NBP09-01 Cruise Report - British Oceanographic Data Centre

ice-ocean boundary layer. To do this Autosub-III was equipped with the following instrumentation: Seabird9+ CTD, with dual conductivity and temperature sensors plus a SBE43 dissolved oxygen sensor and Wetlabstransmissometer; Simrad EM2000 multi-beam echosounder; upward-looking RDI 300 kHz ADCP; downwardlookingRDI 150 kHz ADCP. Unusually light sea ice conditions allowed the ship to access Pine Island Bayduring the early stages of the cruise and provide the perfect conditions for autosub deployment. A total ofeight missions, including two test missions in open water and six science missions beneath the glacier wererun during the two-week period from 17th to 30th January 2009. Total track length was 887 km (taking 167hours) of which 510 km (taking 94 hours) were beneath the glacier.Figure 15: Acoustic fish being deployed from starboard ’A’ frame.3.2 Preparation and Mobilisation in Punta ArenasAutosub mobilisation began in Punta Arenas in December 08 prior to cruise NBP0901. The Autosub gantryplaces very large vertical deck loads and required a custom made deck/gantry interface plate, designed atNOCS but constructed in Punta, to reduce the loads to an acceptable level. The launch and recovery gantrywas bolted to the deck matrix via the adaptor plate. The container/garage assembly was secured in placeand the Autosub vehicle secured within the garage container set up.We had problems with some of our wooden equipment not meeting Chilean requirements for heat treatment.Our acoustic fish bases, weights box, and railway sleepers (used for blocking up the Autosub chocks) weredestroyed, the replacements being made from locally sourced wood.Following discussion with Raytheon employees the aft garage roof was lowered and container doors refittedfor the crossing to the Amundsen Sea (this turned out to be essential, since the aft deck of the Palmerbecomes awash to a depth of 0.5 m, even in moderate seas).NBP09-01 Cruise Report (p. 19 of 83) Revised February 27, 2009