Shipboard Acoustic Systems
When arriving to the ship, the following systems will need to be configured for Coastal Pelagic Species survey work. Each link goes to a Google document that will contain the latest procedures. Any updates and changes to configurations should be made inside the Google Document.
Setting up the EK80 - A suite of transcievers, transducers, and software (ranges from 18-333 kHz). Includes set up of EAL (EK80 Adaptive Logger).
Setting up K-Sync - A synchronization system (Simrad K-Sync; Kongsberg) that staggers the triggering of separate transducers to minimize interference across frequencies.
Ship Acoustic System Orientation:
Kongsberg EK80 Scientific Echo Sounders
On Lasker and Shimada, multi-frequency Wideband Transceivers (Simrad EK80 WBTs; Kongsberg) were confgured with split-beam transducers (Simrad ES18, ES38-7, ES70-7C, ES120-7C, ES200-7C, and ES333- 7C on Lasker and ES18, ES38B, ES70-7C, ES120-7C, and ES200-7C on Shimada; Kongsberg). The transducers were mounted on the bottom of a retractable keel or “centerboard” (Figure 1). The keel was retracted (transducers ~5-m depth) during calibration, and extended to the intermediate position (transducers ~7-m depth) during the survey. Exceptions were made during shallow water operations, when the keel was retracted; or during times of heavy weather, when the keel was extended (transducers ~9-m depth) to provide extra stability and reduce the efect of weather-generated noise. Transducer position and motion were measured at 5 Hz using an inertial motion unit (Applanix POS-MV; Trimble).
Ship Centerboard Drop Keel Depths
Anytime that the ship changes the centerboard depth, the manual depth in the EK80 software should be updated accordingly:
| Reuben Lasker Centerboard Configuration | Manual Depth (meters) |
|---|---|
| Retracted | 5.9 m |
| Intermediate | 7.35 m |
| Extended | 9.1 m |
| Bell M. Shimada Centerboard Configuration | Manual Depth (meters) |
|---|---|
| Retracted | 6.1 m |
| Intermediate | 7 m |
| Extended | 9.15 m |