weather routing meteorological may 2011

11
The forecast t was a very dark, oppressive night, hot and close. The nearest town was more than 60km away. The sound of heavy gunfire was deafening. A whole regiment of tanks (57) were firing their main 120mm rifled guns; each tank was also blasting off tracer bullets at a rate of knots from its two 7.62mm coaxial machine guns. Behind this were advancing two battalions of infantry, about 1,200 men, each soldier heavily armed and using it. Behind them were two mortar troops, and behind them a battery of 155mm artillery. All this metal was getting really busy, all ammunition was live. This was BATUS (British Army Training Unit Suffield) in a remote, but large corner of the Canadian prairies. On this particular night I was stuck somewhere in the middle of the slow move forward. I was a ‘battle captain’, ensuring fuel and ammo went to the forward units. But the lack of involvement in the excitement was compensated by the greatest meteorological experience I have ever witnessed. In this issue of MTI the well- established company Vaisala writes about lightning detection. It describes the establishment of a worldwide network that can detect lightning storms and, based on existing data and modeling, predict exactly how the lightning storm will perform, expand, dissipate, or behave – an extraordinary global system. It amazed me that the company says there are up to 24,000 fatalities a year due to strikes, with 10 times more injuries. Almost as impressive is that the longest single flash detected was 120 miles long, and lasted nearly two seconds. Despite being ‘in the field’ for almost three weeks, this night firing exercise was different: I noticed a change – a fresh chill in the atmosphere and a thick blackness that was creeping in from the west. The advancing gloom was interrupted with almighty flashes within, and a rumble that was starting to grow even louder than the massive roar around me. It did not take long: within just a few minutes the darkness swept across us, and the rain hit, but this was something to be ignored. We were under a vast sky. The nearest tree was miles away – this was the prairies – and bolts of lightning were flying across, from horizon to horizon, up and down, and all joined. It was absolutely spectacular. Apparently an Irish Guards vehicle was hit, with minor burn injuries, but they had been shooting at our tank bins for hours, so rough justice. It is said that streaks of lightning with no obstacle can easily travel across 50 miles of sky, and I am certain this is what I witnessed. Fueled by massive daytime heating, the atmosphere is often highly unstable, and extreme weather virtually impossible to predict. No sooner had the storm started than it passed. My best friend and I had completely forgotten about the exercise. But as the sky cleared, the storm subsided and then the first green curtain gently fell down from the highest reaches of the ionosphere. As I lay on my back atop a grassy hillock, smoking a cigarette, G&T in hand, the amazing phenomenon of the aurora borealis (northern lights) began to play its dance across the night sky. Mesmerizing; tranquility amid mayhem, with greens, pinks, and blues weaving and waving across the heavens, all caused by emissions of photons in the Earth’s upper atmosphere, which are excited by the collision of solar wind particles being funneled and accelerated along the Earth’s magnetic field. Apparently, storm skies are more prone to the spectacle, as storms leave an ‘auroral oval’ open, particularly in this region. The only way to predict this is to study solar winds. It seemed the atmosphere was doing its job of keeping the radiation away, and I was happy to watch the greatest light show above Earth as a mighty encore to the greatest light show ‘on’ Earth. The inclusion of ‘total’ lightning sensors at weather stations allows detection of all types of lightning, and therefore an increased ability to ‘nowcast’ tracking of severe weather events. It could save lives, and a few Irish Guards’ eyebrows. Christopher Hounsfield, editor Meteorological Technology International , the only true review of climate, weather, oceanic prediction, measurement, and analysis technologies I The views expressed in the articles and technical papers are those of the authors and are not necessarily endorsed by the publisher. While every care has been taken during production, the publisher does not accept any liability for errors that may have occurred. Copyright ©2011 Printed by Nuffield Press, 21 Nuffield Way, Ashville Trading Estate, Abingdon, Oxfordshire, OX14 1RL ISSN 2042-7190 published by UKIP Media & Events Ltd Subscriptions £60/US$108 Contact us at: Meteorological Technology International Abinger House, Church Street, Dorking, Surrey, RH4 1DF, UK tel: +44 1306 743744 email: [email protected] Editor Christopher Hounsfield (c.hounsfi[email protected]) Assistant editor Bunny Richards ([email protected]) Chief sub-editor Alex Bradley Sub-editor William Baker Production manager Ian Donovan Production team Carole Doran, Lewis Hopkins, Cassie Inns, Robyn Skalsky Publication & sales director Barry Smith Art director James Sutcliffe Design team Louise Adams, Andy Bass, Anna Davie, Andrew Locke, Craig Marshall, Nicola Turner, Julie Welby, Ben White Proofreaders Aubrey Jacobs-Tyson, Frank Millard Editorial director Anthony James Managing director Graham Johnson CEO Tony Robinson 4 METEOROLOGICAL TECHNOLOGY INTERNATIONAL MAY 2011 If you are looking for new measurement, forecasting, or analysis technologies, weather or research service providers, Meteorological Technology World Expo is your new must-attend event. The international exhibition will be held from October 18-20, 2011, in the center of Brussels, Belgium, one of Europe’s busiest hubs for international business activity. Entrance to the expo is free and there will be free-to-attend forums that delve into the latest meteorological technologies, trends, services, and concepts. Graham Johnson, managing director of UKIP Media & Events Ltd, the global publishing and exhibitions company that publishes Meteorological Technology International and is staging the new expo, says, “Meteorological Technology World Expo will bring the pages of this magazine to life. We’re inviting more than 10,000 key decision makers within the world’s major commercial purchasers of meteorological measurement and forecasting equipment and services, including airports, marine ports, airlines, military operations, wind farms, offshore facilities, and agriculture users, as well as all of the world’s national and regional met offices and research institutes. We’re expecting Meteorological Technology World Expo to be the largest exhibition of its kind ever staged.” So whether you are looking for new business partners or to meet up with your established suppliers in one convenient location, Meteorological Technology World Expo 2011 is the place to be. Visit www.meteorologicaltechnologyworldexpo.com for regular exhibitor and visitor updates and to register for your free entry pass. October 18-20, Brussels, Belgium: The most significant dates of 2011!

