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The 'W' prawn-trawl with emphasised drag-force transfer to its centre line to reduce overall system drag

Citation

Balash, C and Sterling, D and Binns, J and Thomas, G and Bose, N, The 'W' prawn-trawl with emphasised drag-force transfer to its centre line to reduce overall system drag, PLoS One, 10, (3) Article e0119622. ISSN 1932-6203 (2015) [Refereed Article]


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Licensed under Creative Commons Attribution 4.0 International (CC BY 4.0) http://creativecommons.org/licenses/by/4.0/

DOI: doi:10.1371/journal.pone.0119622

Abstract

For prawn trawling systems, drag reduction is a high priority as the trawling process is energy intensive. Large benefits have occurred through the use of multiple-net rigs and thin twine in the netting. An additional positive effect of these successful twine-area reduction strategies is the reduced amount of otter board area required to spread the trawl systems, which leads to further drag reduction. The present work investigated the potential of redirecting the drag-strain within a prawn trawl away from the wings and the otter boards to the centre line of the trawl, where top and bottom tongues have been installed, with an aim to minimise the loading/size of the otter boards required to spread the trawl. In the system containing the new W trawl, the drag redirected to the centre-line tongues is transferred forward through a connected sled and towing wires to the trawler. To establish the extent of drag redirection to the centre-line tongues and the relative drag benefits of the new trawl system, conventional and W trawls of 3.65 m headline length were tested firstly over a range of spread ratios in the flume tank, and subsequently at optimum spread ratio in the field. The developed W trawl effectively directed 64% of netting-drag off the wings and onto the centre tongues, which resulted in drag savings in the field of ~20% for the associated W trawl/otter-board/sled system compared to the traditional trawl/otter-board arrangement in a single trawl or twin rig configuration. Furthermore, based on previously published data, the new trawl when used in a twin rig system is expected to provide approximately 12% drag reduction compared to quad rig. The twin W trawl system also has benefits over quad rig in that a reduced number of cod-end/By-catch Reduction Device units need to be installed and attended each tow.

Item Details

Item Type:Refereed Article
Keywords:drag, strain transfer, trawl energy efficiency
Research Division:Engineering
Research Group:Maritime Engineering
Research Field:Ocean Engineering
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in Engineering
UTAS Author:Balash, C (Dr Cheslav Balash)
UTAS Author:Binns, J (Professor Jonathan Binns)
UTAS Author:Thomas, G (Professor Giles Thomas)
UTAS Author:Bose, N (Professor Neil Bose)
ID Code:99772
Year Published:2015
Web of Science® Times Cited:6
Deposited By:NC Maritime Engineering and Hydrodynamics
Deposited On:2015-04-08
Last Modified:2018-03-29
Downloads:346 View Download Statistics

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