What is the history of submersibles

what-is-the-history-of-submersibles-photoA submersible is any relatively small vessel that operates beneath the surface of the sea. Generally, submersibles are designed to be used at great depths, as protection rather than as undersea transportation, if they carry crew, or as a substitute for divers in dangerous environments. Some submersibles may be lowered from surface vessels, and others – more complex – can be free-swimming.

Size is often the only distinguishing factor between free-swimming submersibles and submarines. One way of clarifying the dividing line between the two sorts of vessels is to consider their function. A submersible is almost without exception an unarmed vessel, designed to let divers and scientists descend far beyond the 165 ft (50 m) limit imposed by pressure on an unprotected diver. Submersibles – even those that are designed to be free-swimming – depend on surface vessels for transport and support.

Submersibles are useful in shallower dives, too. Unlike free-swimming divers, crew members in submersibles are not prone to decompression sickness. This condition, sometimes known as the bends, is caused by divers receiving their oxygen and nitrogen mixture at a pressure related to the depth at which they are working.

If they return to the surface too quickly, the pressure release leads to bubbles of nitrogen appearing in body tissue, possibly causing death or brain damage. Decompression, therefore, is a slow process aimed at preventing the formation of nitrogen bubbles.

In a submersible, crew members receive their air supply at a pressure approximately equal to that at the surface. There is less risk to life, and trained crew members are not caught up in interminable depressurization procedures.