Following the theory of the first report, the author tries to obtain the second approximation of the velocity potential of an infinite draft ship with parabolic waterline. The theory encounters mathematical difficulties from which seems to result the unfavourable conclusion except the diminuation of the wave profile and the wave resistance curve.
These difficulties will be play an unimportant role in lower speed so that we may introduce an approximate relation of the wave resistance in such speed. He tries to compare thus obtained formula with the correction formula which is used by many authors, and finds out that those factors will be related closely to the wave height at bow and stern.

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NACA 4112 and ogival section (thickness 12%) were held stationary in an open flume containing streaming water. The air drawing and flow separation phenomena were observed and the pressure distribution were measured at several different submergence depth, speed and angle of attack.
In § 2, the observed phenomena were descripted for the inception of air-drawing, occurrence of flow separation and form of cavity.
In§3, the necessary and adequate condition is considered for occurrence of flow separation due to the air-drawinp;, and the surface tension and stalling is enumerated.
In § 4, the effect of the flow separation on the pressure distribution, lift and drag of the hydrofoil section is examined, and also comparison is made with Greens discontinuous flow theory.
In § 5. the scale effect on the flow separation due to air-drawing is examined and the critical Weber number is determined for the NACA 4412 and ogival section.
In § 6, the criterion is proposed for the occurrence of flow separation and the concrete example is shown.

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In order to obtain a reasonable ship-model correlation line, scale effect experiments were performedl on some ship forms in the tank of Transportation Technical Research Institute.
This report deals with results of these tests, and presents a new conception for form factor of ship's, resistance by analysing the test results in this tank and those for the Lucy Ashton and Victory ship, models.

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The paper records the result of experiments with a systematic series of six-bladed aerofoil propeller models, designed in accordance with present-day practice.
Charts of series are shown by so called √B_Pδ design diagrams.

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The characteristics of rudder working behind propeller are investigated with model tests.
According to the above, they are much different from those of open rudder, and the existence of optimum rudder area ratio can be explained, at least, from rudder side.
Finally, design-charts based upon these test results are presented for general use.

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This paper relates to Kempf's zig-zag test results for a super-tanker model with several alternative rudder sizes and a special rudder arrangement shown in Fig. 8, following the preceding papers published in the journal of the Society of Naval Architects of Japan, No. 103, 1958.
The results are analyzed in terms of the steering quality indices which has been developed by the author and published in the I. S. P. Nr. 35, 1957. This procedure provides a successfull investigation for the effect of relative rudder size on steering quality. It should be noted that a considerable reduction of steering quality indices K and T with increase of turning angular velocity is experienced.

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Randomness of ship's oscillations among waves is almost as the same as that of wave heights. Precisely speaking, even in one component of oscillation, namely rolling, randomnesses of amplitude, velocity, and acceleration are a little different to each other. This is because of response operator, as higher time differentials exaggerate high frequency part of wave spectrum, so that regularity increases from amplitude towards to velocity, acceleration, …
If we prefer the irregularity of amplitude n=2, which means Rayleigh's distribution, for velocity becomes n=3, and for accelerantion n=4 for moderately rough sea surface. As waves grow up fully from seas to swells, these regularities gradually increase.
The index number “n” is almost constant for every magnitude of maximum of oscillation, but if There are other strong resonances and there are several maxima in frequency distribution, we must consider regularity for these each component separately.
The occurrence of “n=2” is to he expected most frequently in the case of pitching and rolling amplitude.

