Optical validation data were collected using the Tethered Optical Assessment Device (TOAD), a sled equipped with underwater video cameras and lights. These data are used to provide ground-truth validation for benthic habitat maps based on multibeam echosounder surveys and to gather additional information regarding benthic communities. Camera sled deployments were conducted at night and during the day. The camera sled was deployed off the starboard J-frame on NOAA ship Hi'ialakai. The TOAD was lowered slowly to the bottom by a winch holding 360 m of cable and operated from a control station in the dry lab of the ship. The TOAD operator monitored a live video feed from the camera and record data on a video tape recorder.
Equipment Description: The TOAD sled body used for the data collection is constructed from a shortened Phantom ROV body with a tail piece added for stability.
The frame has been extensively modified from its original configuration and was equipped with two Deep Sea Power and Light Multi SeaCam 2060 color video cameras. One camera is mounted to point at approximately a 45 degree angle toward the seafloor and is the primary data collection instrument. The second camera is aimed straight ahead and the signal from this camera is fed to a second video monitor to provide warning of underwater obstructions. The video signals from the sled are sent via coaxial conductors within a 360 m long and 19 mm diameter umbilical cable to a topside control unit. The cable between the sled and the surface includes an internal strength member to support the sled frame. The cable is paid out and recovered using a dedicated custom-built winch equipped with slip rings and powered by a 5 hp electric motor. The winch is controlled at the winch itself for sled deployments and recoveries. The rest of the time a remote controller located in the dry lab is used to enable the operator at the video console to adjust the sleds altitude. All TOAD surface components are located in the Dry Lab in an equipment rack on the after bulkhead. Illumination is provided by two 250 W DeepSea Power & Light Multi-SeaLite model 1050 underwater lights mounted on the sled frame. The lights are located on each side of the sled to provide the maximum possible horizontal distance from the camera. An ORE Offshore model 4330B Multibeacon is attached to the sled to provide a response to acoustic interrogations sent by the Hi'ialakai's Model 4410D-01 Trackpoint II Plus Ultrashort Baseline acoustic tracking system. The sled is also equipped with a sonar altimeter to detect the height of the camera above the seafloor, a pair of parallel lasers to determine the size/scale of viewed objects, a compass to determine the sled heading and orientation, and a depth (pressure) sensor. Neither the altimeter nor the pressure transducer functioned reliably during this cruise.
Name & address of person collecting data:
John Rooney NOAA IRC NMFS/PIFSC/CRED 1845 WASP Blvd., Building 176 Honolulu, HI 96818
Data Files: Video data are recorded on a mini DV video tape recorder. The position of the camera sled is recorded using Hypack Max version 6.2b survey software.
File naming convention: Each tow is given a name consisting of a 3-letter designator for the island area followed by two-digit year and three-digit tow number. For example, during HI0804 (NOAA Ship Hi'ialakai's 4th cruise in calendar year 2008) the first tow was called FFS08001. Video tape labels and paper log forms are annotated with the tow name. Data files recorded in Hypack software followed their CHS filename format consisting of the year, the first two letters of the platform name, the Julian date, and the hour and minute in which the file was started. For example, a file collected on July 18, 2005 (Julian date 199) aboard the Hi'ialakai starting at time 1935 would be 2005HI1991935.
Time Correlation: All times are based on UTC. Four clocks were manually synchronized prior to starting data collection; the clock in the on screen display that was used to annotate the video tape, in one of the video cassette recorders, in the Trackpoint II system, and in the computer running the Hypack Max software. These clocks are set to UTC at the beginning of each operation.
Resource Description: Digital video imagery that is geo-referenced to navigation files.
List of navigation files: 2008HI1421148 2008HI1421317 2008HI1470625 2008HI1471008