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Page 1: Weather Routing Meteorological May 2011

The forecast

t was a very dark, oppressive night, hot and close. The nearest town was

more than 60km away. The sound of heavy gunfire was deafening. A whole regiment of tanks (57) were firing their main 120mm rifled guns; each tank was also blasting off tracer bullets at a rate of knots from its two 7.62mm coaxial machine guns. Behind this were advancing two battalions of infantry, about 1,200 men, each soldier heavily armed and using it. Behind them were two mortar troops, and behind them a battery of 155mm artillery. All this metal was getting really busy, all ammunition was live. This was BATUS (British Army Training Unit Suffield) in a remote, but large corner of the Canadian prairies.

On this particular night I was stuck somewhere in the middle of the slow move forward. I was a ‘battle captain’, ensuring fuel and ammo went to the forward units. But the lack of involvement in the excitement was compensated by the greatest meteorological experience I have ever witnessed.

In this issue of MTI the well-established company Vaisala writes about lightning detection. It describes the establishment of a worldwide network that can detect lightning storms and, based on existing data and modeling, predict exactly how the lightning storm will perform, expand, dissipate, or behave – an extraordinary global

system. It amazed me that the company says there are up to 24,000 fatalities a year due to strikes, with 10 times more injuries. Almost as impressive is that the longest single flash detected was 120 miles long, and lasted nearly two seconds.

Despite being ‘in the field’ for almost three weeks, this night firing exercise was different: I noticed a change – a fresh chill in the atmosphere and a thick blackness that was creeping in from the west. The advancing gloom was interrupted with almighty flashes within, and a rumble that was starting to grow even louder than the massive roar around me. It did not take long: within just a few minutes the darkness swept across us, and the rain hit, but this was something to be ignored. We were under a vast sky. The nearest tree was miles away – this was the prairies – and bolts of lightning were flying across, from horizon to horizon, up and down, and all joined. It was absolutely spectacular. Apparently an Irish Guards vehicle was hit, with minor burn injuries, but they had been shooting at our tank bins for hours, so rough justice. It is said that streaks of lightning with no obstacle can easily travel across 50 miles of sky, and I am certain this is what I witnessed. Fueled by massive daytime heating, the atmosphere is often highly unstable, and extreme weather virtually impossible to predict.

