Final answer:
In 1794, the United States ordered the construction of frigates under the naval act. These ships were key in establishing early American naval power and prominence, with the USS Constitution being a notable example.
Step-by-step explanation:
In 1794, the first US ships ordered for construction under the naval act were frigates. This decision was part of an effort to bolster the young nation's naval capabilities in response to threats on the high seas, particularly from pirates in the Mediterranean and elsewhere. One of the most famous frigates produced during this time was the USS Constitution, also known as 'Old Ironsides', which became a symbol of American naval strength. These frigates, constructed from American oak, were a source of pride for the United States and played a crucial role in the country's early naval history.