 To date, 11 sediment holes have been cased by drilling-in, collectively saving 30–40 days of ship operational time.The deepest single casing string was drilled-in to 842 m. A hydraulic release tool (HRT)was adapted to drill-in a reentry system with a short casing string to start a hole in bare rock seafloor at Southwest Indian Ridge (Expedition 360).The HRT and related hardware are now being used as the standard drill-in casing system to establish a single casing string for deep sediment penetration.