PRIESTMAN GRABS

Dominion, Volume 12, Issue 309, 25 September 1919, Page 7

PRIESTMAN GRABS

IMPORTANT REPORT

DANGER OF CRANES DISCOUNTED

At last night's meeting'of the Harbour Board an Mnteresting report on the cost of working the Priestman grabs on the , wharves was tabled by the board's en- • . cineer (Mr. J. Marchbanks). The rc- . port ran as follows:—"It ja. not possible ; .to prepare an exact return giving the ■ information asked for, as the board' 6 accounts. as kept, do not give the details of costs of maintenance and working charged against tho mechanical equip- > tnent on each wharf separately. Prom •; the information available I beg to submit the following particulars: Six grabs imported and three made in the board's shops cost ,£1636 lis. 5d., or an average of nearly iCIB2 each. The cost of installation waa ,£2O per crane., The cost of upkeep of grabs, including repairs, hire, rope, etc., cannot be,given, but the cost of maintaining all the cranes on the Railway Wharf, together with the grabs, and (including alterations to some of them, to enable wire ropes to be used, ths wages of attendant, _ all repairs; renowal of ropes and chains, amounts to about .61026. which is equal to about 2s. Gd. per hour of use of.the two-ton cranes. For the cranes when using grabs the estimated cost of repairs and maintenance to cranes, grabs, ropes, chains, including all material and labour is 3s. 9d. per hour of use. Interesting Facts. "With regard to the depreciation of 'oranes, grabs, and-.wire rapes, judging from' the condition of the oldest established cranes, and taking into account the maintenance they receive, the useful life of the two-ton gantry cranes should bsv. not. less than .froa.- twenty-five to thirty years, the amount written off for depreciation: from all machinery, viz., 5 per cent, is, I think, sufficient. With . respect to grabs, the .wear and 'tear, is heavy, but repairs are executed as required; this is-covered under cost of upkeep. The probable life of one of Hhe grabs, taking intoacoount the repairs executed, I would, estimate at about ten •years. ■ Wire ■ ropes on. the Railway Wharf have a life of about one year, against one and a quarter years on the King's Wharf and: on".and a half years (in the 'Glasgow -Wharf. Chains have a- ' life of about one and a half years on tho Eailwav Wharf and'tKree years on the King's Wharf. The cost of lifting wires at Dresent is about ,£ls per crane. The oostiof lifting chains at present is about J!2S per crane; (The pre-war cost was «1G 105..) Suitability of the Cranes, "With regard to the suitability of the . cranes for ute with grabs, any jib crane ia suitable for .use with a grab,'up' to its capacity. .■" 'Jib cranes fitted with gTabs are iargely 'used' for handling all classes of rough material all over ' the world. They are, however, not nearly bo suitable as transporter or bridge cranes would be for the discharge of. coal from' vessels. A transporter crane, besides handling a much larger grab than we use. would easily run at three timc-s the speed of. our two-ton ■ hydraulic cranes.: The latter, .however, do very fair work on the ordinary type of New Zealand collier, particularly when working local coal. On the ocean-going cargo boat, which is high out of the water, . the cranc3 are required to do a good ' deal of higli hoisting and luffing, to clear the vessel's, structure, and they are not vers- suitable for tlie class of work.. They have, however, been used to a considerable extent in unloading Newcastle coal, from this type of vessel; but recently very, little New Zealand coal has been unloaded by grabs. This is said .to be . because different olassei of coal are stow-. Ed in on? hold. It: this were obviated ' it would permit the grab to be used. ' "The charges made for the use of cranes and grabs is ss. per liour for the crane and 53. per hour for the grab, so that if a crane is employed working a grab the charge i 3 10s. per hour."An annroximate comparison of the cost of' working oranes on the King's, Glasgow, and Railway, Wharves is given be- ' low. with wages based on the rate up to Maroh 81 : . ....... ... „...., . ...Increase Pre- , ,Tl.'in'wages sent cost. ' now. cost;' g.i d. s. d. King's Wharf, K 5. 2d. .4 7 . Glasgow Wharf ...... 3 7 2d. 3 9 Bailwav Wharf 8' 8 6d. 9 2 It will' be seen that'there is not'a great surplus left towards-the payment of standing charges; and it has. recently been recommended that the chargo for oranes be increased to 7s. 6ti. per hour. "With regard to whether cconomy is secured by the use of grabs under present circumstances, 1 no information ■is available on this point; the board simply ' hires, the plant out to the users. I have no- doubt, however, from my- own observation that considerable economy results from the use of grabs when they aro. used to discharge West Coast colliers loaded with New Zealand cool."_ In a supplementary • report the engineer stated that lifting chains broken on the Railway Wharf when in U6o • with grabs during the last' two years had been as. follows:—One on November 13, 1917, through grab lifting bundles of bar iron underneath coal;- one on July 23, 1919; . ono on September 11, 1919. , . The Discussion. Mr. ,C. -H.. Chapman ".considered that the board was not as careful,in the interests of the men as.it might.be. The chains should be, made stronger, He ' al">. <"*i«sidered the charges should ,bo increased* - - ,jL Cohen contended that the safety oi the men had always been the first aim of the board. There was, however,- ,; no pccviDation: in the world ontircly free from .risk. According to the chairman the board Was taking every- possible precaution -for . the safety of the men. Pour cranes had been recently fitted with the wire ropes, in place of chains, and this would bo done with t-liera all. ' The original oharges wore experimental, and were now beinir increased from ss. to'7s. Gd. The discussion then dropped, after the . engineer had pointed out that the appli- . ances were .perfectly safer '