The free-fall corer is a sampling tool for fairly undisturbed sampling from the top layer of submerged sediments either or not consolidated.
The free-fall corer consists of a frame with strengthening ribs, falling weight and sampler. Using a hoisting unit (davit) on board of a boat the sampler is lowered in free fall. By its own weight and velocity the apparatus penetrates the submerged soil.
The depth of penetration is partly determined by the composition of the submerged soil. In soils rich of mud, penetration will reach to about 80 cm, in more sandy soils this will be about 30 cm.
After lifting the sampler an immediate rough description of the stratification of the submerged soil is possible due to the transparent tube and also the depth of penetration can be measured. After removing the sample further description regarding the composition, colour, smell and particulars if any, is possible.
Note: During sampling with the free-fall corer samples are compressed, in some cases this may amount to a factor 2. The problem of compression can be avoided by using a sediment sampler, type Beeker sampler (04.23.SA).
Free-fall corer. Standard set