Showing papers on "Beam (nautical) published in 2002"

Single beam aircraft passenger seat

Abstract: A passenger seat, including at least one leg assembly having fore and aft attachment elements for attachment to a supporting surface and a single laterally-extending beam carried by the leg assembly in vertically spaced-apart relation to the fore and aft attachment elements, and first and second laterally spaced-apart seat frames positioned on respective opposite sides of the leg assembly and mounted on the beam for being supported thereby.

Analytical Expressions of Capsize Boundary for a Ship with Roll Bias in Beam Waves

Abstract: We have considered Melnikov's method for assessing ship safety against capsize in beam waves when there is some steady heel due, for example, to beam wind loading. For a generic restoring lever parameterized with respect to the degree of lever asymmetry (bias) we have derived closed-form relationships characterizing capsizability and linking the critical wave-slope, the amount of bias, and the damping. Qualitative differences in the safe basin characteristics are identified, which depend on whether the bias is small or large. A critical look into the accuracy of the Melnikov formulas is also presented for nearly symmetric and for strongly asymmetric rolling, based on comparisons with numerical predictions.

Roll dynamics of a ro-ro ship

Abstract: The prediction of ship stability during the early stages of design is very important from the point of safety. Ships experience six modes of rigid body motions in a seaway, which can be split into two groups as translatory and oscillatory motions. Out of the six motions of a ship, the critical motion leading to capsize of a vessel is the rolling. In the present study, particular attention is paid to the performance of a ship in beam sea. The rolling motion of a ship has been described by a nonlinear differential equation taking into account the nonlinearities in both the restoring moment and the damping moment. Solution of differential equation of roll motion is sought using MATLAB. The effect of different representation of restoring moment on roll motion is investigated. It is seen that, the effect of different representation of restoring moment on roll motion depends on the characteristics of the GZ curve. A parametric investigation is undertaken to identify the effect of different parameters viz., wave steepness, encountering frequency etc., on the capsizing conditions of a ship. The rolling response of ship is determined in the frequency domain. The analysis has been carried out by varying both the wave steepness and the wave frequency. The approach has been demonstrated considering a Ro-Ro ship as test vessel.

Load securement method for general cargo

Abstract: Method of securing cargo to a deck with includes providing a beam of rectangular structural tubing or other shape having multiple D-rings or other lashing apertures along its length The cargo is then lashed to the deck of a roll-on roll-off ship through the beam, with indexed aperture connections at each end which removabley connects the beam to the ship's deck using a pair of twist locks With the application of the method, cargo lashing schemes with tighter packing of cargo and faster, more accurate placement, and safer stevedoring operations are effected according to shoreside prestowage plans Top and bottom mounting points for twist locks allow easy storage, transport, and shoring

Cruise or leisure ship with a large beam

Abstract: The ship has an open or semi open main public space (4), which is situated around the axial longitudinal plane of the ship at the base of the port, and starboard longitudinal superstructures (3). The port and superstructures are located away from the axial longitudinal plane so that the ratio of the width of the superstructures and public space to that of the ship lies between 1.3 and 3.

Conveyor belt scraper

Abstract: A conveyor belt scraper comprises a beam 1 and at least one buffer 2 which is removably mounted on the beam by snap-engagement of a flexible attachment part 5 of the buffer with the beam. The beam may have one or more projecting pins 12 which are received in one or more corresponding holes 7 in the attachment part. The attachment part preferably fits closely around the beam and embraces more than half its circumference. The buffer may be formed from an elastomeric material and may have a hollow region 8. The buffer may support an individual scraper blade 3 or may have an integral blade portion (18, Fig. 3). The integral blade portion may comprise a wear line (20, Fig. 3) along a face thereof so as to indicate the maximum extent of wear before replacement is necessary.

Resistance reduction by increased beam for displacement-type ships

Abstract: The resistance of a conventional hull with a parallel middlebody was compared with its modified version having no parallel middlebody. The modified hull was obtained by parabolizing the waterlines, that is, by extending the waterlines continuously about the middlebody, which results in an increased beam and elimination of shoulders. Numerical and experimental results suggest that there could be a significant reduction in the ship's EHP by parabolizing the waterlines at modest Froude numbers. Also, a theoretical justification based on Michell's integral is presented.

Stop position detecting system of ship-lift

Abstract: A stop position detecting system for ship-lift is disclosed. The measuring well in ascending detection system is positioned on upstream gate. The electric float and sequentially arranged photoelectric tubes are fixed to ascending beam. The measuring well of ship cage contains also an electric float. The reflecting plate on ship cage is coupled with the photoelectric tubes optically. In the descending detection system, the magnetic approach switches are sequentially arranged in the measuring well of ship cage, the electric float is in the measuring well, and the magnetic on the transverse beamis coupled with said approach switches magnetically.

Method of restoring crane runway beam carrying capacity

Abstract: mechanical engineering; heavy duty cranes (7K - 8K). SUBSTANCE: according to method, damaged crane runway beam is demounted and upper belt and upper damaged part of wall are cut off by means of gas cutter. T-section and two channel sections of area equal to section area of cut off part of beam are prepared. Holes are drilled in web of T-section and in webs of two channel sections using cut off belt as template. T-section and cut off belt are connected by channel sections with webs pointed outwards to form closed tubular block divided by T-section wall into two parts. Tubular block is welded by cut off belt to non-damaged part of beam wall by continuous concave weld with penetration through entire thickness of wall. End face of T-section wall has either tight contact with beam upper belt, or clearance DELTA which is closed in case of rise of vertical concentrated forced P from each of crane wheels over their normal value. EFFECT: complete restoration of carrying capacity and increased service life of crane runway beam. 2 dwg

