Well, around 300. Some are out of order, and only a few can still work.
no
They can submerge, remain submerged and resurface. They are water-tight so that when submerged they do not fill up with water and so lose their buoyancy. Also they have buoyancy tanks into which water is allowed to enter and so increase the mass of the submersible. This makes it submerge. But that water can be pumped out to increase the buoyancy when the submersible wishes to return to the surface.
Infinitely many. Infinitely many. Infinitely many. Infinitely many.
Infinitely many. Infinitely many. Infinitely many. Infinitely many.
so many hours
YES, most true submersibles have a 'pilot' and a systems operator. The submersibles that do not carry people are usually called ROV's or AUV's
Very small, if it even exists. Most submersibles do not carry cargo
Deep sea submersibles help get research from the ocean floor.
alvin
july 21, 1856
John Wilkes Booth did
no
Submersibles work on undersea oilwells, recover practice torpedoes, search for sunken ships or things that have fallen off ships and sunk.
They come in different shapes and sizes
Submersibles are commonly used by researchers and security forces such as the navy and the coast guard. The coast guard can use them to inspect the underside of ships for any smuggled items.
One of the major advantage of personal submersibles over scuba gear is you can't feel the changing pressure while ascending and descending.
Bathyscapes and submersibles have.