Marine Propulsion History and Electric Propulsion Future Technology.pdf

Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh.

Marine Propulsion History And

Electric Propulsion & Future Technology

1

40,000 years before christ, man built boats and paddled through the waters with them. And, they paddled and paddled and paddled for 35,000 years until a major discovery revolutionised ship propulsion for the first time.

History of Marine Propulsion

5/17/2014 2 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh

Mankind paddled round for 35,000 years just like the indians and then they began using oars similar to the tourists on the alster lake.

Then mankind oared round for several thousand years namely, up to 3,000 b.c. until the sail was discovered, supposedly in Egypt. finally, more than just the nile and the coastal regions of the Red and Mediterranean seas could be explored. the seafarers could then set off on voyages crossing the seas and circling the continents.

For a long time, the seaman couldnt give up using the oar and combined the oar with the sail.




The ships got bigger and bigger, Hamurabi lived and died, and, finally, the oars were completely done away with. And, in this manner, mankind sailed almost 5,000 years until the year 1770 A.D.

Roman warship with sail and oars around 200 B.C.




when James Watt, further developed the steam engine so that it, a short time thereafter, could be built into a ship.


Cross-section and full-view of a 2-stage steam engine 5/17/2014 5



At this period in time, the propeller had not yet been invented and, what was more convenient to make use of than the old-familiar paddle-wheel of the flour and lum- ber mills.

The paddle-wheel propelled the ship, and the steam engine drove the paddle-wheel. The coal-fired boilers provided the steam for the steam engine.



Contemporary depiction of propulsion (steam engine and paddle-wheel) of the steamboat "Claremont" 5/17/2014 7



There were certainly attempts at in- terim solutions. This illustration is not a comic drawing but rather the then contemporary depiction of a submarine propelled by muscle power, which sank the "Housatonic" in 1864.

Submarine "H.L. Hunley" on 17.02.1864 while attacking the "Housatonic"



Mankind didnt throw the sail overboard and install a steam engine, rather one slowly felt his way forward the ships had a sail and a steam engine and a paddle-wheel (later a propeller, as well).

Steamship "Great Eastern" around 1860. The ship had 6 masts, 2 paddle-wheels and a four-bladed propeller 5/17/2014 9



Steamship "Helena Sloman" around 1850. The ship had a full set of sails and a propeller



Then, 60 years later, in the year 1827, Joseph Ressel had the ship propeller patented. He was an Austrian and had the exciting title of a Marineforstintendant.

The iron propeller was a great improvement as compared with the wooden paddle-wheel with its many fragile pieces.

The propeller was able to be adapted to all of the following types of propulsion and output standards of today.



Depictions of a paddle-wheel and a prototype of a propellerr



Meanwhile, propellers are built which can manage 120,000 hp and weigh over 130 tonnes having a diameter of just short of 10 metres. Here, the limit of possibility certainly seems to have been reached.

5-bladed control pitch propeller for a container 5/17/2014 13



Lets take just another look back into the century before the last, in which the steam engine set about replacing the sail. The demands made on output got bigger and bigger; the steam engines, as well. The performance limit of 20,000 hp per steam engine was quickly reached. So, several steam engines had to be built into a ship in addition to numerous boilers sometimes 15 or more. Besides that, many hundreds of tonnes of coal had to be brought on board and stored.



One of the two steam engines of the steamship

"Kronprinzessin Cecilie" (1907), 22.000 hpi 5/17/2014 15



Around 1900, the first steam turbines were built into ships. While having a larger output, they required much less space than steam engines, but the old steam boilers remained on board, and they were still fired manually with coal.

Cross-section of a high-pressure stage of a modern steam turbine 5/17/2014 16 Mohd. Hanif Dewan, Chief Engineer and


The amount of effort required to fire the boilers with coal is no longer imaginable today! One needed the coal heaver, who transported the coal from the storage room from the coal bunker up to just in front of the boiler; one needed the stoker, who shovelled the coal into the boilers and maintained the steam pressure; one needed the many helpers, who transported the ash from the boiler overboard. And, all of that for each individual boiler and for each of the three shifts.

View of the boiler room of a coal-fired steam boiler system 5/17/2014 17



Around 1920, when the Hamburg-Sd steamship "Cap Polonio" was refitted from coal-firing to oil-firing, the boiler room personnel was able to be reduced by just 110 men.

