The multiple sediment corers are hydraulically damped enabling the sample tubes to be lowered with minimal disturbance of the surface sediment. The sampling tubes enter the sediment at approximately 5 cm per second. No acoustic or electronic controls are required for operation, leading to minimal operator handling and simple winch deployment. Each core tube is held in a separate detachable holder, enabling the sealed samples to be removed from the corer. The head of the larger corers is made on a modular basis so that the number of holders is carried by the Midi and Maxi can be increased at a later date.
Corer deployment rates are in the region of 1 metre per second on the descent, and at any speed on retrieval as the samples are positively sealed. On retrieval, the top cap seals the tube before withdrawal, and the base catcher operates immediately the sediment is cleared. This procedure includes some supernatant water in the core preserving sediment/water interface, and producing samples of a high quality.