Generally speaking, it is impossible to express, by the equations, the area and moment of inertia curves of the variable cross sections. This is the reason why such problems of beams and columns cannot be solved except only a few special cases and they are treated approximately by graphical or by other methods.
But if the curves of area and moment of inertia of the sections are replaced by the “Stufenkurve”, they are able to be expressed by Fourier's series.
From this point of view, the author made an attempt to the solutions of beams and columns with variable cross sections of stair types and the satisfactory results were obtained.

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Discussing the longitudinal strength of ship, we should feel that our present knowledge is not enough to explain the effective flexure rigidity of hull girder, the buckling of deck or shell plating, and the effects of transverse members such as frames and deck beams, etc. So it will be necessary to develop the experimental investigation of bending of the thin-hollow girders having many longitudinal and transverse stiffeners.
To carry out an experiment of such a complicated structure, it is required the larger possible test pieces, and consequently a large testing machine.
I had been investigated an invention of a large testing machine of simple bending, and fortunately gained a draft of original idea. Then as a trial manufacture I made a small machine of which maximum bending moment is about 10 kg-metre, and studied its principle, its moving states, and its possibility of developing into a large one.
Since then I am repeating its improvements and calibrations. Even yet there are left a few points to be reformed, I bound its moving states almost satisfactory and came to the conclusion that the possibility of its developing is highly conceivable. So in this paper, I am going to give a description of its general principle, and expecting your considered criticisms, and I have a pleasure in promising you my future effort for its ultimate completion.

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Since a wooden ship was left behind the development of, the theory of naval architecture too much, we hesitate to apply a theory of construction of ships which have been developed in steel vessel on designing its construction.
In wooden ships, specially in European type, many narrow planks are tightened on big and narrow-spacing frames as outer strakes, and on connection is given to their seams, moreover their ends are connected on frames as simple butt joints and merely tightened to frames by some nails.
On dealing with the longitudinal strength of such structure, there are many multiple problems which are neglected hitherto such as follows ; how the bending stresses are distributed, how the section modulus is calculated, how the shearing stresses in seams, which are strictly argued at steel vessel, are dealted with, how are the effect of diagonal tie-plates, which are only found in wooden ships, what is the cause of large deflection which is regarded to occur many times in wooden ships, and so on-.
This paper has scarcely actual prooves and is founded upon very rough assumptions, but the author ventures to publish it as some introduction of such investigation and has a wish to bring the wooden ship which are left hitherto behind the progression of the naval architects into the division of structural dynamics.

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The authors make both theoretical and experimental researches about the so-called shallow water effects upon the wake of ships which run on a restricted water, not only with its depth but also with its breadth such as a canal and an experimental tank. As it shallows, the decreasing cross-sectional area of water results in certain singular phenomena on wake percentages ; which may serve as a reference for the design of marine propellers of shallow draught vessels on inland waters, besides offering a key to the elucidation of the so-called shallow water effects on the resistance of ships.
Brief descriptions are also given on the experimental apparatuses, viz, a quick-acting pitot tube and a current meter of the blade-wheel type respectively.

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In the following paper, the author investigates mathematically the wave resistance of a propeller working in a shallow sea, and obtains an expression for the wave wake at the propeller centre produced by itself. The former results in the reduction of thrust, and the latter, owing to the increase of the actual speed of advance over the propeller disc, causes the reduction of thrust and torque of the working propeller.
Taking these factors into account he clears up the problem of the shallow water effect upon the propeller efficiency.
Numerical calculations are also carried out by him in several cases of propeller immersion and depth of water.

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Die Verfasser lösen das Problem über zweidimensionalen diskontinuierlichen Strom um eine ebene Platte nach Demtchenko Forschungsverfahren und ausserdem noch mittels des Villatschen Formels. Sie berechnen dann den Auftrieb sowie den Widerstand als die Funktionen von dem Abstand zwischen den zwei auseinander liegenden Wändeu bei dem Anstellwinkel 0°, 5°, 10°und 90° beziehungsweise, und vergleichen die ausgerechneten Resultaten mit den bekannten Ergebnissen vom ähnlichen Problem über den kontinuierlichen Strom. Sie geben zuletzt die Berichtigungsfaktoren wegen des Druckes innerhalb der Kavitation und des Reibungswiderstandes an.

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Assuming the uniform longitudinal induced velocity on the propeller stream and the elliptical loading on the blades, the Voith-Schneider-propeller is solved approximately. And the characteristic curves are calculated, with which man can roughly select and design the propeller.

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Authors investigated on the transient variations of the deflection and the bending moment of a impulsively loaded beam of finite or infinite length, and the impacts vary proportionally to following functions of time t : -
(a) for t<2π/ω;sinωt
_??_t>2π/ω;0
(b) for t<2π/ω;1-ωt/π;
_??_ t>2π/ω;0
Where ω is a constant concerned with the interval of impact.

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