a newsletter published by sspa sweden ab 482009 by undul845

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a n e w s l e t t e r p u b l i s h e d b y s s pa s w e d e n a b 4 8 / 2 0 0 9
Contents 2 The sea is never calm – Design with respect to overall performance 4 When Hermes met Wally or New applications for Ramform 6 Green shipping – from hull improvements to alternative fuels 8 Short comments

PHOTO: COuRTeSy Of WHy-Wally HeRmèS yaCHTS / aRTefaCTORy lab.

The sea is never calm – Design with respect to overall performance
My sincere Seasonal Greetings to all of SSPa’s clients, partners and colleagues in the maritime society. Thank you all for the opportunities provided and confidence shown in us while working together with you during the year 2009. The global financial crisis is source of stress for many organisations today, but it also opens the door for unconventional thoughts and means. When professionalism from different branches meets as part of an open creative process, the outcome can be extraordinary. Combine fashion, yachting and offshore and what do you get – WHy 58x38. Why not? The future is bright, we are creating it together. susanne abrahamsson

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tello, one of Wallenius lines vessels.

PHOTO: fOTOfliTeS

A hull design optimised with respect to calm water performance is not necessarily the most efficient one in rough seas, and the fact is that most of the time there are waves at sea. The probability of the waves exceeding Sea State 3 is larger than 60 per cent in the North Atlantic and about 80 per cent in the North Pacific. Thus the efficiency of a ship in service is dependent on the following three main factors: – Speed – power performance in calm water – involuntary speed reduction due to added resistance in wind and waves – Voluntary speed reduction to guarantee the safety of ship, crew and cargo. in order to design a ship that performs well overall the impact of wind and waves should be taken into account throughout the entire design process. at the early stages the use of different seakeeping software is a cost-efficient way of deciding upon the main dimensions. Today, model tests are the most efficient way of fine-tuning the hull

with respect to the overall performance at the final design stage.

Sea margin
Traditionally a speed – power prediction consists of calm water performance and a “sea margin”. The sea margin is a standard percentage value of the available engine power. This normally covers the added resistance in waves up to Sea States 3 to 4. However, as early as in Sea State 6, the wave resistance can be of the same magnitude as the still water resistance and, in Sea State 7 and above, the wave resistance can be several times greater than the calm water resistance.

Involuntary speed reduction
Due to the added resistance in wind and waves, a ship can only keep the predicted calm water speed in the lowest sea states. in order to minimise the involuntary speed reduction in higher sea states, the added resistVertical acceleration vs. speed Bow sea, Sea State 7
Left:

Relative speed vs. sea state Bow sea
1.1 1.0
■ Reference ■ Hull 1 ■ Hull 2

3.3 3.1 2.9

Relative ship speed

0.8 0.7 0.6 0.5 0.4 0 2 4 6 8 10

Vert. acc.

0.9

2.7 2.5 2.3 2.1 1.9 1.7 1.5 5 10
■ Hull 1 ■ Hull 2 ■ Limiting value

Involuntary speed reduction due to added resistance in wind and waves. Comparison of different hull designs.
RIght:

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Sea State No.

Speed

Voluntary speed reduction in wind and waves with respect to vertical accelerations.

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The sea is never calm – Design with respect to overall performance

