Marion initially entered service operating between Glasgow and Greenock before being placed in Loch Lomond in 1818 where she plied the loch in summer. Passengers would embark at Balloch for the sail up Loch Lomond. The first point of call was the place where the Inversnaid Hotel is now situated to enable passengers to visit Rob Roy's Cave. The trip continued to Pulpit Rock, a Covenanters' meeting place, at Inveruglas, 6 miles north of Tarbet then to Ardlui for a short stay before returning to Balloch. {i}

References:
{i} Loch Lomond Steamers; http://www.geograph.org.uk/article/Loch-Lomond-Steamers [accessed 06Nov2019]
{ii} EGERTON, MICHAEL, Airy Nothings; or, Scraps and Naughts, and Odd-cum-Shorts. (London, Thomas M'Lean, 1825) Plate 12