Unmanned lifesaver

While unmanned commercial shipping is raising controversial debates, there are possible applications that would provide undisputable advantages over conventional solutions. QinetiQ has developed a concept for an autonomous firefighting vessel
The last few years have seen a marked increase in interest of autonomous technology. In the marine industry, there are[ds_preview] already numerous small-scale unmanned vessels, which are proving the worth of this technology. As technology advances, autonomous vessels will become larger, more capable and operate in a wider range of areas.

With considerable experience in the design and operation of unmanned aerial vehicles and robotics, QinetiQ sought to utilise this experience to develop a concept design for an autonomous/unmanned ship to illustrate the possibilities for autonomous shipping and to enable discussion of the considerations needed. The intent of the project focused on the naval architecture, marine engineering and the overall philosophy behind the ship.

Areas of adoption for autonomous technology typically include clearly defined tasks which are dull, dirty or dangerous, and where there are clear economic benefits. QinetiQ identified offshore firefighting as a role, which could be conducted by an unmanned vessel which would fulfil these criteria. A practical approach has been taken throughout the design process to produce a design that could be built today to demonstrate feasibility of building an autonomous vessel using today’s technology.

Design intent

The primary design intent for the vessel is to form part of the emergency response provision in offshore oil fields, supplementing manned vessels by providing a high performance unmanned firefighting capability for a number of offshore installations. The operational philosophy behind the concept involves the following tasks:

– Loitering in the field on standby duty

– Sprint capability to attend scene of fire or accident

– Firefighting duties

– Rescue duties

The ship is intended to be fully autonomous when loitering on standby; or remote controlled from shore during emergency response.

The ship features a monohull platform, preferred for this application due to ease of construction, efficiency in station-keeping and performance in higher sea states. The ship has a wave-piercing bow to cut through waves and length optimised to minimise wave making resistance. Without need for accommodation, the size of upper decks is reduced which in turn lowers the ships’ centre of gravity, allowing a much finer hull-form with higher length/beam ratio for efficiency at high speed.

Principal particulars are as follows:

LOA: 80.0 m

Beam: 12.0 m

Depth: 7.0 m

Draught: 4.6 m

Power is provided by a diesel electric power plant consisting of six generator sets, supplemented by a large battery bank and solar panel array.

Safety through redundancy

For an unmanned vessel it is fundamentally important to consider the question of how to assure safe operation, not just for the vessel itself but also other vessels and oil-field installations. Without crew on a vessel to rectify any component failures, the question of designing safety into the vessel through redundancy of systems and criticality of components becomes more important in order to prevent an incident developing. To define the required level of redundancy, the potential failure modes need to be identified.

Major sources of potential failure were identified including but not limited to:

– Fire or flood in machinery or other spaces;

– Loss of sensor/positioning sensors or false sensor readings;

– Loss of communications with remote control centre;

– Mechanical/electrical failure of critical systems and/or components;

– Piracy/hijack, either physically or by cyber-attack.

Many of these risks are the same as those identified on offshore support vessels (OSVs) fitted with dynamic positioning systems, hence the implementation of DP systems on offshore vessels can be investigated for guidance in answering these questions and similar solutions implemented in terms of redundancy of systems.

This design utilises duplicated engine rooms and propulsion spaces, providing a fully redundant arrangement in case of any of the identified failures, including fire or flood. For control systems the intent is to provide a level of redundancy equivalent to a manned vessel, so autonomy, communication and control related systems are triplicated with voting mechanisms to identify computer program related failures.

Capability

Throughout the design process, the emphasis remained on maintaining simplicity in design with respect to maintenance and operation. The final concept presents a traditional mono-hulled vessel, with a high degree of redundancy to avoid failures, or minimise the consequences of failure during operation.

The vessel has sufficient fuel capacity to remain on standby for in excess of 90 days. A single generator set can charge the installed battery bank in approximately eight hours, which then provides sufficient power for 12–24 hours operation. This reduces engine running hours to by approximately 80% compared to a typical four engine standby vessel, thus reducing the need for engine maintenance during the 90 day standby period and allowing completely unmanned operation.

If an alarm is raised by an installation in the oil field, a shore operator would be notified who would remotely command the vessel to proceed to the location, either autonomously or via remote control. The ship has a design speed of 20 knots, providing a coverage area of approximately 40,000km2 within three hours.

A firefighting system to DNVGL FIFI III notation is provided, capable of delivering 9,600m3/hr via four fire monitors. Firefighting could be conducted autonomously using a variety of sensors and control algorithms or through remote control with a human operator ashore.

The primary objective of the vessel is to conduct firefighting duties, however the capability of recovering persons from the sea or survival craft is also provided. The vessel is designed to provide self-help recovery, with the option of crewed recovery using a rescue team deployed by helicopter to the winch platform on the ship.

Technology available now

Whilst widespread use of fully autonomous ships may still be some time away, the naval architecture, marine engineering, and technological solutions to support autonomy are available now.

The primary consideration in this design was that of redundancy in order to ensure safe operation of the ship. This is essentially a development of existing dynamic positioning technology and philosophy of operation, ensuring that systems are sufficiently duplicated to diminish the consequence of any single system or component failure.

Integrating an autonomous vessel into existing regulatory frameworks also represents a challenge. By adopting an approach of equivalence in the design through duplication or triplication of systems, the risks associated with maritime operation and unmanned operation can be reduced, meeting the intent of regulation.

Implementation of autonomous technology will take time – it is unlikely that the maritime industry will take a giant leap en-masse to full autonomy in the near future. It will require a combination of approaches to prove the technology step-by-step before mass adoption takes place. This »proving« phase may happen on manned ships with partially un-manned bridge operation, or on smaller ships operated remotely or in limited areas of navigation. In both cases, the concepts presented here will need to be implemented on new-build vessels as interest in autonomous technology increases in order to facilitate the »proving« of autonomous technology.