Vibrocore, Sediment Sampling & Marine CPT
Mini Hamon Grabs
The CMS-Geotech 0.1m² Hamon Grab is ideal for obtaining bulk samples of seabed sand and gravel as well as for sampling benthic macrofauna This smaller grab was introduced several years ago and approved by CEFAS in order to allow acceptable benthic samples to be collected using smaller vessels.
In addition a 0.1m² sample area is a standard convention used in many benthic sampling applications. The Hamon Grab is a box shaped sampling scoop mounted in a triangular frame. Upon contact with the seabed, tensioned wires are released, which causes the sampling bucket to pivot through 90º pushing seabed sediment into the bucket. On completion of its travel the open end of the bucket comes against a rubber sealed steel plate which stops the sediment escaping during recovery. The reason it is called a 0.1m² Hamon Grab is because the bucket size is such that the area of seabed sampled during its travel is approximately 0.1m². The depth of sample penetration can be up to 20cm.
On recovery the grab is landed onto a rectangular base from where access can be gained to the inside of the bucket via an inspection window. Whilst in the stand the grab sample can then be easily emptied into a sampling container located under the bucket.
