Engineering Wonders of the World
Volume III

HARBOUR CONSTRUCTION. 75 a detached mole which occupies about three- quarters of the distance between the extremi- ix ties °f the shore moles. The Gibraltar. island, or detached break- water, consists of a vertical wall of large concrete blocks built upon a rubble mound centre of the mole, and sunk on to the rubble mound. The interior was then filled in gradu- ally with concrete, and eventually an artificial island, weighing 9,000 tons, came into exist- ence. On it were erected two Titans, which worked away from one another, laying the BREAKWATER AT VERA CRUZ, SHOWING “ RANDOM ” CONCRETE BLOCKS TO PROTECT THE WALL. formed in from 45 to 65 feet of water. As it was impossible to connect the site of this breakwater with the shore, the engineers adopted a novel plan for providing a founda- tion from which the Titan cranes could com- mence their task of block laying. A huge steel caisson, 101 feet long at the bottom, 74 feet long at the top, 33 feet Monolith. Wlde’ and 48- feet was built in England, taken to pieces, and shipped to Gibraltar, where it was reassembled, towed to its position at the blocks which were brought up by barges as required. At Zeebrugge a breakwater 5,000 feet long has been built recently to protect the entrance to the Bruges Canal. The outer part of the breakwater, which has to bear the brunt of a storm, is com- posed of huge concrete mono- liths weighing about 4,400 tons each, and measuring 82 feet in length, 29J feet in width, and 28j feet in height—probably the largest series of concrete blocks ever made. On A Novel Process.