Submarine Appliances And Their Uses
Deep Sea Diving, &c., &c.

Quantities of Air, calculated at Atmospheric Pressure, REQUIRED BY A PlVER WORKING AT VARIOUS DEPTHS down to 210 feet = 35 fathoms. Depth in fathoms. Feet. Quantity of air at atmospheric pressure required per minute. Number of cylinders needed of Siebe, Gorman & Co.’s patent double- acting pumps (hand- worked). ® Revolutions of the pump per minute. Cubic feet. 0 0 1.5 1 15 2e 16 2.2 1 22 5à 33 3.0 1 30 11 66 4.5 2 22 16 j 99 6.0 2 33 22 132 7.5 4 21 27| 165 9.0 4 27 33 198 10.5 6 23 35 210 11.0 6 28 In cases where power-driven, instead of hand-driven pumps are used, the air should be delivered into a steel receiver, and the divers supplied from the latter, the quantity of air delivered to them being regulated according to the levels at which they may be working. It is well to have a non-return valve on the inlet side of the receiver from the air compressor. * This Pump is of the Two-Cylinder, Double-Acting type, and is the standard pump used throughout the British Navy. APPROXIMATE AMOUNT OF WORK THAT CAN BE DONE WITH PNEUMATIC TOOLS. Drilling Mild Steel.—A lin. hole can be drilled at the rate of lin. to i|in. per minutç ; smaller and larger sizes in proportion. Boring Timber.—A pneumatic auger will bore a lin. hole at the rate of ßin. to 6in. per minute, according to the nature of the material. The following is an example of work actually accomplished with a pneumatic wood-boring auger operated at a depth of 50 feet below the surface, viz. :— Nature of Work.—Cutting off to six inches above ground level pitch pine sheeting- piles, 24‘in. by 6in. In each of these piles eleven 2in. holes are bored, one diver doing twelve piles in eight hours=i32 holes 2m. diameter by 6in. deep. Rock Drilling.—See pages 98 to 105. 97