Ictíneo II was a pioneering submarine Its launching took place in the Port of Barcelona on October 2, 1864 by the Spanish engineer Narciso Monturiol and it was the first air independent and combustion powered submarine and the first submarine to overcome the basic problems of machine powered underwater navigation.

A submarine is a watercraft capable of independent operation underwater. It differs from a submersible, which has more limited underwater capability. The term is also sometimes used historically or colloquially to refer to remotely operated vehicles and robots, as well as medium-sized or smaller vessels, such as the midget submarine and the wet sub. Submarines are referred to as boats rather than ships irrespective of their size.