Why navies adopted regular gunnery drill

When did navies begin taking gunnery drill and training seriously?

By the late sixteenth century, Dutch and English fleets were drilling frequently because effective and safe handling of shipboard guns demanded disciplined practice.

Dutch and English fleets around the 1588 Spanish Armada campaign could practice gunnery roughly twice a day. Early firearms and shipboard powder made disciplined handling a matter of survival as well as combat effectiveness. Formal drill followed quickly once navies depended on weapons whose mishandling could destroy their own crews and ships.