Engineering Wonders of the World
Volume III

SOME EXTRAORDINARY stand impact with heavy ice. Her trans- verse form is such that when wedged between masses of ice she will tend rather to rise than be depressed. Her bow slopes upwards from below, so as to enable her to run up on the ice and thus use her weight to break it ; while her stern is so shaped as to afford the maximum protection for the screw propellers against ice. When she left her builders’ hands the Ermack, in addition to three screws aft, had one fitted at the fore end, which vzas in- tended to disturb the water below the ice, and so assist the weight of the ship in break- ing through. While working in thick field ice, however, the shaft of the forward screw became bent, and it was found necessary to remove the screw. Later, the vessel returned to the Tyne, and a new fore-body was built, omitting the forward screw. The ship was then docked, the old bow cut away, and the enlarged fore-part joined on, the length of the ship being increased to 320 feet. Fig. 2 is from a photograph taken while the ice- breaker was in dry dock for this alteration, SHIPBUILDING FEATS. 123 and shows the new bow in position. The Ermack proved herself capable of crushing with comparative ease the ice met in the Baltic in the middle of winter, and on an experimental voyage to the Polar Sea north of Spitzbergen she made her way through vast ice-fields, and successfully encountered floes of the greatest thickness. The increased use of submarines as adjuncts to the world’s fighting fleets has confronted the naval architect with a good many prob- lems apart from those in- volved in the design and con- Transporting struction of the craft them- selves. It is well known that when a flotilla of submarines are engaged in manoeuvring some distance from shore, they are usually accompanied by a “ mother ” ship ; but the general public are not so familiar with, the special moans employed for transporting sub- marines when it becomes necessary to convey them from one part of the world to another. Recently Messrs. Vickers Sons and Maxim, Fig. 2.—ICE-BREAKER “ ERMACK ” IN DRY DOCK, WITH NEW BOW IN POSITION.