Wave dir Sea State 0 –1 2 3 4 5 6 7 8 >8 %

180 8.3 %

150 16.7 %

120 16.7 %

90 16.7 %

60 16.7 %

30 16.7 %

0 8.3 %

0
7.2 22.4 28.7 15.5 18.7 6.1 1.2 0.05

1.00 1.00 0.99 0.97 0.87 0.68 0.50 0.44 0.42 0.87

1.00 1.00 1.00 0.97 0.86 0.67 0.53 0.45 0.45 0.87

1.00 1.00 1.00 0.97 0.87 0.77 0.67 0.67 0.67 0.90

1.00 1.00 1.00 1.00 0.87 0.77 0.67 0.67 0.67 0.91

1.00 1.00 1.00 1.00 0.87 0.77 0.67 0.67 0.67 0.91

1.00 1.00 1.00 1.00 0.87 0.77 0.67 0.67 0.67 0.91

1.00 1.00 1.00 1.00 0.87 0.77 0.67 0.67 0.67 0.91

1.00 1.00 1.00 0.99 0.87 0.75 0.63 0.61 0.61 0.90

ven Jacobsson B.Sc (1999) in Mechanical engineering and complementary courses (2003) in Naval Architecture from Chalmers. he was employed at SSPA Sweden AB since November 1999.he is working as Project Manager and has been involved in numerous research and consultancy projects in the fields of seakeeping and manoeuvring. Previous employments include work at sea and in shipyards. telephone: +46 31-772 90 75 sven.jacobsson@sspa.se

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atrix with predicted speeds (normalised relative calm water) for different sea states and wave directions. the speeds are weighed with respect to the probability of occurrence for a specific route. the average speed for the total time that the ship will spend on a specific route is shown in the lower right-hand corner.

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■ Calm water speed region (include sea margin) ■ Involuntary speed reduction region ■ Volontary speed reduction region

ance must be considered early in the design process. The resistance in waves is largely dependent on how the ship moves in waves. The severity of the motions is in turn directly dependent on the ship’s main dimensions in relation to the wave characteristics that it will encounter. Seakeeping software can handle these types of issues quite well and should be used in the initial design process. However, for a sufficiently reliable speed prediction in waves, model tests are required at the final design stage, especially for fine tuning the shape of the fore body both below and above the waterline. The bottom left figure on the previous page shows an example of a comparison of the ship speed vs. sea state number for different hulls.

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omparative model tests at the final design stage.

Voluntary speed reduction
although the speed of the ship will be reduced involuntarily in waves, the motions can also be so severe that they endanger the crew, ship and cargo. if this is the case, the master will voluntarily reduce speed or change course. The reasons for such an action are often related to:

a comparison of the vertical accelerations at the bow vs. ship speed for two different hull designs.

Overall performance
from the model test results, in calm water and in various combinations of sea states and wave directions, the ship speed for a specific design can be predicted taking into account both involuntary and voluntary speed reduction. a method for ranking different designs is creating a matrix with the predicted speeds for the different sea states and wave directions. a seakeeping index, an average speed or fuel consumption for the total time that the ship will spend on a specific route, can then be calculated, see the matrix above. at SSPa the focus on designing for overall performance is driven by foresighted ship-owners and ship yards requesting low emission vessels. The photos above shows a snapshot from a recent comparative sea keeping test program for a DSme/ Wallenius PCTC. The tests once again highlighted to the owner, builder and SSPa the importance of considering the impact of wind and waves throughout the entire design process. ingvar rask sven Jacobsson

ngvar Rask M.Sc (1975) and Lic. eng. (1986) in Naval Architecture from Chalmers has been employed as Project Manager at SSPA since January 2008. he was also employed at SSPA during the period 1978–88 and, in the meantime, he was working as a senior researcher at Swerea IVf AB, with product development methodology. At SSPA he is involved in various researchand consultancy projects in seakeeping and manoeuvring. telephone: +46-31 772 90 35 e-mail: ingvar.rask@sspa.se

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– – – – –

accelerations Roll angles Slamming (bottom or flare) Green water on deck Propeller racing

limiting values can be found in literature for different types of ships and commissions. The above mentioned phenomena can only to some extent be predicted by means of theory-based software and should only be used at the early design stages. The precision of such seakeeping software is not good enough to detect differences when fine tuning a ship design with respect to the seakeeping criteria. However, in model tests in a realistic seaway at the final design stage, a ship design can be scrutinised both quantitatively by means of measuring relevant parameters and qualitatively by visual observations. The bottom right figure on the previous page shows

