Early navigation relayed on mariner's ability to read the stars, which were not always exact and led to failure, discretion and less disposition to explore.
The Renaissance created an intellectual ambiance that promoted exploration, bringing massive interest in science, ergo scientific methods made navigation more exact and safer while traveling by ship.
Exploration was enabled by the evolution and development of geography, the development of navigational tools such as compasses, accurate maps, sea charts, and the scientific advancement in vessel designs.
Thus "explorers were able to take long and far trips across the ocean because of the development of navigational tools".