Kellian underwater line setting device

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MIT2011-04 Kellian underwater line setter development report (PDF, 2,260K)

Summary

The Kellian underwater line setter was developed to mitigate the catch of black petrels and shearwaters in New Zealand’s inshore snapper fishery, but could be easily applied in any demersal longline operation, including autolining, once the design has been further refined in at-sea trials.

A new prototype was fabricated and tested at the Australian Maritime College Circulating Water Channel (‘flume tank’). The new prototype consists of a stainless steel cowling and funnel arrangement that incorporates two rollers. The device was tested for its towed stability and entanglement issues while setting. As part of this testing a continuous long line setter was developed to allow for visualisation of how hooks, floats and weights interacted with the device.

The most significant problem identified in the flume tank was that of weights causing the backbone to be pulled out of the device. The design purpose of the rear roller is to stop weights pulling the backbone off the bottom of the first roller. We envisage that when deployed under fishing conditions it will be necessary to specify the size and types of floats that are used.

The weight and dimensions of new prototype exceeded initial design parameters, given our desire to produce a design that is easily deployed. The entire unit weighs around 32kg, which may pose manual handling issues. This risk will be best mitigated by a specific cradle and winch to raise and lower the bait setter, thus avoiding manual handling where possible. We also recommend a safety assessment be undertaken before at sea-trials commence.

Publication information

This report was commissioned by the Department of Conservation, Project MIT2011-04

By Barry Baker & Rowan Frost