The British royal, who had been invited to fire the ship's guns with Prince Charles, dissolved into giggles as she tried to protect herself from the ear-splitting noise.
Her husband, however, didn't flinch during the demonstration on the vessel, which is now used as a naval museum and sea cadet training ship.
Camilla is clearly having fun on her first official trip to Canada – to which she has strong ancestral links.
As Prince Charles revealed on their arrival for their ten-day trip, the 62-year-old royal is the great, great, great granddaughter of former prime minister of the United Province of Canada, Sir Alan MacNab.
The couple got the chance this week to look around the leader's home and final resting place - the 72-room Dundurn Castle in Hamilton near Toronto.