HOW AN ICEBERG WORKS.

Hawera Star, Volume XLVIII, 23 February 1925, Page 8

HOW AN ICEBERG WORKS.

How many people know how an icebreaker works ? There is an idea that it simply ploughs through the field of ice and smashes things up on the wav. This is not the case.

In the largest shipbuilding yard on Clyde, that of William Reardmore ana Co., Ltd (writes a, .Scottish correspondent), I saw an ice-breaker in course of construction to the order of the Government of Latvia, intended for keeping the port of Riga, open through the winter. This particular ship was 2,75!) tons, with a fength of 185 ft. She has a cast steel stem and sternpost, and an iee belt one inch thick at the water line, and about six feet above and below it. ’ In the vicinity of the bow and the stern the hull is similarly strengthened. The lines of the vessel are somewhat like those of a shallow river punt. The procedure in breaking a field of ice is for the ship to charge the edge of the ice at a. fairly high speed; On striking it the stem slides up, until the weight of the vessel, combined with the action of the forward propeller (there is a propeller at each end of the ship), which sucks the water away below the ice, thus depriving if of support, breaks down the edge of the field. When the field is too thick for the vessel to break it. however, further measures are necessary. In order to increase the weight on the how, there are special tanks at- stem and stern; and pumping arrangements for transferring about 150 tons of water from aft to forward in ten minutes by two pumps, and each with a capacity of 1,000 tons per hour. The protected pro. pellers at e'ach end are driven by tripleexpansion engines aft, developing 4,000 li.p., and one set forward of about 1500 b.p. The speed on service will be about 13 knots.