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    THE LARGER LNG CARRIER (145,000 m3TYPE)AIMING AT LOW OPERATION COST

    UN METHANIER DUNE PLUS GRANDE CAPACITE (TYPE 145000 m3) VISANT A LA REDUCTION DU COUT DEXPLOITATION

    Keiji MiyashitaManager, Initial Planning Section

    Kazuya KobayashiSenior Manager, Initial Planning Section

    Yuukichi TakaokaManager, Structure Planning Section

    Kazuyuki EbiraAssistant Manager, Hydrodynamics Section

    Yoshihiko TomaAssistant Manager, Machinery Planning Section

    Masaji KuboAssistant Manager, Electrical Planning SectionInitial Design Department, Kawasaki Shipbuilding Corporation

    1-1 Higashi Kawasaki-cho 3-chome, Chuo-ku, Kobe 650-8670 [email protected], [email protected]

    ABSTRACT

    Kawasaki Shipbuilding Corporation built a 145,000 m3type LNG carrier named En-

    ergy Frontier and delivered her to the Owner, Tokyo LNG Tanker Co. Ltd., in September

    2003. Energy Frontier was the first one of Kawasakis latest developed LNG carriersaiming at high transportation performance and low life cycle cost. The Ship is positioned

    as a new global standard of latest LNG carriers in the following points.

    The Ship has a tank capacity as large as 145,000 m3 in consideration of the largest

    hull size (Japan Max Size) for an LNG carrier to be allowed to enter Tokyo Bay. The

    four-tank design of Moss type, which is free from partial filling restrictions, is adopted

    for the Ship, and a new hull form was developed on a novel concept so as to realize a

    great improvement in the propulsive performance. To ascertain effects of wind in

    Moss-type LNG ships, a large-scale wind tunnel test was carried out.

    The tank insulation system with the worlds lowest boil-off rate of 0.1 %/day andnewly developed IAS (Integrated Automation System) for the operation of cargo handling

    and steam turbine plant are adopted as well.

    RESUME

    Kawasaki Shipbuilding Corporation a construit un mthanier de type 145 000 m3bap-

    tis Energy Frontier et la livr au client, Tokyo LNG Tanker Co. Ltd., en septembre

    2003. Energy Frontier est le premier navire de la dernire srie de mthaniers dvelop-

    pe par Kawasaki avec objectif dobtenir une haute performance de transport et de r-

    duire le cot de cycle de vie. Ce navire est considr comme standard mondial des

    derniers mthaniers pour les points mentionns ci-dessous.

    CONTENTSSESSIONS

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    Le navire a une capacit de stockage de 145 000 m3, la plus grande capacit possible

    compte tenu des dimensions maximales de la coque (Japan Max Size) imposes aux m-

    thaniers pour avoir accs la Baie de Tokyo. Le navire adopte la conception du type

    Moss quatre cuves, qui est exempte des restrictions pour le remplissage partiel, avec

    une nouvelle forme de coque mise au point sur un nouveau concept pour raliser une

    grande amlioration dans la performance de propulsion. Afin de vrifier les effets du ventsur les mthaniers du type Moss, des essais en soufflerie grande chelle ont t effec-

    tus.

    Un systme de calorifugeage de cuves permettant un taux dvaporation de 0,1%/jour,

    valeur la plus faible au monde, ainsi que le systme IAS (Systme dAutomatisation

    Intgr) nouvellement dvelopp pour la manutention de la cargaison et la manipulation

    des turbines vapeur sont galement adopts.

    FEATURES OF S. S. ENERGY FRONTIER

    Cargo Tank Volume (145,000m3)

    In order to decrease the LNG transportation cost of a single vessel, it is effective to

    increase the quantity of transporting cargo on each voyage on a large-size LNG carrier.

