and optimise the transportation.
The two reallife tests of new logistics concepts were powerful tools and important steps in visualising the potential of using Göta älv for city logistics in Gothenburg and container transport upstream and downstream. Relevant actors were involved in the demonstrations and showed great interest in a future development towards commercialised logistics concepts. Goods owners are willing to ship their containers on Göta älv when such a logistics solution is in place, and urban logistics actors consider the waterways a valuable alternative for reducing the amount of trucks in Gothenburg. The demonstration has therefore provided unique experiences and set up a network of value for commercial players as a first step towards new logistics concepts.
The two projects DenCity and NÖKS II have provided SSPA with valuable experiences in relation to the actual design, planning, execution and evaluation of demonstration activities, taking into account all actors’ views and requirements. This in combination with a wide knowledge of shipping, logistics and naval architecture contributes to great experi ences and possibilities for SSPA to further support actors in the process of utilising urban and inland waterways to a greater extent.
The demonstrations have provided unique experiences
and a network of value for commercial players as a first step towards new logistics
concepts
are important parameters when operating in populated environments. Urban waterways also set restrictions with regards to narrow passages, low bridges and shallow waters which need to be taken into account.
For inland waterways, other options than a pusher/barge combination may be a more appropriate, such as a puller/barge combination or an IVV vessel. The size of the vessel is restricted due to the size of the locks that need to be passed through while sailing along Göta älv, and therefore the maximum load capacity is estimated to around 80 TEUs. The vessel also needs to be adapted for container handling to ensure efficient loading and unloading operations at the ports.
Pusher/barge combination used in the container transport demonstrator for NÖKS II. Photo: Christian Finnsgård
There are multiple reasons for carrying out accident investigations, but the primary reason is often a need to gain a deeper understanding of the course of the events from both a human and technical perspective. From this analysis, conclusions can be made that may result in recommendations for decreasing the risk of a similar accidents occurring. SSPA regularly conduct accident investigations for our clients, covering a range of accident types and factors such as running aground, collisions, ship stability and seakeeping issues, oil spills and structural issues. This article briefly describes how SSPA assisted with an investigation of the tragic accident that occurred at the Port of Genoa, Italy in May 2013. A ship backed into a port control tower, causing it to collapse and killing nine people. By simulating the accident and running alternative scenarios, SSPA were able to give our clients thorough understanding of the events as well as important documentation to use in the legal process.
12 Highlights 64 / 2017 – Investigating maritime accidents
Investigating maritime accidents
Many of our maritime regulative instruments are a result of improvements after major accidents. Learning from accidents is valuable in many aspects, from helping to implement onboard operational procedures to creating new or developing existing regulations. SSPA’s expertise in hydrodynamics, manoeuvring and seakeeping simulations, model testing, computational fluid dynamics, structural computation, measurement techniques, signal processing, risk assessment and human factors, and knowledge of ship operations, puts us in a unique position to grasp the overall complexity of accident investigation and analysis. From this analysis, conclusions can be made that may result in recommendations for decreasing the risk of a similar accident occurring in the future.
Generalised data flow diagramThe introduction of recording devices, e.g. VDR, logging of AIS data and logging of Derived data
(eg. CPA, TCPA)
Simulation model
Ship particulars
Geospatial data in a common time frame
Manually extracted data (e.g. from voice
and radar)
Meteorological and hydrological dataCompiled data
in common time frame
VDR
Ship sensors (GPS, Compass, Voice, Radar, etc.)
AIS database
VDR data is used initially. When a manoeuvring device is used, the system switches to simula-tion mode. Figure: SSPA.
Utilisation of data sources in simulations for the various sources that form the basis of the simula-tion system. Illustration: SSPA.
weather and hydrographicrelated data has dramatically changed the ability to reconstruct and investigate accidents in the last decade.
Today we usually have access to one or more of these data sources to reconstruct scenarios and to validate models for simulations of alternative scenarios.
The generalised data flow diagram shown here uses the typical sources of data indicated. The data from all these sources is compiled in a database with a common timeframe. This ensures that all data is well defined and synchronised throughout the analysed timespan.
Forming the simulation systemIt is always important to identify the flow of communication and sequence of events during accident investigations. The digitisation of some parts of the data extracted from the voice recording sources and radar images is therefore often relevant. What and when certain information was received and orders were given can be identified using voice data.
Radar images can be used to determine when actions such as initiating plotting of a radar target or a change of range were taken.
Important derived data can be calculated by combining the data sources, e.g. CPA (Closet Point of Approach), TCPA (Time to CPA), distances to targets and geospatial data (e.g. depth contours of interest).
The simulation technique developed by SSPA permits the running of seamless scenarios generated using recorded data (e.g. from VDR), and the option of switching over to simulation at any given moment is a very useful tool for investigating the incident itself as well as elaborating on alternative action that could have been taken.
The realtime manoeuvring and seakeeping software SEAMAN is an extremely competent software for analysing situations when it comes to confined water phenomena, ship interaction and seakeeping.