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本論文では前回に引続き, 同じ系統模型船について前後動に対する附加質量を計測した。
x軸方向の附加質量として必要なのは非定常運動に対するもの, すなわちm_x1である。したがつてその測定も非定常な過程を用いなければならない。

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左右動に対し, 船は自己周期を有しないから第1報で述べたごとく, 非定常運動に対する附加質量m_y1/mが最も必要である。
本論文では前に述べた系統模型船につきm_y1を求め, C_b, L/Bおよびd/Bとの関連を調べて見た。

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The paper gives some investigations into a second spectrum of the natural frequency of the flexural vibrations of ships' hulls. Some aspects of the nature of the existence of the second spectrum, the estimate of the frequency of the second spectrum and also the effects of shear flexibility and rotatory linertia force upon the second spectrum of the natural frequency of the vibration of uniform section beam with free ends are investigated as preliminary consideration of hull vibrations of ships in part I. As a numerical example, the spectra of the frequencies of the vertical vibration of the stern of a large tanker considered as a half length of a uniform section beam are illustrated.

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When side-walls of a rectangular tank which is filled with water is vibrating, the water will also make a vibratory motion. The author has made a calculation of the amount of kinetic energy of vibratory motion of water thus set up. The calculation was carried out about four specific cases as follows, the opposite two side-walls being assumed to be vibrating as shown by Fig. 1; (A). The rectangular tank is completely full of water, the two side-walls making “in-phase” vibrations to each other. (B). The same as (A), but two side-walls are vibratiag in “opposite phases” to each other. (D). The rectangular tank is almost filled up with water, but there is left on top a small vacancy. The two side-walls are making “in-phase” vibrations. (C). The same as case (D), but two side-walls are vibrating in “opposite phases” to each other.
From the calculated values of kinetic energy of vibrating water, we deduced the value of so-called “virtual mass” of water, with regard to vibration of side-walls of the rectangular tank. This will enable us to make an approximate estimation of the value of natural frequency of vibration of sidewall of the rectangular water tank. The calculation throughout is made, regarding the water to be an incompressible, non-viscous fluid, and the amplitude of vibration to be infinitesimally small.

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In the previous paper, the elastic behaviour of the simple superstructure constructed with horizontally and vertically corrugated plates was investigated.
But the horizontally corrugated wall, in general, will have to be stiffened by transverse frames or stiffeners, to maintain sufficient transverse stiffness of the cross section of superstructure against the lateral loads. When the stiffeners are rigidly attached to the every corrugation and the corrugations are restrained from distortion of their cross sections, the merits of the corrugated plates will vanish and the large longitudinal stresses may be transmitted from hull girder.
To find out the construction of the corrugated side wall of the superstructure which has sufficient transverse stiffness and does not transmit the large longitudinal stresses from main hull to the bridge deck, the effects of the stiffener attached to the corrugated wall on the tensile and bending rigidity of the superstructure were researched.

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This paper presents a practical method of predicting the longitudinal stresses of ships in rough seas by means of Neumann-Pierson's wave spectrum theory and St. Denis-Pierson's theory. Given the principal dimensions of ships, the wind velocities, the durations and the fetches, we can statistically find the logitudinal stresses. In an experiment the predicted stress was in good agreement with the observation.

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In order to investigate the behaviour of permanent deflection of deck plate of patrol ships, the t-requency distribution of deflection and its change were measured over a long period. The allowable limit of initial deflection and the collapsing strength of ships were calculated as well.
To examine the stress of patrol ships among waves, the actual ship experiment was carried out, and the statistical values of ship stress were calculated.

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In this second report, the author presents the deduction of the more generalized theoretical plane stress system in a homogeneous elastic rectangular plate than the one reported in the first report in collaboration with Dr. Akita.

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In this third report, the method of theoretical analysis to the box-shaped girder after the model of tankers is presented, in order to analyse the effectiveness of the longitudinal bulkhead mainly, using the plane stress system deduced in the previous reports.
As one of the example, the result calculated to D. W. 65, 000 t type supertanker is added.

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In this fourth report, the results of experiment of orthogonally stiffened continuous panel under distributed and concentrated loads are given. Comparing them with the value derived from the orthotropic continuous plate theory, it is shown that the orthogonally stiffened plate in such case can be also expressed by the orthotropic plate theory as concluded in the preceding reports.

