Long Coring on UNOLS Vessels: A Feasibility Study and Workshop Report

Long piston coring (40 m and greater recoveries) is feasible on the current Class 1 UNOLS vessels. The following observations and analyses lead us this conclusion: 1) In order to penetrate 40 m into typical marine sediment lithologies, a coring system with a weight on the order of 20,000 lbs will be required. 2) Empirical observations and modeled values for pullout tensions experienced by long piston cores weighing 10,000 to 22,000 lbs fall in the range of 30,000 lbs up to extreme values of 50,000 lbs (modeled for high shear strength sediment lithologies). 3) These likely pullout tensions fall well within the range of capabilities of the large UNOLS vessels for stern deployment of a coring system, based on an analysis of ship strength and stability conducted by Glosten Associates. 4) Synthetic rope with the necessary strength and reliability is commercially available for a reasonable cost. 5) A traction winch can be designed to safely handle the synthetic rope that is required by these pullout tensions. A safe and suitable deck layout can be accommodated on the large vessels