What was the size of the Ming navy in 1420?

In 1420 the warship fleet of the Ming dynasty in China was immense. It consisted of the following:

1. 1,350 combat vessels;

2. Among the 1,350 were 400 large floating fortresses; and

3. 250 ships designed for long range cruising.

This did not include the hundreds of merchant vessels that could be used in a sea battle.