VIDEO: Maintenance dredging goes autonomous and underwater

Written by Nick Blenkey
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Autonomy offers advantages that include ability to put dredge underwater

Netherlands-based C-Job Naval Architects has unveiled a concept design for an Autonomous Underwater Maintenance Dredge (AUMD) at a conference in Trondheim, Norway.

Developed by C-Job’s Research and Development department, the AUMD has been specifically created for maintenance dredging in port environments. The team took advantage of the opportunities and out-of-the-box solutions autonomous vessels allow, such as completely submerging a dredging vessel.

The AUMD requires significantly less power than a conventional dredge, with a 16 MWh battery pack providing enough power for up to 12 hours of maintenance dredging.

“When we developed this exciting design, we performed a comparison study with a conventional Trailing Suction Hopper Dredge,” says Rolph Hijdra, Autonomous Vessels Research Lead at C-Job. “This showed that the Autonomous Underwater Maintenance Dredge requires 55% less propulsion power and that, by submerging the vessel, we could reduce the suction head, cutting the dredge pump power demand by 80%.”

The reference conventional dredge has a length of 104.6 m, beam of 18 m and hopper capacity of 3,5999 cu.m. The AUMD has a length of 80 m, beam of 20.m and a hopper capacity of 3,430 cu.m. Both operate at a dredging depth of 35 m.

The submersible design also increases operability as it mitigates wave motions as the dredge is capable of remaining submerged throughout the dredging cycle. It only needs to surface for repair, maintenance and charging of the batteries. The AUMD features a similar hopper volume to a traditional dredge even though the overall length of C-Job’s design has been reduced by 20%.


“Autonomous shipping provides enormous potential for shipowners, with both technical design and economic benefits,” says Hijdra.” According to our research, even with a conservative approach, we found that with the AUMD shipowners can expect nearly twice as much profit after 15 years. Though there’s a higher initial investment, operational costs are much lower which makes it an interesting option for companies to consider.”

While the C-Job R&D team focused on reduced power demand, sustainability, and operability, they also considered other aspects of the design. This includes emergency access which can be obtained through the diver’s lock included in the design. Data communication with the vessel was envisaged via shore-based communication networks such as 4G/5G.

Tim Vlaar, Technical Director at C-Job, says, “In order for autonomous vessels like the Autonomous Underwater Maintenance Dredge to become reality more work is needed and requires all stakeholders such as class, port authorities, autonomous technology companies and launching customers to come together. Of course, continued development of autonomous vessel designs is also needed to fully explore the possibilities autonomous shipping presents even further.”

Download the full C-Job research paper HERE

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