The famous Dutch shrimps are harvested off our splendid coasts of the North Sea and Wadden Sea. By tradition, trawl nets are used on both sides of the cutter to catch shrimps in the Netherlands. This trawl net is kept open by means of a beam and dragged across the sea floor. The rigging comprises a chock string with rubber chocks (rollers) fitted to it that are dragged along the sea floor. The advantage of these rubber chocks is that they hardly stir the soil, because they are rolling across the sea floor. The chocks cause vibrations that startle the shrimps, causing them to jump up from the sea floor into the net. In addition, these rollers ensure that the net is kept clear from the sea floor, thus reducing the bycatch of sea floor marine life as well as contamination.

Proper wear resistance and lifetime of these rollers are crucial. In-company research has demonstrated that several kinds of wear and tear occur during the use of these rollers. Rapid wear of the roller’s shaft hole and flange have a negative effect on the running of the roller. This effect is then increased by the contamination that builds up between the shaft hole, flange and roller. As a consequence of the impaired operation of the roller its running surface is subject to faster wear while longevity is reduced as well.

The consequences of worn rollers are dramatic because the net starts dragging across the sea floor, so that there is more resistance, which increases the cutter’s fuel consumption. In addition, the amount of contamination and bycatch in the nets is bound to increase, which is undesirable. The new hybrid roller that RIS Rubber and Pavaman have developed jointly provides the solution to this issue.

Hybrid shrimp roller

RIS Rubber is a producer of rubber mould products and has been manufacturing rubber rollers for the fishery industry for many years. Pavaman produces polyurethane products and boasts many years of experience and expertise in relation to this wear-resistant material. Pavaman’s polyurethane products are successfully used in the pulse fishing industry.

By virtue of the combination of the unique properties of both materials we have succeeded in developing a hybrid roller that is interesting price-wise as well as providing multiple benefits as compared to the full-rubber variety. The roller’s base and running surface are made from rubber; however, wear-resistant PU material is used for the core and flange. This combination ensures that the roller keeps running properly so that wear is decelerated while its lifetime is extended. Since these rollers are not dragged across the sea floor, the cutter’s energy consumption is reduced; furthermore, bycatches are reduced as is the access of contamination to the net.

Are you interested in our new hybrid shrimp rollers? Please contact our sales department.

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