Indeed Howard’s book is a nice read. All under Heaven: 天下, the imperial mandate to rule the world. On the matter of the size of the vessels, big as they were there is debate and the considered view of late is that they were in the order of 300 feet or so. Still twice the size of the largest vessel in Vasco da Gama’s “fleet” of four vessels that reached India in 1498 with a total crew complement of about 70 men! Hardy something to make local quake. But then the Portuguese made up for size in the level of violence.