The Belfast shipyard that built the Titanic has won a contract believed to be worth £20m to expand a huge windfarm off the East Anglian coast.

Harland and Wolff Heavy Industries Ltd has secured the manufacturing of 60 steel foundation jackets for the East Anglia One offshore windfarm, which will safeguard 200 jobs.

At more than 65 metres high and weighing over 845 tonnes, the three-legged steel jackets will be almost as prominent on Belfast’s skyline as Samson and Goliath, Harland and Wolff’s giant yellow cranes.

Work on the foundation jackets will start in the second quarter of 2017 and should be completed towards the end of 2018, Scottish Renewables said on Friday.

The firm says East Anglia One, a £2.5bn North Sea windfarm, will generate 714 megawatts of electricity by 2020, enough to power 500,000 homes.

Jonathan Guest, Harland and Wolff’s director of business development said: “In a global supply chain environment it is significant when a developer stands over its commitment to give opportunities to local fabricators, as Scottish Power Renewables have demonstrated for East Anglia One.”

Keith Anderson, the chief executive of Scottish Power Renewables said: “East Anglia One will be the best value offshore windfarm ever constructed, at the same time as delivering industry-leading levels of UK content.

“We are pleased that Belfast will play important roles in delivering their project supporting hundreds of skilled jobs.”

Formed in 1862, Harland and Wolff is based in the east inner city overlooking Belfast Lough. It built more than 70 ships for the White Star Line, including the Titanic.

Between 1900 and 1930 it was Belfast’s biggest employer. By the second world war it employed 35,000 people, but from the 1950s onwards it went into decline with advent of the jet age and competition from yards in Japan and Korea.

Although with a much reduced workforce, Harland and Wolff has survived by diversifying away from shipbuilding to the construction of oil and gas rights. It also recast Halfpenny Bridge over the river Liffey in Dublin.

It began to exploit the boom in offshore windfarms in 2012, which at present constitutes 75% of the company’s work.