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48/2009

When Hermes met Wally or New applications for Ramform
What would your dream yacht look like if you let your mind flow free from conventions and traditions (and had a well-filled bank account)? The Joint Venture between the iconic Parisian house Hermès and the equally iconic Monaco based yacht brand Wally presented their view on this concept at the Monaco yacht Show recently and filled the yacht world with amazement. What was shown was a floating palace, 58m long and 38m wide, with a radical look at every aspect of yachting or rather living at sea. The creation is called WHY 58x38. The background is as follows. back in Norway, a naval architect named Roar Ramde had been struggling for years with the general requirements for more deck load and a greater deck area but was restricted by the conventional ship’s limitations regarding stability. after designing about 50 conventional ships his self confidence was strong enough to go outside the brackets set up by traditions. He just widened the aft part of the hull until he got the deck area, the deck load and stability he needed, and then added a pointing bow for speed. and Ramform Sovereign being the latest contributions, commissioned July 2009. SSPa has been involved in the development and testing of each generation of these vessels from the very beginning. Sessions with us have included tests in all our laboratories (Towing tank, Cavitation tunnel and maritime Dynamic laboratory (mDl)), ranging from standard tests to many special studies to improve the performance and details of this family of vessels, making them suitable for a wide range of applications.

Idea, solution – and questions
When Hermès and Wally were looking for a base for their new concept they identified Ramform as the ideal choice. With its sinusoidal hull it offers exceptional stability and unprecedented volume for its displacement. but in order to adapt it into a motor yacht, some other features had to be checked. Would the motion characteristics be very different from a standard yacht of a comparable size? Of particular interest were the motions and accelerations at anchor since this is a condition very common for yachts.

atz Brown, Project manager at SSPA. he graduated (M.Sc.) from Chalmers University of technology in 1979 and was then employed at götaverken Arendal. he has also worked at Uddevallavarvet and has been teaching for a number of years. he has been employed at SSPA since 1997 and is specialised in hull design and model tests of sailing yachts and fast vessels. telephone: +46-31 772 90 06 e-mail: matz.brown@sspa.se

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A 27m Cable Ship to begin with
With his experience and knowledge of hydrodynamics he managed the trick, without increasing the specific required power (power/displacement) for propulsion. as an extra bonus, he also ended up with a very silent ship with low vibrations. The first ship with this design was a 27m cable ship for the skerries of the Norwegian coast. The next ship and best known as the first large Ramform was marjata, a Norwegian surveillance ship built in 1993. On one occasion one of PGS (Petroleum GeoServices) ship was moored just behind marjata and the company’s scientists and engineers became very enthusiastic. That is what we need! They quickly recognized that the silent operations and wide stern made her perfect for seismic acquisition. The unique broad stern design and ultra-stable hull enables quick and safe deployment and the retrieval of massive volumes of towed seismic equipment. Today PGS have a large fleet of Ramforms with Ramform Sterling

Testing – and more testing
at this stage SSPa was commissioned again and performed a series of tests to compare WHy 58x38 with a standard yacht. With its outstanding stability there were no doubts that the vessel would roll less than a standard yacht, but would the vertical accelerations be worse due to the very high Gm and short roll period? Roll decay and sea keeping tests in regular beam sea for determining RaO (Response amplifier Operator) for roll were the first step. These tests gave us a roll period of about 6.5 s which was a bit more than expected, indicating a very large damping in roll. at the same time a resistance test was run and, once again, it was noticed that the specific resistance did not change very much in spite of the increased beam and in fact, the residuary resistance coefficient was reduced. We moved on to our mDl and exposed the vessel to a sea condition likely to be met in the mediterranean

WhY Wally- hermés Yachts.
PHOTO: COuRTeSy Of WHy-Wally HeRmèS yaCHTS / aRTefaCTORy lab.