No sooner had the storm started than it passed. My best friend and I had completely forgotten about the exercise. But as the sky cleared, the storm subsided and then the first green curtain gently fell down from the highest reaches of the ionosphere. As I lay on my back atop a grassy hillock, smoking a cigarette, G&T in hand, the amazing phenomenon of the aurora borealis (northern lights) began to play its dance across the night sky. Mesmerizing; tranquility amid mayhem, with greens, pinks, and blues weaving and waving across the heavens, all caused by emissions of photons in the Earth’s upper atmosphere, which are excited by the collision of solar wind particles being funneled and accelerated along the Earth’s magnetic field. Apparently, storm skies are more prone to the spectacle, as storms leave an ‘auroral oval’ open, particularly in this region. The only way to predict this is to study solar winds. It seemed the atmosphere was doing its job of keeping the radiation away, and I was happy to watch the greatest light show above Earth as a mighty encore to the greatest light show ‘on’ Earth.

The inclusion of ‘total’ lightning sensors at weather stations allows detection of all types of lightning, and therefore an increased ability to ‘nowcast’ tracking of severe weather events. It could save lives, and a few Irish Guards’ eyebrows.

Christopher Hounsfield, editor

Meteorological Technology International, the only true review of climate,

weather, oceanic prediction, measurement, and analysis technologies

I

The views expressed in the articles

and technical papers are those of the

authors and are not necessarily

endorsed by the publisher. While every

care has been taken during

production, the publisher does not

accept any liability for errors that may

have occurred. Copyright ©2011

Printed by

Nuffield Press, 21 Nuffield Way,

Ashville Trading Estate, Abingdon,

Oxfordshire, OX14 1RL

ISSN 2042-7190

published by

UKIP Media & Events Ltd

Subscriptions £60/US$108

Contact us at:

Meteorological Technology

International

Abinger House, Church Street,

Dorking, Surrey, RH4 1DF, UK

tel: +44 1306 743744

email: [email protected]

Editor

Christopher Hounsfield

([email protected])

Assistant editor

Bunny Richards

([email protected])

Chief sub-editor

Alex Bradley

Sub-editor

William Baker

Production manager

Ian Donovan

Production team

Carole Doran, Lewis Hopkins,

Cassie Inns, Robyn Skalsky

Publication & sales director

Barry Smith

Art director

James Sutcliffe

Design team

Louise Adams, Andy Bass,

Anna Davie, Andrew Locke,

Craig Marshall, Nicola Turner,

Julie Welby, Ben White

Proofreaders

Aubrey Jacobs-Tyson,

Frank Millard

Editorial director

Anthony James

Managing director

Graham Johnson

CEO

Tony Robinson

4 • METEOROLOGICAL TECHNOLOGY INTERNATIONAL MAY 2011

If you are looking for new measurement, forecasting,

or analysis technologies, weather or research

service providers, Meteorological Technology World

Expo is your new must-attend event.

The international exhibition will be held from

October 18-20, 2011, in the center of Brussels,

Belgium, one of Europe’s busiest hubs for

international business activity. Entrance to the expo

is free and there will be free-to-attend forums that

delve into the latest meteorological technologies,

trends, services, and concepts.

Graham Johnson, managing director of UKIP

Media & Events Ltd, the global publishing and

exhibitions company that publishes Meteorological

Technology International and is staging the new

expo, says, “Meteorological Technology World Expo

will bring the pages of this magazine to life. We’re

inviting more than 10,000 key decision makers

within the world’s major commercial purchasers of

meteorological measurement and forecasting

equipment and services, including airports, marine

ports, airlines, military operations, wind farms,

offshore facilities, and agriculture users, as well as

all of the world’s national and regional met offices

and research institutes. We’re expecting

Meteorological Technology World Expo to be the

largest exhibition of its kind ever staged.”

