It’s exactly 50 years since thousands of Chatham Dockyard workers gathered to celebrate the launch of the submarine Okanagan.

As they posed for this photograph on September 17 1966, they did not know she would be the last warship ever built at the dockyard.

It signalled the end of four centuries of frontline naval shipbuilding in Chatham.

Okanagan was the last in a long line of remarkable vessels that stretched from the Age of Sail, including Nelson’s flagship Victory, to the 1960s.

Although Chatham Dockyard went on to play a key role in the refit of nuclear submarines before the yard closed in 1984, Okanagan holds a key place in its shipbuilding history.

Okanagan, commissioned by the Royal Canadian Navy, was the third of three Oberon class submarines built in Chatham and commissioned by the Royal Canadian Navy, following HMCS Ojibwa and HMCS Onondaga which were both launched in 1965.

Sir Trevor Soar, chairman of Chatham Historic Dockyard Trust, is a former commander of HMS Ocelot, an Oberon class patrol submarine and sister ship to Okanagan that is now a Historic Dockyard attraction.

He said: “For 400 years, Chatham was renowned for its shipbuilding excellence. Thousands of workers with skills in key trades gave Chatham a reputation that went around the world.

“HMS Victory is perhaps the most famous but there were hundreds more, including HMS Namur, whose timbers were discovered under the floor of the old Wheelwright’s Shop and are now the centrepiece of our exciting new Command of the Oceans exhibition.

“We may regret that Okanagan was the last vessel to be built in the dockyard, but it’s a cause for celebration that Chatham enjoyed such anenviable reputation that it was entrusted to build three Oberon Class submarines that entered service with the Royal Canadian Navy.”

Richard Holdsworth, trusts preservation and education director, added: “During the 20th century, Chatham Dockyard built 57 submarines – more than any other Royal Dockyard.

“Six were “O” class boats – three for the Royal Navy, including Ocelot, the last of over 400 warships built for the Royal Navy at Chatham and now open to visitors at the Historic Dockyard, followed by three for the Royal Canadian Navy.”

Cdr Lawrence Trim, the Royal Canadian Navy attaché in the United Kingdom, said: The HMCS Okanagan and the other Royal Canadian vessels from Chatham Dockyard symbolise the closed, historic and enduring links between our two countries and or shared seafaring tradition.”