At present small- and medium-sized vessels under 2000G/T occupy 97.3% of the total number and 65% of the total gross tonnage of Japanese coastwise shipping, and they carry 65% of cargo volume (ton·kilometers) by homewaters. Firstly this report researches the present situation of the fuel consumption and reveals that those small- and medium-sized vessels consume about 80% of the fuels for the freight transportation by homewaters. Therefore small- and medium-sized vessels, especially cargo-boats and tankers, should be paid attention for the fuel economy. So secondly the actual condition of the transport energy efficiency of those vessels is researched. The three main factors, which determine the transport energy efficiency, that is, hull resistance, propeller efficiency, and payload-to-total weight ratio are discussed in regard to present vessels. The result shows there is some room for the improvement of about three main factors, especially, with respect to the hull resistance and the propeller efficiency. Finally the report estimates that, if the former would be reduced to the level estimated according to the Yamagata's method, and if, as for the latter, the propeller diameter would be increased so far as the after draught at ballast voyage permits, then the amounts of fuel consumption could be cut down to about 64% of the present one.

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Operating speed and actual fuel consumption are investigated and compared with design valve for new building ships equipped with medium speed engines.
Operating results of ships having low speed propellers show better performance compared with ships with normal propellers.
Actual saving of fuel oil consumed to generator engine for ships having exhaust gas economizer T/G system and availability of ships equipped with medium speed engines are investigated.

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At the point of marine engineering technology view, the shipping project is to be the kinetic energy planning.
To move the some weight cargo with the some speed, and to transport most economically from ports to ports, it should be studied the problem of kinetic energy, and we must consider that the shipping project must be the planning of the energy converting from thermal calorific fuel oil energy to the kinetic moving energy.
So, routine works of the shipping project to be the save energy planning.
And the practical work of the shipping project is to research what is the most efficient method to change the calorific energy of fuel oil unto the kinetic energy.
Thus, save energy planning to be the most important object for the shipping project.
At present, Diesel engine has the best thermal efficiency for the method of fabricating kinetic energy from fuel oil calorific energy.
But, at the recent oil crisis, we must consider more seriously the save energy plan at the standpoint of new circumstances.
Now, author presents following new save energy plans as the shipping technical references.
(1) Practical save energy plan for sailing
(2) Super sonic under water cleaning apparatus for the low speed large dia propeller.
(3) Emersion treatment method of more heavy C oil for marine Diesel engines.
(4) Super sonic filtering apparatus for catalysis powders of cracking residual heavy oil.
(5) Slow propulsion safety apparatus for main Diesel engine.

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Due to drastic soaring of fuel oil prices and petroleum supply crisis, the needs to review the effective use of oil have been the most important subject in the world shipping industries.
Under such circumstances, the conversion of steam turbine plants of existing VLCC or ULCC to more efficient internal combustion engines of the diesel type have been studied seriously and earnestly among ship owners of domestic and foreign countries.
Introduced as follows are the outline of IHI's recent achievement and experience of re-engine works of the “MOBIL HAWK”, one of the VLCC's owned by Mobil Shipping and Transportation Company, where the original 36, 000 SHP steam turbines were replaced successfully with two sets of new IHI-S.E.M.T. Pielstick 12PC4V medium speed diesel engines of 18, 000 PS each.

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Recently in addition to a steep rise of fuel oil prices starting from oil crisis of 1973, the world-wide demand for saving the oil resources have become strong and consequently the need of saving energy for ships increasingly has been raised.
There are following three items as the counterplan for saving energy of ships.
1) Reduction of the fuel oil consumption of main engine itself.
2) Advance of the efficiency of whole system by the waste heat utilization of the main engine or improvement of electric power consumption in the auxiliary equipments.
3) Reduction of propulsion power by advancing the efficiency of hull or propeller. Until present engine manufacturers and shipyards continuously have carried out the development research having an eye to those saving energy plants, and already it realized the remarkable improvement in aspect of reducing the fuel oil consumption of main engine.
Here we introduce counterplants for the low fuel oil consumption or the actual example of propulsion plant development mainly in the region of the medium speed diesel engine.