So whether you are looking for new business

partners or to meet up with your established

suppliers in one convenient location, Meteorological

Technology World Expo 2011 is the place to be. Visit

www.meteorologicaltechnologyworldexpo.com

for regular exhibitor and visitor updates and to

register for your free entry pass.

October 18-20, Brussels, Belgium: The most significant dates of 2011!

Page 2: Weather Routing Meteorological May 2011
Page 3: Weather Routing Meteorological May 2011

by Keith Thomson

SHIP’S LOG

W eather routing of ocean-going shipping has been practiced for many hundreds of years. Early Arab

traders used the regular monsoons of the Arabian Sea to navigate to East Africa and to the Indian subcontinent, while 15th century sailors took advantage of their knowledge of prevailing trade winds and currents to optimize their routes from Spain and Portugal to the New World and back.

In the 19th century, systematic

compilation of atmospheric and oceanographic data from ships’ log books meant that climatological averages of ocean weather and ocean currents became available to mariners, and this information was used by early pioneers to develop seasonally recommended routes for sailing ships and early steam-powered vessels.

In the mid 20th century the modern concept of ship weather routing began to be put into operation by national

meteorological centres and private meteorological companies, and by applying available surface and upper air forecasts to transoceanic shipping, it became possible to effectively avoid much heavy weather while generally sailing shorter routes than previously.

In the last 20 years, the rapid development of computers, the internet and communications technology, together with advances in meteorological analysis

Weather routing provides

a major role in vessel economyA combination of weather forecasting and the study of ocean currents has led to the

rise of the shipping route agencies

Weather routing

6 • METEOROLOGICAL TECHNOLOGY INTERNATIONAL MAY 2011

Page 4: Weather Routing Meteorological May 2011

“The more accurate the starting

analysis of the atmosphere from

which the model is run, the better

the final forecast will be”

techniques and atmospheric modeling, has made a much more detailed and accurate weather routing service widely available to marine users on all scales.

Weather routing servicesThere are several private companies and publicly funded bodies providing ship routing services. One such private company is Aerospace & Marine International (AMI) which has been providing weather services

to the maritime industry for more than 20 years. The company maintains two operations centers; one in the USA and one in the UK. Together the two offices deliver 24 hour marine weather forecasting and ship routing services to a global client base.

Across the industry there are different variables to the traditional weather routing service. To a large extent two different groups can be identified; those actively optimizing a vessel’s sea passage to achieve a

pre-determined goal (fuel savings, avoiding damage to cargo on deck and so on) and those services dedicated to passively tracking a vessel’s progress to evaluate the speed and consumption performance for contractual purposes. In the case of Aerospace & Marine these services are Optimum Voyage Routing (OVR) and Performance Monitoring (PMO).

The goal of OVR is to develop the best route for a ship based on existing weather

Weather routing

METEOROLOGICAL TECHNOLOGY INTERNATIONAL MAY 2011 • 7

Output of forecast winds (wind barbs) and wave height (colored contours) from present day atmospheric and ocean wave models

A typical bulk carrier which makes regular use of weather routing services

Page 5: Weather Routing Meteorological May 2011
Page 6: Weather Routing Meteorological May 2011

For most transits optimum shipping routing will mean the minimum transit time that avoids significant risk to the vessel, crew and cargo. The goal is not to avoid all adverse weather but to find the best balance to minimize time of transit and fuel consumption without placing the vessel at risk to weather damage or crew injury.

Route planning normally will start by reviewing the appropriate Pilot Chart Atlases and Sailing Directions (planning guides) to determine the normal weather patterns, weather risks and prevailing ocean currents. The Routing Service then reviews recent weather patterns and weather forecast charts to determine the most likely conditions during the course

to the voyage. A preliminary routing message is transmitted to the master of a vessel prior to departure with a detailed forecast of expected storm tracks, an initial route proposal with reasoning behind the recommendation, and also the expected weather conditions to be encountered along that route.

