Why autonomous

Much of the interest in autonomous ships is in fact driven by the new possibilities that fully unmanned ships offer. In fact, these possibilities have the potential to create completely new maritime transport systems and may very well prove to be disruptive in parts of the maritime transport business. Some of the important possibilities that are inherent in unmanned ships are briefly described as (Rødseth, Ø. J. 2018).

• Improved working conditions: Autonomy and automation are first and foremost applied at tasks that are "3D"; Dirty, Dangerous, or Dull. One can question which onboard jobs fall into the 3D category, but it has been shown that working on a ship is often much more dangerous than working in similar jobs on land. This is mainly due to work-related accidents onboard, including exposure to harmful substances.
• Lower damage-related costs: It has been argued that the human factor is responsible for a majority of the incidents and accidents that happen at sea. Most are relatively unharmful, and typically associated with collisions with port structures. However, repairs and off-hire will still be costly. Whether it is human errors, poorly designed control systems, or fatigue due to lack of rest and boring work, that causes these incidents, can be argued. Regardless, there is good reason to believe that improved and increased degrees of automation will help to avoid many incidents.
• Reduced crew costs: One generally accepted benefit of unmanned ships is that crew costs will be reduced. This is a truth with some modifications, for instance, if increased shore maintenance and the need for a shore control center are taken into account. However, crew-related cost reductions are very relevant for smaller ships. This supports a transition from today's very large ships that are driven by large-scale benefits, to smaller transport units and more flexible transport systems.
• Slow steaming: An interesting issue related to operational cost is the ability to operate at lower speeds to save fuel costs; slow steaming. This requires a trade-off between time-dependent costs such as capital expenses and crew and the speed-dependent cost of fuel. Unmanned ships reduce crew-dependent costs, but the balance depends heavily on the costs of fuel and available capital. For smaller and less expensive vessels, it may be a good business case. Again, defeating the "economy of scale" is an important part of the picture.
• Lower structural costs: An unmanned ship will not need a hotel section, nor most of the deckhouse. It does not need any life support or personal safety systems, such as a galley, laundry, heat and ventilation, water, sewage, lifeboats, and many other costly sub-systems. The removal of these systems will also reduce the ships' weight, or it can be used to increase cargo capacity. If a ship can be built for completely unmanned operation, there are obvious benefits in construction costs and increased cargo capacity.
• New ship designs: The removal of the deckhouse and other crew-related features allow for more innovative designs of ships. Unmanned ships will in particular lend themselves to smaller, more flexible, and more efficient ship designs that may defeat the general economy of scale thinking which is pervasive in the industry.
• Better environmental performance: Weight reduction, or increased cargo capacity, will consequentially improve energy efficiency. The removal of the hotel section and associated power drains will further increase the efficiency. Removal of deckhouses will also decrease air drag, and general optimizations to the hull may also contribute to better energy efficiency.

These benefits are, however, offset by increased costs. Some major issues are the increased need for maintenance and off-hire, as no maintenance can be done during operation. Related to this is the fact that the use of heavy fuels may need to be abandoned, as they normally require significant human attention. Additional infrastructure is also needed in ports and possibly fairways, and the cost of a shore control center must be included in the equation as well.

The dimensions and elements of risk are far from clear, and sufficient safe operation will require additional investments. More advanced ICT systems, including new sensors, will most likely further increase costs. Finally, the regulatory framework will have to be addressed. In reality, a lot is possible when autonomous ships are operated in national waters (as with Yara Birkeland), or even regional waters where bilateral agreements between flag states, coastal states, and port states can be made However, general international shipping will be difficult to achieve without significant changes in today's regulations and contractual arrangements.