Answer:
They allowed Portuguese and Spanish navigators to sail across oceans rather than only along the coast
Step-by-step explanation:
The development of vessels was extremely important for the maritime expansion of Portugual and Spain, being essential for the discovery and colonization of the American continent.
The vessels allowed Portuguese and Spanish navigators to navigate across the oceans, being able to travel everywhere in the world, explore all existing trade routes and establish a great commercial and colonial empire.
The development of vessels established Portugual and Spain as great navigation pioneers, which generated many riqeuzas for both kingdoms, in addition to being a technological advance.