The Guild of Navigators fulfils one of the most important jobs in the Archipeligo of Albion—it provides transport between the numerous islands and across rivers. Without it, much of the trade within Albion would fall apart. For the large part, the trade ships of the open sea are too deep to travel amongst the islands, and their captains certainly don't have the knowledge of the various inlets and shortcuts and so on that allow the Navigators to do their business so well.
You've just managed to scrape together enough money to buy a boat (or acquired it in some other way), and you've just joined the guild. You'll be given a small unimportant route to run, but nobody'll pay much attention to how well it's done.
Note: this rank alone will not provide you with sufficient reason to be at court.
At this stage you'll have proved yourself an able river navigator, and are given much more freedom in where you ply your trade.
Navigators are given complete freedom to choose their routes and so on, and are trusted with much of the day-to-day running of the Guild. If you have your own fleet, it is assumed you can afford to keep it running on your own. If not, you'll be placed in charge of a number of Guild Members and Boatmen, who you'll have to keep happy.
You run the Guild, and as such control the vast majority of transport about Albion. When things go well, you get the glory. When things go badly, well, that depends on how good you are at running.
When the flood waters began to rise, it rapidly became clear that the best mode of transport for the forseeable future would be water based. Before long, pretty much anybody with a bit of entrepreneurial spirit and something larger than a floating ale barrel was touting a ferry service between the various isolated parts of Albion. Competition was rife, and rarely friendly—on some popular crossings, it was necessary to hire two or three boats to ensure safety in the event of a rival attempting to sink a ship.
In 1613, the Guild of Navigators was formed, and with astonishing pace, riverboatmen and women began to join the guild. Passengers soon realised that prices remained steady, and travelling in guild ships was far safer than in non guild vessels, and so to ensure continued custom, the few remaining non-aligned riverboatmen were forced to join up.