Why could Spain no longer block English entry into the ne world?

The destruction of the Spanish Armada in 1588 by the English under Francis Drake. The Spanish Armada and army badly outnumbered and out-gunned the English, but the tactical use of fire ships in the narrow English channel allowed an English victory. The Spanish Fleet was devastated as was the power of all of Spain.

This is where the term "Black Irish" comes from. Remnants of the Armada sailed north and their ships crashed upon Ireland's rocky shores, the Spaniards integrated with the local population bringing with them their dark hair.