View of the furnace of two oil-fired steam boiler systems 5/17/2014 18



With the steam turbines, finally the industry had ship propulsion systems with - for ship standards huge performance reserves available (today, stationary steam turbine systems are built with over 1.5 million horsepower per turbine). The oil-fired boilers were also quite comfortable.

But, in this case, fuel consumption was very high. The efficiency of a steam turbine was, in comparison with a steam engine, from which only 10 to 20% of the energy used made it to the propeller, considerably better but still left loads of room for improvement having only 25 or 30% efficiency.

So, in regard to ship propulsion, the steam engine and the steam turbine only had a relatively short cameo-appearance in the greater scheme of things.



In the year 1876, thus 130 years ago the combustion engine was invented by Nikolaus Otto. It had to be driven with benzine, which at the time had to be purchased at the chemists with high prices.

The combustion engine was, thus, discovered, but it wasnt originally good for ship propulsion because it used too much expensive petrol.

Even 50 years before the invention of the Otto motor, the Frenchman, Carnot, described a thermo-dynamic cyclic process with theoretically the highest possible degree of efficiency. 5/17/2014 20



With the above in mind, Rudolf Diesel developed a combustion engine which operated according to the Carnot-principle and had the same patented in 1892. The 'diesel engine' reached a spectacularly high efficiency of 20, then 30, then 40 and finally 45 %.

Around 1910, one began to build diesel motors into ships as the main source of propulsion. The entire diesel engine took up approx. as much as three boilers and, thereby, replaced a steam propulsion system, which perhaps was comprised of 2 turbines, 15 boilers and countless auxiliary units and, thereby, required 30 % less fuel.

From 1910 to today, the diesel engine has gone through an unparalleled technical develop-ment. Similar to the propeller, the diesel engine was able to be adapted to every demand on size and output performance.



Left: View of a large two-stroke diesel engine around 1912 (1,500 hp at 120 RPM)

Right: Embedding of a crankshaft in a 12,000 hp 6-cylinder MAN two-stroke engine



Ship diesel engines of today are available in every size and output class up to 135,000 hp. They are extremely reliable, and the so- called specific fuel consumption is unbeatably low with 119 grams per hp and hour (g/hph) at its time, the steam engine consumed approx. 700 g/hph.

In addition, the 'combined heat and power' principle, which is talked about so often today, has been common practice in ships with diesel propulsion for ages. Heat is detracted from the diesel engines exhaust gases, which, in spite of everything else, still contain about 50 % of the thermal energy used, by connected turbo chargers and steam boilers so that the efficiency of the entire system rises to over 70 %.



Cross-section of a MAN-B&W ship diesel engine 6S 70 ME-C (25.000 kW @ 91 RPM , weight - 550 t, height 14 m)

The diesel engine has many advantages. It has displaced every other type of propulsion in shipping. Today, approx. 90% of all merchant vessels are propelled by diesel engines, world-wide.



However, the times of rapid technical developments in the ship diesel engine are gone which, for one, lies in the fact that the highest possible degree of efficiency has almost been reached, and, for another, that now possible output of 150,000 hp can no longer be surmounted by one single propeller. There is no longer any reason to boost the output of any one single ship diesel engine. In case its necessary now, two engines would have to power two propellers - and then there would be 300,000 hp of installed propulsion output. The size of merchant vessels which would require such an amount of output are not imaginable today, and such vessels wont be playing a roll in shipping in the intermediate-term.



The diesel engine has almost displaced every other type of propulsion and is absolutely market dominating.

It displaced the steam turbine, which today only plays a secondary role in regard to ship propulsion.

It displaced the nuclear powered merchant vessels which were built in the 60s of the previous century namely, the Savannah (USA), the Otto Hahn (Germany) and the Mutsu (Japan).

NS "Otto Hahn" - 1965



All three ships were powered by propellers, which, in turn, were driven by steam turbines typical of merchant ships only that the steam was not produced in oil-fired boilers but rather in a so called pressurised-water reactor. The ships were extremely expensive and uneconomical, and at their time they were only able to touch at very few ports worldwide owing to a lacking acceptance in the population. They also required a large number of well-trained crew members. The "Otto Hahn" had e.g. a regular crew of nearly 60 men plus 35 scientists on board.

View of the pressurised-water reactor of the NS "Otto Hahn"



The diesel engine also displaced ships with gas turbine propulsion. These ships had airplane jet engines, which functioned as so-called gas generators which, in turn, powered turbines. The latter rotated similar to a steam turbine and powered our old-familiar propeller.