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To cope with the demand for energy saving on marine propulsion plant, many investigations had been carried out in concerned fields, then, as well known, new type of long-stroke, large-bore, marine diesel engines with low fuel consumption were developed and some sort of energy saving propulsion plant were published, and they are now in service.
We would like to mention, in this paper, various kind of measures applied on large-bore marine diesel engines to reduce fuel consumption through some examples on KSZ-C/CL type engines and also introduce the outline of our Kawasaki Super Economical Propulsion Plant (KSE plant) and its service experiences as an example of now used energy saving propulsion plants.

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It is essential, in the philosophy of energy saving ships, that the system to be proposed must keep proven reliability and stability or adaptability against various circumstance of ship's operation, such as grade of uel oil, quality and number of ship's crew, level of maintenance, course of ship and condition of sailing, etc.
Placing emphasis on this basic concept, Hitachi Zosen has developed a uel saving ship since 1976 which consists of the twin-bank engine, the low pressure turbo generator and the single-loop steering gear.
The newly developed twin-bank engine is the most reliable two-stroke, low-speed, crosshead type diesel engine together with reduction gear, enabling propeller to be selected at any rate of revolutions. Of the various advantages of the twin-bank engine, the most important ones are the capability of burning low-grade uel oil and compactness which allows smaller engine room space, even with cross-head type.
Also the newly developed turbo generator makes it possible to obtain the electric power needed on board and the stearing gear contributes to reduction of the propelling power loss.
Thus the reduction of uel consumption reach 20-35% in total.

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The main engine exhaust gas of motor ships has high heat content. The gas temperature is, however, fairly low, and in order to recover as much heat as possible, a multi-pressure steam generating system is effective. Mitsubishi Heavy Industries has developed the dual pressure steam generating plant which is practical and highly efficient in waste heat recovery. It is capable of supplying steam to generate the required shipboard electric power and ship service steam even with a main engine of less than 10, 000 PS.
This report describes the practicality, economy and construction of the dual pressure steam generating system, exhaust gas economizer and solid brushing soot cleaning device.

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Most of the super-economical ships adopt the low speed propeller which has prominent effect for energy saving and consequently the propeller shaft transmission torque and reduction ratio of the main reduction gear are much increased. In this case, the epicyclic gear is mostly adopted as the main reduction gear, because the feature of the epicyclic gear, its compactness and concentricity of input shaft and output shaft, is effective to reduce the length of the engine room.
Kawasaki has recently developed KSE plant (Kawasaki Super Economical plant) for the super-economical ship, and for this plant the epicyclic gear is adopted as the main reduction gear. We introduce Kawasaki-make epicyclic gear in this paper.

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We firstly introduce a variable speed pump system as an example of the energy saving in the ships and an outline of the development.
We chiefly mention in this paper the results of performance test of the first unit at sea trial and the actual running performance at the first voyage of the ship.
Furthermore, we refer to some notical points in case of the installation of this unit on board and the wide applications of this energy saving system.

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According to the recent forecast of a major oil company, the bunker fuel primarily used today, which is based on residual oil from atmospheric distillation, will be replaced in future by that based on residual oil from a thermal cracking process.
This report gives the details of an experimental investigation carried out on a four-stroke medium speed diesel engine using degraded fuels.
Fuels used for the investigation were as follows:
1. Standard Bunker Fuel - ordinary bunker fuel; used as a reference fuel
2. Degraded Bunker Fuel - based on visbreaker bottom oil
3. Degraded Bunker Fuel - based on fluid catalytic cracked bottom oil
4. Degraded Bunker Fuel - fuel which had caused excessive wear on the piston rings of a low speed two-cycle diesel engine in service.
5. Coal Tar - made by extracting light oil from crude coal tar obtained as a by-product from a coke furnace.
Results showed that no major difficulties arose when degraded bunker fuels were burned in a marine diesel engine, notwithstanding the complicated combustion mechanism.
However, since the results were obtained from a short term bench test, the authors were unable to determine the long term reliability and durability of marine diesel engines running on degraded fuel.

