In this paper, measurement results of propeller shaft displacement at the part of aft stern tube bearing of NOPS (NKK Off-center Propeller Ship) is reported. The feature about locus of shaft center, Lissajous figure of shaft center, harmonic analysis result of vibratory component, etc. are related.

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The Contra-Rotating Propeller system was mounted first in the world on the “Toyofuji No.5”, a large car carrier of Toyof u ji Kaiun Kaisha Ltd. at Mitsubishi Heavy Industries, Ltd., Nagasaki Works in 1988 and she was put in service.
In the shafting of the contra-rotating propeller, though there were many unknown factors in various fields, and the techniques in design and in the strength and vibration calculations had not been established, we could accomplish those techniques as a result of our long time investigation.
The above design technique was applied to the “Toyofuji No.5” for verification, and consequently we are confident that it would be applicable to larger ships.
We would introduce the above in detail in this paper.

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PBCF (Propeller Boss Cap Fins) which is composed of small fins attached to propeller boss cap was proposed as a novel energy-saving device. Currently about 150 PBCFs are attached to full scale propellers and also demonstrating the PBCF effct. This paper describes principle, effect and design condition of PBCF, and also reports actual results of significant efficiency gain in full scale ships. Theses resultes lead us to believe that PBCF is an excellent energy-saving device because of its simple structure and efficiency gain of about four per cent.

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ACM (Advanced Cmoposite Material), typically classified as CFRP (Carbon Fiber Reinforced Plastics), is applied to the material for aeronautical and astronautical engineering, armaments, and general use for sporting goods such as skis, tennis racket and etc.
In this paper, a CFRP intermediate shaft for marine use has been studied for adaptability in order to avoid the engineering problems on the shafting and propulsion system, which are increasing of torsional stress and vibration of the shafting in the case of an advanced high performance marine diesel engine. First, the various land ecperiment of the mechanical properties, by using the scale models of CFRP tubes, was carried out for the practical use. And then, a conventional steel-made shaft of the small ship was replaced to CFRP one and sea-trial tests were performed for evaluating torsional stress and hull vibration. Last, from these data we designed the optimum CFRP intermediate shaft of 80, 000 DWT Tanker and were able to verify that this advanced shaft should be practical for marine use and has the same function as a conventional highly elastic coupling assembled into the steel-made propulsion shafting.

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With the recent increasing interest in scientific and engineering researches into ocean and deep sea, larage and high powered oceanographic ships with controllable pitch propellers (CPPs) has become necessary.
In such ships, because of necessity for detection of the deep sea bottom and telephoning and communication between the support ship and the deep sea submergence vehicle using acoustic instruments, it has become a very important technical object to reduce the underwater noise around the hull, especially the propeller cavitation noise, below the required level.
In this paper, firstly, general relations among properller geometry, cavitation and noise are explained, considering characteristics of CPP, and the f ollwing three fundamental methods which are found effective for reduction of the propeller noise are described
1) Equalization of wake distribution at a properller plane
2) Optimum selection of particulars and shape of CPPs
3) Optimum combination of CPP blade angle and revolution number Secondly, theoretical and experimental studies of the low noise CPP on the support ship“Yokosuka”for a 6500m deep submergence research vehicle in application of the above methods are briefly described.
The full scale propeller noise was measured at her sea trial and compared with the predicted one. It was found that the noise level of this propeller was very low and the above described methods were very effective for the noise reduction.

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