Liquid Robotics, a US-based company which makes autonomous ocean-going robots, has raised $45m in its series E round from a consortium including oil services firm Schlumberger.
Venture capital firm Riverwood Capital led the E round, while Schlumberger and VantagePoint Capital Partners had participated in $22m D round in 2011.
The 2011 series D was the first institutional investment in the company, but according to the data provider Crunchbase it had previously raised $10m in a series C, $3m in a series B and $75,000 in seed funding, taking its total funding to more than $80m.
The company’s marine drones are wave-powered and can be controlled by satellite, relaying data back to its users over long periods of time and reducing the cost of ocean surveys.