Uncrewed Systems Technology 044 l Xer Technolgies X12 and X8 l Lidar sensors l Stan UGV l USVs insight l AUVSI Xponential 2022 l Cobra Aero A99H l Accession Class USV l Connectors I Oceanology International 2022

89 she is designed to cut through the tops of the waves instead of bouncing over them, which reduces the pitching motion, and she has four fixed stabilisation fins, which reduce roll motion by up to 40%,” Williams says. The Accession, then, has the internal volume of a monohull available for payload or energy, but with stability closer to that of a catamaran. The payload module in the centre of the Accession 425 shown at Ocean Business featured a multi-beam sonar from R2Sonic linked to an SBG Systems Navsight Ekinox INS and an onboard PC. The sonar’s ‘wet end’ acoustic head is in a flooded compartment at the bottom of the module, while all the electronics sit above it on a dry top with a watertight gland fitting for the cables. The different centre module sizes provide more flexibility to tailor the boat to a given mission. “For the really long endurance missions we would put in a 1.5 m section with a 10 kVA generator and 300 litres of fuel, giving us a range of more than 1500 nautical miles at a speed of 4-5 knots,” Williams explains. Swapping modules USS has developed a means of swapping modules with the boat out of the water and supported by three trolleys, one for each section. Swapping them out involves going in through a deck hatch in the stern section, disconnecting it mechanically and electrically, and pulling it out of the way on its trolley. The process is repeated for the centre section so it can be exchanged for another. The power and signal harness includes jumper cables between the sections, providing quick connections for 48 V power through the boat and an Ethernet connection in every section that links to the comms router and the PLC that runs the power management system. “The whole power management and control system is set up so that you can plug in all the different components; the PLC recognises them and everything works,” Williams says. Technical project manager Kevin Wittamore notes that USS can provide customers who want to install their own survey equipment with an empty hull section. “You don’t have to worry about comms or power, you just put your kit in and plug it into our systems,” he says. The PLC monitors all the electrical loads, so it will report when a Accession Class USV | Digest Uncrewed Systems Technology | June/July 2022 The Accession 425 underway at sea showing the reverse bow designed to cut through the tops of waves rather than riding over them, enhancing stability (Courtesy of USS)