The free-fall corer sampler is designed to sample submerged soils/sediments at >30 metres depth, from the bottoms of rivers, lakes, etc.
By using a winch/hoist the sampler is lowered in free fall. By its own weight and obtained velocity, the apparatus will penetrate the submerged soil. Semi-disturbed samples can be obtained from the top layer of submerged sediments and the system is fitted with a non-return valve at the top of the sampler so that no water remains floating above the sample, this ensures that the sample remains in place.