Serving as the surgeon aboard a ship is difficult work. Not only do you have your daily ship's duties to carry out, but you have to tend to some nasty wounds with limited resources at your disposal. You've learned to make supplies yourself from whatever you could find, be it ingredients that you grew on the ship, or dried herbs from a barrel. And as a result of your skill in stitching up people, you've become quite adept at stitching up clothing as well.
All societies that have a system of writing and a distance between nodes of power rely on letters as a form of communication, and there has to be someone to carry them. Whether it is from one street to another or from continent to continent messengers are given the task. Over the centuries and the evolution of civilization professional messengers have had to become keenly aware of the dangers that exist on the routes that they travel and of known or unknown adversaries that may attempt to wrongfully take the messages that they carry.
The tailor sets up shop to form wondrous cloths on the loom, that are used to create bags and outfits that hearty souls wear into perilous adventures. As skills are honed, new areas of craftsmanship open up and incredible trinkets of all kinds are brought to life on the tailor's workbench. Late in life, as necessity dictates, medicines begin to be procured from foraged herbs.