Japan’s Marubeni Corp has signed a deal to buy engineering firm Seajacks International for about $850m (£535m).

Marubeni and Japanese-state backed Innovation Network Corporation of Japan (INCJ) revealed earlier this week they had signed a joint acquisition agreement to buy Seajacks, which owns and operates purpose-built self-propelled jack-up vessels for the installation of wind turbines.

Marubeni and INCJ will each pay half of the $850m price tag to Seajacks’ owner Riverstone, a US investment firm, with the sale expected to close at the end of April 2012.

Marubeni plans to integrate Seajacks into its Power Projects & Infrastructure division, bolstering its position in the offshore wind farm supply chain. The deal will allow Marunbeni to make further in-roads into the UK market, after it last year bought a £200m stake in Dong Energy’s Gunfleet Sands offshore wind farm, near Clacton-on-Sea, Essex.

Marubeni was also recently confirmed as the leading partner of a Japanese consortium developing the world’s first floating offshore wind farm. The innovative project is being developed off the coast of Fukushima and is hoped to spark economic recovery in the Japanese region last year ravaged by a tsunami.

In addition, Marubeni said it was looking to expand its offshore wind business to North America and other parts of Asia.

Coolin Desai, partner at PwC, which advised Marubeni on the buyout, said the deal was a boost for the offshore wind supply chain.

“This is a landmark transaction that evidences increasing investment in the renewables and offshore support services sector,” he said. “Seajacks’ custom-built vessels are critical in meeting the turbine installation needs of the wind farm industry. The transaction consolidates Marubeni’s position as a leading player in the industry.”