In situ vane system for seafloor strength investigations

The In Situ Vane (ISV) system has been developed to determine the strength profile within the upper 1.5 m of deep sea clays. The system is designed to operate in 6000-m water depth after one-year dormancy on the bottom and consists of four integrated packages; controller and data acquisition system, mechanical system, volume compensator, and power supply. This paper describes development of a prototype which was used under a pressure of 550 bars after a 30-day dormancy and of the full system which was successfully used in a deep water (5800 m) test. In the first full application of the system the ISV will be used to measure changes in sediment strength caused by high temperature ( C) as part of the U.S. Subseabed Disposal Program.