The results of model and in-situ tests of control algorithms providing coordinated movement of a group of heterogeneous underwater robots in an uncertain three-dimensional moving environment in order to search for sunken objects on the bottom are being considered in the paper. Autonomous optical navigation of each robot, simulating the use of SLAM algorithms based on side-scan sonar (SSSI), interaction of robots with each other by means of surface buoys or a hydroacoustic modem, transfer of the detected objects` coordinates between robots in the group, and building a digital bottom map in the memory of each robot are used. The proposed control algorithms can be used both in centralized and decentralized control. Simulation model and field experimental data, confirming the performance of the proposed algorithms and protocols, are presented. The developed algorithms can be used in the control systems of mobile robots for their group control in uncertain 3D environments.