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As the ratio of depth to length of cargo oil tanks of tankers up to 40, 000 deadweight tons approximates to 1, it is no way unreasonable to construct wing tanks with vertical webs only. In the case of the so called mammoth tankers, however, while they are made much greater in depth, tanks to be installed in most cases are limited to 12 meters in length, with the result that the tank depth often shows a ratio of 1.7 to the tank length. In such cases, the writer considers it better to use the grid girder construction made up of the main girder installed horizontally and the secondary members vertically.
Since little has been studied about the grid girder construction in the past, the writer has worked out how to calculate the strength of the construction, as follows :
1. Calculate each rahmen by the Hardy-Cross method.
2. Solve a simultaneous linear equation where the deflection at each joint is the unknown value. Having 4 or 6 unknowns, this equation is by far simpler than the 56 unknowns simultaneons linear equation by the slope deflection method.
3. In calculating rahmens, shearing and the effect of the end bracket cannot be neglected.
4. Although some problems, such as the effective breadth of the structural members, stress causea at the brackets, etc. are yet to be solved, the value found out by the method well agrees with that obtained in the tests conducted.

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鉄筋コンクリート構造物に関する最近の研究は多くの問題を弾性学の分野に提出し, A.Pucher⁴の板の“影響面理論”を生んだが, その理論は橋梁床板の場合に限らず船体構造のごとく多くの平板より構成されている構造物に対して非常に有用と思われるのでここにその研究結果を報告したいと思う。本論文においてはA.Pucherの展開した等方性板の影響面の理論を直交異方性板の場合に拡張し, 単純支持無限帯板に対する影響函数を導出した。求められた影響函数は撓みの場合を除き, すべて初等函数で表わせたから数値計算がずつと楽になり精密なダイアグラムの作成も容易になることと思う。影響函数の有する特異性について一般的な考察も同時に行なつた。

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In this paper, the authors propose two new formulas for the plastic buckling of plates as well as the plastic buckling of corrugated plates, one of which is called T-formula (isotropic tangent modulus formula) and another is nai icd Orthogonal Anisotropic Tangent Modulua Formula. The former which gives the lower limit of plas lc buckling stress of plates, corresponds to “Shanley load” in case of column instability, and G_t =E_t/2 (1-ν). The latter is obtained from a plane stress problem in which the yielded plate subjected to comp essive load is regarded as a orthotropic corrugated plate, and G_t=E E_t/ E+ (1+2ν) Et. These two formulas tabulated in Table 1 with other famous formulas, showed a satisfactory agreement with the test results (Fig. 10).
The authors also established the general calculating method to obtain the ultimate strength of corrugated plates in plastic range (using τ-formula explained above) as well as in elastic range for design purposes, including the determination of all the rigidities of corrugated plate. Especially, the torsional rigidity D_xy, was checked by a test which coincided with the calculated value.
The behavior of elastic buckling stress (σ) of orthotropic plates is also studied in this paper. Provided D_x, D_y=αD_x, H=βD_x and α =β² (where α= anisotropic coefficient for bending and β= anisotropic coefficient for torsion), it is shown in Fig. 7 that σ decreases gradually as βdecreases from 1 to 0 and the corresponding buckling mode also changes as σ varies.

