Caravel

One of the very practical innovations from 15th century was the two-decked caravel, invented by Portuguese fishermen. It was revolutionary and very effective - it was used during the big exploration expeditions - in groups of a few; not solely. For example two of the ships of Christopher Columbus - Ninia and Pinta, were large caravels.

The squat, 3-masted caravel, was not as fast as the galley, but it was designed to sail stably into the wind. It had more space for cargo, and more spacious living quarters. So it was more adopted for long voyages. In the beginning lateen rigged - triangular fore-and-aft sails were adjusted on two masts, however, the caravel soon sported whole three masts - foremast, mainmast, and mizzenmast - with square-shaped sails on the forward two and a lateen sail (which is in triangular shape) on the third. The lateen sail made it possible for a ship to use wind coming from the side of the vessel.
This caravel, which replaced the oared galley, was itself later replaced (for long voyages) by the more massive, with bigger draft carrack.