    An increase in the size of the LNG carrier needs to secure the safety of the LNG cargotank structure and ship operation as major premises. In addition, it is necessary to ensure

    the compatibility of the vessel to existing LNG terminals. In the case of service to Japan

    as a present major market of LNG, in particular, a displacement limit of 105,000 tons

    must be taken into consideration as a condition of compatibility to the LNG terminals

    within Tokyo Bay. That is, very strict restrictions are imposed on the enlargement of the

    LNG carrier. The subject vessel was developed as an LNG carrier in Japan Max size in-

    corporating Moss type spherical tanks with a cargo capacity of 145,000 m3, which is

    compatible to overseas major loading/discharging terminals as well.

    CONTENTSSESSIONS

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    Table 1. Principal Particulars of Energy Frontier

    Length overall 289.53 m Designed ship speed 19.5 knots

    Length p.p. 277.00 m Main turbine 1 x Kawasaki UA-400Breadth moulded 49.00 m Max. cont. output 26,900 kW x 80 rpm

    Depth moulded 27.00 m Main boiler 2 x Kawasaki UME

    Draught moulded 11.404 m Max. evaporation 56,000 kg/h/setDeadweight 71,642 t Tank insulation

    Kawasaki Panel Sys-

    tem

    Displacement 104,998 t Boil-off rate 0.10%/day

    Gross tonnage 119,381 Tons Cargo pump 8 x 1,500 m3/h

    Cargo capacity 147,598 m3 Spray pump 4 x 50 m3/h

    (-163oC, 100% full, excl. dome volume) H/D compressor 2 x 32,000 m

    3/h

    Cargo tank 4 x Moss type L/D compressor 2 x 6,700 m3/h

    Figure 1. General Arrangement of Energy Frontier

    Four-tank Design

    It is effective to reduce the number of various cargo equipment by decreasing cargo

    tank numbers for the simplification of cargo operation and reduction of maintenance cost

    of LNG carriers. Conventional large-size LNG carriers used to incorporate five tanks. For

    improvement in the operation and maintainability of this LNG carrier, the vessel adopted

    a design of four tanks. Furthermore, all of these tanks are the same in diameter and ca-

    pacity for the simplification of cargo operation.

    Excellent Propulsive Performance

    Due to the design of four tanks adopted, the tank diameter is larger than that of ves-

    sels designed with five tanks. Therefore, this LNG carrier has large breadth comparativeto the ship length. Generally, a vessel with relatively large breadth is disadvantageous

    from a viewpoint of propulsive performance. With improvement in the hull form, the

    adoption of low-rotation and large-diameter propeller, and the employment of a en-

    ergy-saving device, the LNG carrier achieved great improvement in propulsive perform-

    ance.

    Low Boil-off Rate

    It is possible to reduce loss of LNG at sea by reducing boil-off gas generated during

    the voyage. This vessel adopted the Kawasaki Panel System for heat insulation, which

    was originally developed by Kawasaki. Therefore, the boil-off rate of the LNG carrier

    CONTENTSSESSIONS

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    attained the world's minimum value of 0.10%/day while the boil-off rate of standard LNG

    carriers is 0.15%/day.

    Compatibil ity to LNG Terminals

    Recently, there has been an increasing tendency for the employment of LNG carrierson a spot basis. Consequently, LNG carriers compatible to as many LNG terminals as

    possible are in demand.

    In order to secure the compatibility of an LNG carrier to a terminal, precise checks

    are necessary. These checks need to be made on not only the major dimensions, such as

    the length overall, width, draft, and displacement, but also the contact conditions of the

    ship flat side and the fenders of the terminal, mooring arrangement, calculation of moor-

    ing force, manifold operating range, flanges, loading and discharging rates, gangway lo-

    cation, and ship-to-shore communications equipment. In some cases, the changes of the

    design and layout are required.

    At the designing and building stage of the Energy Frontier the compatibility of thevessel was secured with eight LNG loading terminals and 20 LNG discharging terminals

    where the cargo operation of the vessel was expected. Five of these LNG discharging

    terminals were located outside Japan.

