The Bay class were designed and ordered as replacements for the Second World War-era minesweepers that the Royal Canadian Navy operated at the time.

[2][note 1] The Bay-class minesweepers were powered by two GM 12-cylinder diesel engines driving two shafts creating 2,400 brake horsepower (1,800 kW).

[2][3] Thunder's keel was laid down on 17 May 1951 by Canadian Vickers at their yard in Montreal, Quebec.

The vessel was commissioned into the Royal Canadian Navy on 15 December 1953 with the hull identification number 144.

She was transferred to France the same day, but the French flag was only raised aboard the ship on 1 April.