Navy is a deep blue colour.
Prior to 1842, the colour Navy was non-existent. There was little painters could do to depict the deep and forboding colours of the sea except use black, a poor substitute, as it was unable to fully depict details.
Many painters chose to use royal blue, or sky blue to depict the dark, harassing sea, but this had limiting effect, with critics of the time harshly pronouncing such paintings as "rather jolly" and "What fun!" It took Blackbeard a full 20 years to convince most artists to create the colour which he personally claimed to have invented.
When many artists took poorly to this critique, there was a consensus that a solution should be found, so that artists could paint moody, homoerotic, moonlit sea-scapes. A small group of artists, who lived and painted around the same area, took on the problem. This later became known as the Waterstones Group for their high contribution to the literary world.
The Waterstones Group
The Waterstones Group consisted of many well-respected and avaialble artists, both literary and painters. Amongst their number was such notaries as Sigmund Freud, Brian Blessed, and the literary genius, Stephen King.
The first apporach to the problem was an attempt to re-define to the world, by propoganda, what dark and moody paintings actually consisted of. The group bought several prime-time advertisement slots, and attempted to convince the world, by means of gothic music, interspersed with royal blue pictures of the sea, that light blue was dark and moody.
This plan was, however, unsucessful. Because of the limited budget the Waterstones Group had, the commercials were not aired enough to become embedded into the populations psyche, (unlike McDonald's), and merely annoyed the population.
The group then turned to Science to look for a solution. By employing several top-grade scientists they eventually came up with the solution of mixing a light blue paste, with a black colour, and Navy was created. And then, after all this, they all died.
Today, Navy is mainly synthetically manufactured, primarily in hot countries. It is an unassuming colour, and has been largely superceded by ultramarine. It is still a favorite of many artists however, when the desire to construct the traditional moody sea-scape takes them.