The Motion Decoupled Hydraulic Delivery System (MDHDS) is a new downhole tool delivery system that is deployed by wireline and uses drillstring pressure to advance a penetrometer (or other downhole tool) into the formation at the bottom of offshore boreholes. After hydraulic deployment of the penetrometer, it is completely decoupled from the BHA; this eliminates the adverse effects of ship heave. We tested the MDHDS at Site U1402 (the location of Site 1073, ODP Leg 174A), offshore New Jersey, during two days of ship time during Integrated Ocean Drilling Program (IODP) Expedition 342. In one deployment we emplaced a penetrometer successfully and documented that it was decoupled from drillstring movement. Based on this successful field test, the MDHDS has been certified by the U.S. Implementing Organization (USIO) for shipboard use. The MDHDS will replace the previous deployment system, the Colletted Delivery System. The MDHDS is an IODP-funded engineering development led by The University of Texas at Austin, in conjunction with the USIO and Stress Engineering Services. This sea trial was the culmination of a seven-year development effort that included extensive engineering design and fabrication.