The LacCore MUCK (Multi-Use Coring Kit) can function as a gravity corer (self-activated or messenger-activated) or as a rod-deployed piston corer. In gravity mode the MUCK is deployed on a rope, and lowered into the sediment under its own weight to recover an undisturbed sample of the near-surface sediments. Penetration depth is determined by the amount of weight on the core head, which can range from 5 to 40kg. A valve in the core head closes when the deployment rope becomes slack (or can be configured to close when a messenger is sent down the rope), and provides suction during recovery. In drive rod mode the corer couples the drive rods to the tube, and prevents the piston from coming out the top of the tube.
The Surface Coring (PDF, 1.4MB) PDF includes thorough, step-by-step instructions for using the MUCK surface corer, a list of necessary supplies and images of it in use.