The design of the propellers and nozzles has been made by CFD. We pay special attention to the efficiency at the speed of 10 knots and silent operation. The nozzle fulfills a function of protection of the propeller together with a good response at high speed, for this reason, a special profile has been developed shorter and with a lower leading edge.
This is the second in a series of 8 auxiliary vessels ordered to serve the bases of the French Navy.
Named Y623 Criquet, it has a 24 m length and 8 m beam. With 53 tons of displacement, it can reach the speed of 10 knots and is distinguished by the adoption of hybrid propulsion. For the transit phases, when the speed is the highest, the diesel generators drive the electric propulsion motors. But for low-speed operation, the motors run on batteries, allowing up to 8 hours of sailing at a speed of 2 knots. It can be recharged on the quay or at sea by the diesel-generator sets. This battery mode allows to operate without polluting emissions, a technology that is already in service in civil ships but that is the first time it is implemented in a French naval vessel.