Abstract: The device comprises two independently operating systems which are separated from each other in kinematical and actuating respects, viz, a system for closing the jaws of the sample-taking grab and a system for dropping the ballast weights. Said system for dropping the ballast weights is based on the principle of unstable fixing of the weights, the weights being detached from the sampling device after the leader rod strikes the bottom of the basin. Various embodiments of the grab-closing system incorporate, for example, a pulley block and cable mechanism intended first to close the grab jaws, and then to lift out the entire apparatus by taking up the free length of the cable.

Abstract: A method for moving an object on the bottom of a body of water comprising producing a positive buoyancy in the region of one of the supports of the object to lift the support from the bottom of the body of water and then turning the object in the desired direction around another of the supports which remains at rest on the bottom of the body of water. Upon completion of the turning movement of the object, the raised support is lowered by producing a negative buoyancy in the region of such support. The positive and negative buoyancy is produced by means of gas and water pumped into containers mounted in the region of the supports.