English corsairs and pirates stole valuable navigation information and letters.
All of their maritime knowledge had been obtained by and stolen from other countries. For centuries the English stole not only ships and wealth from their competition but also their most valuable belongings. They stole their naval maps, their descriptions of maritime routes, their naval techniques and the problems which had encountered on certain routes and their solutions to those problems.
Thanks to this bounty the English disposed of the peninsular ships at no expense and improved their navigational instruments and weapons.
All of this information and knowledge allowed them to rob the Portuguese of the Eastern routes and lay a secure foundation on the route that would be used by the "East India Company" on which their empire was later founded.