iXblue has been testing a prototype DriX autonomous surface vehicle for over six months. Meanwhile the first production batch is approaching completion at the group’s boatbuilding yard at La Ciotat on France’s Mediterranean coast. More production batches are in the pipeline and the system, comprising an ASV and its payload, has been selected by New Zealand to map the country’s seabed.
iXblue developed the DriX multimission ASV primarily to carry out hydrographic surveys. The group’s Sea Operations division (formerly iXsurvey) has long specialised in this type of work while drawing on the expertise of the La Ciotat yard when required. Both the DriX ASV and the FeliX catamaran (see New iXblue vessel for MRE research) are examples of in-house cooperation between Sea Operations and the La Ciotat yard.
The wave-piercing hull is designed to ensure optimal stability. The decision to use composite materials results in weight savings and less noise, and therefore higher quality data collection. The sensor payload — including a sonar, a multibeam echo sounder and an ultra-short baseline (USBL) acoustic transponder — is housed in a gondola that also provides keel ballast. The shape and size of the gondola are tailored to each payload. The mast houses the navigation and communications systems along with the motor’s air intake and exhaust.
The hull is coated in Kevlar for added strength. In addition to a collision bulkhead, it features a compartment for the onboard electronics, including the automatic control system, complete with the mission software, interfaces for the onboard sensors, and a data processing system. This compartment can also accommodate an iXblue inertial platform.
The simple rugged propulsion system features a 37.5-hp Nanni diesel driving a conventional shaft line and propeller. One or two alternators can be coupled to the shaft line, depending on the range of onboard equipment, to deliver 2 or 4kW. The 250-litre fuel tank offers an endurance of five days at 7kts or ten days at 4kts. The USV’s maximum speed is 15kts for transits while tests using the prototype demonstrated good data collection at speeds of 10kts or more.
iXblue claims that the DriX hull is faster and more stable than other designs currently marketed for hydrographic surveying. The craft can be controlled from a support vessel using direct remote control or be deployed alone in fully autonomous mode. “Where local regulations permit, DriX can operate autonomously. It is also effective when controlled from a support vessel equipped to carry out part of the survey workload. In this mode, one member of the support crew monitors USV safety while others process data from the boat’s sensors along with data received via the USV’s WiFi link, then transmit processed survey data to shore in real time. When conducting large multibeam echo sounder surveys, the combination of a support vessel and a DriX USV saves time and money,” says iXblue business developer Guillaume Eudeline.
To deploy the DriX ASV, iXblue has developed and patented a dedicated launch and recovery system, or LARS. “The aim is to perform as many missions as possible without taking the USV out of the water. We only envisage using the LARS to put a USV on deck in the event of a mechanical failure or to swap out the payload or the gondola. Otherwise, launching, bringing the USV alongside, refuelling and sensor data collection (when stored on a memory device rather than transmitted over a radio, WiFi or satellite link) are performed using the LARS, but without taking the USV out of the water. This concept offers considerable flexibility. The DriX USV and its LARS fit into a standard 40-foot container, enabling the system to be transported and deployed anywhere in the world.”
Original by Vincent Groizeleau published on 12 December 2017. This version translated and adapted by Steve Dyson.