Definitely the 'Spanish Ladies' could be the Spanish Man O War military ships.

Hardly likely at all. Yes in general ships, aircraft and cars are invariably referred to as "she", apart from the contradiction to this "convention" you mention yourself - In days of sail a vessel was always referred to as a MAN OF WAR and a Merchant Vessel was always referred to as a MERCHANTMAN. Taking into account the years throughout the 16th, 17th and 18th centuries that England and latterly Great Britain found itself in conflict with Spain, France and Holland. Sailors in the Royal Navy would only view the ships of those nations, men o' war or merchantmen, as "the enemy" and a welcome source or riches and plunder.