Free fall penetrometers (FFP) have increasingly gained in attention regarding a cost-effective and rapid characterization of the upper seabed. A variety of probes are available ranging from devices utilizing a piezocone penetrometer from cone penetration testing (CPT) to systems adjusted in size and sensor suite to allow deployments from small vessels and in areas of difficult access. Different penetrometer shapes, weights, and sensor suites also call for different deployment techniques. More specifically, the larger systems equipped with a piezocone penetrometer incorporate a winch for handling and recovery and may include a pilot weight trigger for release of the free fall penetrometer at a short distance above seafloor. In this study, pilot weight trigger deployment versus winched deployment is explored for Fugro’s SEADART 1 featuring a piezocone penetrometer plus four accelerometers, inclination sensor, and a piezoelectric mudline detection sensor. Test results are presented for two locations in water depths of about 135 m and 1500 m. Winched deployments were conducted at both sites, while pilot trigger weight deployments were performed additionally at Site 1. The results suggest that pilot weight trigger and winched deployments both can provide high quality data.
Nina Stark, Nico Parasie and Joek Peuchen
Keywords: free fall penetrometer, deployment strategy, winch
Publisher: DFI