Submersible
From Wikipedia, the free encyclopedia
A submersible is a type of underwater vessel with limited mobility which is typically transported to its area of operation by a surface vessel or large submarine. Apart from size, the technical difference between a 'submersible' and a 'submarine' is that submersibles are not totally autonomous. They may rely on a support facility or vessel for charging of batteries, high pressure air, high pressure oxygen replenishment, or all of these.
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[edit] Operation
Submersibles differ from submarines in that submersibles typically have shorter range, and operate underwater almost exclusively, having little function at the surface. Many submersibles operate on a "tether" or "umbilical", remaining connected to a tender (a submarine, surface vessel or platform).
[edit] Bathyspheres and bathyscaphes
The bathysphere is a type of tethered submersible which lacks any self-propulsion. A predecessor of the bathysphere, the diving bell, consists of a chamber with an open bottom simply lowered into the water.
The bathyscaphe is the predecessor to deep submergence vehicles. It has less mobility than deep submergence vehicles, but is untethered, and will use something like a bathysphere for a crew compartment. Because of the extreme depth of operations of a bathyscaphe, its buoyancy is provided by tanks filled with aviation fuel or another light, incompressible fluid. Return to surface is facilitated by jettisoning lead shot or clump weights.
[edit] ROVs
Small unmanned submersibles called "marine remotely operated vehicles" or MROVs are widely used today to work in water too deep or too dangerous for divers.
Remotely operated vehicles (ROVs) repair offshore petroleum platforms and attach cables to sunken ships to hoist them. Such remotely operated vehicles are attached by a tether (a thick cable providing power and communications) to control center on a ship. Operators on the ship see video images sent back from the robot and may control its propellers and manipulator arm. The wreck of the Titanic was explored by such a vehicle, as well as by a manned vessel.
Among the most famous submersibles is the deep-submergence research vessel DSV Alvin.
