Diesel-Electric Ship TANKER BRUNSWICK COMING

Sun (Auckland), Volume II, Issue 552, 3 January 1929, Page 2

Diesel-Electric Ship TANKER BRUNSWICK COMING

Epoch in N.Z. Shipping

AX event of outstanding interest in marine and oil codes in New Zealand will be the arrival at Auckland in midJanuary of the Atlantic Union Oil Company’s diesel-electric tanker Brunswick —the largest vessel of her type in the world to-day. She is also the first electrically driven ship to visit New'Zealand —perhaps even the first to visit the Southern Hemisphere.

The Diesel-electric system was conceived by Captain Durtnal, an Englishman. who first propounded it in a lecture before the Institute of Engineers in London in July. 1914. The principle, however, was not adopted for practical purposes until about 1916. when it was tried out in a vessel on the Mississippi. Unlike other motive power for ships, the vibrations of the Diesel-electric system are so light and rapid that the effect is one of apparent vibrationless movement. Moreover, there is the further advantage of reduced noise. The hull of the Brunswick was built bv Scotts’ Shipbuilding and Engineering Co., Greenock. Messrs. Carols Freres constructed the Inger-soll-Rand type engines at Ghent, while the electrical part of the installation was manufactured by the British. Thomson-Houston Company, Rugby. * REMARKABLE SHIP She is a single-screw tanker, built on the Isherwood system of longitudinal framing, and is a true “electric*' ship, in that she is not only propelled by electric power, but the whole of her deck and engine-room auxiliaries, including her cargo pumps, are electrically driven also. The following are the main dimensions of the Brunswick: Length. between perpendiculars, 496 ft. Breadth, 63ft. Depth, moulded, 36ft 9in. Draught, loaded, 26ft lOin. Deadweight capacity, 13,210 tons. Immersion, 60.4 tons per inch. Block coefficient, 0.79. Service speed, loaded. 11 knots. Engine power, total 3.000 b.h.p. Propelling motor, 2,800 s.h.p. Engine speed. 225 r.p.m. Propeller shaft speed, 95 r.p.m. Number o engines, 4. Cylinder diameter, 19.5 in. Piston stroke, 24in.

An unusual feature is the location of all the accommodation aft, no bridge being provided amidships. The more customary practice is to arrange accommodation for the captain, deck officers and certain of the staff approximately amidships, where the navigating position is usually situated. To look along the deck from the bridge of the Brunswick, therefore, is to gain a remarkable impression of the length of the ship. There are ten pairs of

main cargo oil tanks and summer tanks; these tanks, together with the necessary piping, are arranged specially for the carriage of light oils. Not only as a large Diesel-eleetri-cally propelled ship is the Brunswick a departure from established practice, but she is further to be singled out a> r, vessel handled entirely from th* bridge. Moreover, she is fitted with l Sperry gyroscopic compass and automatic helmsman, enabling the ship steer itself on any course lhat maybe set. Once the gyro-pilot takes charge of the steering any deviation from the course is corrected automatically and the actual course of the ship is recorded on a dial, thereby affording a means of reference.

The propelling machinery consists primarily of four Diesel engine-driven direct-current electric generating sets, arranged athwart-ships, these supplying power to a single double-armature propulsion motor direct-coupled to the propeller shaft. The four Diesel engines are six-cylinder, four-stroke cycle, trunk-piston, airless-injection, heavy, oil engines of the Ingersoll-Rand type. Each engine develops 750 brake horsepower at 225 revolutions a minute. The cylinders are each 19iin. in diameter, with a piston stfoke of 24in. Each engine is direct-coupled to a 600 k.w. 2,400 amp. 250 volts at no-load generator; and each generator is direct-coupled to a 75 k.w. auxiliary generator, which is driven off the after end of the main generator spindle. These auxiliary generators supply current for driving auxiliaries and any one can also be used for exciting the main generators and propulsion motor.

The main generators are electricallycoupled in series, and although all four are in operation at full power, three, two or only one set may be used for reduced power. The main propelling motor is rated 2,800 shaft horse-power at 95 revolutions a minute. It comprises two units, each complete with a separate magnet frame, armature and commutator, the two armatures being electrically connected in series and mounted on a common shaft. SUCCESSFUL TRIALS On the forecastle is an Emerson, Walker anchor windlass driven by a 65 h.p. B.T.H. electric motor running at a speed of 940 r.p.m., which is located on deck and operates a worm shaft: the usual spur-reduction gears are fitted on the windlass. There are two electrically-driven warping winches on deck.

In a compartment aft is the Hash© electro-hydraulic steering gear. This is of the double-ram design: the rams being arranged athwartships: the hydraulic pump apparatus is driven by a 15 h.p. B.T.H. electric motor running at a speed of 600 r.p.m. The Brunswick carried out a scries of exhaustive and very successful trials on the Clyde. Over the measured mil© the ship attained a maximum speed of 11.48 knots on a mean loaded displacement of 17.250 tons. Afterwards an additional 2,000 tons of water ballast was added, the ship reaching a maximum speed of 11.17 knots.

The Atlantic Union Oil Company owns several other vessels of the Diesel-electric type—an instance being the J. W. van Dyke, which carrie* 7.500 tons of oil. The Brunswick’s capacity is nearly 75 per cent, in excess of that figure. Few more interesting ships than she have taken the water so far as the mercantile marine is concerned. She is expected at Auckland on January 20 from San Pedro.