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

THE REMOVAL OF SUBMERGED ROCK AND THE DISPERSAL OF WRECKS BY BLASTING. ___________________________________ So much depends upon the varying conditions under which work of this description is conductedit fs impossible to la/A any hard and fast rule for o submarine blasting operations; but on receipt of particulars of any rock‘ r^ovalkw°17 t may be contemplated, viz., depth of water at high and low tide nature of the rock to moved, its situation and approximate depth and area, we shall be pleased to advise the best method and appliances to employ. The following notes as to preparation of explosive charges and general mode o pro- cedure, and particulars of some methods employed, may prove useful. SOME METHODS EMPLOYED IN BLASTING ROCK. Of the two systems of power-operated drills—Pneumatic and Steam—the former is un- doubtedly the more economical and satisfactory. COMPRESSED AIR ROCK DRILLS. Three systems of pneumatic boring are employed in connection with submarine rock removal : — (i) Drills operated from a floating vessel or raft, or from a staging. (2) Hand Drills which the divers take under water with them. Tripod Drills, which are heavily weighted and lowered under water, and are con- trolled by divers. Where the pneumatic tools, HAND-WORKED JUMPER DRILLS. quantity of work to be done is so small as not to warrant the purchase of ____the old-fashioned Jumper Drill, operated by men pulling on ropes carrie over sheaves, can be recommended for efficiency and simplicity In all cases where the boring is conducted from the water surface, the drill rods^should be carried through iron piping resting on the sea bed and reaching up to the craf <g This arrangement gives lateral support to the drill rods, and, on completion of t , pipe acts as a conduit for the placing of the explosive charge in the hole. In m ) > however, the charges are placed by divers. DIAMOND ROCK DRILL. Excellent work has been accomplished with this type of drill, but its cost makes the use of this appliance almost prohibitive, except in very special cases. APPROXIMATE AMOUNT OF WORK THAT CAN BE DONE WITH PNEUMATIC ROCK DRILLS.* Hand Drills. The drilling capacities of various sizes of Hand Rock Drills working on granite are as follows :— DIA. OF HOLE. DEPTH. PERIOD 2 inches 2à „ 3| and ) upwards j 45 feet 50 ,, 55 „ 60 „ 70 „ Per day of 10 hours. 9 Î 19 •The above figures represent the amount of dry work at the surface. In the altered conditions of submarine work the quantities would, of course, be less. 00 o