Montclare was launched in Scotland in 1921 as a transatlantic liner for the Canadian Pacific Steamship Company.

She had twin screws, each driven by high-, intermediate- and low-pressure steam turbines via double reduction gearing.

[5] On 18 August 1922 Montclare left Liverpool, on her maiden voyage, bound for Quebec and Montreal, with Captain RG Latta as her Master.

[6] As built, the ship suffered from excessive fuel consumption, so in 1929 by Harland & Wolff in Belfast rebuilt her turbines with single reduction gearing.

[6] While heading for Greenock on 22 March 1931, she ran aground on Little Cumbrae with a number of passengers aboard.

[6] She was converted into an Armed Merchant Cruiser, and commissioned into the Royal Navy in October 1939 as HMS Montclare with the pennant number F85.

She left Hong Kong on 3 January 1946, her crew having played a vital part in getting the colony back on its feet again.

She arrived back in Portsmouth on 21 February 1946, and was reduced to Reserve status before conversion to submarine depot ship, as which she spent much time at Rothesay.

[2] In the early 1950s Peter O'Toole did national service in the Royal Navy, and was a Signaller aboard Montclare when she was a submarine depot ship.