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When Hermes met Wally or New applications for Ramform

Ramform Sterling (left).
PHOTO: HaRalD m. ValDeRHauG

the Norwegian Navy surveillance ship Marjata (right).
PHOTO: HaRalD m. ValDeRHauG

at possible spots for anchoring according to available statistics. This sea state chosen was a bit special and was a combination of wind-generated irregular waves from one side and a simulated swell by regular waves from a direc-

10 8 Roll angle, SSa [deg.] 6 4 2 0 Vertical acceleration, SSa [m/s2] Sea Swell

2 Sea 1,5 Swell

●

1

0,5 ▲ ● 0

● ▲ 0

▲

● ▲

tion perpendicular to the wind waves. as can be seen from the plots, the behaviour regarding roll was excellent for WHy 58x38 and was better than the standard yacht in most conditions. See the figures below. for vertical accelerations at a point at the centre line in the aft region of the ships the situation was very similar for the two types of vessels. The criteria used for limiting curves are established by Nordforsk and are valid for cruise liners. The vessel is also designed with the environment in mind. in fact, the whole concept breathes green thinking. The design speed is leisurely low. it is powered using diesel electric engines. a surface of solar cell panels measuring approximately 900 square meters provide part of what is needed to subsist the boat. Special attention has been paid to the choice of materials and how to recycle them etc.

0.5 1 Total wave height, H1/3 [m]

1.5

0

0.5 1 Total wave height, H1/3 [m]

1.5

Opinions on WHY 58x38
Who will dare to put their money into a vessel like this? When discussing with the hull engineer, Roar Ramde he explains his own theory. it will have to be people that don’t look at what has been done in the past, – people who dare to see the benefits with their eyes not blinkered by conservatism and are independent of infrastructure and financiers. – We didn’t design a boat, we gave shape to an idea, states Gabriele Pezzini, design director of Hermès. – WHy is the union of our dreams, the green path that carries us away in its wake, Pierre-alexis Dumas, artistic director of Hermès, explains. – a new and unique way of living on the sea while caring about it, protecting it, and loving it…, luca bassani antivari, president and CeO of Wally, adds. a special feature of the hull is that the over side of the bulb has a flat area suitable for a sun chair. So imagine entering monaco harbour sitting on the bulb sipping on a drink. Wouldn’t that be something! Matz brown

10 Sea 8 Roll angle, SSa [deg.] 6 4 ● 2 ▲ 0 0 0.5 1 Total wave height, H1/3 [m] ▲ WHy 58 38 motor yacht ● Traditional 95 18 motor yacht limiting value (NORDfORSk) 1.5 ▲ Swell ● Vertical acceleration, SSa [m/s2]

2 Sea 1,5 . Swell 1

0,5 ▲ ● 0 ● ▲ 0 0.5 1 Total wave height, H1/3 [m] 1.5

hY 58 38 vs traditional yacht Roll angle and vertical acceleration at anchor exposed to wind waves and swell.

w

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48/2009

Green shipping – from hull improvements to alternative fuels

lrika Roupé, Project Manager, MBA, environmental economics, graduated from gothenburg University in 1995. She has worked as a consultant, both in Sweden and internationally, on environmental and development co-operation projects. In 1999 she joined SSPA where she has worked mainly with coastal zone management, environmental economic analysis, risk analysis, international cooperation, and environmental projects on transports and shipping. telephone: +46-31 772 90 60 e-mail: ulrika.roupe@sspa.se

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wo of the existing ferries crossing the river.
PHOTO: bJÖRN fORSmaN

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SSPA Sweden AB has lengthy experience of analysing and evaluating vessels and their possible environmental impact. In many of the latest SSPA research projects, the focus has been not only on finding new technical solutions for reducing emissions, but also on how to effectively use alternative sources of fuel. Over the decades, SSPa has evolved from providing clients with optimised and efficient hull forms in order to minimise their fuel consumption and thus their environmental footprints, to becoming an experienced environmental partner for assessing and analysing the total environmental impact of ships. Currently several research projects are ongoing at SSPa with a focus on green shipping; alternative fuel for ferries, environmentally adapted ship concepts, and means for reduced fuel consumption. These research findings are also used in commercial applications for the benefit of our clients and in order to bring the results of research into practice.