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In the previous paper the buckling of a stiffened panel with a symmetric type of stiffener was treated as an eigenvalue problem of an orthotropic plate with proper moduli of materials in the strainhardening range. The equation of echuilibrium of a stiffener can be generalized for an arbitrary shape of thin-walled open cross-section attached to a plate if proper consideration is given to the mutual interaction between plate and stiffener.V if a beam with an arbitrary cross-section is subjected to transverse load, the beam is bent and twisted simultaneously unless the line of loading passes through the shear center. When a beam is attached to a plate, the enforced axis causes twisting of the stiffener if it is bent or the other way around, bending of the stiffener if it is twisted. Therefore the bending and the twisting of the stiffener are no longer separable for such a stiffener with an unsymmetric cross-section.
When the plate starts to buckle, the distributed resistance due to the longitudinal and or transverse stiffener can be obtained from the equation of equilibrium of a stiffener attached to the plate. The integral equation for the buckling of a longitudinally and transversely stiffened plate can be formulated as in the previous paper. The buckling strength of a stiffened plate is obtained as an eigenvalue of the integral equation. From the computation given in this paper it may be concluded that a longitudinal stiffener is tolerably effective to prevent the buckling of a plate compared to a transverse stiffener, and the efficiency of an inverted angle stiffener is considerably lower than that of a Tee stiffener when the stiffener is subjected to axial loads as in a longitudinal stiffener. In other words, the existence of axial load weakens the torsional resistance of a stiffener with an unsymmetric open cross-section as well as the bending resistance of the stiffener, and its influence for an unsymmetric cross-section is considerably greater that for a symmetric one. The results of this paper, together with the previous one, are used to specify the proper geometric conditions of the siffened plate such that each panel may develop large plastic deformation without buckling and a consequent fall-off in load. These requirements are essential for a successful application of Plastic Design Methods to plate structures.

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In this report, the corrugated beam of section as shown in Fig. I with both supported ends under transverse impact is discussed first before the problem on large plastic deformations of corrugated bulkheads will be taken. The deformation of ', finite solid beam under transverse impact is solved by Bleich and Salvadori applying the elastic-plastic analysis. There, however, are some unreasonable phenomena with plastic moment conditions along the lengthwise direction.
From the other different view-point of this analysis, the same problem is again carried out by Lee, Symonds and Pian applying the perfect plastic analysis of plastic moment idea. They point out that the perfect plastic analysis is available with sufficient accuracy to obtain the large deformation of beam Tenerally considered as elastic-plastic, only if the final strain after finite time elapsed is considerably larger compared with the elastic strain.
In order to get the final plastic deformations systematically under impacts with several load shapes, the author wants to develop solutions about beam of both supported ends to make them ppplicable to the present case. Experiments were worked out with several specimens made from mild steel or copper alloy. The experimental formulas are decided from both theoretical and experimental results. The approximate formula including the several load shapes is also given to be available to practical purposes of initial design.

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This paper deals with the impact force which the ship receives from quay-wall when she is pulled' into the pier. Several possible means of avoiding or decreasing the heavy shock of the ship's contact are then to be considered in order to avoid damages of the ship.
Theoretical calculation tells that even the low rotation opposite to the quaywall reduces the impact force greatly. Another way of reducing the impact force due to existence of fender is a so discussed.

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The fourth series of test was performed to investigate the effect of residual welding stress on onttle fracture fracture of steel, especially on the propagating direction of brittle crack.
Oblique welded specimens were prepared and half of them were stress relieved by annealing. Fracture test procedure was same as slow notch bend test. In as-welded specimens, propagating directions of britte crack were deviated at welded joint, but in annealed specimens, there was little deviation.
To show the change of principal stress direction, photoelastic experiment was also performed.
Our former conclusion that residual welding stress effects on brittle fracture, was recognized in such a problem-propagating direction of brittle crack.

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The crack speed and the dynamical stress around a propagating brittle crack were measured using the ESSO Brittle Test specimens. The plastic surface energy was obtained from the measured crack speed by applying the modified Griffith conception.
The results obtained during this investigation can be summarized in the following conclusions :
(1) The measured dynamical stress around the propagating crack front decreases with the increasing crack speed and fairly agrees with the theoretical one obtained in the previous report.
(2) The crack speed increases with the increasing applied stress, plate thickness, and the decreasing temperature.
(3) The plastic surface energy decreases with the decreasing temperature and the increasing plate thickness.
(4) The plastic surface energy of quenched and tempered steel “2H” is much greater than that of normalized killed steel.