The Jolly Nero accidentOn the evening of 7 May 2013, the container/roro ship Jolly Nero backed into the 50metre port control tower at the Port of Genoa, causing it to collapse, and killing nine people. Assisted by two tugs – Genua at the bow and Spagna at the stern – Jolly Nero had completed a more than twonauticalmilelong stern manoeuvre from the Messina Terminal to the turning basin at the eastern exit of the port.
When the ship was in the middle of the turning basin, its pilot ordered engine ahead. The attempt to start the engine were unsuccessful, and during the elapsed time of uncertainty regarding the engine status, ship came so close to the control tower that evasive actions became ineffective.
SSPA was contracted by Studio Tecnico Navale Ansaldo, Genoa, Italy, to carry out an investigation in order to reconstruct the course of events during the the final manoeuvres that led to the collision, and to assess alternative
Simulations can be run to gain valuable insight to support decision-making and provide solutions to complex problems. For each simulation assignment, SSPA communicates with the client to ensure that the simulation has the right level of detail with regard to both accuracy and cost-efficiency. To ensure the appropriate level, there are a number of areas that SSPA will tailor to the client’s needs: Ship Dynamics, Modelling, Instrumenta-tion, Visualisation and Analysis.
The reconstructed track of the Jolly Nero and the tug prior to the collision with the control tower. The stern and bow tug is indicated in red and green respectively. Illustration: SSPA.
scenarios. Studio Tecnico Navale Ansaldo was commissioned by the juridical defence for the pilot in charge.
The reconstruction of the accidentThe data from the VDR of Jolly Nero was extracted, as was the AIS data of the bow tug Genoa. The tug Spagna was not equipped with an AIS transponder, so its position had to be estimated based on information from the client.
A mathematical model of the ship dynamics of Jolly Nero was developed. The development was based on available data such as pilot card and model tests with similar ships. The two tugs, Spagna and Genoa, that assisted Jolly Nero at the time of the accident were also modelled.
For validation of the models, SSPA’s experts used results from sea trials carried out after the accident. The trials included:• Stopping from 3 knots astern speed using
various ahead manoeuvres• Turning test at 3 knots astern speed using
tugs (this manoeuvre is similar to the manoeuvre carried out prior to the accident)
By running these simulations, it was possible to estimate the forces and position of the tugs.
Erland WilskeProject Manager. Erland graduated in 1988, MSc in Electronic Engineering from Chalmers University of Technology. After
graduation, he worked on research into opto-electronic sensors and developing software for cargo-handling systems. He joined SSPA in 1994 and since then he has been involved in projects linked to the development and use of ship-simulation tools.
Contact informationE-mail: [email protected]
The simulation of alternative scenarios gave insight into the required timing and margins for avoiding collision with the control tower.
In the autumn of 2016, SSPA’s experts gave testimony of the investigation and its findings at the court hearings in Genoa.
To cap greenhouse gas emissions, the International Maritime Organization (IMO) has introduced the Energy Efficiency Design Index (EEDI). This
14 Highlights 64 / 2017 – fw – the unknown factor
fw – the unknown factor
Legislation on the Energy Efficiency Design Index (EEDI) requires the determination of a “weather factor” – fw – reflecting the percentage of its calm-water speed that a ship can maintain in Beaufort 6 and corresponding waves. The higher the fw value, the smaller the speed loss and the better the ship will perform in a seaway. But how do we determine this unknown fw factor, and how do we strike a balance between accuracy and costs? As a member of the International Towing Tank Conference (ITTC) SSPA is actively involved in developing guidelines on fw and as an independent maritime consultant and established model testing basin we have the knowledge and tools required to realistically determine the “unknown weather factor”.
Added waveresistance
Power setting = 75% MCR
Calm water resistance
WIN
D +
WAV
ES Propeller curves
CALM
WAT
ER
fw =Vw /Vref
Added wind resistance
Wind tunnel /SSPA Database
Total resistance
Vw
speed in wind and wavesVref
speed in calm water
Power prediction(ITTC 1978 method)
Speed power curve in calm water
Speed power curve in wind + waves
Calm water resistance
Power prediction(modified ITTC 1978 method)
Two things are required to obtain a more realistic and above all ship-specific value of fw : determination of the calm water speed and determination of the ship speed in Beaufort 6. At SSPA, we have the knowledge, tools and facilities to help with both.
where fw is the socalled “weather factor” that takes the influence of wind and waves into account. It is defined as:
index is a measurement of the amount of carbon dioxide that a ship emits in relation to its cargo capacity and speed:
Ship speed
Eng
ine
Pow
er
75% MCR
CALM W
ATER
WIND +
WAVE
S
fw=Vw/Vref
VrefVw
place at the concept stage of a design. However, if manoeuvring and seakeeping tests are scheduled to prove a final design, why not test for fw as well?
Power prediction and fwOnce the total resistance in wind and waves is known, the corresponding engine power to overcome this resistance can be calculated using the principles of the “ITTC 1978 Performance Prediction Method”. As illustrated in the speed power plot, such predictions are made for several ship speeds and a speedpower curve in wind and waves is plotted. Finally, the fw value is determined from this.
Here VW denotes the speed of the vessel in Beaufort 6 (3 m significant wave height and 12.6 m/s wind speed) and Vref is the speed of the ship in calm water.
