What was the main reason imperial nations built large naval forces?
to initiate sea-based attacks on other nations
to support nearby merchants
to protect their economic interests
to resist attacks on their harbors

They had big navies in order to protect their economic interests. They needed big navies to have power projection around the world towards opposing nations and to protect their foreign interests. Colonial nations needed strong navies so that they could control and protect their colonies from other imperial nations that were their rivals.

to protect their economic interestsC

Explanation:

they had a lot of depression during the revolutionary war