How did the Navigation Acts set limits on colonial exports?

The Navigation Acts were a series of laws that restricted the use of foreign ships for trade between every country except England. This ended 200 years later. They reflected the policy of mercantilism, which sought to keep all the benefits of trade inside the Empire, and minimize the loss of gold and silver to foreigners. They prohibited the colonies from trading directly with the Netherlands, Spain, France, and their colonies. The original ordinance of 1651 was renewed at theRestoration by Acts of 1660, 1663, 1670, and 1673 subsequently subject to minor amendment. These Acts formed the basis for English overseas trade for nearly 200 years. Another way to define this is laws created by England to limit their colonies' trade with other countries. Additionally the Navigation Act restricted the employment of non-English sailors to a quarter of the crew on returning East India Company ships.