VESSEL REVIEW | X-16 – Battery hybrid USV to take on survey and environmental monitoring duties

Irish underwater data acquisition services provider XOcean has introduced a new catamaran unmanned surface vehicle (USV) to its fleet. The craft belongs to a series of 12 vessels, the first example of which was completed in 2021.

Designed and built by XOcean’s in-house engineers, X-16 has a length of 4.5 metres, a beam of 2.2 metres, and capacity for up to 100 kilograms of various sensor and equipment combinations. These will enable the USV to perform a range of missions such as bathymetric surveys, environmental monitoring, data harvesting, and even fisheries enforcement.

The wave-piercing catamaran USV is fitted with a hybrid propulsion setup consisting of a lithium-ion battery pack and a small diesel generator. In addition to enabling the USV to sail up to 1,512 nautical miles at a cruising speed of four knots, it also means the craft can carry out missions each lasting 18 days even with full 24/7 operations.

The propulsion arrangement also includes two bow-mounted outboard thrusters to assist in station keeping. The two electric bow-mounted thrusters are controlled separately to adjust the speed on each side, steering the USV on the desired course. These and the two main electric pod drives generate an extremely low noise signature, making the craft ideal for operations in sensitive marine environments.

Recharging of the batteries is done during daylight hours with the aid of deck-mounted solar panels XOcean said the use of electric propulsion will produce only about one-thousandth of the emissions of a conventional survey vessel.

The USV’s compact size allows it to be easily and quickly deployed and re-deployed, either via a road trailer or a standard 20-foot container. When underway, the vessels are controlled remotely by human pilots at XOcean’s shore-based operations centres with the aid of a highly secure cloud-based system for monitoring battery status and the quality of the data being collected. The system will also allow pilots to adjust both the USV itself and sensor parameters as required.

The USV also has a broadband satellite transceiver that provides continuous over-the-horizon connectivity, thus allowing images and situational awareness data to be relayed to the shore operations centre in real time.

The remainder of the electronics suite consists of an AIS, a thermal imaging camera, visible light cameras, and image detection sensors. As the craft has no autonomous collision avoidance system, it has to rely on a human operator to manoeuvre it clear of any obstacles that are detected in its way, and the visual sensors will aid in this regard.

Lastly, a proprietary mobile app developed in-house by XOcean allows customers access to real-time updates on the USV’s disposition and other parameters such as weather. Customers may even view live video feeds from some of the onboard cameras that are also used by operators in manoeuvring the craft remotely.