    When contracts for sister ships were entered, the compatibility of another LNG load-

    ing terminal and 10 other terminals outside Japan was checked and secured in addition to

    the above terminals.

    Long-life Design

    The structure of this LNG carrier was designed to withstand a fatigue life of 50 yearssufficiently with cargo loaded on the worldwide sailing basis.

    The paint specifications of the LNG carrier were decided by considering the long op-

    erating life. Special attention was paid to the specifications of the paint on the hull shell

    and ballast tanks, in particular.

    From a corrosion preventive viewpoint, pipes are distributed to the hull part through

    the under-deck passageway as much as possible with a reduction of exposed pipes. Anti-

    corrosive material, such as stainless steel (SUS316L), is applied to pipes that require ex-

    posure portions for the purpose of operation.

    Environmental Aspect

    LNG carriers are dedicated to the transportation of LNG as an environment-friendly

    fuel. Such vessels need to be suitable to the environment. The following countermeasures

    are taken to this LNG carrier.

    A reduction of fuel consumption is made with improvement in propulsive effi-

    ciency.

    Anti-fouling paint of tin-free type is used for the hull.

    The outflow of fuel oil is prevented with the double-hull construction of the fuel

    oil tank.

    The air conditioners and inert gas generator uses HFC (Hydrofluorocarbon),which causes no problems in ozone layer depletion.

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    A stern tube sealing of air type is adopted, which causes no oil pollution prob-

    lems.

    A system to perform a sequence of ballast water exchange automatically is incor-

    porated to reduce the harmful aquatic organisms and pathogens in the water.

    HULL FORM DEVELOPMENT AND PROPULSIVE PERFORMANCE

    This LNG carrier has excellent propulsive performance the same as or better than

    conventional 135,000-cubic-meter LNG carriers of five tanks by conquering the

    disadvantageous conditions of the relatively large breadth peculiar to vessels designed

    with four tanks. The design of the LNG carrier was based on the hull form design

    development technology of Kawasaki and its abundant experience in the construction of

    vessels.Specifically, the following measures achieved great improvement in the performance

    of the vessel.

    Hull FormCompared with a five-tank system, a four-tank system makes it possible to shorten the

    length overall of the LNG carrier from a view point of tank arrangement. The length

    overall of this LNG carrier was, however, extended to the permissible berthing limits of

    the LNG terminals for improvement in the propulsive efficiency. Therefore, the hull form

    design can be flexible for improvement of propulsive performance.

    Improved Bow and Stern Form

    For the purpose of reducing the wave resistance of the hull by taking advantage of the

    flexible designing of the hull form, bow and stern form was developed by carrying out

    model tank test and CFD (Computational Fluid Dynamics) analysis. As a result, the waveresistance of the LNG carrier was reduced to half of that of 135,000-cubic-meter LNG

    carriers incorporating a five-tank system. Figure 2 is a result of wave patter obtained by

    CFD.

    Figure 2. Wave Profile Obtained by CFD

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    Adoption of Large Diameter Propel ler

    Kawasaki Heavy Industries as a steam turbine manufacturer used its high technology

    to develop a low-rotation and high-torque reduction gear. Furthermore, the LNG carrier

    adopted a low-rotation and large-diameter propeller as well, which greatly improves the

    propulsive efficiency.

    Adoption of RBS-F MkII

    As an energy-saving device, the RBS-F (Rudder Bulb System with Fins) MkII, as

    shown in the Figure 3, was adopted for improvement in the propulsive performance sav-

    ing of energy loss of the rotational flow of propeller downflow. The RBS-F [1] has been

    adopted by 80 or more tankers, container ships and other types of vessels.

    Figure 3. Kawasaki RBS-F MkII

    Reduction of Propeller Exciting ForceThe following measures are taken for a reduction of pressure exciting force to reduce

    the vibration of the hull structure.

    (1) With the development of the stern form, the flow field of the stern was improved

    and the cavitation of the propeller was decreased for a reduction of propeller ex-

    citing force.