Pratt & Whitney gas turbine FT 4 A12 (30.000 Ps) of the GTS "Asia Liner" 5/17/2014 28



Even this type of propulsion was extremely uneconomical in that it, for one, required the same top-quality, expensive fuel as that of an airplane jet engine and on top of that, it had an efficiency of only 21 % which was at least in comparison to that of a diesel engine awfully low. Every ship with gas turbine propulsion known to me was converted to diesel engine propulsion after a few years.

In the table below, we can compare the degrees of efficiency and specific fuel consumption of the various types of propulsion. The specific fuel consumption is, by the way, the amount of fuel that the system must be given in order to produce 1 hp for one hour (g/hph). we see that the modern Engine Makers have worked down from 700 g/hph to 120 g/hph today.



Comparison of the thermal degrees of efficiency and specific fuel consumption

efficiency specific fuel consumption

sail ./. 0

steam engine 10 15 % 700 g/hph gas turbine 21 % 320 g/hph

steam turbine 30 % 220 g/hph

diesel engine 45 % 120 g/hph

hydrogen 30 % ./.



The ship propulsion must be reliable and, above all, economical. Diesel propulsion satisfies both requirements thoroughly and without any competition at least as long as heavy fuel or diesel oil or, as the case may be, liquid gas (LNG) is readily available and affordable.

Beginning in 2070, oil appears in comparison to today to play a rather inferior role. In other words, there is little to be said against the diesel engines maintaining its dominating role in the market at least until 2030.

the SKYSAIL or the FLETTNER-ROTOR dont really help us out of the predicament, either. Our ships need propulsion independent of the weather and with enormously large output. "Auxiliary propulsion units" cannot manage this by far.



SkySail only suitable for auxiliary propulsion



Flettner-Rotors only suitable for auxiliary propulsion



Special ships such as submarines is hydrogen propulsion. The term "hydrogen propulsion" is just as misleading as "nuclear propulsion". A ship with hydrogen propulsion is still powered by the propeller and the latter by an electric motor. Both components are old friends the propeller, anyhow, and the electric motor has already been implemented in the so-called diesel- electric propulsion for many years. Thereby, a diesel engine powers an electric generator of which energy goes to an electric motor, which, in turn, powers the propeller. The last step of this development is the so called 'AZIPOD', which contains the electric motor directly in the pod (gondola) behind the propeller.



Electric 'Azipod' propulsion Left: View of the 'gondolas' with drag-propeller Right: Schematic diagram with view of the mounted electric engine in the 'gondola'



In regard to hydrogen propulsion, we can manage without a diesel engine and a generator as we produce the energy for the electric engine e.g. from the fusion of hydrogen and oxygen, whereby water and heat are generated so to speak as by-products in addition to the energy, itself. In Hamburg, some buses are already powered by hydrogen cells, and THYSSEN KRUPP has been successfully building submarines using this technology.



Left: Functional principle of a hydrogen cell

Right: Technical layout of a hydrogen cell for submarines



To introduce solar energy to the ship we need to convert the solar energy to electrical energy. electrical energy we can use and transport throughout the ship. photo-voltaic cells convert solar into electrical energy. An inverter is needed to convert the direct current (dc) to an alternating current (ac), so the 50 or 60 hz electric grid can transport the electrical energy through the ship. These energy conversions reduce the efficiency of the whole chain.

With a dc grid in a diesel-electric propulsion system less energy conversions are needed, There is no need for bulky transformers.

WIND & SOLAR ENERGY FOR SHIP



Sail and solar power ship



Marine Electric

Propulsion System

Marine Electric Propulsion

Integrated electric propulsion (IEP) or full electric propulsion (FEP) or integrated full electric propulsion (IFEP) is an arrangement of marine propulsion systems such that gas turbines or diesel generators or both generate three phase electricity which is then used to power electric motors turning either propellers.

It is a modification of the combined diesel-electric and gas propulsion system for ships which eliminates the need for clutches and reduces or eliminates the need for gearboxes by using electrical transmission rather than mechanical transmission of energy.



Marine Electric Propulsion System



Marine Electric Propulsion Electric propulsion for many new ships is now re-

established as the popular choice where the motor thrust is governed by electronic switching under computer control.

The high power required for electric propulsion usually demands a high voltage (HV) power plant with its associated safety and testing procedures.

Passenger ships have always been the largest commercial vessels with electric propulsion and, by their nature, the most glamorous. This should not, however, obscure the fact that a very wide variety of vessels have been, and are, built with electric propulsion.




