SubBlue Robotics Gets Support for Propeller Cleaning Robot From Danish Investors

Rather than send divers to do dangerous, time-consuming cleaning and polishing of ship propellers, SubBlue is developing a remote-controlled robot.

SubBlue Robotics


Prominent Danish investors have supported the development of a robot that cleans and polishes ship propellers.
SubBlue Robotics, which is a resident at the Odense StartUp Hub in Odense, Denmark, has obtained funding as it offers leases for an underwater robot to help ships be more efficient.

Cleaning and polishing ship propellers is a dangerous and time-consuming task for human commercial divers. Two well-known Danish investors have become co-owners of SubBlue Robotics, which has developed a remote-controlled robot for the job.

The shipping industry has realized the potential benefits of an improved working environment, time saved in port, and a significant reduction in the use of climate-impacting bunker oil as a consequence of ships having cleaner propellers.

“SubBlue Robotics have moved into an especially interesting niche in the automation of the shipping industry,” said Thomas Visti Jensen, owner of Visti Unlimited. “It is a problem that is of the greatest interest at the moment, which SubBlue Robotics aims to solve, where we can see major energy savings and greater safety.”

“And let me tell you that the company founders possess extraordinary drive,” he added. “I am looking forward to myself and Ralf Astrup hopefully being able to help the company on its journey.”

Danish innovators, shippers support startup

Visti is former co-owner of Universal Robots and Mobile Industrial Robots, two of Denmark's most successful robotics vendors (now owned by U.S.-based Teradyne). Astrup is chairman of SubBlue Robotics, and he and Visti each now own a sixth of the company.

In addition, international shipping and logistics company DFDS, several other shipping companies, and the Danish Maritime Fund have given financial support to SubBlue. The fund provided early-stage seed funding in 2019 and 2020.

The robotics cluster in Odense, Denmark, has also welcomed the start-up. SubBlue Robotics is based at the Odense Robotics StartUp Hub at the Danish Technological Institute, so the entrepreneurs and their families have relocated from Greater Copenhagen to Funen.

The startup plans to use the capital for to finance major phases of product development of its remote-controlled robot, which dives down and secures itself to a ship’s propellers, which can have a diameter of 10 m (32.8 ft.). Once attached, the robot then cleans and polishes the propellers, removing corrosion and marine growth.

Currently, to save on the consumption of bunker oil, all commercial ship propellers must be cleaned and polished manually once or twice a year by commercial divers. At the same time, several ports forbid divers from working in the port, which means the ships have to anchor outside the port and wait for favorable weather for the propeller cleaning to get under way.

SubBlue teleoperation

Ship propeller maintenance can be managegd remotely with SubBlue's technology. Source: SubBlue Robotics

Millions could be saved in fuel costs

Don Fischer was inspired to co-found SubBlue Robotics by his time as a trainee in the shipping company Torm, where he saw up close the challenges involved in maintaining energy-efficient ship propellers. He decided to develop a robot for cleaning and polishing propellers.

As soon as Fischer had finished his education in mechanics, automation, and financing, he was ready to set sail with SubBlue Robotics in collaboration with engineer Michael Blom Hermansen. During the six years spent on product development, Fischer said was in close dialogue with commercial divers and shipping companies in order to meet their requirements and to ensure a faster, greener solution to propeller cleaning, as well as with sound operating costs.

“Once propeller polishing becomes automated with robots and the danger to human life is thus eliminated, SubBlue Robotics can bring propeller polishing back inside the busiest ports all over the world,” said Fischer. “Using the robot, several shipping companies can get their propellers polished while they load and unload.”

“Propeller polishing shall be made so simple and so easy that the frequency of polishing can be increased to a more ideal level, for example, three to five times a year,” he added. “The more polished a propellor’s surface is, the greater its energy efficiency.”

“A shipping company using robot cleaning and polishing of propellers can save DKK 0.5 to 1-5 million [$74,000 to $220,000 U.S.] a year per ship in terms of bunker oil costs and eliminate eight to 12 hours from time spent in port,” Fischer claimed. “And this calculation is based on the lower price level of $450 per tonne for ship fuel from before the war in Ukraine. The price of bunker oil is currently $900 per tonne.”

SubBlue ROV

SubBlue says its robot can improve safety, energy efficiency, and environmental sustainability for shippers. Source: SubBlue Robotics

SubBlue Robotics to offer systems for lease

Service providers in the maritime sector have contributed specifications and requirements for SubBlue's robot and will be able to lease the finished product. The company estimated that the global market for its propeller-cleaning system will be about 60,000 commercial ships.

“Our advanced robot uses intelligence to feel its way across the propeller’s surface, even in poor visibility,” said Michael Hermansen, chief technology officer at SubBlue Robotics. “The advanced algorithms are similar to the diver’s eye-to-hand coordination of the polishing disc, and the robot therefore achieves polishing as good as an experienced and fresh diver. But our robot doesn’t get tired and easily works at night.”

“The robot consists of a remotely operated vehicle (ROV) and has an underwater arm that can be as long as 3 m [9.8 ft.], and we have personally developed the hardware and software,” he said. “We will spend the rest of this year further developing and fine-tuning, because we know that operational reliability from Day 1 is alpha and omega.”


Email Sign Up

Get news, papers, media and research delivered
Stay up-to-date with news and resources you need to do your job. Research industry trends, compare companies and get market intelligence every week with Robotics 24/7. Subscribe to our robotics user email newsletter and we'll keep you informed and up-to-date.

SubBlue Robotics

Prominent Danish investors have supported the development of a robot that cleans and polishes ship propellers.


Robot Technologies