This allows the master to better plan his route and offers an opportunity to communicate with the service any special concerns that he or she might have due to special cargo requirements or ship condition. Once the vessel departs, the vessel’s progress is monitored closely with weather and route updates sent as needed.

OPTIMUM SHIP ROUTING

forecasts, ocean current patterns, ship characteristics and special cargo requirements. For most transits this will mean the minimum transit time that avoids significant risk to the vessel, crew and cargo. The aim is not to avoid all adverse weather but to find the best balance to minimize time of transit and fuel consumption without placing the vessel at risk to weather damage or crew injury. During the voyage, regular forecasts and route recommendations are provided to the vessel to aid the master in choosing the best route as described.

In contrast to active routing, the goal of performance monitoring is to measure and prepare a report on the performance of the subject vessel in terms of speed and consumption of fuel along its route versus the contractual speed and consumption for the same vessel. This report requires an independent analysis to determine what loss of speed was due to weather and currents, and what was due to the vessel’s ‘malfunction’ if any.

The route forecaster uses specialized geographic information system software which enables display of the vessel route on charts overlain with wind, wave, current, and several other types of relevant meteorological factors such as sea ice, icebergs, and freezing spray. The route waypoints are plotted and compared to several other reasonable variations of the same route. The full set of routes is then simulated taking into account the vessel characteristics, forecast weather and ocean currents so that the optimum route can easily be determined. Once underway the vessel’s actual positions are added to the route, and the vessel’s progress is continuously monitored and updated when necessary, due to adverse weather or other factors.

Latest technologies in forecastingThere have been major advances in recent years in meteorological analysis techniques and atmospheric modeling. Much effort has been applied to developing methods to assimilate the vast amounts of available satellite and other forms of remotely measured data into global atmospheric models.

The more accurate the starting analysis of the atmosphere from which the model is run, the better the final forecast will be. As a result these models are now capable of producing accurate global forecasts of winds and waves for up to a week ahead, and to give some detail about larger scale patterns for another week beyond that.

An example of the type of output available from such models is shown in the

METEOROLOGICAL TECHNOLOGY INTERNATIONAL MAY 2011 • 9

graph on the previous page. This means that vessels can be routed to avoid an expected storm which may not even exist yet, but which with a high level of certainty will form somewhere ahead along the vessel’s present track. The global models are also now beginning to pick up some tropical storm development days before the storm has even been officially recognized by the respective regional forecast centers.

Another area where there has been a significant improvement is in the modeling of ocean currents. In the past, current data was painstakingly extracted from ships’ logs by comparing distance sailed over ground with distance actually sailed through the water, and these observations were collated into charts of monthly averages which were the main source of ocean current information for masters and other interested parties. The introduction of satellites capable of measuring to a high degree of accuracy the elevation of the sea

surface has meant that dynamic ocean current models are now initialized with real-time surface elevation data. This allows much greater precision in the modeling of ocean currents down to a fine scale of a few miles and it means that ships can be routed much more accurately in relation to adverse or favorable currents.

For example, strong current gyres in the Gulf of Mexico change only slowly over a period of days and these can be used to great effect by the routing agency to reduce sailing times by a couple of hours for the addition of a few extra miles. Slower vessels are much more affected by currents, as the speed of the current is a much larger percentage of the vessel speed, and the vessel remains under the influence of the current for longer. A good example is shown in the graph above left which depicts a typical westbound track taking advantage of the current patterns off the north-east coast of Brazil, close to the Equator.

A very strong current flows parallel to the coast from east to west throughout the year, and this strong current occasionally breaks down into an eddy so that there is a branch moving from west to east some way to the north. A slow vessel, say a drilling rig being towed by a tug, can save three days or more on a trip from the Gulf of Mexico to Brazil despite adding 100-200 miles to the journey, by remaining to the north of the strong adverse current core and in the following current branch of the eddy. Vessels sailing east to west stay further south within the core of the current and in this way can improve voyage times by several days.

