"About an Idea of Ship Brake" (Abstract)(Reports from the Research Committees)

Abstract

It is a fired idea that a ship can not stop immediately. The author wants to challenge this idea, and made some investigation about a ship brake. Since the appearance of gigantic ships, there arose many problems. But it seems that the problem of uneasiness of maneuvering a ship, especially in the area of near shore, is one of the most urgent. In this paper, the author reports about fundamental problems of ship brake and tried mathematical rough caloulation of the brake force in order to find the way of realization, as a step prior to experiments. There exist many devices or ideas of immediate stopping a ship already. For instance, reversing of the main engine and the propeller, antipropulsion jet of water, the parachutes in the water, etc. But unfortunately, most of them do not sutisfy the desire of captains or pilots yet. The author mentions that the most reasonable ship brake must be a simple type of strong resistance steel rod, which will be pushed out under water horizontally, from both sides of a ship, with remote control method; and also this brake must be used for turning the ship's head immediately, and consequently used for effective course keeping, especially during the ship is in slow speed, while the conventional rudder is rather no use. And if the shape of rods are designed to have turning mechanism, it will be used for roll-suppressing of the ship, too. It is also a problem what the efficiency of ship brake must be. As for this problem the author aimed at the maneuvability of a ship equivalent to a tenth size of its own ship; for instance, by using this device one could reduce the stopping distance and diameter of turning circle of a 200,000DWT tanker to these of 20,000DWT tanker. The author's speciality is the nautical instrument, and this problem does not fall in his proper field. But he had the necessity to consider this device in the aspect of ship dynamics from his own standpoint. That is the reason why he attempted a rough calculation of the brake force acoording to the fundamantal data. The curve he obtained will be applicable to a ship 170,000DWT, with varying speed, for an example. Finally, the author explained the relation between control lever in the bridge and the brake rods on both sides of the ship, by a diagram.