THE T.S.S. RANGATIRA

Otago Witness, Issue 4029, 2 June 1931, Page 78

THE T.S.S. RANGATIRA

NEW FERRY STEAMER (From Our Own Correspondent.) (Photographs in This Issue.) LONDON. April 17. The t.s.s. Rangatira, which was successfully launched by Lady Wilford at 'Bar-row-in-Furness yesterday, is intended for service between Lyttelton and Wellington. Iler principal characteristics are: Length 8.P., 400 ft; breadth mid.. 58ft; depth, moulded to upper deck. 29ft, load draft, 17ft: maximum speed, 21J knots. The vessel will have five decks and will be sub-divided by watertight bulkheads to meet »the full requirements of the Board of Trade. Fire screens will ’also be fitted on the main, upper, and promenade decks, and altogether, every precaution is being taken to ensure the maximum amount of safety for the passengers and crew. Accommodation will be provided for about 720 first saloon passengers, about GOO being accommodated in cabins and the remainder in public rooms; 236 second saloon passengers, 170 in cabins and GC> in public rooms; and a crew totalling about 112. There will be a handsome dining saloon, entrance lounge and smoke room for the first saloon passengers and a dining saloon and entrance lounge for the second saloon passengers. Ample lavatory accommodation will be provided for the passengers and the Thermotank sys-

tern of ventilation will be fitted throughout the vessel. Provision is being made for carrying a certain amount of cargo, including large spaces for motor cars in the ’tween decks, where a certain numberof horse stalls will also be fitted. Each cargo hold is provided with a hatchway trunked up through the accommodation decks and served by means of two steel derricks and two electric winches. An electric windlass and capstan will be fitted forward and twin electric capstans aft for mooring purposes. A BOW RUDDER. ■

Electric-hydraulic steering gear, with telemotor control from the bridge, is placed on the lower deck aft, and a bow rudder is fitted forward for manoeuvring purposes, with similar type steering gear. Twelve lifeboats, with a total capacity of 680, will be fitted, with Welin-MacLach-lan gravity lowering davits. The Rangatira when completed will be of handsome appearance with a raked stem and cruiser stern, two masts and two funnels. The main propelling machinery consists principally of two separate turbo-alternators each with its own condensing plant and auxiliaries, two double unit synchronous motors which are coupled direct to the twin propeller shafts, a contractor cubicle to control the power from the alternators to the propulsion motors and two balancer booster sets for excitation purposes. The ratings of the machines are: — Two B.T.H. impulse type turboalternator sets maximum rated 5120 k.w., 3080 r.p.m., 3150 volts three-phase. Two Double unit synchronous propulsion motors each 6500 s.h.p., 220 r.p.m., 3150 volt, three-phase. Isolators are provided on the forward end of the control cubicle to enable each alternator to be electrically connected to its respective propeller motor or either of the alternators to be connected to both propeller motors. Provision is also made on the forward end of the control cubicle to enable one half unit of each propeller motor to be isolated when running on one turbo alternator set. Controls are interlocked so that damage cannot be done to any portion of the equipment when manoeuvring by an unskilled operator. At the same time indicating instruments are provided by means of which an operator can carry out orders in a very short space of time with a minimum of manual effort. For each propeller, three controlling levers are provided, namely, a direction lever, field lever and speed controlling lever for varying the speed of the turbine. These are all mechanically interlocked to ensure correct operation. The whole of the control cubicle is “ mistake proof.” and. with the special keys incorrect switching is impossible. For example, whenever it is necessary to open or close an isolator, it is essential to have all the levers in the “ off ” position. AUXILIARY MACHINERY. For supplying all the auxiliary, lighting ami cooking loads three B.T.H. 350 kw.„. 220-volt, geared combined condenser turbo, generator sets are installed. The maiii condensers are two in number of Weir’s Regenerative type, having a total cooling surface of 13,500 square feet, the capacity of the condensers being sufficient to maim tain a vacuum of 281 inches of mercury with a sea temperature of 70 Fahrenheit. The steam generating installation consists of six Yarrow high-pressure water tube boilers of the five drum, single flow, front fired type, fitted with superheater* and tubular air heaters. Steam is gener. ated at 4001 b per square inch, and super, heated to 725 degrees Fahrenheit. The ’ total generator surface is about 27.600 ; square feet, and total superheater surface about 9000 square feet. The total area of the tubular air heaters is about 27,648 i square feet. The boilers are arranged to burn oi] only under the forced draught air duct system. Air is supplied to the i boilers by six electrically driven fans of Howden’s double inlet type, against a water guage pressure of six inches. The oil fuel installation comprises two duplex units, electrically driven, one working and one standby set, one simplex unit being provided for harbour with steam-driven pump. The auxiliary machinery is of the latest and most improved type, consisting of fou tmain, and two auxiliary electrically driveij , circulating pumps, electrically driven exr traction pumps for the main closed feed i system, also for the auxiliary closed feed ' system. Surface type feed heaters are fitted for raising the temperature of the feed water, comprising one low pressure, one inter? - mediate pressure, and one high pressure heater, heating steam being taken from the auxiliary exhaust system, and bled at suitable pressures from the main tur? bines. A boiler evaporating plant is pro? vided, comprising one Wyndham heater and high pressure evaporator with dis? tiller and one low pressure evaporator for supplying double distilled make-up feed water. A fresh water distilling plant i? also provided for ships purposes consist? ing of two evaporators, two distillers, and two filters, each set capable of supplying 2000 gallons of fresh water per 24 hours. The remaining auxiliaries are electrically driven and are of the latest type suitable for this class of vessel.