    (2) A high skewed propeller was adopted for a further reduction of propeller excit-

    ing force.

    (3) In order to reduce the propeller surface force and reduce the vibration of the hull

    structure, KAWASAKI DAMP TANK [2] was installed just above the propeller.

    MANEUVERABILITY

    For the enlargement of the form of a vessel, it is necessary to examine whether the

    size of the vessel has any problem in maneuverability.

    In comparison with an LNG carrier designed with five 135-type tanks, the length

    overall of this LNG carrier is shorter, which is advantageous from a navigational view-

    point. Due to large-sized tanks, however, there is an increase in an area, on which the

    wind force is imposed. To know the influence of the wind force on the LNG carrier,

    which is an important factor while the LNG carrier is in ship operation or at berth, a wind

    tunnel test using a model ship was conducted.The dimensions and photo of the model ship used in the test are shown below.

    CONTENTSSESSIONS

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    Table. 2 Particulars of Model Ship

    Actual Ship Model Ship

    Scale (Base) 1/193Length overall 289.5 m 1.500 m

    Breadth 49.0 m 0.253 m

    Lateral Area 8,620 m2 0.23 m2

    Front Area 1,940 m2 0.05 m2

    Figure 4. Photo of Model Ship

    As shown in the graph of the result of the wind tunnel test(Figure 5), when the wind

    is in the direction to the starboard side, the lateral wind force coefficient is smaller than

    that in the wind direction to the port side. This is due to the influence of the vertical wallof the cargo machinery room on the starboard side.

    -1.50

    -1.00

    -0.50

    0.00

    0.50

    1.00

    1.50

    -180 -150 -120 -90 -60 -30 0 30 60 90 120 150 180

    AWind angle (deg.)

    Wind

    ForceCoeff.

    (Cy)

    A

    Fy

    Wind

    (Wind from starboard side) (Wind from portside)

    Figure 5. Result of Wind Tunnel Test (Lateral Wind Force Coefficient: Cy)

    In comparison with the lateral wind force coefficient reported by the collaboratedpublication of OCIMF and SIGTTO [3], the peak values in the wind direction to the beam

    on the starboard side and port side are as small as 68% and 76%, respectively. The reason

    is that old Moss type LNG carriers have semi-cylindrical tank covers while recent Moss

    type LNG carriers including this vessel have semi-spherical tank covers, the lateral wind

    force coefficient of which is smaller. Therefore the lateral wind force coefficient of the

    entire vessel decreased.

    So, Moss type LNG carriers of recent design and Membrane type LNG carriers have

    no difference in total wind force.

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    (An Old LNG Carrier) (A Latest LNG Carrier)

    Figure 6. Comparison of Tank Cover Shapes

    HULL STRUCTUREFatigue Design

    Recently, there has been an increase in shipowners' concern over the longer operating

    life of hull structures.

    Fatigue strength analysis of hull structure was carried out by FE (Finite Ele-

    ment)-Analysis of a large scale FE-model for the stress concentrated parts, such as con-

    nection parts between the cargo tank skirts and foundation decks and between inner

    bottoms and bilge hopper plates, embedded as fine mesh FE-models.

    Figure 7 shows an example of the finite element model and Figure 8 shows a result of

    the FE-analysis of the stress concentrated part in a hold structure.

    Figure 7. Example of Finite Element Model

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    Figure 8. Results of FE-Analysis at Stress

    Concentrated Part in Cargo Hold

    Kawasaki Apple Slot [4], which enhances fatigue life comparing with the conven-

    tional slot structure, was applied to the penetrating parts of the longitudinals to the trans-

    verse webs in water ballast tanks. Figure 9 shows a comparison of Kawasaki Apple Slot

    and the conventional slot structure. In addition, back brackets were provided on the con-

    nection parts between the longitudinals and the transverse bulkheads for the enhancementof fatigue life by the results of FE-Analysis for the stress concentration parts of longitu-

    dinals as shown in Figure.10.