These regions of strong current were depicted on the historic monthly averaged

Ocean current chart showing a vessel route to take maximum advantage of favorable Brazil westerly current

Weather routing

Page 7: Weather Routing Meteorological May 2011

charts, but the day-to-day fine detail was not available from these charts and masters would find the favorable currents or avoid the adverse currents by trial and error. Nowadays the routing company has access to this fine scale current detail and voyages can be tweaked and updated on a daily basis to ensure the best and most favorable route is used which takes maximum advantage of the currents.

Other routing considerationsOther non-meteorological factors also inf luence the choice of routes available. A recent and unforeseen development has been the rapid increase in piracy in the Indian Ocean originating from the failed state of Somalia. As recently as five years ago, vessels sailed with impunity across the Arabian Sea into and out of the Gulf of Aden.

Attacks were carried out by small groups of pirates in skiffs which were vulnerable to strong winds and rough seas. The attacks then began to become more sophisticated, making use of larger hijacked vessels as mother ships, pushing the area at risk across the Arabian Sea to the west coast of India. This has meant a drastic change in routing patterns over the area, so that safety is now the sole concern. What used to be one of the

busiest sea routes in the world connecting the Far East with Europe via the Red Sea and Suez Canal is now a risky undertaking, and some operators are sending their vessels around South Africa and adding many days to their voyages.

Another factor which is having a major impact on vessel routing is the price of fuel. Recent geopolitical events have conspired to send the price of crude oil to historically high levels.

Traditional weather routing still plays a vital role in minimizing fuel consumption, but other methods of fuel conservation are being practiced regularly by operators, including sailing at most economical speed or suggesting an optimal RPM setting for a given voyage. All these ‘variants’ to traditional weather routing continue to be totally dependant on accurate weather and ocean currents data to provide meaningful advice to the vessel. These methods will continue to be expanded on in the coming months and years, especially in scenarios of high fuel price and increased concern over greenhouse emissions regulations for shipping.

Weather routing is a tool which can be used to reduce fuel consumption and greenhouse gas emissions in the global shipping industry. Collaboration between routing providers and vessel operators will result in improvement of existing services and development of new ideas, ensuring that weather routing continues to play an important role in vessel economy and safety in the future. ❚

Keith Thomson is the UK operations manager of

Aerospace & Marine International (UK) LtdFive days outlook animated wind and wave charts for Atlantic north east

Tropical storm charts depicting historic and forecast track and area of uncertainty in relation to a deep sea tow’s track

10 • METEOROLOGICAL TECHNOLOGY INTERNATIONAL MAY 2011

Weather routing

Page 8: Weather Routing Meteorological May 2011
Page 9: Weather Routing Meteorological May 2011

by Aiste Hoffbeck

PORT OUT,

STARBOARD HOME

co Voyage is a tool that was designed to provide the planner of a trans-ocean voyage with information on

optimal speed through every part of the journey. This enables the propulsion power to remain as constant as possible to obtain the lowest possible fuel consumption and CO

2 emissions. Based on vessel particulars

and detailed up-to-date information on expected currents, wind, waves, and depth restrictions along the planned route, the optimal power and revolutions/minute (rpm) profile can be chosen. This way unwanted oscillations in the ship’s power can be avoided while still maintaining a fixed estimated time of arrival. The improved tool has an impressive potential: by utilizing environmental information fuel savings of 0.5-1% are expected.

The project was developed by the Vessel Performance section in Maersk Maritime Technology (MMT), in cooperation with Maersk Line Vessel Management (MLVM) and Maersk Tankers (MT). The development is supported by The A. P. Moller Foundation.

Eco Voyage functions in a way that updated sea current information is received from other vessels on the same route through a central server. In addition, the weather forecast program provides wind, wave, and current forecasts. This information is used to plan the most optimal and efficient route for every vessel.