Early large passenger vessels employed the turboelectric system which involves the use of variable speed, and therefore variable frequency, turbo-generator sets for the supply of electric power to the propulsion motors directly coupled to the propeller shafts. Hence, the generator/motor system was acting as a speed reducing transmission system. Electric power for auxiliary ship services required the use of separate constant frequency generator sets.

A system that has generating sets which can be used to provide power to both the propulsion system and ship. ..(contd)




services has obvious advantages, but this would have to be a fixed voltage and frequency system to satisfy the requirements of the ship service loads. The provision of high power variable speed drives from a fixed voltage and frequency supply has always presented problems. Also, when the required propulsion power was beyond the capacity of a single d.c. motor there was the complication of multiple motors per shaft. .(contd)



A Typical Layout HV Propulsion System




Developments in high power static converter equipment have presented a very convenient means of providing variable speed a.c. and d.c. drives at the largest ratings likely to be required in a / marine propulsion system.

The electric propulsion of ships requires electric motors to drive the propellers and generator sets to supply the electric power. It may seem rather illogical to use electric generators, switchgear and motors between the prime-movers (e.g. diesel engines) and propeller when a gearbox or length of shaft could be all that is required.

..(contd)




There are obviously sound reasons why, for some installations, it is possible to justify the complication of electric propulsion:

1. Flexibility of layout 2. Load diversity between ship service load and

propulsion 3. Economical part-load running 4. Ease of control 5. Low noise and vibration characteristics



FLEXIBILITY OF LAYOUT

The advantage of an electric transmission is that the prime-movers, and their generators, are not constrained to have any particular relationship with the load as a cable run is a very versatile transmission medium. In a ship propulsion system it is possible to mount the diesel engines, gas turbines etc., in locations best suited for them and their associated services, so they can be remote from the propeller shaft. Diesel generator sets in containers located on the vessel main deck have been used to provide propulsion power and some other vessels have had a 10 MW generator for ship propulsion duty mounted in a block at the stern of the vessel above the ro-ro deck. Another example of the flexibility provided by an electric propulsion system is in a semi-submersible, with the generators on the main deck and the propulsion motors in the pontoons at the bottom of the support legs.



LOAD DIVERSITY Certain types of vessels have a requirement for substantial amounts of electric power for ship services when the demands of the propulsion system are low. Tankers are one instance of this situation and any vessel with a substantial cargo discharging load also qualifies. Passenger vessels have a substantial electrical load which, although relatively constant, does involve a significant size of generator plant. There are advantages in having a single central power generation facility which can service the propulsion and all other ship loads as required.



ECONOMICAL PART-LOAD RUNNING

Again this is a concept that is best achieved when there is a central power generation system feeding propulsion and ship services, with passenger vessels being a good example.

It is likely that a typical installation would have between 4-8 diesel generator sets and with parallel operation of all the sets it becomes very easy to match the available generating capacity to the load demand. In a four engine installation for example, increasing the number of sets in operation from two that are fully loaded to three partially loaded will result in the three sets operating at a 67% load factor which is not ideal but also not a serious operating condition, It is not necessary to operate generating sets at part-load to provide the spare capacity to be able to cater for the sudden loss of a set, because propulsion load reduction may be available instantaneously, and in most vessels a short time reduction in propulsion power does not constitute a hazard. 5/17/2014 52



The propulsion regulator will continuously monitor the present generator capability and any generator overload will immediately result in controlled power limitation to the propulsion motors. During manoeuvring, propulsion power requirements are below system capacity and failure of one generator is not likely to present a hazardous situation.



EASE OF CONTROL

The widespread use of controllable pitch propellers (cpp) has meant that the control facilities that were so readily available with electric drives are no longer able to command the same premium. Electric drives are capable of the most exacting demands with regard to dynamic performance which, in general, exceed by a very wide margin anything that is required of a ship propulsion system.



LOW NOISE

An electric motor is able to provide a drive with very low vibration characteristics and this is of importance in warships, oceanographic survey vessels and cruise ships where,/-for different reasons, a low noise signature is required. With warships and survey vessels it is noise into the water which is the critical factor whilst with cruise ships it is structure borne noise and vibration to the passenger spaces that has to be minimised.



For very high power, the most favoured option is to use a pair of high efficiency, high voltage a.c. synchronous motors with fixed pitch propellers (FPP) driven at variable speed by frequency control from electronic converters. A few installations have the combination of controllable pitch propellers (CPP) and a variable speed motor. Low/medium power propulsion (1-5 MW) may be delivered by a.c. induction motors with variable frequency converters or by d.c. motors with variable voltage converters.

