MARINE IMPROVEMENTS.

Kumara Times, Issue 884, 31 July 1879, Page 4

MARINE IMPROVEMENTS.

The Nautical Magazine gives the following description of recent marine improvements for which applications for patents have been made : Improvements in Steering Apparatus for Vessels,—A rudder or paddle in the form of a blade or fish’s fin is made capable, by means of a moveable joint, of being caused to lie close against the vessel or to protrude into the water, in wh ch nosition a acallina motion, which may be reversed, is imparted to it, and throughout such movement the blade exerts a propelling effect, its focus being during the whole time at some efficient working angle to the direction of movement. The motion thus imparted to the blade renders it capable of turning the vessel when not in rapid motion. To turn her in rapid motion the blade is simply turned to a suit* able angle as an ordinary rudder. The paddle or blade has motion imparted to it for active steering by a connecting rod constantly turning it to the angle suited to the point of its travel, motion being given to the connecting rods by a crank-shaft, which may be turne • by any suitable engine. An Improvement in Screw Propellers.— This has for its objeot the rendering more durable of iron and steel screw propellers, and making them less likely to foul than as at present constrncted. On account of the blades of iron and steel propellers rusting and consequently becoming weakened and often breaking, they have been constrncted of a much greater thickness than necessary for strength, in order that their inevitable dissolution may be retarded, and, in consequence, gun metal has been largely used as a substitute, though a much inferior metal in point of strength. With the view to combine the advantages of lightness and strength, and to prevent fouling and oxidation, the inventor constructs screw propellers .of iron or steel, and protects them by producing on their surfaces, by means of an atnmoniacal cyanide copper bath, and subsequently an ordinary sulphate of copper bath, a deposit of copper which enables the screw to resist oxidation and fouling. Improvements in Ship Telegraphs.—This relates to telegraphs for the purpose of conveying orders between officers and men, and of repeating back those orders to show that they have been received. A transmitter, having a dial with divisions marked respectively with the different orders that have to be transmitted, and an index moveable by band over the dial, is placed on the bridge ; the receiving instrument placed in the engine-room has a dial and index corresponding with those of the transmitter, each dial having another hand for repeating the signals sent. On the axis Of the index, under the dial in the transmitter, is fixed an arm carrying a roller, which is pressed by springs against the interior surface of an insulated ring, into which ebonite (a non-conducting mater a') is let in at places corresponding with the spaces between the orders marked on the dial above. Upon turning the index to transmit an order, the roller, passing over the ebonite and conducting portion of the ring alternately, causes an interrupted electrical circuit, which, by means of an electromagnet, with a pawl upon its arxniture working a ratchet wheel at the receiver, records the order upon that dial, a bell being set ringing at the same time by another elecfromaghet, continuing to do so till the order has been signalled back, a secondary dial, but with the mechanism reversed, being fixed to each instrument for this purpose. A modification of this signalling apparatus is also shown.