The main innovation during the period of the great voyages was the use of caravels, a type of rare boat for explorations.
The caravel was a fishing boat, used mainly along the coast of Europe, but which could also be used at high tide.
The caravels were small, with a maximum of three masts and they used sails in a type of format called "lateen" (triangular). They were easy boats to steer and control.
What made the naval expeditions possible was the use of boats with three masts and four sails, a different type of boat from the caravel, which was developed at the end of the 15th century.
The type of sails used in these boats ended up being adapted for the caravels, which allowed the boats to go further away from the coast of Europe and Africa and adventure into the high seas.
The essential navigational instruments at the time were the compass, to find out what direction you were sailing in, and the log book, to estimate the speed.
Once you knew the direction and speed, the other aspects of navigation were relatively simple.