The crude way – fw from IMO’s standard curvesA very simple, if somewhat rough, method of obtaining an initial estimate for fw is described in IMO Circular MEPC.1/Circ.796. The method is based on regression analysis of fullscale measurements, i.e. on the actual speed reduction of existing ships, and only requires ship type and cargo capacity as input. Three kinds of standard fw curves are provided for bulk carriers, tankers and containerships. The disadvantage of this simplistic method is obvious: it will not give a ship-specific fw value, i.e. it cannot distinguish between a good and a bad design.
Two things are required to obtain a more realistic and above all ship-specific value of fw: determination of the calm water speed and determination of the ship speed in Beaufort 6. At SSPA, we have the knowledge, tools and facilities to help with both.
Calm water model tests already mandatory under existing EEDI rulesAs shown in the flow diagram, these speeds are determined separately. Finding calm water resistance and calm water speed Vref is relatively straight forward and part of the model tests that have been mandatory under the EEDI rules since 2013. As shown on the righthand side of the flow diagram, this includes a combination of model towing tests, model selfpropulsion tests and model propeller open water tests.
Speed in wind and wavesFinding the total resistance in wind and waves and the corresponding ship speed – Vw – is a bit more complex and also requires knowledge of wind resistance and added wave resistance.
As illustrated on the left-hand side of the flow diagram, the aerodynamic resistance of the ship is best determined through wind tunnel testing. As an alternative, we can normally find values for similar ships in our windforce database.
A ship sailing in a seaway experiences a hydrodynamic force component known as “added resistance in waves”. This force can be determined using CFD calculations or free sailing model tests in SSPA’s Maritime Dynamics Laboratory. The choice of method depends on how far the design of the ship has progressed and on many other factors that need to be considered carefully. A full seakeeping test would clearly be out of
Photo of MDL, the Maritime Dynamics Laboratory for seakeeping and manoeuvring tests.
What is fw?A “weather factor” reflecting the percentage of its calm water speed that a ship can main-tain in Beaufort 6 and corresponding waves.
What is EEDI?The Energy Efficiency Design Index (EEDI) is a measurement of the amount of carbon dioxide that a ship emits in relation to its cargo capacity and speed. The achieved EEDI value of most new-build ships has to be below a certain limit set by the Interna-tional Maritime Organization (IMO). If a ship fails to comply with the required EEDI, it is not allowed to be taken into service.
Is it mandatory to determine fw?Yes, but currently a poor fw value will not influence the attained EEDI. It is expected that this situation will soon change.
Why test for fw at SSPA?To obtain realistic and ship-specific fw values. The generic IMO curves are too pessimistic. We have the knowledge and the tools to provide cost-effective fw predictions. SSPA’s fw database makes it possible to compare a new design to other ships and their energy efficiency.
Can fw tests be carried out in a towing tank equipped with a wave maker?No, fw determination requires a performance prediction in short crested waves. Tests in head waves alone are not sufficient.
Can you calculate fw?Yes, this is a viable and sensible option at the early design stage.
16 Highlights 64 / 2017 – fw – the unknown factor
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For shipowners: A realistically determined fw value makes it possible to compare design options and ships from different yards. A ship with a high fw value is fuel-efficient under realistic conditions; bear in mind that wind speeds between Bft 4 and Bft 6 prevail for 65 per cent of the year in the North Atlantic.
For shipyards: SSPA’s measurements show that the “fw standard curves” from IMO Circular MEPC.1/Circ.796 are too pessimistic, i.e. they overpredict the speed loss in a seaway. It is possible to obtain a more favourable and ship-specific fw value.
Frederik GerhardtSenior Technical Expert. Frederik received a Dipl.-Ing. in Aeronautical Engineering from RWTH Aachen in Germany in 2005 and a PhD in
Mechanical Engineering from the University of Auckland in 2011. He has been employed at SSPA since 2011 and has mostly worked on research and consultancy projects related to seakeeping and manoeuvring issues. Frederik has been a member of the International Towing Tank Conference (ITTC) Seakeeping Committee since 2014.
Contact informationE-mail: [email protected]
0.6
0.65
0.7
0.75
0.8
0.85
0.9
0.95
1
300 000 200 000 100 0000
f w
Capacity [DWT]
SSPA fw databaseFull-scale measurementIMO standard curve
Typical LNG carrier
SuezmaxAframaxVLCCProduct carrier
LNG bunker vessels
SSPA database for fw of tankers As part of a strategic research project, SSPA has by way of seakeeping model tests determined fw values for a number of tankers ranging from 2,500 to 150,000 deadweight tonnes. The results are illustrated in the fw values versus “Capacity” plot above. Also shown are fullscale values from IMO Circular MEPC.1/Circ.796 and the “Standard Curve” from the same IMO publica tion. As can be seen, agreement between fullscale data and SSPA’s model test results is good. The generic IMO standard curve on the other hand is extremely conservative because fw is underpredicted, i.e. speed loss is significantly overpredicted.
Want to know more?Further reading at our webpage:http://www.sspa.se/ship-design-and- hydrodynamics/fw-the-unknown-factor