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By expressing the surface plastic work done with the aid of Forscher's conception of relaxation centre, the authors examined the significance of the critical stress obtained by the earlier proposed double tension test with flat temperature gradient and explained its temperature dependence. Further the authors studied theoretically and experimentally the correlation between the temperature dependence of the critical stress and that of yielding stress.

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The author suggested in his previous paper that the orders of resistance of steel to the propagation of brittle crack can be determined by the pressed-notch Charpy tests. The present paper shows the actual data of the van der Veen tests with 3mm and 8mm notches, from which the previous suggestion was originated. In addition, the simple theory of notch brittleness lectured by E. Orowan is referred and supplemented in order to explain the meanings of different two tests.

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The new proposed experimental “Restrained-Joint” method, includes a reproductive condition which tboth ends of plate are fixed in perfect rigid. The distance between both rigid ends fixed, we call it restrained distance, are always let constant.
For this purpose, a gauge with a dial indicator that is equal to restrained distance, is set, and the ensile loading suffered from the both of plate that are bitten by chuck of the Mohr tension tester, are as well as controlled in quick responsible to maintain the gauge length constant. Due to the experiments carried out, it could be considered that so-called intensity of restraint was equivalent to the reaction stress which was obtained by this loading test method.
Hence. 400 mm breadth, 20 mm thickness of plate and 300, 400, 600, 850 and 1, 000 mm restrained distance, the condition was appreciable for varios restraint intensity, and 3. 7 and 12 mm root openings was used to find effect of excessive root opening and the material for every specimens was SM-41 (mild steel).
Thus, the obtained results was summarized as follows.
1. Expanding and shrinking region upon restrained condition, plastic and elastic deformating zone in adjacent butt joint was clarified.
2. Some excessive root opening not hardly effected on intensity of restraint and amount of locken-in stress residual welding stress on restrained butt weld, was found.
3. The intensity of restraint could be varied by various restrained distances, in 400 mm and the less was increased abruptly but in 600-1, 000mm. restrained distance-intensity of restraint curve had a gently-slope.
4. Longitudinal residual welding stress along weld line on butt weld was decreased and transverse locked-in stress due to welding was increased by increasing of restraint, was appeared. The increased amount of transverse locked-in stress from free joint (no restraint) was almost equal to the intensity of restraint i. e. reaction stress value measured by the test.
5. Reaction stress of each passes during multi-pass welding showed a maximum value when weld metal was deposited 30-40% throat per full thickness of plate.
6. At the condition t =20 mm, b=100 mm and R. D =850 mm it was a significant result that the reaction load was measured by tester as large approximately 130 Tons according to this experiments.

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It is usually one of undesirable designs and procedures that a welded construction has mutually two or more abjacent butt joints.
But in common ship yards or in repair yards, their designing engineers and manufacturing engineers sometimes would encounter the occasion as above.
The minimum mutual distance between two or more adjacent joints for proper and safety welded construction has not been clarified and established.
The authors applied for this two mutually adjacent joint test, our “Restrained-Butt-Joint” method, (see Report No. 1) to which the residual stress surrounding the two mutually adjacent butt joints were measured the stress distributions were established.
The testing conditions, thickness of plate ; 20 mm, breadth ; 400 mm, restrained distance, (see Report No. 1); 850 mm and distance between two joints ; 40, 80, 150 and 250 mm was applied for this tests.
From this experimental results, we could reach the summarized conclusions as follows.
1. The intensities of restraint were not hardly varied by the various distnce between two joints, and the values were approximately the same as the one-butted specimen (Report No. 1).
2. In the 40 mm joint-specimen, the longitudinal stress distribution along perpendicular direction to weld could be regarded such as the same one on the one-butted specimen.
3. in 80 mm, it was appeared that the longitudinal stress had a hump distribution 2 peaks in the surrounding the joints.
4. Noticeably, in 150 mm, the longitudinal stress in the initial butt weld, are usually tension at one-butt, became compressive for whicts, was suffered from a influence of the 2 ad welding.
5. The 250 mm distance between two joints the two separate peak of longitudinal distribution along perpendicular direction for weld line, was clearly found.