Testing of the system is almost finished and the Vessel Performance section in Maersk Maritime Technology is now ready to evaluate the results. To illustrate how the program works, Kim Henriksen, the Eco Voyage prime mover in the vessel performance section of MMT, prepared an exclusive simulation of calculating and planning a voyage for one of the company’s

How the world’s largest container carrier uses met data to save fuelBy analyzing information on wind, waves, and currents, Eco Voyage is proving to be a

useful cost-cutting tool in commercial shipping, as well as an aid in oceanic research

E

Voyage case study

12 • METEOROLOGICAL TECHNOLOGY INTERNATIONAL MAY 2011

Page 10: Weather Routing Meteorological May 2011

Voyage case study

METEOROLOGICAL TECHNOLOGY INTERNATIONAL MAY 2011 • 13

“The improved tool has an

impressive potential: by utilizing

environmental information fuel

savings of 0.5-1% are expected”

Page 11: Weather Routing Meteorological May 2011

vessels. The voyage is from Hong Kong to Tanjung Pelepas in Malaysia with one alternative route following the Vietnam coast and the other one in open sea.

Focus on currentsThe first step in preparing the voyage plan is looking at the navigational requirements – the shortest route at deep water. However, there are restrictions, such as traffic zones, that need to be followed correctly. For each voyage a passage plan needs to be made that describes the route and that route must be checked within an electronic chart display and information system (ECDIS). “We need to be aware of all points where the route will change and these points need to be included in route description,” explains Henriksen. “We call them waypoints.”

This is where the weather comes in. When creating an overview of waypoints, one should look into the weather forecasts for the period of the voyage. Of course, it is especially bad weather that is of most interest, but sea currents also get a fair share of attention as avoiding a head current can significantly save on the amount of fuel.

After the route is defined in the ECDIS, it gets transferred into Eco Voyage program, where additional information such as speed restrictions, shallow water or planning restrictions can be added. A map function shows the route and a number of hub points that are used for segmenting the voyage and for sharing sea current information with others. The observations of currents from

sister vessels are received from a server located in Copenhagen.

The latest update of the program also includes zones with increased pirate activity. This is important as vessels are required to sail faster through such areas, as speed remains the best method for preventing pirate attacks. In this case Eco Voyage calculates the higher speed in pirate-populated areas that need to be matched with lower speed later in the journey to compensate for increased fuel consumption.

Calculations for passing shallow water are similar, but in this case, lower speed is advised that need to be made up for at a later stage in order to stick to the schedule.

Many route choicesMost of the voyages follow a fixed schedule where arrival and departure is known, and to save fuel, Maersk vessels try to avoid wasting time that is caused both by late departure and early arrival. Therefore speed needs to be carefully calculated and that is done with regard to the effects of currents.

After it is done, the route description is transferred to the route planning program in which the weather forecasts can be seen,

14 • METEOROLOGICAL TECHNOLOGY INTERNATIONAL MAY 2011

Voyage case study

Eco Voyage is a flexible program that can benefit both performance and science because of the data collected

including a prediction of ocean currents. This program does have a relatively simple model for calculating speed loss due to wind and waves. It is possible to calculate up to four route alternatives of which three follow navigational lines: Rhumb Line (direct line), Great Circle (shortest distance) or a combination of both.

“There is one more alternative and that is an optimal route where an algorithm optimizes the balance between extra distance and speed loss,” says Henriksen. “Sometimes the longer way might take less time and vice versa. But voyages are not equally easy to optimize, as the waypoints of the original route are kept and the more waypoints there are the less optimization is possible.”

After calculation, the influence of the weather on the speed will be available in the Eco Voyage program. Eco Voyage has an advantage as it is working on the same database and models as the vessel performance monitoring system and therefore all information of vessel’s performance is up-to-date. Therefore weather predictions are important, but their influence can vary, depending on the overall condition of the vessel.

Hub points are used to segment the voyage and make information sharing more precise

Vessels can receive updated current information from sister vessels that are on the same route

Shortest way on the map does not mean the most efficient voyage, therefore routes are optimized

Voyage planning includes weather forecasts and prediction of sea currents