Multiple RMT Net System

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Description

The multiple rectangular midwatertrawl [RMT 1+8M] is an opening and closing net system which can sample at user selected depths. Control and monitoring can be performed either acoustically or via a conducting cable. Renowned worldwide for its reliability and ease of use, it holds an almost unique position in the oceanographic marketplace.

The multiple RMT net system consists of three pairs of nets combined within the same frame; each pair comprises an RTM1 (mesh size 0.33 mm, nominal mouth area 1.0 m2) and an RMT8 (mesh size 4.5 mm, nominal mouth area 8.0 m2).

This combination saves on deployment and recovery times in deep water. The mouths of the nets are mounted on bars which slide down fixed side wires. The bars are held in place by bridles which locate into a mechanical release gear. The release is operated by transmitting an acoustic signal from the ship. The signal is decoded by the net monitor which activates the release and the pairs of nets open and close sequentially.

Technical Specifications

Overall height (unfolded) 12 m

Overall height (folded) 6 m (minimum 4 m)

Overall width 3 m (with clearance)

Overall weight (in air) 500 kg

Mesh sizes RMT8 -4.5 mm RMT1 -0.33 mm

Working Depth 6000 m cable

Towing speed 2 knots to maintain nominal 1+8 m2mouth areas

Flowmeter Monitors net speed and estimates volume filtered

Communication The RMT is controlled via a (strain bearing) conducting cable.

Deployment By crane and winch, or A-Frame (multiple winch system)

Data Sheet