Merchant Charter

Each merchant ship serves its fleet under an arrangement called a Merchant Charter. Not all charters are the same; some confer more power and responsibility to the ship’s captain than others. There are different types of Merchant Charter. All types take the form of a feudal oath sworn to the fleet authorities on behalf of the Emperor. A captain may not register his vessel with the fleet authorities until this oath has been sworn and a record of it entered at the Segmentum Fortress for that zone and on the Segmentum Fortress on Mars.

Segmentae Registration
All interstellar spacecraft are registered as belonging to one or more of the Segmentae fleets. Registration allows a ship to be identified and permits the fleet authorities to record and administrate shipping within each of the Segmentae. A ship that is not registered in a Segmentae may only travel to that Segmentae with the special permission of the fleet authorities. This is purely an identification measure. An unidentified and unregistered ship may be assumed to be hostile, and attacked or destroyed.

Notable Merchant Charter Variants

 * Fleet Charter - A Fleet Charter is the least prestigious level of interstellar captaincy, and is also the least secure. A Fleet Captain may be deprived of his command and given a shore posting at anytime, and his ship reassigned to someone else. A Fleet Captain is appointed to his position in exactly the same way as a free captain, but plies fixed routes like the Hereditary Captain.
 * Free Charter - A more desirable form of merchant charter is the Free Charter. So-called Free Captains are appointed to command individual vessels by fleet officials. They are usually established fleet officials themselves, having worked their way up the ranks to a position of responsibility. Free Captains may trade as they wish within the fleet Segmentae, except that they are usually forbidden from trading along established routes. Instead, they roam the less densely populated and unexplored sectors, areas where regular services are either not needed or would be too costly to run.
 * Hereditary Charter - Less common, but far more sought after, is the Hereditary Charter. A Hereditary Captain may nominate his successor, and that successor may swear the oath of allegiance and thereby becomes the new captain of the ship when its current captain dies or retires. As well as inheriting a ship, the captain inherits a route or routes, and is obliged to carry cargo and passengers only along this route. Some routes are more profitable than others and so are more highly regarded. A Hereditary Free Charter is the most coveted and highly honoured form of captaincy. It is also the most ancient. A captain may be raised to a Hereditary Free Captain as a reward, but Hereditary Captains are no longer simply created as once they were. The captain is free in that he may trade freely within the confines of the Segmentae where his fleet is based. Most of these old captaincies are members of more than one Segmentae fleet, and some are registered in all five of the Segmentae Majoris. Although the Hereditary Free Captain is theoretically an imperial servant, his obligations are relatively few. The ship may trade where and how it pleases within the confines of its charter.

Source

 * Rogue Trader: Core Rulebook (RPG), pp. 315-316