OSI operates both custom-made and Benthos piston corers to obtain continuous core samples of unconsolidated, fine-grained sediments. This type of core sampling tends to be the most cost and time efficient especially in shallow water environments. The core rigs are comprised of a steel or lexan core barrel 3 or 4 inches in diameter with varying lengths, core catchers, and sealed piston assemblies to reduce core compaction.
The corers are driven into the bottom to the desired depth or refusal “by hand,” gravity, or by employing light vibration. Once the piston corer reaches full penetration into the substrate, the rig is pulled out and returned to the surface with a winch. A core catcher at the bottom of the barrel and the piston at the top maintain the seals in order to hold sample retention during the core liners extraction. Once on deck, the core liner is serviced (if an outer barrel is used), the sample is labeled for identification, and stored for shipping according to the project specifications.