Sorry I don't have time to read this thread carefully, but I didn't see it on a quick skim... The phrase "blow the man down" means a sudden gust of wind lays a sailing ship down on her side. Last time that happened to me it was an astonishment. So it's an expression of emotional emphasis.

Ships were colloquially called a 'man'. Hence the phrase 'man of war'. https://en.wiktionary.org/wiki/man-of-war#Noun def. 2 confines it to a warship; I think it's more general but whatever