A large‐diameter (14 cm) long piston corer (20–40 meters) has been used successfully to obtain relatively undisturbed sediment samples in water depths from 80 to 5500 meters with recovery ratios ranging between 0.76 and 0.87. The first recovered core (KN‐10‐1) was taken in the Stellwagen basin, western Gulf of Maine, at 81‐meter water depth using a pipe length of 33.5 meters and total core weight of 3500 kg. The 21.74 meters of recovered sediment is black, gray to olive green silty illitic clay. Visual observations and results of consolidation studies indicate that structural disturbance to the sediments was not severe, that it is normally consolidated, and that no postdepositional compaction occurred. Another core (KN‐27‐1) was taken about 3 km east of the first core location, and 19.65 meters of sediment were recovered. An anomalous zone in core KN‐10‐1 reveals high water content (96%) and high shear strength (260 g/cm2). A marked abundance of diatoms may explain the high water content, and the highly flocculated nature of the abundant clay minerals observed with a scanning electron microscope accounts for the high shear strength. A similar anomalous zone in core KN‐27‐1 occurs where the water content is 53% and shear strength is about 250 g/cm2. Preliminary correlations with the 3.5 kHz subbottom profiles suggest that changes in both texture and water content may produce reflecting horizons.