When the trawl is off the bottom, gravity will cause the sensor to hang close to the vertical position, thus the bottom contact sensor will indicate that the trawl is not on the bottom. When the trawl is on the bottom, the sensor will be in a horizontal position on the bottom and will indicate that the trawl has touchdown.
Some of the features of this sensor are:
* Battery life of 200 hours;
* Telemetry Range of 2 kilometers;
* Update rate between 5 and 9 seconds;
* Operating Depth of 1500 meters;
* Telemetry beam-width is 50° conical;
* Telemetry power is 190 dB re 1 uPa @ 1 meter;
* Telemetry frequency 30 kHz nominal;
* Weight: 7 kg in air, 3.5 kg in water; and
* Activation is via a Seawater Switch.
Along with the addition of the BOTTOM CONTACT SENSOR, Northstar is pleased to announce that new NETMIND(tm) display software is being developed which will incorporate recent advances made in trawl monitoring technology. NETMIND(tm) software currently provides many features unique to the trawling industry. Software capabilities include:
* Time/history display of data from any one, or all, the sensors; this feature displays the performance of a sensor over a specified period of time.
* Ability to customize the system to receive information from the sensors at different repetition rates, such as 5-second intervals, 6 seconds and so on.
* Ability to utilize multiple sensors of the same type, if required, for example using three temperature sensors at the same time.
* Ability to log GPS information along with the sensor information in the NETMIND(tm) log file.
Feedback from the industry during field testing this year in eastern Canadian waters has been extremely positive. Results have indicated that the BOTTOM CONTACT SENSOR was instrumental in indicating trawl touchdown and lift-off, thereby allowing the user to take measures to place the trawl where it needs to be.
The BOTTOM CONTACT SENSOR is the latest addition to the NETMIND(tm) suite of wireless acoustic sensors. Northstar Technical Inc., manufacturer and distributor of the system, reports that the year 2001 has continued the company’s trend of success in marketing and selling the NETMIND(tm) Trawl Monitoring System. In addition to a significant growth in sales in the domestic market, the company has continued to develop markets in Iceland, Scandenavia, Morocco, New Zealand, Korea and Russia. Sales in the United States have also increased significantly and plans are currently underway to aggressively pursue greater opportunities for NETMIND(tm) worldwide.
