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"
Cowal subsequent invasion by Norsemen, the Hebridean islands of Dal Riata became the Kingdom of the Isles, which following Norwegian unification became part of Norway, as "Suðreyjar" (historically anglicised as "Sodor"). The remaining parts of Dal Riata attracted the name "Argyle" (later "Argyll"), in reference to their ethnicity. In an unclear manner, the kingdom of Alba was founded elsewhere by groups originating from Argyll, and expanded to include Argyll itself. However, an 11th-century Norse military campaign led to the formal transfer of Lorn, Islay, Kintyre, Knapdale, Bute, and Arran, to "Suðreyjar". This left Alba with no part of Argyll except Cowal,