The author first deals with the vicissitude of the Japanese tonnage in the past and that of the shipbuilding industry, the lists of the particulars of the vessels with special features built during such period being also given.
Under the heading of “the Measures taken by the Government for the Japanese Shipbuilding, ” the provisions for the exemption of the customs duties regarding to the articles for marine uses, the subsidy system for the encouragement of manufacturing steel for ship construction, the marine loan system and the system of the governmental permission for importing operable ships, are described, and also the contents and results of the provisions for facilitating the improvement of ships are explained.
Then the author discusses the development of marine engines in Japan, pointing out the fact that the fuel consumption at the same power has been lowered up to sixty per cent in comparison with that in ten or more years ago. Further, he deals with the model tests of ships and timer effects, and explains that the shaft horse power required for the operation of the same ship at the same speed has been reduced to seventy per cent of that in old time Thus, the progress of Japanese shipbuilding technique, by which the fuel consumption of ships has been reduced by at least one-half in total, is clarified.

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With a view to obtaining the reliable value of GZ in the earlier stage of the ship design, the author derived the approximate formulae by assuming for the form of the locus of centres of buoyancy as an ellipse for a fine ship or a continuous curve consisting of a parabola and an ellipse for a full ship. He compared the results calculated by his formulae with those by the “Integrator” method and showed the correctness and the simplicity of method. In addition diagrams ready for immediate use for estimating the maximum righting arm and the range of stability are appended.

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The auther briefly touches, in the first place, on the signification of “Air Conditioning, ” its origin and development and describes on air conditions v.a.v. human susceptibility. Then he generally explains the methods of conditioning the air, now usually employed; and tries a short survey on the present state of air conditioning of communication means such as railway wagons, tram ears on land, and vessels on water. He, finally, enters into the explanation of the design, lay-out and the results of provisional tests of the air conditioning equipments on board the two ships above named, which are not only the pioneer ships in Japan furnished with these equipments, but also the foremost vessels in the world in which the equipments are most extensively employed, viz. all public rooms and all cabins in the quarters for all classes of passengers have been completely air conditioned throughout.

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A form (with a broken line in the profile) is suggested for the bottom of a body gliding over the water. A broad conclusion for the case of such bottom form is derived from the results of the pressure distribution on the lower surface of an aerofoil with trailing edge flap, the existence of a theoretical analogy being assumed. Its calculation as a two dimensional flow of the half plane along a broken line form is given. The minimum value of the lift-drag ratio is found reduced as anticipated. Throughout the paper the effect of the buoyancy has been neglected.

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The motion of a ship during the flooding stage is obtained by the numerical integration of the equation of her transverse motion, with the assumption that the level of the flooding water is always horizontal, its quantity increasing with time. The typical passenger ship of 20, 000 tons with the met. ht. of 0.44 m. is adopted and the length of the flooded compartment is taken to be one fifth amidship of the ship's length, and the area of the damage hole is chosen at the side, its value being changed variousely. Main results obtained are as follows :
(1) Max. heel changes with the initial conditions, that conditions being that the ship is initially at rest and inclined at θ₀. The value occurs at nearly θ₀=1°5°.
(2) Max. heel changes with the area of the damage hole. The greatest value occurs at nearly 10 m², and if the area is greater than 40 m², the max. heel is very small.
(3) The greatest heel obtained is nearly twice of the value which can be calculated by the statical consideration, i.e. by assuming the water quantity being constant, if the resistance to the motion is neglected, and is 1.4 times, if the resistance is taken into account.
(4) For the larger met. ht, if the damage hole is very small, say less than 5m², the oscillatory motion of increasing amplitude gives rise to, in the early stage of flooding, resulting to the very great heel. But in such a case, the flooding water may act so as to damp that motion, the assumed condition of horizontal level not being fulfilled, but the actual procedure should be studied experimentally. If such cases be put aside, the max. heel for the larger met. ht, is generally less than that for smaller met. ht.
(5) From the above investigations, it is concluded that the max. heel statically obtained, as is generally adopted, does not indicate the real one, and that such a problem should be treated dynamically.

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As a result of the experience gained with the Mitsubishi two-cycle single-acting airless fuel injection MS type Diesel engine, Messrs. Mitsubishi Jukogyo K. K. have developed a new double acting MSD type Diesel engine of a similar principle a', their Nagasaki Works, and the first two engines were installed in a c_??_uple of cargo liners for Messrs. Nippon Yusen Kaisha, further three sets for the same owners being now under construction.
The first engined vessel “Akagi Maru” has completed her first round voyage after 4 months at sea, and we are informed that the engine has shown remarkably good results and many novel characteristics.
This paper deals with the prominent features and some of the trial and service results of the engine.

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With several types of rudders of a single screw Ship, i.e., 5 kinds of stream line balanced rudders, of which one without and the others with fair waters in front of them, the following model experiments were carried out : -
(1) Propulsion.
(2) Measurements of turning force experienced by the ship when the rudder is put over and the propeller is working.
(3) Measurements of normal pressure, lift and drag on the rudder and twisting moment in the rudder head, when the rudder is put over in both cases of going ahead and astern, while the propeller is working.
The results of experiments are shown in a table and curves annexed.

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On the prosperous epoch of ship building, the launching of Tandem system will be certainly necessary enterprise for the benefit of quick construction of vessels.
In this paper, the author describes first, provisional definition of Tandem system, and then,
Launching calculations,
How keel to be laid,
Construction of launching ways,
Tallows,
Launching operations,
Attentions and preparation of implements.

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An experimental research on riveted single butt strap joints was carried out at the Kure Naval Dockyard.
The work was directed to the study, under tensile forces, of the ultimate strength, water tightness and slip phenomena of joints. Three grades of rivets were used, respectively mild steel, high tensile steel and high elastic limit steel.
These combinations permitted a study to be made of the effect upon the ultimate strength and behaviour of joints.
In addition tests were made on specimens containing three strakes to ascertain the effect, upon the behaviour of joints, of laying plating adjacent to the joint.

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