Design of an Autonomous Underwater Maintenance Dredger: A teaser to the maritime industry

Abstract

A hopper dredger was chosen as a first autonomous concept design, since dredgers, next to Offshore and Passenger Vessels, are part of C-Job Naval Architects’ main market segments. By submerging a Trailing Suction Hopper Dredger (TSHD) a major benefit was identified in ship’s resistance and required vacuum for the dredge pump. The first aspect due to reduction in wave making and -breaking resistance, the second due to reduced suction depth relative to the pump. In addition, an increased part of the ship’s volume would generate displacement resulting in additional payload and a new arrangement of the vessel could be created resulting in a reduction in overall hull girder loads and reduced steel weight. To prove these insights, a comparative study was performed between a conventional, manned TSHD and the Autonomous Underwater Maintenance Dredger (AUMD). During this study the following aspects were quantified: hydrodynamic resistance, power requirements, sustainable power supply, general arrangement, redundancy / maintenance. The operational profile of the conventional TSHD, was used as a reference for the new concept. The developed concept showed very promising, both from operational as well as sustainability point of view. Some of the key benefits of the design are reduced dredge pump power (2x175 kw versus 2x675 kW), reduced propulsion power (2x575 kW versus 2x1100 kW), low OPEX, zero emission power supply and reduced hull girder loads. Amongst others, based on this concept design, C-Job feels strongly that Autonomous vessels have an enormous potential on (operational) improvements for ship operators. Not only by omitting the ship’s crew, but by fully utilizing the opportunities this presents.