Spanish colonial ships were primarily used during the 15th to 18th centuries for exploration, trade, and military purposes. These vessels, such as the galleon and caravel, were designed to navigate the vast oceans and transport goods, people, and resources between Spain and its colonies in the Americas and Asia. The ships were often equipped with multiple sails and sturdy hulls to withstand long voyages. They played a crucial role in the Spanish Empire's expansion, facilitating the exchange of commodities like silver, sugar, and spices, which significantly impacted global trade during that era.