In the Charter granted to the House in 1797, it is stated that the Fraternity had "tended to promote, increase and further commerce and navigation" of the United Kingdom, chiefly of Scotland and the port of Leith. There are no records, however, to prove that this Fraternity of Masters and Mariners was directly concerned in maritime affairs. As seamen they were anxious for the safety of their ships, but they held no formal power other than as consultants. The harbour of Leith belonged to the town of Edinburgh. Its management and maintenance were the charge of the town council. The lights in the Firth of Forth were maintained by their owners who imposed a duty on the ships of Leith for the provision of fuel. By Act of Parliament in 1861, prime gilt was abolished. The more or less permanent income of the House which had been gradually increasing was greatly reduced. During the year ending 1860, it had amounted to £1984.17s.7d.
Although initially created for charitable purposes, these brotherhoods inevitably became associated with lighthouses, themselves intricately bound up with the safety of seamen. Whilst in the earliest days, they exerted varying degrees of influence over the wide range of plans put forward by speculators, later legislation gradually focused the authority towards London. Thus, from 1836, the Trinity House of Deptford Strond assumed complete authority over lighthouses and the Trinity Houses of Newcastle, Leith and Hull, together with the Seamen's Fraternity of Dundee had to apply to the Trinity House of Deptford Strond for its sanction and to receive directions as to the positions and characters of lights.