Towed Ocean Bottom Instrument (TOBI)
Parent Body: Southampton Oceanography Centre, Empress Dock, Southampton, SO14 3ZH

Principal Functions
Deep towed vehicle with 30kHz sidescan and swath bathymetry, chirp sub-bottom profiler, high resolution magnetometer and CTD systems.

Subsidiary Functions
Stable platform for user defined instruments.

General Details
TOBI is a stable instrumented vehicle towed typically 300 to 400m above the seafloor using a two bodied tow system at depths down to 6000m. The current standard instrument suite consists of a 30kHz sidescan sonar with swath bathymetry capability, chirp sub-bottom profiler, three-axis high resolution magnetometer, CTD, gyrocompass and vehicle attitude sensors. The vehicle design permits easy fitting and interfacing of a variety of user defined packages. Data are transmitted up the armoured coaxial tow cable for logging and display on the ship. A winch system comprising of launch, umbilical and main tow units with 10,000m of cable is available if required. This system is mounted on a 20’ container base plate along with its electrical power pack.

Specification
The vehicle is 4.25m x 1.25m x 1.5m (l x w x h) and weighs 2500kg in air (slightly buoyant in water). The sidescan has a swath width of 6km with along track resolution increasing with range from about 3m to 30m and across track resolution of 2m. The maximum swath width of the bathymetry system is 6km although this is somewhat dependant on terrain. The chirp sub-bottom profiler has a potential resolution of 0.25ms and can penetrate over 40ms into soft sediment. Three components of magnetic field are logged with a 1nT resolution. Data from the vehicle attitude sensors, CTD and user defined packages are logged at 4 samples per second. Winch power requirements are 3 phase 415/440V 50/60Hz 150kVA.

Special Features
On-line display of sonar and sensor data. Replay of anomorphically and bend corrected sidescan data for on board mosaic production using hard copy thermal recorder images. Optionally a fully digital mosaic can be produced. Hard copies of the sub-bottom profiler data are replayed corrected for vehicle depth and motion to provide a true representation of the topography. Logged data is copied onto CD-ROM for easy importation into data processing and replay packages.

Future Plans
A reversed acoustic navigation package is being developed for the precise location of the TOBI vehicle to aid data processing and real time operational flying of the vehicle.

Availability
The facility is available to both the private and public sector.

Charging Basis
Charging rates are subject to negotiation.

Contact Information
Keith Birch
Business Development
Ocean Technology Division
Southampton Oceanography Centre
Empress Dock
Southampton
SO14 3ZH
Telephone:  +44 (0)23 8059 6105   Fax +44 (0)23 8059 6149
Mobile:        077 1865 6294
Email:       kgb@soc.soton.ac.uk
Web site:  www@soc.soton.ac.uk

Technical Enquiries
Ian Rouse
Southampton Oceanography Centre
Empress Dock
Southampton
SO14 3ZH
Telephone: 023 8059 6158    Fax: 023 8059 6149