The early years of the application of steam-power to coastal navigation on the river and firth of Clyde remain an intriguing area of study. A good deal has been uncovered by careful research, but the lack of surviving documentation has meant that an understanding of much important information relies on scant newspaper accounts and advertisements, and anecdotes drawn from memories of a dim and distant past. The subject of this essay is the “Castle Company,” one of the most successful of the early steamboat concerns; one that reorganized on at least two occasions; one that had rivals on several fronts that attempted to topple its prominence; and one that eventually succumbed to a take-over by Messrs G. & J. Burns in June 1846, though it effectively carried on for a few years afterwards. Surprisingly little has been written about this important company, and as far as I am aware, there...