This paper considers the performance of subsea intervention tasks from an unmanned untethered submersible while using acoustic communications. It is argued that the low bandwidth and high delay imposed by acoustic modems makes it unwise to adopt conventional teleoperation techniques and a system is presented which permits subsea teleoperative tasks to be carried out using such limited communication resources. The described implementation employs active techniques to assist the operator both in

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... erforming actions and in recovering from those problems which will inevitably occur during realworld interaction. It provides the operator with both simulated and real visual imagery and is designed to adapt dynamically to changing bandwidth and computational resources. Experiments are described in which an operator in Philadelphia, PA, controlled a robot manipulator mounted on the JASON underwater vehicle submerged off the Massachusetts coast. All communication over this 500-km distance was via a combination of internet and a simulated acoustic link. Analysis of the bandwidth requirements showed them to be consistent with those from acoustic subsea networks.