New trawl sonar delivers real-time refresh rate

01 Mar 2016
FM90 data showing mackerel, captured from Danish combi vessel HG333 'Isafold'

FM90 data showing mackerel, captured from Danish combi vessel HG333 'Isafold'

Simrad has launched the new FM90 Multibeam Trawl Sonar System, which features a near real-time image refresh rate.

This provides a detailed live representation of the trawl, enabling the skipper and crew to maximise catch and reduce the potential for expensive damage by better trawl positioning.

The Simrad FM90 is a ‘third wire’ system, which builds on the Simrad FS70 trawl sonar system. In addition to the increased one image per second refresh rate, it features a completely redesigned sonar unit. The FM90 Deployment Pack has a yellow top and black bottom to confirm correct orientation prior to launching and to assist in visual sighting during recovery. It also has improved hand holds to assist handling even with gloves on.

Based on Kongsberg Maritime subsidiary Kongsberg Mesotech’s highly regarded multibeam sonar technology, the FM90 is claimed to deliver a far superior net outline image compared to one generated by a scanning sonar. Also, unlike, scanning sonar, the FM90 is a solid-state sonar system with no moving parts, which eliminates potential failure points and increases reliability and availability during trawl operations.

The FM90 deployment pack also communicates with Simrad PI/PX 40 kHz sensors (up to a maximum of six measurements) by means of hydroacoustic links. Supported sensors include Catch, Depth, Temp, Bottom Contact, Rip, Door Spread, Door Depth, Net Geometry, Pitch/Roll, and Height. Existing 70kHz sensors can be converted to 40kHz sensors, ensuring a cost-effective upgrade path to the latest generation system. The FM90 Trawl Multibeam System also includes downwards and upwards looking 200kHz echo sounders.

“Together, the robust, reliable and accurate sensors that make up the FM90 system deliver a real-time view of the trawl opening, its contents and the net itself, which allows captain and crew to maximise catch while minimising potential system stress and damage,” said Thor Bærhaugen, product manager Catch Monitoring Systems, Kongsberg Maritime AS, Simrad. “The amount of data available, its quality and the rapid refresh rate means the system can provide significant ROI quickly, when used for all types of commercial fishing.”

The Simrad FM90 introduces new simplified software with automatic adjustments based on an updated version of Kongsberg Mesotech’s tried and tested M3 multibeam processing software, which has been successfully deployed for subsea survey and engineering applications worldwide for over six years. It features manual override, colour threshold and range settings to assist the interpretation of visual data. Unlike the FS70, the FM90 software does not require a ‘dongle’, which experience proves can be easily lost. The software runs on a marine-grade PC, ensuring reliability of the system in rough seas, while upgrades are provided free of charge through a self-serve FTP site.

Trawlers upgrading from the FS70 to the FM90 will also be able to use their older system as a back-up, negating the need to purchase a second FM90 deployment pack for redundancy.