MSC 134 Fishing Gear Technology II - Cape Fear...
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MSC 132/134 Fishing Gear Technology I & II Appendix: Netting Theory and Tapers Excerpts from: FAO Cataloque of Small Scale Fishing Gear , Edited by C. Nedelec, Fishing News Books Ltd. & Whitefriars Press Ltd., London, England. 1975 Fisherman’s Workbook, compiled by J. Prado, Fishing News Books, Oxford:1990 Shrimp Trawl Design & Performance , D. Harrington, J. Watson, L. Parker, J. Rivers, C. Taylor, Georgia Sea Grant Program, Marine Extension Service, University of Georgia, Athens, Georgia. 1988
Transcript of MSC 134 Fishing Gear Technology II - Cape Fear...
MSC 132/134
Fishing Gear Technology I & II
Appendix: Netting Theory and Tapers
Excerpts from:
FAO Cataloque of Small Scale Fishing Gear, Edited by C. Nedelec, Fishing
News Books Ltd. & Whitefriars Press Ltd., London, England. 1975
Fisherman’s Workbook,compiled by J. Prado, Fishing News Books,
Oxford:1990
Shrimp Trawl Design & Performance, D. Harrington, J. Watson, L. Parker, J.
Rivers, C. Taylor, Georgia Sea Grant Program, Marine Extension Service,
University of Georgia, Athens, Georgia. 1988
Meshes: Types and Measurement Methods
Knotted Netting Knotless Netting Hexagonal Mesh
Bar or Square Bar or SquareBar
OM = Mesh Opening
a = Stretched Mesh
OM = Mesh Opening
a = Stretched Mesh
a = Stretched Mesh
Mesh
Opening
Primary Hanging Ratio
“Horizontal Orientation of Netting”
E1 is the Primary or Horizontal Hanging Ratio.
L is the “hung” length of the netting or the length of rope
on which a net panel is mounted.
Lo is the length of netting when fully extended. (stretched
netting before hanging)
E1 = L ÷ Lo
Therefore L = E1 x Loand
Lo = L ÷ E1
Secondary Hanging Ratio
“Vertical Orientation of Netting”
E2 is the Secondary or Vertical Hanging Ratio.
H is the “hung” height or depth of the netting or the fully
mounted net.
Ho is the height of the netting when fully extended.
(stretched netting before hanging)
E2 = H ÷ Ho
Therefore H = E2 x Hoand
Ho = H ÷ E2
Geometric Determination
of
Hanging Ratios
1 - E²
E2 = 1 – E1² E1 = 1 – E2²and
Common Hanging Ratios
Hydrodynamic
Gear
GillnetsEntanglement
Gear
Hanging Ratio Tables
Surface Covered at Different
Hanging Ratios
(A-2)
Sample Plans: Gill NetBottom set, Germany
(A-3)
Sample Plans: Gill NetBottom set, Australia
(A-4)
Sample Plans: Entangling NetBottom Set, Japan
(A-5)
Sample Plans: Entangling Net
(Trammel Net) Bottom Set, France
(A-6)
Sample Plans: Seine NetNigeria
(A-7)
(A-8)
Sample Plans: Four-Seam Flat TrawlShrimp, Gulf & South Atlantic, USA
(A-9)
Standard Net Plan Layout:
Cutaway View
Net Plan with Hidden Lines:
Uncommon
Full Net Plan Layout: More Detail
but not commonly used.
Sample Plans: Two-Seam Balloon TrawlShrimp, Gulf & South Atlantic, USA
(A-10)
Plans: Four-Seam Semi-Balloon TrawlShrimp, Gulf & South Atlantic, USA
(A-11)
Plans: Western-Jib 4-Seam TrawlShrimp, Gulf & South Atlantic, USA
(A-12)
(A-13)
(A-14)
Sample Plans: Bottom TrawlCod, Germany
(A-15)
Sample Plans: PotSnapper, Venezuela
(A-17)