    Figure 9. Comparison of Kawasaki Apple Slot

    and Conventional Slot Structure

    Figure 10. Results of FE-Analysis at Stress Concentrated

    Part of Longitudinal Members

    Design fatigue life for hull structure could be confirmed to exceed 50 years for

    worldwide sailing basis by the above consideration from the structural viewpoints.

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    Fatigue Damage Monitoring

    The LNG carrier was designed to be satisfied with the required fatigue life for hull

    structure. In addition, five typical stress concentrated parts of hull structure were selected

    in order to monitor their fatigue damages actually accumulated during operation. A sub-

    miniature high-sensitive fatigue-detecting sensor of crack gauge type (see Figure 11) de-veloped by Kawasaki Heavy Industries Ltd. was attached to each of them [5].

    Figure 11. Plan View of Newly Developed Fatigue Detecting Sensor

    The fatigue-detecting sensor ensures ease of installation for the estimation of the fa-

    tigue life of structural members. The sensor has the following principle.

    The sensor makes use of crack propagation characteristics of metal foils. The gauges

    directly attached by spot welding or with an adhesive to the stress concentrated parts of

    the structural member will pick up fluctuating stress histories of the members resulting in

    crack propagation from the slit edges of metal foils on the sensors even if crack initiation

    on the members is not observed. (See a in Figure 11 showing the crack propagation

    length) Fatigue cumulative damages of the sensing structural members can be evaluated

    by analysis of the crack propagation lengths on the gauges measured directly, or indi-

    rectly with a replica method application.

    Cumulative fatigue damages for stress concentrated parts of hull structure can be

    known by checking those for the sensing parts.

    CARGO TANK DESIGN AGAINST SLOSHING LOAD

    In order to estimate the sloshing load precisely at the cargo tank design stage, a nu-

    merical analysis of the sloshing of the spherical tank [6] was made by using CFD (Com-putational Fluid Dynamics) in addition to the conventional designing method. The design

    load of spherical tank against sloshing was estimated by computing the pressures on the

    pipe tower and on the spherical shells when the severest sloshing occurs due to the ship

    motion by using CFD. Figure 12 shows an example of the simulation results of sloshing

    at LNG half loaded.

    As a result of the numerical analysis, the conventional sloshing load estimation

    method for the Moss type spherical tank was confirmed to be reasonable.

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    Figure 12. Sloshing Motion Analysis at Half Loading by CFD

    CARGO TANK CONSTRUCTION

    Improvements in Non-destructive Test

    Non-destructive testing on the welding joints of each Moss type spherical tank was

    conducted during construction to maintain the high quality control for the spherical tank.

    Kawasaki newly developed two types of ultrasonic flaw detection systems in order to

    realize improvement in the safety of the non-destructive testing on the welding joints of

    the spherical tank along with the improvement of reliability and the contraction of thetime required for the testing [7].

    The automated ultrasonic inspection system (named Kanitaro) was applied to the

    weld joints of the hemi-spherical assembly. This system uses pulse echo technique.

    For the equator joints and the grand assembly joints of the hemisphere and equator

    where the application of pulse echo technique was difficult due to differences in plate

    thickness and space restrictions, the multi-channel TOFD (Time of Flight Diffraction)

    system named Tofuzowas applied, which adopts a system of highly precisely measur-

    ing the position and height of each flaw from the flight time of the upper and lower tips

    echo of the flaw.

    In both systems, the scanner runs on the guide rail, and the results of inspection are

    recorded and managed in a PC. It was difficult to record objectively monitor on conven-

    tional ultrasonic testing method. These new systems make it possible to record results of

    inspection objectively.

    The application of the automatic ultrasonic inspection system, Kanitaroas one of

    the above systems are shown in Figure 13. These systems have flaw detection perform-

    ance the same as or higher than that of the conventional ultra sonic testing method. In ad-

    dition, these systems are not influenced by the skills of inspectors, and the automatic

    recording of inspection results and stable detectabilty of flaw were realized, which im-

    proved the reliability and traceability of the testing.

