HARBOUR WORKS.

New Zealand Herald, Volume LXIX, Issue 21116, 25 February 1932, Page 13

HARBOUR WORKS.

BOARD'S ANNUAL VISIT. UP-TO-DATE CRANES OPERATING EARTHQUAKE PRECAUTIONS. The annual inspection of works under the jurisdiction of the Auckland Harbour Board • was made yesterday when the chairman, Mr. G. R. Hutchinson, and members of the board made a tour in the board's pilot vessel Waitemata. This visit to tho port equipment and improvements, extending from the harbour limits at tho Rangitoto and Motuihi Channels to tho upper roaches of the harbour is made to enable tho members to keep in touch with developments. First tho party went to the Western Wharf area, the boat harbour and tho Curran Stieet roadway now in course of construction for tho purpose of giving access to tho boat harbour wall. At Western Wharf tho members were interested in the operation of two new threeton electric cranes, fitted with extra long jibs for quick handling of coal and other cargoes. These cranes were being used to coal tho Union Company's Kanna from tho hulk Gladbrook. . Iho jibs of these cranes were of sufficient length to reach across the .Kanna and lift the coal by means of automatic grabs from tho holds of the hulk to the chutes of the steamer. It was explained by the board's engineer, Mr. D. Holderness, that these cranes were so fast that they onch lifted and deposited 51 tons of coal an hour for every hour they had been worked. From the deck of the launch the members were able to observo the speciallydesigned raker piles which had been driven to strengthen the mam wharves as a protection against damage that might bo done by earth tremors or oilier forces which could not bo foretold and which might tend to create heavy lateral stresses. It was explained that these piles were 24in. by 16ln. and driven in lengths ranging from 55 feet to 85 feet on a batter of 3 vertical to 1 horizontal. The actual additional lateral stiffness thus introduced at deck level was 1600 tons in the caso of Prince's Wharf, 1030 at King's Wharf and 900 tons at Queen's Wharf. Viewing other equipment on the way tho party proceeded to the board's quarries at Rangitoto Island, where the quarry «.nd crushing plant is at present closed. All this plant was seen to bo in an excellent state of preservation and ready to be put into operation at short notice when further major port works require its use. The board commenced quarrying operations there in 1913 and up to tho end of 1928, when it was closed, tho plant had supplied 667,457 cubic yards of stone for use in major works. In 1922, owing to the impossibility of securing suitable shingle, tho board installed tho existing crushing plant to provide 100 cubic yards of concrete aggregato a day and this output was regularly maintained. It was stated that in 1922 this aggregate was costing the board 10s a cubic yard delivered to tho dumps at the various jobs, but with its own plant it had been able to place it on the job at between 7s and 7s 6d a yard, at the saipe time allowing generous depreciation on tho plant. It was shown that at the end of the board's last financial year this plant stood on tho books at £6217, whereas it was valued at over £250.000, which, as a member sail, was pretty good business. An inspection was also made of the ferry steamer wharf at Rangitoto Island. Requests have been made for more adequate facilities, and tho matter is being considered.