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the receiver pipes have been con- nected to the lower halves of the tur- bines in every case. Emergency con- nections have been fitted, so that any of the turbines can be cut out if this should be found necessary. In each set the high pressure tur- bine is fitted with an Aspinall patent governor combined with a fore and aft indicator and control, while the intermediate pressure and low pres- sure turbines are fitted with fore and aft indicators and controls only. With this arrangement, the steam would be shut off in the event of the turbine speed exceeding a certain limit. The fore and aft indicators show any axial movement of the tur- bine rotors; and should the wear on the thrust pads make this movement excessive, the control would then op- erate and shut off steam. Steam would also be shut off in the event of the oil pressure in the lubricating system dropping unduly or failing entirely. The main condensers, which are of the Weir two flow regenerative type, with a large reservoir at the bottom - for storing the water required for the successful operation of the closed feed system, are slung underneath the low pressure turbines. Each in- board condenser has a cooling sur- face of 20,700 square feet, the tubes being %-inch in diameter and 14 feet 6 inches long; while each out- board condenser has a cooling sur- face of 9600 square feet, with %- inch diameter tubes 11 feet 6 inches long. The tubes for all the condensers are made of cupro-nickel. A particular feature of the con- densers is the water doors, which have been designed to facilitate the quick examination of the_ tubes. Large hinged doors have been fitted in each end, and these are jointed with rubber rings recessed into the casing. The doors are secured by swivel bolts and dogs, which may be removed for inspection purposes in a few minutes. Gearing, Propellers and Boilers The main gearing is of the usual double helical, single reduction type, and the main gearwheels of the in- ner and outer shafts have diameters of 14 feet 6 inches and 11 feet 3% inches respectively. All the pinions are connected to their respective ro- tors by flexible claw type couplings. The gearwheels and pinions are en- closed in strong cast iron gear cases. The thrust of the propellers is transmitted to the vessel through Michell thrust bearings of the single collar type, fitted to the main lines of shafting immediately aft of the gearing; and the tunnel shafting is supported by bearings of the Michell pivoted pad journal type. The propellers, which are of solid bronze, have diameters of 19 feet 3 inches and 14 feet for the inner and 36 outer shafts respectively. When de- veloping the normal service power of 60,000 shaft horsepower, the speeds of the propellers are 150 and 200 revolutions per minute and the corresponding speeds of the turbines are 1365 and 1795 revolutions per minute for the inner and outer shafts respectively. The reduction ratio, therefore, is about 9 to 1. The boiler installation consists of eight oil fired water tube boilers of the Yarrow type and one oil fired water tube boiler of the Johnson type. The boilers are arranged in two compartments, and the same principle of division of power has been carried out in the boiler ar- rangement as with the main engines. Six of the boilers are placed in the after boilerroom, normally sup- plying the forward inboard engines; while three boilers are installed in the forward boilerroom, supplying the outboard engines in the after engineroom. The arrangements are such that any or all of the boilers can supply the ahead and astern tur- bines in the forward engineroom. The Yarrow boilers are of the double flow side fired type, having one steam drum, three water drums, and one superheater drum. The flow of the gases is through both sides of the boiler, after which it passes through a large tubular air heater and thence to the funnel. The boiler and superheater drums are hollow rolled forgings with ends formed integrally, and represent the latest practice for high pressure boiler work. The Johnson boiler consists of two large-diameter drums, placed verti- cally one above the other and con- nected to each other by curved tubes which are: arranged longitudinally and across the ends in such a man- ner that the combustion space is al- most entir eenclosed by water tubes. In addition, there is a wall of wate. tubes along the center of the boiler, which divides the combustion space into two separate compartments. This arrangement of tubes provides for a considerably larger amount of tube surface exposed to radiant heat than in other types of marine water tube boilers. The boiler was constructed at Clydebank and a series of very com- plete trials showed that it is capable of generating double the amount of steam per square foot of heating sur- face, while registering the, same effi- ciency as a Yarrow or other stand- ard type of boiler worked at ordinary mercantile rating. Supreme vortex steam dryers have been fitted to the boilers in the after boilerroom, while tangential steam dryers are installed in the boilers in the forward room. Each main boiler is fitted with two automatic feed regulators, one of the Weir and the other of the Mumford type, while Parry soot blowers are also provided. MARINE REVIEW—May, 1931 In order to give the alarm when the water in the boilers falls below a predetermined level, Mumford low water alarm gear has been installed, In the forward boilerroom there are also two cylindrical boilers of the return tube for domestic and other auxiliary purposes. These boil- ers are arranged to burn oil fuel with the Howden system of forced draft, and are designed for a work- ing pressure of 200 pounds per square inch. The oil fuel pumping and heating installation is of the Wallsend-Howden type. Diesel Electric Generating Plant In the separate compartment be- tween the forward main engineroom and the after boilerroom are situated four Fiat British diesel engine- driven generators. Each of these generators, which has an output of 450 kilowatts is driven by a Fiat British single act- ing, two stroke cycle, four cylinder engine developing 660 brake horse- power at 260 revolutions per minute, and each driving its own double-act- ing scavenging pump, three stage air compressor, circulating water pump and lubricating oil pump. For emergency use and for sup- plying the starting air, there is a Reavell electrically driven compres- sor, and in the auxiliary engineroom there are also two fuel oil transfer pumps. In addition to the diesel engine- driven generators, there are two Brit- ish Thomson-Houston turbo-driven generators of 800 kilowatts eack. These are situated in the forward main engineroom and are supplied with high pressure superheated steam from the main boilers, the exhaust being connected directly to the con- densers. The turbo-driven generat- ors are driven at 670 revolutions per minute through gearing, the turbines running at 6000 revolutions. The remaining auxiliaries, which are mostly electrically driven, are ar- ranged in three pairs, so that one pair will serve each of the larger main engines and the remaining pair the smaller outboard sets. The Weir closed feed water system comprises electrically driven centrif- ugal extraction pumps, feed pumps of the turbo-driven centrifugal type, and the necessary filters and primary and secondary heaters. The Drysdale main circulating pumps are of the vertical-spindle centrifugal type, driven by electric motors. Nine Drysdale centrex pumps have been supplied for the forced lubrication system, and Vickcen cen- trifugal separators are installed for the purification of the lubricating oil. On her preliminary trial trip in the open sea off Wemyss bay on April 6, the new liner averaged be- tween 18 and 20 knots with engines not open. The ship is expected to do better than 24 knots. De ot Cee END eee bi ne BT Bae Shh