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    Figure 13. Inspection of Hemisphere Assembly Weld Joints with Kanitaro

    Improvement of Production Facility

    Kawasaki newly introduced two gantry cranes each with a lifting capacity of 800 tons,

    which is the highest lifting capacity in Japan. These cranes made it possible to mount the

    completed Mosstype aluminum spherical tanks to the hull on the construction dock effi-

    ciently.

    It became possible to complete the spherical tanks on the ground where good working

    conditions were secured because the cranes allowed the installation of the full assemblies

    of the spherical tanks as they were. This fact not only shortened the fabricating time re-

    quired but also improved the quality control of the tanks and the safety of work.

    Figure 14 shows a gantry crane mounting a completed cargo tank.

    Figure 14. Completed Cargo Tank Installed onto

    Ships Hull under Construction

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    CARGO TANK INSULATION: KAWASAKI PANEL SYSTEM

    The Kawasaki Panel System is a heat insulation system for spherical cargo tank

    originally developed by Kawasaki. The system was adopted for the first time by the "Go-

    lar Spirit," which was the first LNG carrier constructed by Kawasaki. Since then, the sys-

    tem had been adopted by 30 vessels for 22 years by the end of 2003. The system achievedgood service results.

    Features of Kawasaki Panel System

    The Kawasaki Panel System has the following excellent features of a panel structure,

    panel mounting method, and the integration of each panel. Consequently, the heat insula-

    tion performance of the system is high. Furthermore, the system is sturdy and reliable.

    The low temperature side (inner side layer) and normal temperature side (outside

    layer) of the heat insulation panel consist of a PRF (Phenolic Resin Foam) layer and PUF

    (Poly-Urethane Foam) layer, respectively. A wire net is inserted between the PRF layer

    and PUF layer for the prevention of crack damage to the heat insulation layer. The PRFand wire net are firmly integrated as a result of the self-adhesiveness of the PUF in a state

    of foaming.

    The panel is firmly secured on the surface of the tank with fastening bolts studded on

    the tank surface and plastic washers.

    The PUF layer of each panel is a size smaller than the PRF layer. A joint is formed

    between PUF layers. By injecting PUF into the joints in the yard, the panels are coupled

    together and the insulation layer became a perfect shell structure.

    The 0.1%/day heat insulation system for Energy Frontier has a thickness of 320

    mm.

    Figure 15. Insulation Panel Allocation Figure 16. Insulation Panel

    Insulation Work

    Heat insulation panels are manufactured in the factory of a heat insulation manufac-

    turer, stored in containers, and delivered to the shipyard. Insulation work on cargo tanks

    is conducted by using rotating-type material transfer equipment also used as a scaffold

    while the cargo tanks are covered with tank covers.

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    In the major processing stages in the shipyard, the tank surfaces are marked off, fas-

    tening bolts for mounting the heat insulation panels are studded, the panels are mounted,

    PUF is injected to the joint of the panels, and surface material is installed for the joint.

    Figure 17. Revolving Type Scaffold Figure 18. Panel Carrier on Scaffold

    Study for Low Boil -off System

    If re-liquefaction plant of boil-off gas is installed on an LNG carrier in the future and

    a reduction of the boil-off rate is possible, the power of the vessel required for the plant

    can be reduced in proportion to the reduction of the boil-off rate.

    For example, if the BOR of an LNG carrier with a capacity of 145,000 m 3 is

    0.15%/day, the required power of the compressor for the refrigeration equipment and

    BOG compressor is a total of approximately 3,800 kW. On the other hand, if the BOR is

    0.10%/day, the power will be reduced down to approximately 2,300 kW, the merit ofwhich is high.

    Kawasaki will continue improvement in the system with a reduction of the boil-off

    rate.

    PROPULSION PLANT

    The steam turbine propulsion plant of this vessel is designed with the following points

    taken into consideration.

    Simplification of the system and less maintenance

    High efficiency

    High reliability

    The features of the propulsion plant of this vessel are shown below along with typical

    examples of the above.

