The author investigated the resistance of thin parallelogram plates and found that in the case of complete immersion the amounts of frictional resistance are quite the same as those of rectangular plates having the same nature of surface, length and wetted surface area, while in the case of partial immersion, the resistance of parallelogram plates is generally less than that of rectangular plates, and the frictional resistance of the former is proportional to e^-αθ, where θ is the inclination of fore and after edges to the perpendicular in degrees and α is a numerical constant.
Thus, for partially immersed thin parallelogram plates, Admiral Hiraga's formula for the frictional resistance must be rewritten as follows:-
Rf=KS(1+x/d)V^1.9010^-mθt,
where Rf=frictional resistance in kg,
K=coefficient of frictional resistance,
S=wetted surface area in m²,
x=lower edge effect in m,
d=draught in m,
V=speed in m/sec,
θ=angle of inclination of fore and after edges of the plate in deg.,
m=a constant having value of 0.000555,
t=temperature correction factor
Considering from the results of this investigatjon it seems that the exsting method of estimating the frictional resistance of ships admits of some improvements.

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A dynamometer for self propulsion test was designed and made as in Fig. 1 and Fig. 2. The main principle of the apparatus is as follows:
The propelling power is supplied by a motor which is set on the bottom of model ship, and connected to the propeller shaft with 2 spar gears.
The number of revolution of the propeller is known from the record of the revolution of the motor shaft, which is indecated on the revolving drum by means of worm gear and electric contact.
The turning moment of propeller is known from the measurement of the rotating force of the motor case, which is supported on motor shaft using ball bearings at both ends of the ca-ing, and made to revolve by the repulsive force of armature with equal and opposite amount, the method of the measurement being the same as in the case of a brake dynamometer.
The thrust is measured by the balance, an arm of which is pushed by 2 knots of a ring supported around the propeller shaft by 2 ball-rings of the thrust bearing type fixed to the propeller shaft.
The above 3 elements, viz. revolution, turning force, and thrust, are recorded on the rotating drum, and beside these, the time, the running distance, and the relative position between ship and truck, are recorded on the same drum, as shown in Fig. 3.
The weight of the dynamometer without variable balancing weight is 12.5kg, and the total weight with balancing weights will not over 15.0kg, even at the usual high speed for common fishing boats. (model length P.P. 2.5m)
Few experiments were made by the dynamometer, and the results were compared to that of behind test by the ordinary propeller dynamometer with the resistance dynamometer, showing the good reliablity of both the experimental apparatus, as seen in Fig 4, Fig. 5 and Fig. 6.

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The present paper gives the records of torque-fluctuations of the intermediate shaft measured by the Author's torsion-meter on the sea trials of merchant ships, and deals with some qualitative analyses of them. The shaft horse-powers of 64 ships, whose normal powers ranged from about 3, 000 to 10, 000 S. H. P., were measured by us during the past 6 years, and in the present paper the records of 27 ships are taken as their representatives. The records for oil tankers are harmonically analysed.
The principal results obtained are summarized as follows:
1. The torque-fluctuations of intermediate shafts are caused by the unbalanced torques of drivers and periodic resisting torques of followers.
2. The unbalanced torques of reciprocating engines interfere with the periodic resisting torques of propellers, so, for example, in the case of four-bladed propellers, it seems to be practically, possible to reduce the 4th order vibrations of shaftings by arranging propeller blades and cranks at suitable phases.
3. In the case of turbine ships, only the periodic resisting torques of propeller and reduction gears should be considered in connection with torsional vibrations.
4. The violent vibrations with one node can be seen at the shaftings with shorter intermediate shafts, owing to the higher frequencies of free vibrations of one node.
5. Assuming the positions of nodes of forced vibration to be the same as those of free vibrations, the amplitudes of the vibrations and the distributions of stresses of shaftings can be computed from the records of torque-fluctuations. Therefore, the Author's torsion-meter may be said to be an inertialess torsiograph.
6. The distributions of stresses thus obtained give the data available for the design of shaftings.
7. Since, in general, propellers are situated at the loops of all modes of vibrations of shaftings, the fluctuations of angular velocities of propellers can be computed from the records of torque-fluctuations. And also the fluctuations of torques and thrusts of propellers due to those of their angular velocities can be found.
8. The torques of intermediate shafts are the sums of the inertia torques of the virtual mass of propellers and hydrodynamical torque of propellers. Therefore, the effects of torque-fluctuations of intermediate shafts should be considered for designing propellers.
9. It is natural that the torsional vibrations of shaftings cause the lateral vibrations. Therefore, they must be considered the sources of other vibrations.
10. The approximate values of the rates of torque-fluctuations at 3/4 loods of engines are as followes:-
±2%_??_±9%, for turbines, diesel engines with hydraulic couplings, steam reciprocating engines with low pressure turbines, etc.
±8%_??_±20%, for diesel engines with longer intermediate shafts.
±30%_??_±50%, for diesel engines with shorter intermediate shafts.
±160%, for the steam reciprocating engine dealt with.

