A device that takes samples with a scoop rotating on an axle mounted on a heavy frame that rests firmly on the bottom. The device is lowered open with the entire weight taken by a shackle on a balanced arm. Closure is not effected on touching bottom. On hoisting, the pressure of water on a vane attached to the balanced arm tips a lever allowing a pin to slip out, releasing the shackle. The weight is then transferred to a rope rotating around a large drum. This in turn rotates a small pulley and drags the sampling hemisphere through the bottom via a second pulley to which it is attached by a light wire. The maximum volume of the sample is 5« L, and in practice, usually about 3 to 4 L are collected.