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The magnitude of residual bending deformation of beam caused by thermoplastic working is much influenced by the method of heating and cooling. As a fundamental research, the author performed theoretical and experimental analysis of stress and strain in beam in four typical cases of temperature changes.
Comparing these results, he get the qualitative explanation of the mechanism of dependence of deformation upon the method of heating and cooling, and show some important rules in the practical applications.

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In this paper, the author proposes a new quick drawing process of the lines of under water form for the basic design of merchant ships having block coefficient ranging between 0.65 and 0.80.
With systematic hand works, this process needs less labour than the customary process. The key points of this process are as follows : -
(1) Drawing the sectional area curve from standard series of sectional area curves with C_⊗ and 1_cb corrections.
(2) Picking up the offset points on the standard size from the offset curves.
3) Drawing the body plan of actual size from standard size by means of the similar translation method.
The item (1) was already described in the first report, and the item; 2) and the item (3) are reported in this second report.

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It is not always possible that a curved surface in the Euclid space of three dimensions is developed on the Euclid plane of two dimensions. Therefore, we use many approximate methods for the development of undevelopable curved surfaces which are shell plates, because the amount of expansion and contraction of parts of shell plates are not much in practice.
Then the author analysed these methods by differential geometry for the purpose of investigating the accuracy. Namely two geodesic lines being at right angles on the shell surface and being competent for making the correct developed plane, are found out by the calculus of variations, and the position of base points or base line of each method being relaitive to the geodesic line on the curved shell surface, are compared with the correct position of them on the developed plane, then the accuracy of each method is known.
And the author analysed the question of back-sets and the roll line of the shell plate by differential geometry.
After all, it was verified that the geodesic line method had the best accuracy in practice.

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An ejector of new type is devised by the author, which has multi-nozzles parallel to the direction of flow.
Experiments as of steam ejector carried out and analysed theoretically.
The results obtained are as follows.
(1) An analysis of a multi-nozzle ejector has been obtained by means of a method similar to an analysis of a single-nozzle ejector.
(2) A comparison between the experimental and analytical results showed good agreement over a broad range of variables.
(3) Experiments show the length of mixing tube required is about 78d/√m (d=diameter of mixing tube, m=number of nozzles)
(4) It is proved by not only experiment but also analysis that performance of multi-nozzle ejector is better than that of single nozzle ejector equivalent to the former,
(5) Divergent type diffuser following mixing tube causes worse effect.
(6) The smaller the throat area of nozzles is and the lower the steam pressure is the larger the mass ratio of flow is.
(7) At constant steam consumption better performance can be obtained when nozzles having the smaller throat area are used and steam of the higher pressure is used.

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Stresses to which the propeller shaft of a small diesel ship was subjected under its operating conditions were measured by means of electric resistance strain gauge of foil type. The bending stress was measured on the shaft just forward of the propeller hub, and the torsional and axial stresses were on the aftermost intermediate shaft. The following results were obtained.
(1) Amplitude of vibratory bending stress increases with the shaft peed.
(2) The first order bending stress which is caused by shifting of thrust centre from the propeller centre, increases with shaft speed.
(3) As a result of harmonic analysis of bending stresses, a definite forth order whirling resonance is shown at about 360370 r. p. m., and this coincides to a speed calculated by the Panagopulos' formula.
(4) Vibratory combined stress is most affected by vibratory torsional stress and indicates the maximum value at the critical speed of torsional vibration.
(5) The stresses measured on the propeller shaft are not so remarkable, but we must consider the effects of stress concentration of key way, fitting of the shaft in propeller hub and corrosion by sea water to fatigue of the shaft.

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