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靜止してゐる流體中を物體が運動するとき、流體の一々の分子が空間に固定した座標軸に對して時間の進行と共に畫く經路を絶對流跡と名づける。この絶對流跡は近來一般の關心を呼んでゐない樣に思はれたので、著者等は之れに就て一通りの理論的研究を遂げると共に、各種の斷面型を有する直〓模型を以て水槽實驗を行ひ絶對流跡を撮影して實驗的研究をも施行した。

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The authors measured the actual starting forces at the launching instants of ships by means of the hydraulic triggers and compared the frictional coefficients of the sliding ways thus obtained with those by the model experiments.
The result shows that both cases nearly coincided.

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The retirement of the famous Cunarder in 1935 after her unbeaten career of nearly 30 years, had brought forth a fresh battle for the premier place for passenger traffic on North Atlantic.“Bremen, ” “Europa, ” “Rex, ” “Normandie, ” “Queen Mary” etc., one faster and finer than the other appeared in quick succession, and there are “Queen Elizabeth” and “Bretagne” still to appear to surpass all. Germany not to be left behind in the fray, is said to be contemplating a super Bremen with even higher speed-length ratio than her predecessor, and to have a speed of 37 knots with 272, 000S.H.P. So the race goes merrily on.
Judging by the event taking place in shipbuilding world in Europe, it would seem the construction of leviathan for North Atlantic service is justified as a national policy, even if a shipping company has to face the need of a fleet of economical revenue earning ships to supplement the loss.

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It is well known that the anchor chain, when paid out, suffers oscillations so severe that it is obliged to reduce the payout speed. Its cause is quite clearly the resonating phenomenon of the disturbing period of the links of the chain paid out with that of the chain, under tension and with travelling speed, of the span between the gipsy wheel and the chain stopper. This fact is treated theoretically in the present note, arid, the natural period of the chain being obtained, the relation between the pay-out velocity and the number of links within the span is given for the resonating condition. Some suggestions are also described for the purpose of reducing the oscillations.

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The “Argentina Maru” is the first motor passenger and cargo ship to he constructed under the special Shipbuilding Subsily of the first grade grented by the Japanese Government, and this magnificent Round-the-World Liner is wholly of Japanese construction and materials. In vi w of these circumstances, it seems to be appropriate to make some reference to the ship; therefore a general description of the vast design, construction, equipment, etc., is given in this paper.

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In modern high powered and high speel motor ships, the understanding of the introduction of torsional vibration damper as the best and even some times the unique solution to obviate or mitigate the critical speeds of the torsional vibration of shafting is increasingly necessary.
For this purpose, a new torsional vibration damper has recently been developed by Messrs. Mitubisi Jukogyo K. K. at their Nagasaki Works, and several sets have already been put in service proving their novel characteristics.
This paper fully describ s about this new damper by firstly dealing with its theory to derive simplified formulae for design, then illustrating its construction and novel features, and finally showing the performance of one of the dampers tried at sea

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The patrol ship“Kainan Maru”60.71m in length and of 524.69 gross tons is propelled with two Diesel engines of 500 B.H.P., each coupled on one propeller shaft through Mitubisi Vulcan fliud coupling.
The Diesel engines are supercharged by Mitubisi Büchi supercharging system, and the exhaust gas turbine driven supercharging blowers applied in this system are designed and manufactured first time in Japan.
Some performance of this supercharged engine on test bed is described in these papers.

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