One of the fastest-growing firms in the East Anglian energy industry has been bought by an American private equity firm in a �130m deal.Great Yarmouth-based Seajacks has been bought by Riverstone Holdings, a New York-based specialist investor in energy industry companies for $207m.

One of the fastest-growing firms in the East Anglian energy industry has been bought by an American private equity firm in a �130m deal.

Great Yarmouth-based Seajacks has been bought by Riverstone Holdings, a New York-based specialist investor in energy industry companies for $207m.

Riverstone said it was planning to “devote a substantial amount of new capital” expand Seajack's fleet of two giant self-elevating lift boats, Leviathan and Kraken, which can be used as mobile maintenance and construction platforms for offshore wind farms.

While Kraken is about to start work on the construction of the Walney windfarms in the Irish Sea in a �48m contract with Dong Energy, its sister ship Leviathan is working on the Greater Gabbard windfarm off the Suffolk and Essex coast in a �39m deal with Fluor.

The Riverstone deal comes just weeks after the announcement by the Crown Estate of the award of nine offshore windfarm licences.

Among the new windfarms will be the "East Anglian Array", a windfarm of about 1,000 turbines about 15 miles offshore from Great Yarmouth and Lowestoft.

Seajacks was founded in 2006 by energy industry veteran Blair Ainslie and Norwegian investors and was quoted on the Oslo stock exchange.

Mr Ainslie said: “It's business as usual here in Great Yarmouth.

“No changes to the operation. With Riverstone's considerable financial backing however it does give us the opportunity to look at expansion plans and we are in the process of finalising new build designs targeting growth in the offshore wind farm market particularly, building on the contracts and experience we are gaining on Greater Gabbard and Walney 1 and 2 in the Irish Sea with Dong Energy, which will start this summer.”

Robin Duggan, principal of Riverstone, said: “We are impressed with the track record of the Seajacks management team. The company has delivered two purpose built vessels on time and on budget, successfully secured contracts with both offshore wind and oil and gas customers and created a number of skilled jobs.

“Our ambition is for Seajacks to be the leading UK-based provider of offshore wind installation and maintenance services to the European market, a sector poised for rapid expansion, and to provide focused support services to the North Sea oil and gas industry.”