MV Cowal in 1954. She inaugurated the regular Wemyss Bay to Rothesay car ferry service, on 1 October 1954 and remained in the upper Clyde for her whole career. From 1957 the three "A, B, C" sisters were working interchangeably. In May 1970, "Cowal" inaugurated a short-lived seasonal Fairlie-Tarbert-Brodick service. When this ended in September 1971, "Cowal" operated between Largs and Millport, until displaced in March 1972 by the former Skye ferry on the quicker Largs to Cumbrae Slip run. With linkspans at Gourock and Dunoon, the hoist-loading "Bute" and "Cowal" were restricted to the Wemyss Bay to Rothesay crossing, where "Cowal"
MV Cowal the last vessel to receive the new CalMac livery, retaining the vivid CSP yellow funnel until 1974. After 24 years' service, she was laid up in East India Harbour, Greenock from early June 1977. Surviving a galley-fire on 9 June, she was moved to the James Watt Dock in 1978 and offered for sale. Increasingly forlorn and "cannibalised" for parts to keep "Arran" running, "Cowal" was finally sold to Phetouris Ferries in Greece on 5 January 1979, and left under tow for Perama on 15 May. Despite the tow parting in the Bay of Biscay, she arrived in Piraeus, and