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Empress of Britain is Nearing Completion at Clydebank BritTAIn, Which will leave Southampton on her first voyage to Quebec on May 27, is arousing great- er interest than the entry into serv- ice of any other British-built Atlantic vessel since 1914. With her gross tonnage of about 42,500, not only will the new liner be the largest, swiftest and most luxuriously ap- pointed ocean-going vessel to ply be- tween any two ports in the British Empire, but her propelling machinery represents the latest and in many respects the most outstanding ex- ample of high pressure and high tem- DVENT of the new Canadian A Pacific liner EMPRESS’ OF perature steam practice in the world’s mercantile marine. (See photo on page 19). The EMPRESS OF BRITAIN was launch- ed on June 11, 1930, at John Brown & Co. Ltd., Clydebank, Scotland. She is by far the largest ship built for the Canadian passenger trade and also the speediest. An average sea speed of 24 knots is to be maintained when she enters the Southampton-Quebec service of the Canadian Pacific Steamships, Ltd. Her length overall is 758 feet; length on the load waterline, 755 feet; length between perpendiculars, 730 feet; beam molded, 97 feet 6 inches; depth to B deck 60 feet 9 inches; load draft, 32 feet and gross tonnage, of about 42,500. Passenger capacity is 452 in first class; 260 in tourist class and 470 in the third class. The Prince of Wales was the sponsor at the launching. No pains are being spared to make her one of the finest transatlantic liners. First class staterooms have been arranged for one and two passengers each. Seventy-five per cent of the first class staterooms have either a private bath and toilet or shower and toilet. There are two de luxe suites of rooms, com- prising a sitting room, bedroom, ver- anda, bathroom, separate toilet and a large box room. There are 18 spe- cial staterooms for two persons, each room having its own private bath and toilet. Bedsteads of large size are fitted in all first class staterooms. One of the Great Liners From all this it will be seen that in size, in speed and in luxury of pas- Senger accommodations the EMPRESS OF BrivTain will take second place to very few of the vessels of the world. The progressive policy of the Cana- dian Pacific line in creating during the last six or seven years a large and up-to-date fleet of ocean steam- ships of all classes, for both passenger and cargo-carrying services, has in- volved new construction and the re- engining of existing vessels on an unprecedented scale. Not the least inducement to embark on this ex- penditure of many millions sterling, whieh has culminated in the build- ing of the EmMpRESs or BRITAIN, was provided by the economies in the cost of propulsion and operation which John Johnson, the company’s chief superintending engineer, was able to offer through his new conceptions of high pressure steam practice. It may be recalled that the Duchess pas- senger steamships of the Canadian Pacific line attained a fuel economy of 0.625 pound of oil per shaft horse- power per hour for all purposes, and still more recently the same owner’s EMPRESS OF JAPAN set up a world rec= ord of 0.603 pound for all purposes. It is anticipated in technical circles that this record will be surpassed by the latest and largest Empress. The hull of the EMPRESS OF Brit- AIN, has been constructed by John Brown & Co. Ltd., Clydebank; and the same company has also built and installed the main engines, gears and. boilers under Mr. Johnson’s care. Four Propellers Are Used The vessel is propelled by four screws, each driven by an independ- ent set of single reduction geared turbines of the Parsons type. To suit the conditions under which the ship will run, viz., voyages between Great Britain and Canada during the summer and world cruises during the winter, the engines driving the two inboard screws are designed to de- velop two-thirds of the total power, while the engines driving the two outboard screws develop the remain- ing one-third. In other words, the power of the outboard engines is only - one-half that of the inboard engines. Under cruising conditions, if full power is not required, only the in- board engines will be used, and the vessel will then be twin screw. The machinery has been designed to develop normally a total output of 60,000 shaft horsepower continu- ously at sea, in order to maintain a normal speed of 24 knots. If an in- crease of speed is necessary at any time, however, an overload power of 64,000 shaft horsepower can be maintained for long periods. Two engine rooms are necessary for the main propelling machinery, the two inboard sets being arranged in a compartment forward of that in which the two outboard sets are in- stalled; while certain of the auxiliary machinery, which will be described MARINE REVIEwW—May, 1931 later, is situated in a separate auxili- ary engine room immediately for- ward of the two main engine rooms. The main turbine sets each com- prise one high pressure, one inter- mediate pressure and one low pres- sure turbine, working in series; and each turbine drives a separate pinion, which engages with the main gear- wheel. For astern running, a high pressure unit is incorporated in the same casing with each of the two intermediate ahead turbines and a low pressure unit in the exhaust end of each of the two low pressure ahead turbines of the inner shaft machinery only. No provision is made for astern working on the outer shafts, which are employed exclusively for ahead duty. The astern turbines are capable of developing 60 per cent of the aggregate ahead service power. High pressure turbines are all con- structed to withstand a maximum working pressure of 425 pounds per square inch and an initial steam tem- perature of 725 degrees Fahr., but they have been designed to develop the service and overload powers when employing steam between the limits of 3875 pounds per square inch (gage) and 0.50 pound per square inch (absolute), with an initial steam temperature of 700 degrees Fahr. Turbines of Impulse-Reaction Type The high' pressure ahead turbines are of the impulse-reaction type, com- prising a two-row velocity wheel with blades of stainless steel, and a re- action portion fitted with end-tight- ened blades of Monel metal. Nozzle control valves are fitted to enable a gradual increase of power to be ob- tained, while at the same time main- taining as high a pressure as possible in the control chest for quick opera- tion. The intermediate pressure ahead turbines are of the reaction type throughout, with end-tightened blades of phosphor-bronze. The low pressure ahead turbines are also of the reaction type, with phosphor- bronze blades. High pressure astern turbines each consist of a three-row impulse wheel, while the low pressure astern tur- bines each have two impulse wheels with two rows each, in which the blades are of stainless steel. To eliminate vibration, all the ro- tors have been dynamically balanced. The low pressure ahead turbines are of the double flow balanced type, and each of the other turbines is fitted with a dummy to reduce the end thrust due to the difference in steam pressure. Michell thrust bearings of the spherical seated type are fitted to each rotor to take up any remain- ing axial thrust. Owing to the high steam temperature employed, the tur- bine casings are of cast steel, with the exception of the low pressure casings, which are of cast iron. To facilitate the lifting of the up- per portions of the turbine casings, 35