THE RANGATERA.

Press, Volume LXVII, Issue 20243, 22 May 1931, Page 18

THE RANGATERA.

* NEW FERRY STEAMER. MACHINERY AND ACCOMMODA- . TION. IIT.OU OUR OWN COSBEBPONDEST.) LONDON, April 17. The T.S.S. Eangatira, which was successfully launched by Lady Wilford at Barrow-in-Furness yesterday, is intended for service between Lyttelton and Wellington. Her principal characteristics are:—Length 8.P., 400 ft; breadth mid., 58ft; depth, moulded to upper deck, 29ft; load draft, 17ft; maximum speed, 21$ knots. The' vessel will have five decks, and will be sub-divided by water-tight 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 600 being accommodated in cabins and the remainder in public rooms; 236 second saloon passengers, 170 in cabins and 66 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 J;he second saloon- passengers. The thermotank system 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 number of 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-MacLachlan gravity lowering davits, t The Rangatira, when completed; will be oi 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 contactor cubicle to control the power from the alternators to the propulsion motors apd two balancer booster sets for excitation purposes. The rulings of the machines are:— Two B.T.TT. impulse type turbo-alter-nator sets maximum rated 5120 k.w.. 3080 r.p.ni., 31-50 volts '3-pliasc. Two double unit synchronous propulsion motors each 6500 s.h.p., 220 r.p.m., 3150 volt, 3-phase. Isolators are provided on tlfo forward end of the control cubicle to en- : able 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 vti the forward

end of the control cubicle to enable one hal f unit of each, propeller motor to be isolated when running on one turbo alternator feet. ' Controls aro interlocked so that damage cannot bo 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 {in 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 mechanicaly 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, and cooking loads three B.T.H. 350 k.w., 220 volt, geared combined condenser turbo-generator sets are installed. The main condensers are two in number of Weir's Begenerative type, having a total cooling surface of 13,500 square feet, the capacity of the condensers being sufficient to maintain a vacuum of 284 inches of mercury with a sea temperaturo of 70 degrees Fah. The steam generating installation consists of six Yarrow high-pressure water-tube boilers of the five drum, single flow, front fired type, fitted with super-heaters and tubular air-heaters. Steam is generated at 4001b per square inch, and superheated to *725 degrees' Fah. The' total generator Burface is about 27,(#0 square feet, and total super-heater surface about 9000 square feet. The total area ■ of the tubular air heaters is about 27,648 square feet. The boilers arc arranged to burn oil only under the forceddraught air-duct system. Air is supplied to the boilers by six electri-. cally-driven fans of Howden's double inlet type, against a water-gauge 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 purposes with steam-driven pump. The auxiliary machinery is of the latest and most improved type, consisting of four main and two auxiliary electrically driven circulating pumps, electrically, driven extraction pumps for the main closed feed system, also for the auxiliary closed feed system. The main feed' pumps are of "Weir's turbo-driven type. Standby feed pumps of Weir's steam driven direct acting type are fitted. Surface type feed, heaters are fitted for raising the temperature of the feed water, comprising one low pressure, one intermediate pressure, and one high pressure heater, heating steam being taken r from the auxiliary - exhaust system, and bled at suitable pressures from the main turbines. A boiler evaporating plant is provided,, comprising one Wyndham heater and high pressure evaporator with distiller, and one lew-pressure evaporator I'or supplying double distilled make up feed-water. A fresh water distilling plant is also provided for ship's purposes, consisting : of two evaporators, two distillers, and two filters, each set capable of supplying 2000 gallons of fresh water per 24 hours. The rem ning auxiliaries are, electrically driven, and are of the latest type suitable for this class of vessel. ......