Device for testing reclining of seatback for automobile

Abstract: PURPOSE: A reclining testing device of a seat back for a vehicle is provided to prevent reclining direction from changing, to apply rotational force without load and to exactly test endurance of the reclining in the seat back. CONSTITUTION: A reclining testing device of a seat back in a vehicle comprises a driving arm(18) mounted on a reclining shaft of a seat back(10); an auxiliary arm(20) installed on a driving shaft of the seat back; a rotary actuator(30) rotating the driving arm; a rotational arm(16) extended upward by being connected to the driving arm and the auxiliary arm; a cross beam(14) engaging end portions of the rotational arm; a roller(22) pushing up the seat back by being mounted on a middle portion of the cross beam; an upper base(24) rotationally inserting a rotational shaft of the driving arm and the auxiliary arm; a lifting device controlling height of the upper base; a lower base(34) combined to the upper base by containing the lifting device; and a plate(26) fixing the lower base. Thereby, the reclining testing device of the seat back in the vehicle exactly tests endurance of the reclining in the seat back.

Glass roofed passenger boat comprises hull surmounted by arched frame receiving transparent elements

Abstract: The passenger boat comprises a hull (2) extending along an axis (3) surmounted by a glass roof (4) defined by a frame (5), fixed to the hull, receiving a transparent element (6'). The frame is defined by two arches (7,14) perpendicular to the axis and a side beam (9,9A) fixed in the upper part of each arch.

Non-Linear Features in Large Amplitude Ship Motions (1st Report)

Abstract: The purposes of the study are to investigate non-linear features in large amplitudes of ship motions experimentally and to clarify the mechanism of these features. In the first report, a new non-linear feature of ship motions in high waves was presented. In heavy beam seas, large amplitude rolling motion occurs not only in frequency region of the roll resonance but also in wide frequency region higher than the resonant frequency, and a kind of jump phenomena of rolling motion appears. The cause of these phenomena is that drift motion induced by high waves changes encounter frequency and shifts roll resonance to higher frequency. Roll natural period of the model ship used in the experiments are close to heave natural period. There is quite a possibility that a roll natural frequency influences on the non-linear features in the rolling motion in heavy beam seas.In this paper, additional experiments are carried out to investigate relation between roll natural frequency and roll-resonance-shifting to higher frequency, and to confirm a kind of jump phenomena of rolling motion. The experiments show that roll-resonance-shifting to higher frequency is significant with increasing roll natural frequency. This phenomenon is induced by increasing drifting velocity due to increasing roll natural frequency. A non-linear feature of heaving motion is also confirmed near heave natural frequency.In the experiment, the model ship is knocked to induce jump phenomena during the measurement of ship motions in heavy beam seas. The results show that two modes of ship motions appear with different encounter frequencies for the same regular wave.To reveal the reason of the non-linear features shown in the experiments, non-linear hydrodynamic characteristics in the motion equations for drifting and roll-heave-sway coupling motion are investigated.

Lifting attachment with umbrella

Abstract: PROBLEM TO BE SOLVED: To handle cargoes without getting wet in the rain by using an inexpensive and convenient device. SOLUTION: A lifting attachment 16 consisting of a lifting beam 44 and a coil lifter 45 is hung down from a wire rope 59 for a crane. The lifting attachment 16 is covered with an umbrella and the umbrella 13 is centered on the lifting attachment 16 with a centering mechanism and separatably joined thereto with a joint mechanism 17. A cylindrical cover 56 is hung down from the lifting beam 44 and a transparent plate 58 is attached to the umbrella 13. An opening portion 60 of the umbrella 13 is covered with a rope guide 62 for suppressing the vibration of the lifting attachment 16.

Device for making gutter for draining away rainwater from road or path comprises two spaced apart positionable moulds

Abstract: The device for making a gutter for draining away raiwater from a road or path comprises two spart positionable moulds. One mould (1) is provided with a relatively thin plate (2), across which extends a beam (3). The beam on a side turned away from the plate has a concave locating surface (4). The plate is constructed from a number of interconnected segments (5). Through the segments, a polygonal locating surface is created. The number of segments and their width are determined by the number of stones (6) and their width (S), from which it is required to construct the gutter (7). The width of the segments is above all dependent upon the desired height difference (D) between the outermost and innermost stones. The beam on opposite sides of the locating surfacec is provided with level support surfaces (8). On its underside near the plate, the beam is provided with slanting edges (9).

Device for transforming flexible boat hull into efficient sail boat comprises beam with fixing points for superstructure, rigging , rudder blade and fin keel

Abstract: The device for transforming a hull into a sail boat is composed of a beam (1) on which are fixing points for the superstructure, fixing points (2,3,4) for the rigging and fixing points (8,9) for submerged appendages, such as a rudder blade (10) and that of the fin keel (11).

Characteristics of Seakeeping Performance of Philippine Outrigger Craft

Abstract: The Core-University Scientific Corporation Program has started between Philippines and Japan from 1998. The project of fishing craft is conducted to improve the performance of Philippine outrigger craft. Most fishing craft of the Philippines are constructed in the double outrigger form with a main hull and floats at both sides. Generally, a float and its beam are made of bamboo. In this paper, the characteristics of ship motions are experimentally investigated to clarify dangerous sea conditions for the craft in waves. A computer program has been developed to calculate ship motions of the craft. The accuracy of this computer program is checked by measurement of ship motions in waves. Furthermore, results of the calculation are in good agreement with the measured ones. From these results, the outriggers increase heaving and pitching motions in head seas at the short wave length, although significantly decrease heaving and rolling motions in beam seas.