THE VICTORIA CHANNEL. THE SAND PUMP.

Otago Witness, Issue 2241, 11 February 1897, Page 24

THE VICTORIA CHANNEL. THE SAND PUMP.

A visit of inspection was made by the members of the Harbour Board and >of the Chamber of Commerce on Monday morning to thß sand pump in the Victoria channel. The tug Plucky left the Rattray street wharf at 10 o'clock with the party on board, which comprised the Chairman of the Harbour Board (Mr H. Gouriey), Hon. D. Pinkerfcon, Captaia M'Kinnon, aad Messrs W. Dawson, W. Wright, and J. Robin ; Mr G. L. Denniston (chairman of the Chamber of Commerce), and Messrs Jowitt, Henderson, Lane, Sligo, Lee 3, Livingstone, Lefchbri'ige, T.

Browo, J. Stewart, A. 0. Begg, repre§enta&Tet o? the press, C»pt.ain M'Callam (harbourmafttar), and Mr D. G. Stephens, the board's inßpcotor of works. The tug soon stf*tnecJ down to the dredg* Vuluan, which waa moored a little abovo Burkes, tnd was all ready for working. Mr Stephens ar.d the dredgeinaster explained the machinery and its operation. 'The tuWe of the pump is 30ft in length, and is lowered or raised to suit the work. At present it is dredging to a depth of 17ft at low tide, the intention being to leave a ptrmanenb depth of 16ffc. Tbo Urge engiaes in th« hull of the dredge work the pnmp, which is a Vf ry powerful one, and ence facWf d up a groat round »ass of iron — an old wheel. — whu*b. is k6pt se a cu-iosity st tha board's office. Frrm this suction tube the material is discharged through pipes which are carried on five largo punr.s and fastened together with flexible cup and socket joints, aad convey tho material a distance of no lass than 45Wt, and thete dUh*rg« it with great rapidity. When the tides is full the disobnrge i pipe it carried oi~.l.Mcta the training wall, but at j times — »nd this was the case during yentarday's I I viait— th? material is discharged ou the channel | side of the wal), but closs to i*, and »b what is regarded a<» au absolutely safe distance — some i I 300ft — from the channel. This is done with [ the view also of strengthening tha wall, by I filling up a portion which otherwise is likely to I came troublo. At tbe rcootb cf the suction pipo there arotrco sets of cutters which ay« worked by means of chain gear connecting .icth » separate engine fitted up on d«ck nearly amidships. These rotating cu liters tear uy everything within reach, and stir the sand and stonos so that they more readily find entrance to the pump. The material is very heavy, a sort of sandy rempnt, bub this method apunars to be suerensful in de-tiling with it. Some trouble is caused by the dense growth of sea anemoDe", and occasionally ib is nece>sary to stop to clear them away. The end punt, over which the discharge pipe projects, is fastened by means of heavy anchors, and tbe others form a sorb of chain with the flexible pipe joints as connecting links. At tbe other end, ot' coursw, is t>ie dredge with its pumping machinery and other gear. The dredge is moved gradually from side to side of the channel by mentis cf a soparate engine, ! anchor*, and chains. As the dredge moves away | from the wall the chain of punts straightens I out, allowing ifc to reach right across tho j channel, and then on reivueiog the curve again forms, so th*f; work c>utiuues uninterruptedly, the dredge moving aud the point of discharge roni&iniug lUtionary. Tiio 1 saod purop has bees ktpt a(i work at the ; channel since fhe 6?h November, at suoh au ' angle that a. depth of 16fc is cleared ; cutting sometimes a few inches and at other times feet, bat, of course, securing a uai'orm depth. Som-j M chains of the chinnel hud thus been cleared ! when soundings were taken on. the 22ud of last I month, and now the distance finished ia ' approximately thrett-qi&rters of a mile. The ! pump started at a point on tlie Dunrdin aido of Ravensbourne, and ia working her w»y down the channel. Fr>->m what has been said as to the method of working the pump it will be seen that it is often necessary to stop operations in order to get out of the way of passing vessels. The dredge is drawn to the side with tha pump raised, and so it often happens that she is seen occupied in the apparently useless ra»k of pumping clear wster into the sea. This has called forth pome hostile comments, bub it is necessary to let vessels pass, and it is more economical to keep ike puap going discharging water than to stop ifc for a short time and to have to create a fresh vacuum to resume operations. It is estimated th*fc the pump will discharge 800 cubic yards of solid material each day of eight hour*, buS the amount varies according to the nature of tha material and the stoppages that take pl&co. Still it is considered that tho dredge pump w>rks satisfactorily, and that good progress will now be made with the important work of deepening the channel. Soon after the visitors boarded tha dredge, the pump was lowered and the machinery oet going. In a very little time there was a big discharge, first of water and then of water heavily charged with material — a thick, d»rk fluid, which, when caught in a bucket, in a few seconds showed a heavy, dark deposit. Unfortunately the pump was stopped twice — ouc» by tha chain that works the cuttero Riving way and again by a m&m of marine growths blocking the pipe, so that the machinery were not seen at work under at all favourable conditions. The pipe was previously choked in this manner for the first tima last week, and this therefore is not a frequent cause of delay. We understand that with 15 per cent, of aolid matter the dredge would be doing fairly effective work and that the discharge carries from 10 per cent, to 50 per cent, of solid material, the average being quita satisfactory. The Plucky with the visitors relumed to town shortly after 12 o'clock. Oa the way up three brief speeches were made in the cabin. Mr Denniston said he thought ifc only becoming that he should en behalf of the Chamber of Commerce th.*nk Mr Gouriey aad the members of the Harbour Board for the opportunity they had given then of seeing the j new pump at work. It had been very interest- j ing to see the machinery in operation, and although they had not had time to witness any very successful results, owing to the nnfor- | tunate accident that had occurred, they could express the hope that not on'y on account of the public feeling th*t had been recently manifested, but from their own sens* of duty and of i the importances of the work to Dunedin the | Harbour Board would los» no opportunity of prosecuting the work to the utmost of their ability, and would keep the punt at work as steadily as possible. They felt obliged to the I board for the opportunity afforded of seeing the dredge and wished the board all success. — (Applause.) j Mr Goueley said he was never more out of I place than when speaking without preparation, but on behalf of the board he desired to acknowledge the good wishes that had been j expressed. He could assure them that every member of the board was only too anxious to do all that possibly could be done to improve on; harbour. Every available shilling after current i expenses had bceu met would be spent in im- ! proving the harbour, aud that was all they | could do. As they were aware the current expenses were large, and must be met ; bufc after their engagements had been met; they would do all they could and spand all they could on the improvement of the Upper and Lower Harbour. Mr Denniston suggested that Mr Pinkerton { might also appropriately say something. ; The Hon. D. Pinkerton said that he very heartily endorsed all that the chairman of the board had said, and would further remark that, he had no sympathy with the cry of '• Dunedin for Dunedin," or the "Port for the Port" ; the harbour was one, and they should arrange to get the largest ships to Port Chalmers, and do the best they could to bring large ones to { Dunedin. What they did was really not for ' Danedin or Port Chalmers, but for tils advan- j tage oi Oi«£o.