5/17/2014 56



The prime-movers are conventionally constant speed diesel engines driving a.c. generators to give a fixed output frequency. Gas turbine driven prime- movers for the generators are likely to challenge the diesel option in the future. Conventionally, the propeller drive shaft is directly driven from the propulsion electric motor (PEM) from inside the ship. From experience obtained from smaller external drives, notably from ice-breakers, some very large propulsion motors are being fitted within rotating pods mounted outside of the ships hull. These are generally referred to as azipods , as the whole pod unit can be rotated through 360 to apply the thrust in any horizontal direction, i.e. in azimuth. This means that a conventional steering plate and stern side-thrusters are not required. 5/17/2014 57



Ship manoeuvrability is significantly enhanced by using azipods and the external propulsion unit releases some internal space for more cargo/passengers while further reducing hull vibration. Gradual progress in the science and application of superconductivity suggests that future generators and motors could be super-cooled to extremely low temperatures to cause electrical resistance to become zero.



Integrated electric-drive system derived from a commercially available system that has been installed on ships such as cruise ships requires a technology that is more torque-dense (i.e., more power-dense) . Candidates for a more torque-dense technology include a permanent magnet motor (PMM) and a high-temperature superconducting (HTS) synchronous motor. In addition, electric drive makes possible the use of new propeller/stern configurations, such as a podded propulsion ... that can reduce ship fuel consumption further due to their improved hydrodynamic efficiency





- Podded drives offer greater propulsion efficiency and increased space within the hull by moving the propulsion motor outside the ships hull and placing it in a pod suspended underneath the hull. - Podded drives are also capable of azimuth improving ship maneuverability. Indeed, podded drives have been widely adopted by the cruise ship community for these reasons. - The motors being manufactured now are as large as 19.5 MW, and could provide the total propulsion power. 5/17/2014 60



Azipod drive unit



Propulsion motor For efficient operation of propulsion motor there is a

requirement for a compact, power dense, rugged electrical machine to be utilized for the propulsion motor. For the full benefits of electric propulsion to be

realized the machine should also be efficient, particularly at part load, In order to achieve suitable compact designs rare

earth permanent magnet materials may be required. The machine topologies available for PMM are

deemed to be those based on radial, axial and transverse flux designs.



PMM



Marine Electric Propulsion Due to its flexibility, energy efficiency and superior performance, electric propulsion is widely used in today's marine technology Functionally the propulsion drive can be divided into following parts : supply transformer, propulsion motor and frequency converter. - In an AC drive, a frequency converter is used to control the speed and torque of electric motor. The speed of the AC electric motor can be controlled by varying the voltage and frequency of its supply. A frequency converter works by changing the constant frequency main electrical supply into a variable frequency output. - The ideal simplicity of the induction motor, its perfect reversibility and other unique qualities render it eminently suitable for ship Propulsion. 5/17/2014 64



Electric propulsion - Diesel-Generator sets to produce electricity to common grid for propulsion and ship use. - Variable speed drives to rotate fixed pitch propellers. - Commonly used in Cruise vessels, LNG tankers, Off-shore vessels and Ice breaking vessels due to reduced fuel oil consumption, lower emissions and increased pay-load



Generator system of Conventional Cargo Ships

Electricity demand is small. 2 Generators are equipped. Only one set of either is usually operated.

Gen.

Gen.

Laod A

Laod B

Laod C

440V, 60Hz

Laod D

220V/110V

Photo from 5/17/2014 66



Features

Very big (24m, 15m) Super heavy (2000 ton) High Power (60,000 kW) High Efficiency ( over 50% )

Large Diesel Engine for Main Engine

Photo from

Cleaner transport



Configuration of Electric Propulsion

System for Ships

Gen.

Gen.

Laod A

Laod B

Laod C

Laod D

Main Engine

Propeller



Configuration of Electric Propulsion System for Ships

Gen.

Gen.

Laod A

Laod B

Laod C

Gen.

Gen.

Power

Converter

Power

Converter

Motor

Motor




Gen.

Gen.

Laod A

Laod B

Laod C

Gen.

Gen.

Power

Converter

Power

Converter

Motor

Motor




Gen.

Motor speed can be controlled by the frequency of electric power.

Generator outputs constant frequency (60Hz) Power converter supply suitable frequency and demanded

power

Gen.

