A two-dimensional model of the Weis-Fogh mechanism, which is a mechanism of hovering flight of small insects, is applied to ship propulsion. A model of the propulsion mechanism consisting of one or two wings in a square channel is proposed. The thrust and the drag on the wing, which are defined, respectively, the force in the direction of progress of the ship and that of movement of the wing, are measured. The propulsive efficiency is calculated and is high when the moving speed of the wing is small compared with the advancing speed of the ship. A model ship equipped with this propulsion mechanism is made and working tests performed. The applicability of this propulsion mechanism to actual ships is expected to be good.

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To prevent the marine pollution from discharge of the harmful liquid cargo into the sea, reduction of the quantity of cargo remained in the tank after the unloading is required. The effectiveness of the method of gas blowing which is commonly applied to the present chemical tanker for minimizing the quantity of residue in the piping arrangement for the carriage of noxious liquid substances is examined. Characteristics of fluid flow and the quantity of residues during the processes of gas blowing in horizontal pipe using water and air as the working medium have been measured under various operational conditions and piping arrangements. The effects of experimental variables on them are investigated. It is suggested that gas blowing is an effective stripping method and discusses recommend-ed measures to reduce the quantity of the residue in the piping system.
The method for calculating the residues in the range of high quantity in horizontal pipe have been developed. The results predicted are consistent with the experimental data.

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Recently, straight run residual fuels are being replaced by cracked residual fuels due to further processing of straight run residual fuels in order to get more middle distilaties.
Catalytically cracked residual fuel sometimes happens to include catalyst fines which are used in the cracking process, because these cannot be removed completely by a reclaimer. These catalyst fines in fuel are very abrasive ones and wear engine abnormally. It is necessary to remove catalyst fines from fuel before burning for safety operation of a diesel engine. Therefore, the wearing-out tests of 50 hour duration were carried out in a small size diesel engine with heavy fuels processed by a centrifuge or a mixer filter unit in order to investigate the effect of fuel pretreatment on engine wear.
The followings are concluded from the test results:
(1) Engine wear caused by catalyst fines in heavy fuel can be greatly reduced by fuel pretreatment.
(2) A centrifuge is a very effective equipement for reducing wear caused by catalyst fines.
(3) Abnormal engine wear caused by catalyst fines can be avoided by using a centrifuge and a mixer filter unit properly.

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This paper describes an outline of the combustion analysis system aided by a personal computer and presents the results of a study on the combustion tests in the medium speed diesel engines with 220mm bore and 240mm bore. An evaluation is made of the time history for the unburnt quantities of the fuel injected into the combustion chamber. A new understanding is proposed in the relations between the cumulative fuel injection rate and the cumulative heat release rate.

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Allowable minimum revolution of shafting relating to oil film generation on stern tube bearing is described in this paper.

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