EXCAVATION OF SUBAQUEOUS ROCKS 27 



MANCHESTER SHIP CANAL; DEEPENING FROM 26 FT. TO 28 FT.; 



LOBNITZ ROCKCUTTER No. 1. 



Average quantity (over a period of ten months) of rock broken 



up per month 6403 cu.yds. 



Average cost of breaking 8 . 94d. per cu.yd. 



Minimum quantity of rock broken per month 5622 cu.yds. 



Maximum quantity of rock broken per month 10180 ' ' 



The cutter has worked on double shift regularly, and the average 

 cost of working in this manner has been 240 per month, made up 

 as follows: 



Wages 108 



Coals and stores 27 



Repairs and renewals, including new ropes and repairs to needle 105 



240 



The rate of advance of the rockcutter averages 36 ft. per diem,, 

 the bottom width of the canal being 120 ft. 



(Signed) W. HENRY HUNTER. 



ENGINEER'S OFFICE, June 19, 1906. 



The Lobnitz rockcutter has just been introduced in the United 

 States by Mr. Lindon W. Bates, former president of the Empire 

 Engineering Corporation of New York in the work at Black Rock 

 Harbor and the channel of the Niagara Ship Canal. The machine 

 used by Mr. Bates was thus described in the Engineering Record, 

 March 16, 1907. 



The rockcutter which is to be employed in the Black Rock 

 Harbor and channel was especially designed for this work by Mr. 

 F. W. Allen, engineer for the Empire Engineering Corporation. 

 The hull is composite, being composed of two separate hulls, each 

 96 ft. long and 17 ft. beam, w r hich are fastened together by screw 

 clamps, forming one hull 96 ft. long and 34 ft. beam when in service. 

 The hull draws about 3 ft. 6 in. of water when fully loaded, and 

 the rockcutter is ready for operation. The object of building the 

 hull in two parts is to allow each hull to pass the locks of the present 

 Erie Canal, in case the rockcutter should be dismantled for shipment 

 to other points. 



The essential part of the rockcutter, of course, is the cutter, 

 which was made by the Bethlehem Steel Co., Pennsylvania. It is 

 a steel cylinder, 28 in. diameter, about 25 ft. long and weighing 

 46,000 Ibs. It is fitted at the lower end with a hardened steel conical- 



