Nothing - the word "Boat" has been applied to Submarines since they were first used in the Revolutionary War, and the term has stuck with them since then.
A "boat" in Naval parlance is any vessel that is launched from another ship or tender, such as a launch, whaleboat, etc. Early submarines required a support vessel (tender) to launch and recover them;though modern submarines don't require such, they do need support from tenders for supplies and repairs.
Submariners always refer to their ships as boats, and not ships. The reason for this is that to submariners there are only 2 kinds of ships; Submarines, and Targets.
A submarine is a kind of boat. But regular boats only use the surface of the water while subs also can dive and travel below the surface.
U-boat, or Unterseeboot, is just the German word for the English term submarine. It literally translates to under-sea boat. The U-boat engineering led it to be particularly deadly because the destroyers that it was in direct combat against had not been built to defend against them. Links are provided.
the U boat 'is' the German word for submarine. western nations just used submarine. U boat is short for Unterwasserboot, which translates as undersea boat or under water boat or submarine.
A U-boat was a submarine used by Germany in World War 1 and World War 2.
No, a U-boat is a submarine. A torpedo boat is the boat that destroys the submarine.
A submarine is an undersea boat, or submersible.
One is a machine; one is a mammal?
well submersible is for exploring the water as a submarine is a war machine use well in wars
i think a submarine can stay underwater indefinetly but a submersible can only stay down for a limited time.
Ship,boat,life boat,submarine and motor boat
there is no difference
this word is an adjective meaning "under the sea". submarine is the word shortened from the term "submarine boat".