Alternative fuels
effects on the environment mainly come from emissions from the use of fuel; nitrogen oxides and carbon dioxide. Diesel normally produces more emissions than natural gas, which in turn produces more emissions than hydrogen, but adapting existing engines to use gas entails significant investment costs and hydrogen fuel cells are even more expensive. furthermore, as diesel engines are more common, they tend to be easier and cheaper to maintain. The introduction of alternative fuels has therefore, been rather slow so far, but due to higher oil prices and stricter regulations on emissions, this is now changing and the alternative fuels are becoming more and more common. While the use of alternative fuels is increasing in all areas of shipping, certain fields stand out as somewhat quicker in adapting to the new techniques. among these are the short distance ferries, and more specifically, shuttle ferries.

Vessel Hammarby sjöstad seabus Fuel cell BV Zemships Elding Tidekongen

Location Sweden The Netherlands Germany Iceland Norway

Type of fuel Biogas electric engine Fuel cell and battery Fuel cell and battery Hydrogen fuel cell LNG

xamples where alternative fuels have been used or will be used in ferries.

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Green shipping – from hull improvements to alternative fuels

Shuttle ferries
Shuttle ferries used in densely populated areas, divided by a river, are a distinguished field. These areas can often be characterised by levels of nitrogen oxides and levels of carbon dioxide too high compared to the requirements. Therefore new shuttle ferry routes are of special interest in such regions – at least as demonstrators of “green” technology with low local emissions of nitrogen oxides. There are several good examples where alternative fuels have been used or will be used in ferries, as can be seen in the table on the left.

artin Borgh, Project Manager, received his M.Sc. in Naval Architecture from the Royal Institute of technology (Kth) in 2000. he joined SSPA in 2008 after seven years working for the Swedish Defence Materiel Administration (fMV) as a specialist regarding above-water signatures. Now focusing on early concept design and general naval architecture issues with a special interest in waste heat recovery technology. telephone: +46 31 772 91 95 e-mail: martin.borgh@sspa.se

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The Gothenburg example...
Gothenburg is bisected by the Göta River and many of the inhabitants commute across the river. The number of persons commuting on bicycles in Gothenburg is increasing and, to cover the need for transporting bicycles and pedestrians across the river, the transport capacity has to increase. apart from the two existing bridges across the Göta River, there are two public transport ferry lines for pedestrians and bicycles. The currently used ferries are not designed or well adapted for very short distance routes and a high number of passengers with bicycles. a large political focus has been put on improving the citizens possibilities to commute using bicycles, and the possibilities of increasing the capacity of the existing bridges and ferries with new environmental ferries across the river has received new attention. if the City decides to switch to a more environmentally friendly ferry, important criteria for a new ferry route are fast on- and offloading, and flexibility in capacity. an environmentally friendly shuttle, is not, however just a question of fuel. for the users, the inhabitants, the quicker and cheaper option is a much more important argument in the choice between the car and public transport – and in that context a shuttle is just a link. Thus, the total concept must include well working traffic junctions on both sides of the river with ferry quays allowing two or more ferries to dock at the same time, employing bow berthing to allow for fast loading and unloading. bus and train stops and tram tracks close-by allow high capacity and short distances for commuters when changing transport. and very importantly for the transport company - technical and economical factors must be taken into account.
rida Karlge, Project manager at the traffic and Public transport Authority in gothenburg says: “the new environmentally friendly ferry is just in line with the environmental goals set by the City; more public transport and less fossil fuels used”.
PHOTO:ulRika ROuPÉ

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dvard Molitor, Project Manager, has a M.Sc. in Aquatic and environmental engineering from Uppsala University. he has previously worked with marine pollution response for the Swedish Coast guard headquarters and at the european Maritime Safety Agency (eMSA). he joined SSPA in 2009 and works with marine pollution response, risk analyses, and environmental management. telephone: +46-31 772 90 02 e-mail: edvard.molitor@sspa.se