    Heat Cycle

    The heat cycle of the propulsion plant is a regenerative economizer cycle for the pur-

    pose of the simplification of the components, a reduction of maintenance work, and im-

    provement in the efficiency of the plant. In the regenerative cycle, part of steam to drive

    the steam turbine is extracted from the turbine and used for heating of boiler feed waterand combustion air, etc. This cycle along with the economizer that uses the exhaust gas of

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    the boiler to heat the feed water contributes to improvement in the thermal efficiency of

    the plant. This vessel adopts a 2-stage feed water heating system with 3-point bleeding.

    Furthermore, for improvement in the thermal efficiency, the distilling plant is cooled

    down by condensed water.

    Main Turbine and Main Boi ler

    The steam turbine and boiler as the main equipment of this propulsion plant are both

    manufactured by Kawasaki Heavy Industries (KHI). The turbines and boilers of KHI

    have a history as long as approximately a century. Main turbines and boilers adopted by

    LNG carriers are developed by KHIs own unique technology. These main turbines and

    boilers have high performance and ensure high reliability. A large number of main tur-

    bines and boilers in LNG carriers built in the world are manufactured by KHI.

    Kawasaki UA turbine of double-reduction geared, two-cylinder cross compound im-

    pulse type is adopted for this vessel. Figure 19 shows an external and internal appearance

    of the turbine.

    Figure 19. Kawasaki UA Turbine

    Kawasaki UA turbine has the following features.

    (1) High-efficiency semi-curtis control stage which was developed by KHI is adopted for

    the high-pressure turbine.

    (2) The reduction gear adopts a tandem articulated type that is of simple structure with

    very high reliability.

    (3) A low-revolution, high-torque reduction gear was developed for this vessel and in-

    stalled for the purpose of decrease in the speed of propeller revolution for improve-

    ment of propulsive efficiency.

    (4) To ensure warm up of the turbine and save the operation work, a warming up system

    using super-heated steam was developed in cooperation with the shipowners.

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    (5) To reduce the electric power consumption, the scoop system is adopted for cooling the

    main condenser on normal sea going condition.

    Kawasaki UME boiler of two-drum, water tube, dual fuel burning type with the fol-

    lowing features is adopted for this vessel.

    (1) An easy-to-maintain economizer and a steam air heater are provided.

    (2) 9%Cr-1%Mo alloy steel is used for the superheater tube to prevent high temperature

    corrosion.

    (3) The internal desuperheater, which ensures ease of feed water quality control, is

    adopted for the temperature control of superheated steam.

    (4) The boiler is capable of burning only fuel gas during low load condition such as cargo

    loading/unloading as well as during normal load condition, which was considered

    technically difficult.

    (5) A differential pressure control system is adopted for the feed water flow rate control to

    reduce the required drive power of the feed water pump.(6) The KAPS (Kawasaki Automatic Power Control System), as highly reliable control

    equipment uniquely developed by KHI, is adopted.

    FEATURES OF ELECTRICAL AND AUTOMATION PART

    IAS (Integrated Automation System)

    The most significant feature of the electrical and automation part of the LNG carrier

    is the IAS (Integrated Automation System), which is installed in order to provide required

    and efficient control and monitoring of the machinery and cargo handling operation.

    The IAS was developed and manufactured by JRCS harmonizing the state of the art

    control technology of Kawasaki Heavy Industries, Ltd. and the know-how of Kawasaki

    Shipbuilding Corporation accumulated through the experiences of construction of LNG

    carriers over many years. The IAS is a highly reliable system with excellent cost per-

    formance, and has gained high evaluation from shipowners and each party concerned.

