The larger size and stability of the caravels and subsequent ship designs of the fifteenth and sixteenth centuries:

Allowed the ships to become floating artillery platforms

Explanation:

During the 15th and 16th century, the Caravels were the first choice and famous ship in the European age of exploration.  The Spanish built a different ship named Galleon in the 16th century from the caravels and carrack. The galleon ships were cheaper to built and known for their strength and stability. Galleon ships were used by merchants to carry goods and would be converted to warships also became the floating artillery platforms in oceans and seas.  

sumerians were responsible.