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…and the SSPA contribution
SSPa has been contracted to study the possibilities of putting an environmentally adapted ferry into service across the Göta River, and to investigate the capacity, availability, environmental effects, risk and safety and costs connected with the ferry traffic. alternative fuels such as diesel mk1, biogas and hydrogen gas/fuel cells have been analysed. The ferry concept that has been produced is based on several criteria, among them that the ferry should take about 250-300 passengers and that the ship is double-ended to facilitate bow berthing at both quays

to speed up the loading and unloading of passengers. The ship should also be as long, lean and lightweight as possible and travel at a low speed and thus minimise fuel consumption. The greatest difficulty in designing a concept with very low fuel consumption is whether, and to what extent, the ferry must be able to cope with ice in the river. in Gothenburg, using a mixture of natural gas and biogas as fuel is one possibility. This fuel is presently available locally for cars and buses and could also be distributed relatively easily to ships. as the share of biogas increases in the gas fuel, the ferry would also gradually reduce its emissions of carbon dioxide. another recommended choice is to employ an electricity powered propulsion engine and using generator sets to produce the required electricity. The generator sets would most likely have to be fuelled with diesel when the vessel is put into service – this is due to the current lack of suitably sized marine certified gas engines. an electric propulsion concept would, however, provide enough flexibility to make future adjustments in the direction of using more biogas and less diesel. Hydrogen fuel cells have been considered to be a technique that still needs further development in order to be feasible in this specific case. The major issue is the current cost of the fuel cells – they are currently prohibitively expensive. Depending on the chosen underlying technology used in the fuel cells, the size and power capacity is also to an extent a difficulty in this particular study in using currently available fuel cells. However, as fuel cells give no local emissions of greenhouse gases when they are used in vehicles, only at fuel production, they are nonetheless of great interest for the future – especially in areas troubled by high local levels of nitrogen oxides and carbon monoxides. ulrika roupé Martin borgh edvard Molitor

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Short comments
a DP – positioned drillship. Today a key issue for upcoming operations in beaufort Sea deep water areas. Jim Sandkvist presented together with colleagues Johannes Hüffmeier, björn forsman and in cooperation with Transatlantic’s Johan Rafstedt “icemaster – a toolbox for planning of arctic offshore operations”. This icemaster tool is also described in detail in earlier SSPa HiGHliGHTS, 47/2009. SSPa’s Jim Sandkvist, who also joins the POaC international Committee, was also given the opportunity to present an invited paper about “arctic oil exploration – operational challenges”. This year more than 150 participants joined this successful conference in luleå in June. in two year, the 21st international POaC Conference will be held in montreal, Canada. Jim sandkvist

PHOTO: COuRTeSy Of STeNa ab

Stena “air-ships”
merchant ship operators are eagerly looking for fuel cost reduction, today more than ever. fuel consumption is largely dependent on the hull water resistance, of which the friction part is by far the most (up to 90-95%). Reduction of friction by non-polluting air “lubrication” affecting the innermost part of the boundary layer (e.g. micro bubbles) or separating the water from part of the hull (air cavities, air cushion) are old means that can still be subject to innovations. Since some time the Technical department of Stena Rederi ab has pursued the air cushion concept for application to various types of hulls. Right now model experiments for a product tanker are going on at SSPa’s test facilities. a large scale outdoor demonstrator model is being constructed and instrumented by SSPa. an investigation program is scheduled for the first half of year 2010, to be performed by SSPa. The solution has to be feasible and economically viable. before entering into a new-building program it is necessary to confirm the total power reductions obtained in laboratory experiments, and to know how the vessel behaves and how the air system will be controlled in various environmental conditions. lars Gustafsson

Capt. Vladimir Mikhaylichenko, capt. Anders Backman, capt. göran fors, capt. Lawson Brigham, capt. Valentin Davydyants PHOTO: Jim SaNDkViST

SSPA Papers and Reports 2009
allenström, b., Chodorowski, a., Rambech, H. J., Tukker, J.: ”Determination of wetted surface”, Paper presented at 1st international Conference amT´09 advanced model measurement Technology for eu maritime industry, Nantes, france, September 1–2, 2009. allenström, b., Ottosson, P., Hüffmeier, J., et al: ”Squat effects on single screw ships”, Paper presented at the international Conference maRSim 2009 marine Simulation and Ship maneuverability, Panama City, Panama, august 17–20, 2009. bark, G., Grekula, m., bensow, R. e., berchiche, N.: ”On some physics to consider in numerical simulation of erosive cavitation”, Paper presented at

