Submarines in color

The seas are a hostile place. Though an increasing proportion of the world's population are learning to skin-dive, and to feel at home within the marine environment, this is still only playing around the edges. Even the Continental Shelf around most of the land masses poses underwater problems that technology cannot yet completely solve, while the deep oceans have been rightly called the last great unexplored part of our planet. Their immensity is awesome—the Pacific Ocean alone is much bigger in surface area than all the land on Earth—and the pressures in their depths are incapable of being imagined. Into this challenging environment man must advance by small steps. An early Egyptian wall painting shows duck hunters walking on the river bed, breathing (schnorkelling?) through reeds at least 4,000 years ago. The diving bell, in which air is trapped beneath a heavy bell-shaped container, was certainly familiar at the time of Aristotle in 330 B.C. From there it is not a great mental leap to the submarine, capable of locomotion; yet though Da Vinci (c.1500) and British naval officer William Bourne (1578) described and sketched suggestions, there is no evidence that anybody built one until the seventeenth century. Even then it took a long time for improving technology to make possible a submarine that could be described as practical. Until a mere century ago no submarine could be described as reliable, useful or even safe.

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