Autonomous Underwater Maintenance Dredger

The autonomous underwater maintenance dredger (AUMD) concept design is an innovative solution specifically created for maintenance in port environments. The AUMD utilizes the benefits of autonomous shipping combined with C-Job sustainable solutions to design a dredger never seen before.

What is autonomous shipping?

Autonomous shipping refers to the notion a ship can be self-sailing. An autonomous ship relies on a number of systems that reduces and ultimately eliminates the need for crew onboard the vessel. Semi-autonomous ships still have some crew onboard whereas fully autonomous ships can operate without crew. Much like cars, technology to realize fully autonomous ships is advancing at a rapid rate where this is becoming increasingly likely. However, some form of remote control is likely to always be present. This can be either through continuous monitoring and operating from shore or via a notification system where the system pings the remote operator when it is experiencing certain situations or thresholds.

The autonomous underwater maintenance dredger is the result of C-Job’s Research and Development Team’s ingenuity as it combines multidisciplinary skills with out-of-the-box thinking. The AUMD benefits from innovative solutions made possible thanks to autonomous shipping. With no crew onboard the AUMD can be fully submerged. This leads to reduced power requirements for both propulsion and dredging activities. A 16 MWh battery pack is all the AUMD needs to be able to perform 12 hours of (continuous) dredging operations making it ideal for maintenance in port environments. It is not only clean and sustainable but also delivers substantially lower operating costs.

Comparison study: AUMD x conventional TSHD

Dredging is an energy-intensive process. Conventional dredging vessels need powerful pumps to lift sediment from the seabed. They also need propulsive power to handle the ship’s resistance. Therefore, C-Job performed a comparison study between the AUMD and a conventional trailing suction hopper dredger (TSHD). This comparison study shows how different the two dredgers are – even though they have the same dredging performance.

In the study, an existing TSHD of 104.6 m length with 3599 m3 hopper capacity was considered. While the hopper capacity is similar, the AUMD is only 80 m long and therefore 20% shorter in length.

Looking at propulsion, the study found the AUMD has serious reductions in wave-making and wave-breaking resistance. It, therefore, requires 55% less propulsion power: The AUMD requires 2×575 kW versus conventional TSHD requires 2×1,100 kW.

Additionally, thanks to submerging the vessel the suction head of the dredge pump is reduced from 35 meters to 6 meters. In turn, dredge pump power demand is reduced by 80% comparatively. The AUMD is fitted with 2×175 kW versus 2×675 kW of a conventional TSHD.

Benefits to ship owners

Autonomous shipping provides enormous potential for ship owners. Leaving out the ship’s crew presents opportunities that yield both economic and sustainable benefits. In addition to cleaner and greener operations, C-Job research – even with a conservative approach – found that AUMD owners could expect nearly twice as much profit after 15 years. The higher initial investment is offset by much lower operational costs. This swift return on investment makes autonomous solutions an interesting option for companies to consider.