Conference on Port and Ocean Engineering, POAC 2009
This year the 20th international Conference on “Port and Ocean engineering under arctic Conditions, POaC, was held in luleå, June 9 – 12, hosted by the Technical university of luleå. SSPa staff took active part in this conference by presenting a number of papers with a certain focus on efficient operations in arctic ice conditions. Heng Ran presented animated results from simulations of drifting pack ice interaction with

the 7th international Symposium on Cavitation CaV2009, ann arbor, michigan, uSa, august 17–22, 2009. ellis, J., lumsden, k.: “investigation of risk associated with the marine transport of undeclared dangerous goods”, Paper presented at 4th international Conference on maritime Transport, barcelona, Spain, april 27–29, 2009. fréchou, D., Hallander, J., et al: “PiV operation in hydrodynamic facilities”, Paper presented at 1st international Conference amT´09 advanced model measurement Technology for eu maritime industry, Nantes, france, September 1–2, 2009. Grekula, m., bark, G.: “analysis of high-speed video data for assessment of the risk of cavitation erosion”, Paper presented at 1st international Conference amT´09 advanced model measurement Technology for eu maritime industry, Nantes, france, September 1–2, 2009. Grundevik, P., lundh, m., Wagner, e.: ”engine Control Room – Human factors”, Paper presented at the RiNa international Conference ”Human factors in Ship Design and Operation”, london, uk, february 25–26, 2009. Hüffmeier, J., forsman, b., Sandkvist, J. Rafstedt, J.: “iCemaSTeR – a toolbox for planning of arctic offshore operations”, Paper presented at the POaC 09 - 20th international Conference on Port and Ocean engineering under arctic Conditions 2009, luleå, Sweden, June 2009. Hüffmeier, J., Johansson, J., Roupé, u.: “economical gains through environmentally compatible ships”, yearbook of maritime Technology 2009, Scandinavian Shipping Gazette, No 5, 2009. källström, C., allenström, b., Ottosson, P.: ”analysis of the sinking sequence of mV estonia using a combined simulation and model test approach”, Paper presented at the 10th international Conference on Stability of Ships and Ocean Vehicles STab 2009, St. Petersburg, Russia, June 22–26, 2009. li, D.-Q., Grekula, m., lindell, P.: ”a modified SST k-w turbulence model to predict the steady and unsteady sheet cavitation on 2D and 3D hydrofoils”, Paper presented at the 7th international Symposium on Cavitation CaV2009, ann arbor, michigan, uSa, august 17–22, 2009. Pereira, f., aloisio, G., bretschneider , H., Johannsen C., Grekula, m., bark, G., et al: “methods and procedures for high-speed video recording and analysis of pres-

sure fluctuations in propeller cavitation”, Paper presented at 1st international Conference amT´09 advanced model measurement Technology for eu maritime industry, Nantes, france, September 1–2, 2009. Sandkvist, J.: “arctic oil exploration – operational challenges”, invited paper, presented at the POaC 09 – 20th international Conference on Port and Ocean engineering under arctic Conditions 2009, luleå, Sweden, June 2009. Styhre, l.: “Strategies for capacity utilisation in RoRo shipping”, Paper presented at the Transportation Research board 88th annual meeting, Washington, DC, uSa, January 11–15, 2009. Styhre, l.: “introduction of new vessel capacity to existing sea links and ports”, Paper presented at 4th international Conference on maritime Transport, barcelona, Spain, april 27–29, 2009. Styhre, l.: “Strategies for capacity utilisation in short sea shipping”, To be published in Journal of maritime economics & logistics, Volume 11, 418–437, 2009. Vanem, e., ellis. J.: “Cost-effectiveness assessment of an RfiD passenger monitoring system for improved emergency evacuation”, Paper presented at the World maritime Technology Conference WmTC 2009, mumbai, india, January 21–24, 2009.:

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