Today, it sits gently bobbing on London’s River Thames as a floating museum. But more than 70 years ago, the HMS Belfast was at the forefront of the Allied effort to defeat Nazi Germany.

At the time, some 80 Canadians served aboard the British vessel. To honour their contribution to the war, a Canadian flag will be flying atop the 187 metre cruiser until the end of the year.

“Without the Canadian contribution to the Battle of the Atlantic, particularly, and the battles in the Arctic, we would not have had the ships or the manpower to have endured in those battles,” Tim Lewin, vice president of the HMS Belfast Association, told CTV News.

The Belfast, Lewin noted, also played a significant role in the hunt for a feared German warship in the North Atlantic in 1943.

“Belfast, with her 80 Canadians on board, was actually the first to spot Scharnhorst and her accompanying destroyers in the dark and the snow,” Lewin said.

Then, some six months later in June 1944, the ship played a pivotal part in the D-Day invasion of Normandy.

“The Belfast was also involved in providing cover for the landings at Juno Beach and the Canadian sailors were involved in that as well,” Sarah Fountain Smith, Deputy High Commissioner for Canada in the U.K., told CTV News at a recent flag-raising event.

Canadians were sent aboard warships like the Belfast to receive valuable training. Hundreds of Canadians, in fact, served in the British navy during the war, including 94-year-old Rolfe Monteith, a retired naval captain and current HMS Belfast Association member who joined the war effort when he was still a teenager.

“Never,” he said when asked if he was ever afraid of the sea. “And I’ve been through some horrendous gales.”

Monteith survived those seas, and so did the Belfast, which has been a museum since 1971. The Canadian flag will grace the ship until the New Year.

With a report from CTV National News London bureau chief Paul Workman <br />