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In accordance with the recent tendency using the low grade fuel oil for marine use, the behavior of fire-side fouling has been a more important problem on the marine oil-fired boilers.
There are many problems to be considered for the fire-side fouling especially in using the low grade fuel oil, however the mechanism of the fouling on oil-fired boiler has been well established.
Generally the fire-side deposits are scaled off by water washing which occupies greater part of docking works.
For the purpose of reduction in the formation of fire-side deposits in view point of improving the combustion process due to the microexplosion phenomenon of water-in-oil emulsion, the water injection system was installed experimentally to the existing boiler on the turbine ship “KINKOMARU” which was put in service in 1972.
In this paper, the long-term investigation into the characteristic of fire-side deposits under the emulsified combustion extending over a period of 14 months was evaluated, comparing with the property prior to the installation of water injection system.
The following effects were obtained under the lower excess air combustion due to the emulsified combustion, which seemed to have a good influence for the fire-side fouling.
The water injection rate was maintained at 2% to the fuel oil flow in consideration of watersaving for marine use.
(1) Low level fouling was observed on furnace and superheater
(2) Easy scaling off of deposits on superheater
(3) Reduction in carbon monoxide (CO) concentration was measured.

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Thermal analytical technique as a tool to predict combustion behavior of coals has been developed and evaluated by several persons. They used derivative thermograviometric analysis (dTGA) to characterize and predict oxidation behavior of solid fuels by heating them at a fixed rate in an air atmosphere and recording the rate of weight change. A plot of the rate of weight loss as a function of furnace temperature has been termed a burning profile or a combustion profile. Differential thermal analysis (DTA) measured the temperature at which the fuel sample began to give off heat and identified the position of the burning profile representing oxidation.
In present paper, application of the technique to low grade fuels was evaluated. Samples were Bunker C fuel oil, Vacuum residual oil, Visbreaking oil, FCC oil and Coal-oil mixture.
Results showed that each fuel had its proper burning profile and by comparing it with the profile of well known fuel, combustion characteristics in practical use of new fuel was possible to predict.

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With the rapidly increasing fuel oil costs and the deteriorating fuel oil qualities, it is desired to burn heavy fuel on medium speed diesel engines of small and medium sizes.
Therefor, several tests were carried out in DAIHATSU DIESEL Mfg. Co., Ltd.
Bench test to burn heavy fuel on DS-32 engine was carried out in 1976. Satisfactory results in performance of the engine with various tests including continuous running was obtained.
Successively, actual field test to burn heavy fuel on same model of 6DSM-32 engine installed in “KYOKUSEI-MARU”was carried out with cooperation of ASAHI TANKER Co., Ltd. for two years from 1977 to 1979.
Furthermore, the burning test of the emulsified fuel, which is the mixture of heavy fuel and water, was carried out on 6DS-28 engine in 1978. This test is a part of the investigation projects of“The research committee for heavy fuel burning”consisting of N.Y.K. and M.H.I. for saving energy.
The results thus obtained shall be described in this article.

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During recent years, there has been a remarkable increase of using the Blended-Fuel of bunker C and marine diesel fuel on main generating small or medium-sized diesel engines to save the fuel cost.
These blending system in ship is one of the most effective way to use common bunker fuel oil both on main propulsion engine and on generator engines.
In this report, we describe the outline features of In-Ship Blending System, and some of the test results we obtained by running our small-sized and medium speed diesel engines (Cylinder bore: 200 mm and 240 mm) using blended fuel and bunker C fuel (RW No.1 1200 sec at 100°F) .

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Originally A fuel oil has been the main fuel for marine middle speed diesel generator, however from the fuel savings standpoint, test with low grade fuel oil are being considered and implemented.
Our company have started to cope with this problem for some time now, and have actually used A/C blend fuel oil for about 5 years and C fuel oil only for about 1 year and have achieved satisfactory result with both of them.
We therefore wish to relate our experience on the experiment conducted with low grade fuel oil where modifications were made on the engine and enterior equipment of the vessel as well as the current condition of the engine including the condition of the engine in operation and the result of the overhaul inspection as a reference in the event low grade fuel oil are used in the future.

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