    (1) The HMI (Human Machine Interface) adopts 21-inch LCD touch panels. Each pre-

    senting screen of the IAS are functionally and systematically related with each other

    so that the operator can reach his desired graphical screens easily and quickly (user

    friendly). All operational control of the IAS including control parameter adjustment is

    possible on the touch panel. Therefore, no keyboard is provided.(2) The IAS has a fine self-diagnostic function and provides graphical screens showing

    the operating conditions of system components to an extent of each I/O point, so that

    the defective part can be detected with the operation of the touch panel. The IAS is a

    user-friendly system even in case of system failures. (See Figure 20 and Figure 21).

    (3) The IAS is based on a concept of distributed control system and consists of monitor-

    ing system that is developed for marine use and has a good result of operation for

    many years and control system using PLCs, which are integrated on a redundant

    high-speed computer network. No rotating memories are used in the system except

    historical data station, which are not suitable to the environment on board.

    (4) The IAS is powered by the ships battery sources of 24 VDC. No UPS is required.

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    (5) All the control functions of the IAS were verified prior to the delivery to the shipyard

    using a dedicated simulator that is developed based on the plant simulation technol-

    ogy accumulated through experience of a crew-training simulator for LNG carriers,

    one of the products of Kawasaki Shipbuilding Corporation. The verification included

    a variety of critical operational situations and the concerned representatives from

    Classification Society, Ship Owners and Shipyard checked for intended operation ofthe control system and confirmed that the safe operation of the machinery and cargo

    handling would be secured in case that any failure occurs.

    Further to abovementioned, a mimic panel incorporating valve control switches,

    pump start/stop buttons, indication lamps, and analog indicators is provided so that the

    control and monitoring of the cargo handling operation may be carried out in a state of

    emergency.

    Figures 20 and 21 Display Sample (PLC Trouble Shooting)

    Other Features

    Cargo Tank Level Gauge

    A radar-type level gauge is adopted as the main cargo tank level gauge for CTS (Cus-

    tody Transfer System) instead of a conventional capacitance-type level gauge.

    A radar-type level gauge has no electrical components or moving parts installed in

    cargo tank and then is serviceable/repairable without gas freeing of the cargo tank

    even in case that malfunction occurs.

    Navigation Bridge

    Additional rules of one-man bridge notation are applied and the integrated bridge

    console consisting of radars, ECDIS, conning information display, alarm transfer sys-

    tem, etc is installed in the front central of the navigation bridge. Besides, windows are

    provided around the navigation bridge to secure the horizontal field of vision to the

    horizon of 360 degrees, which contribute to safe navigation and reduction of work-

    load of the watch-officer.

    Ship/Shore Communication System

    The LNG carrier has a ship/shore communication system consisting of a pneumatic

    link, optical fiber link, radio link, and electrical wire link with several types of con-nectors for ESDS (Emergency Shut Down System), telephone systems, and mooring

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    load monitoring systems. This ship/shore communication system is compatible with

    almost all LNG terminals in the world.

    CONCLUSION

    The Energy Frontier is the most recent LNG carrier constructed by KawasakiShipbuilding Co. with its all construction technologies for LNG carriers injected. Kawa-

    saki developed time-proven technology and employed it along with new technology

    uniquely developed, and Kawasaki is convinced that these technologies will contribute to

    improvement in the transportation efficiency of LNG carriers of the same type that will

    be constructed in the future.

    ACKNOWLEDGEMENT

    We would like to express respect to the decision of Tokyo Gas and Tokyo LNG

    Tanker as the Shipowners of the Energy Frontier to construct the new-type LNG carrier

    for improvement in the efficiency of LNG transportation, and we are glad at their coop-eration in the betterment of the LNG carrier.

    We would also like to appreciate Mitsui O.S.K. Lines as the operator of the LNG car-

    rier that dispatched superintendents to the shipyard and gave us a number of appropriate

    instructions based on their abundant experience in the operation of LNG carriers.

    We would like to thank all the people related to the construction of the LNG carrier as

    well.

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    [3] Oil Companies International Marine Forum and Society of International Gas Tanker

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    [4] N. Kamoi, T. Taniguchi, T. Kiso, K. Kada and A. Kohsaka (1992),A New Structural

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