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The pioneer of modern icebreakers is the Ermack (or Y ermak), built by Sir Armstrong Whitworth and Company on the Tyne in 1898. In general appearance she resembles a man-of-war, having broad, ponderous, sturdy lines. Originally she had a propeller in the bow as well as at the stern, to serve the dual purpose of aiding steering in ice-floes and to suck the water out from under the ice forward, thus rendering the ice more vulnerable to the crushing weight of the ship as she glided up on to the ice floe. In practice, however, the forward propeller of the Ermack was found to be unnecessary and it was later removed. The fore-part of the vessel was cut away together with the propeller shaft and tube and a new bow was fitted, making the vessel 15ft. longer. To prevent the ice getting a grip on the hull, the Ermack's sides were built without any flat surface, similar to the famous Norwegian Polar ship Fram. Steel-built with a double skin from keel to upper deck the Ermack's outer shell is tin. thick, and stiffened by 48 watertight bulk-heads between it and the inner shell She has two unusually large funnels, copied in the icebreaker Yosef Stalin, and her boilers supply steam to three main engines, which at her maximum speed develop 9.500.h.p. A 70 deg. slant to her bows enables the vessel to ride up on to the ice which she crushes by sheer weight. She has gone through solid ice loft. thick, and pack-ice 34ft. thick.
On her first trip she released nine steamers frozen in heavy ice in the Gulf of Finland. By powerful pumps the 800 tons of water in the ship's double-bottom tanks can be transferred to either end or side of the vessel, thus allowing her to be trimmed by the head or by the stern, or heeled to port or starboard, to enable her to rid herself of ice wherever necessary. Although the Ermack is not the first icebreaker, she was the first really successful ship of her kind. Her particulars are: Displacement 7,875 tons, 4,817 gross tons; dimensions, 305ft. x 71ft. x 25ft The Ermack's Baltic complement is 112 men and her speed 15 knots. SG2314