Abstract: A multi-shell grab bucket apparatus comprises a distributor head having a plurality of engine cylinder chambers rigidly fixed with respect to the distributor head and being disposed in a common horizontal plane and extending radially outwardly from and angularly spaced about the distributory head center axis. Engine pistons are mounted for sliding reciprocatory movement within respective ones of the engine cylinder chamber and define therewith double-acting reciprocating engines. A set of fluid supply passages located internally of the distributor head are connectable to an external source of fluid pressure medium for supplying the medium to opposite ends of the engine cylinder chambers to effect reciprocation of the engine pistons to thereby actuate scoops connected to respective ones of the engine pistons.