This section was prepared by the TOBI team. TOBI was launched and recovered five times during the cruise. The logging times are listed below on Tab.4 along with relevant comments:
The disks used and their relevant times are listed in Table 5.
The Urania is equipped with a stern mounted 5 tonne hydraulic 'A' frame. The frame has three locations for towing blocks. The main sheave was hung from the middle position via a swivel and used for deploying and recovering both the TOBI vehicle and the depressor weight.
The A' frame has been considerably modified since the TIVOLI cruise in 1998. The wider stance and taller cross piece have made the launching and recovery of TOBI much easier tasks, allowing the system to be deployed and recovered in higher sea states than previously. This gives a far greater flexibility to the use of TOBI on the Urania that in turn helps the planning of the scientific survey.
In calm conditions the TOBI vehicle could be launched directly in a fore-aft position. In other conditions and for recovery a normal sideways position was adopted to give maximum control over the vehicle. The only problem encountered was that the stern doors reduce the effective width of the A' frame and make it difficult to position TOBI especially during recovery. Particular care had to be taken to ensure that the umbilical cable was not trapped between the vehicle and the stern doors or undue bending applied. Data Recording and ReplayData from the TOBI vehicle is recorded onto 1.2Gbyte magneto-optical (M-O) disks. One side of each disk gives approximately 16 hours 10 minutes of recording time. All data from the vehicle is recorded along with wire out and ship position taken from the GPS receiver. Data was recorded using TOBI programme LOG.C. The profiler data was corrected for the depth of the vehicle and replayed in programme PROFRAY.C. BLOWUP.C was used to generate large images of areas of interest. Data from the M-O disks were copied onto CD-ROMs for archive and for importation into the on board image processing systems.
During the cruise scaled sidescan images were generated at 1:60000 using the TOBI sidescan data, vehicle positional data from the HPR navigation system and replay programmes ERASDISC.C and DISSCRAY.C. The images were printed out using a Raytheon TDU850 thermal printer and then manually overlaid on track charts to create mosaics of the work area.