Boston-based Sea Machines Robotics, a developer of autonomous systems for ocean-going vessels, accomplished its full $20-million investment goal with a second close of $5 million. The company announced the first close of $15 million in July.

This latest close includes follow-on investments by the Brunswick Corporation and their investment partner TechNexus, Toyota AI Ventures and NextGen Venture Partners. Sea Machines also welcomes a new investor, Dolby Family Ventures of San Francisco.

Sea Machines’ autonomous systems increase productivity of vessel operations by assuming active domain perception and navigation duties. A Sea Machines’ system works under the command of a human operator and—by taking on the long duration and often repetitive control duties—it boosts the predictability and precision of operations while lowering the risk of fatigue-related incidents. The technology also enables new capabilities on water, such as the onshore command of remote offshore vessels.