TS Duchess of Montrose was built by William Denny and Brothers for the Caledonian Steam Packet Company in response to the growing competition from rival turbine steamers.

Her success led to her owners commissioning a sister ship, TS Duchess of Hamilton in 1932 for the important Ayr route.

Duchess of Montrose sailed from her home berth at Gourock on a Round the Lochs cruise, via Ayr, Arran and Ailsa Craig.

Towards the end of the decade, she operated CSP's newly acquired routes to Campbeltown and Inveraray, previously controlled by Turbine Steamers Ltd.

In 1940, she briefly served as a troop ship,[4] but for most of the war, she maintained the Weymss Bay-Rothesay service and continued until 1948, when she returned to her peacetime role.