Arlington-based startup Quartermaster has raised 140 million dollars (around 122 million euros) in a Series B round - just four months after closing a 43-million-dollar Series A in May. About 100 million came from Insight Partners, which pre-empted the round before it even opened, from new investor Overmatch Ventures, a defence-focused fund, and from existing backers such as First Round Capital. The remaining 40 million is a credit line from investment bank Stifel.

Founder and CEO Neil Sobin doesn't pretend the timing is a coincidence. Interest in what he's building, he says, was driven by the war in Iran and the chaos it caused in shipping. "World events bring that clarity, they bring the conviction and the urgency, and when you see that, you have to seize the opportunity," he said.

The product is as simple as it sounds. SmartMast is a package of cameras and radios mounted on the mast that sends real-time images of what's happening around the ship. The existing standard, the AIS system, is essentially a string of location signals. With it you know where a ship is; with the camera you see what it's doing. Each unit records tens of gigabytes a day, and uses range from collision avoidance and measuring congestion on sea lanes to rescuing sailors lost overboard.

The device is already installed on more than 650 ships in 25 countries, and over 800 have been delivered - the gap is because the company is starting to equip entire fleets. Production has doubled, and the design is being changed so it can be built faster. The data is aimed at governments, shipping companies and insurers - exactly those with the most to lose when the sea becomes unpredictable.

Sobin calls this a neglected field: "Mariners around the world have been ignored by technology for a very long time." Maybe. But when a defence fund joins a round that a war accelerated, the question is whose eyes those cameras on the masts will really be - the captain's, or someone else's?