OIL FUEL TO COAL

Evening Star, Issue 23684, 18 September 1940, Page 5

OIL FUEL TO COAL

HOPPER DREDGE OTAKOU CONVERTED WORK PERFORMED BY BOARD'S STAFF SAVING OF £2,148 PER ANNUM Few Dunedin citizens who have seen the Otago Harbour Board’s dredge Otakou proceeding down the fairway to deposit her spoil at sea will have realised that she has undergone an important change since early: last month. To external appearances she is the same

dredge that arrived from the Clyde on November 4, 1930. But she is not the same —on August 7 she was moored at the Victoria wharf, and when she took a trial run on September 6 she was no longer an oil-burner, but had changed to coal. Under the new system she is estimated to save the board the excellent sum of £2,14S a year, whilst _her rate of speed has not decreased, furthermore, this important transformation has been executed solely by the board’s own staff, and the overcoming of mhnv unforeseen difficulties speaks highly of its skill and workmanship. It is interesting to note that this

move was mooted by Captain Coll M’Donald as far back as August 21, 1931, but it was then resolved that no further action should be taken. The replacement involved, amongst other things, the removal of the oil fuel equipment; the alteration and lining ■with timber of the fuel oil tanks to serve as coal bunkers; the fitting of sliding bunker doors; the removal of all bricks from the furnaces of the two boilers; alteration to structural iron work to carry the firebars, and the rebricking of the furnaces with both cellinsulate and fire bricks; the making and fitting of new furnace fronts, doors, and ashpans; and the erection of steel sheeting plates in the stokehold to prevent coat from entering the bilges. These things considered, it was no small work.

Steam was raised on September 6, a short trial run was undertaken, and on September 9 dredging was resumed at the Kitchener street wharf, spoil being taken to Heyward Point. The journey

constituted the initial major trial—its success is illustrated by the fact that the run was accomplished in the same average time as using oil fuel, while no difficulty was experienced in maintaining a full head of steam during the four hours. After a week’s dredging it is significant to note no decrease in efficiency is noticeable. Facilities have also been assured to coal the Otakou at the Kitchener street wharf. Waterfront ramblers may have noticed an enclosure at the south end of that wharf. It is there that tho coal dump for the dredge will be situated, whilt* the North-West crane will

be used with a grab bucket for handling the coal and lowering it into the hopper and chutes on the dredge Tor transmission to the bunkers. A motor is being fitted to the crane so that it can be driven either by electric power or by petrol, as the location of the plant permits. ' The use of coal does not, however, decrease the time of loading the dredge. Probably few Dunedin citizens realise that the Otakou is a twin-screw hopper dredger of 2,000 tons hopper capacity, with a length of 250 ft between perpendiculars, while her dredging depth is 45ft. She was built at a cost of £123,724 (including some extra gear) by Fleming and Ferguson, Paisley. Sailing from the Clyde on July 30, 1929, she came out by way of Gibraltar, Port Said, Colombo, and Australia, and arrived here on November 4 under the command of Captain J. Manning. Her first operation after being taken over by the board on December 6 was an inspection of her off the Rattray street

basin by the members, while she had her first practical dredging experience in these waters on December 16, off Port Chalmers. Now, as she steams down the harbour under a full head, the dredge Otakou is a symbol of saving. She saves the Otago Harbour Board a considerable sum each mouth she is in commission, while conserving oil fuel (and overseas funds) at the same time, and is helping Now Zealand in its war effort through this economy. The technical staff of the board is to be congratulated on its work, which was supervised by Mr Coxhoad.