Navigation Bridge Research Articles

ブロツク式建造漁船における船内磁場の分析(日本航海学会第33回講演会)

The magnetized state of the ship's body by block system differs from that by the system heretofore in use (riveted structure), despite of the magnetic compass deviation depending on it. This report dealt with the magnetism of the ship's body of "Tenyo-maru" built by block system in relation to her structure or to the direction of her head during construction. And the results obtained are summarized as follows : (1) The magnetic force of the ship's body was weaker on the compass bridge deck than on other deck. (2) The components of the magnetic field of the ship's body could be arranged as follows according to the intensity : vertical field, horizontal permanent field, induced field by athwartships horizontal soft iron, and that by fore-and-aft one. (3) The ship's body was more strongly magnetized on building berth than on fitting-out basin, but the direction of permanent magnetic field of the ship's body did not always depend on the building direction. (4) There was great magnetic force at the stations near the transceiver of marine radar. And the effect of local magnetic field due to nearby transceiver of radar, in some case, could not be compensated for by the ordinary correctors. (5) Vertical magnetic field by the ship's structure was directed downwards on the compass bridge deck and upwards on the navigation bridge deck.

Ships' Navigation Bridges

Ships' Navigation Bridges

Some Examples of the Aerodynamical Experiments Concerning Ship's Equipments

This paper deals with the results of three kinds of aerodynamical experiments. Part I is a report on the experiments which were made to know the efficiencies of six types of the cowl-head ventilators in the wind from all directions, namely, circular, elliptical, and obovate types with a vertical and a convex back form respectively. Among these six, the elliptical type with a convex back shows the best efficiency of ventilating.Part II. deals with the experiments made to make clear the effect of the wind-deflector attached to the wing parts of the navigation bridge of the ocean-going cargo vessel. And a device to improve its efflciency is offered.Part III. shows the results of wind-tunnel experiments made to minimize the smoke nuisance of ships' stacks.