Power

Converter Motor

Speed Control

by frequency

Constant

Frequency 60 frequency for

control




Gen.

Gen.

Power

Converter Motor

Power Converter

Converter 60Hz AC DC

Inverter

DC Various frequency AC




System for Ships

Gen.

Gen.

Laod A

Laod B

Laod C

Gen.

Gen.

Power

Converter

Power

Converter

Motor

Motor

Harmo c Distor




System for Ships Special

Transformer for

Power rter

Gen.

Pow

Conver

Gen.

Pow

Conver Gen.

Laod A

Laod B

Laod C Gen.

er

ter Motor

er

ter Motor

Photo from 5/17/2014 74



Comparison with Conventional and

Electric Propulsion system

Gen.

Gen.

Laod A

Laod B

Laod C

Gen.

Gen.

Power

Converter

Power

Converter

Motor

Gen.

Gen.

Laod A

Laod B

Laod C

Laod D

Main Engine

Propeller



Twin Shaft EL Propulsion



FPSO Electrical system Layout



Shuttle Tanker Electrical System Layout



Shuttle Tanker Electrical Line Diagram



Drill Ship Electrical System Layout



Typical system of all electrical ship Generator sets complete with prime movers and engine controls HV/LV Switchboards, distribution systems and group starter boards Propulsion and thruster motors complete with power electronic variable speed drives

Power conversion equipment Shaft braking Power factor correction and harmonic filters (as necessary) Power management Machinery control and surveillance Dynamic positioning and joystick control Machinery control room and bridge consoles Setting to work and commissioning Operator training 5/17/2014 81



THE FUTURE Propulsion of ships by help of standard diesel engines

usually gives a non-optimal utilization of the energy. Today an increased use of diesel electrical propulsion of

ships can be seen. New power electronics and electrical machines will be developed for propulsion and thrusters, as well as other application on board. Knowledge has to be developed about how such large

motor drives will influence the autonomous power systems on-board. Even development of new integrated electrical systems

for replacement of hydraulic systems (top- side as well as sub-sea) are becoming areas of need.



To introduce solar energy to the ship we need to convert the solar energy to electrical energy. electrical energy we can use and transport throughout the ship. photo-voltaic cells convert solar into electrical energy. An inverter is needed to convert the direct current (dc) to an alternating current (ac), so the 50 or 60 hz electric grid can transport the electrical energy through the ship. These energy conversions reduce the efficiency of the whole chain.

With a dc grid in a diesel-electric propulsion system less energy conversions are needed, There is no need for bulky transformers.




Ships also can benefit from the sun. The deck of a ship is always outside in the sun. With a deck area of more than 9000 square meters for a Panamax sized ship, a lot of energy can be harvested for free. With increasing PV-panel efficiency and decreasing cost due to mass production, solar energy can be beneficial next to existing ways to produce electrical energy. There are of course some challenges to overcome before integrating solar energy on a ship, but the maritime industry is driven by innovation to come with clever solution.

Ship already sailing solely on solar energy is the planet solar. With its 500 square meters of solar panels and large li-ion battery, it is accomplishing a journey around the world.




Sail and solar power ship



SKYSAIL TECHNOLOGY



POWERFUL - UNLIMITED - FREE

Wind is the cheapest, most powerful, and greenest source of energy on the high seas. Now, with SkySails, modern cargo ships can use the wind as a source of power not only to lower fuel costs, but significantly reduce emission levels as well.

SKYSAIL TECHNOLOGY



The worldwide patented SkySails propulsion system consists of three main components: a towing kite with rope, a launch and recovery system, and a control system for automated operation.

SkySails can be installed effortlessly as an auxiliary propulsion system on both new builds and existing vessels.

The SkySails propulsion system is efficient, safe, and easy to use and the fact that wind is cheaper than oil makes SkySails one of worlds most attractive technologies for simultaneously reducing operating costs and emissions.

SKYSAIL TECHNOLOGY



Reference Articles, Books and Websites: 1. Electric Propulsion Systems for Ships by Dr. Hiroyasu Kifune 2. Practical Marine Electrical Knowledge by D.T. Hall 3. www.vht-online.de (Speech by Bernd Rder) 4. www.imtech.com 5. www.skysail.info

5/17/2014 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh 90

Any Question?

Thank you!

5/17/2014 Mohd. Hanif Dewan, Chief Engineer and

Maritime Lecturer & Trainer, Bangladesh 91

Documents

Marine Propulsion History and Electric Propulsion Future Technology.pdf