Trawl Rigging
Resistance Calculation
The Program provides the input of data on the headline, footrope and groundrope rigging and
calculation of the forces generated by interaction of rigging parts with their environment (water,
sea-bed).
Purpose and Area of Application
The Program provides calculation of hydrodynamic and ground-dynamic resistance of trawl rigging, the
resultant lifting force for a headline and the resultant weight in water for a footrope or a groundrope.The Program can be used by fishing gear designers and manufacturers during creation of new trawls. The
Program provides the following procedures in this case:
- To Pick up variants of trawl rigging layout, ensuring required value of the headline lifting force.
- To Calculate the rigging resistance for expected trawling conditions (in water and on the seabed).
- To View efficiency (relationship between useful forces and resistance) of the different variants of rigging
layout.
- To optimize rigging for a given condition of trawl utilisation.
- To Investigate behaviour of the rigging when the trawling speed is changed.
The Program can be used while fishing. It is helpful for rigging tuning and rigging reconstruction if the trawl will
be altered.FunctionsThe Program allows a user to enter and store the folowing data:
- General data. Speed of trawling, water and groung properties.
- Lines description. Length, Chord of headline, footrope or groundrope.
- Structure of the groundrope.
- Headline rigging layout. Distribution and properties of the headline rigging units.
- Footrope or Groundrope rigging layout. Distribution and properties of the rigging units.
The program generates drafts to reflect the entered data. The program helps to detect errors in the source
data. The Lines are depicted as a chainline. The Program takes in account the following rigging units:
- Spherical Floats. The bouyancy force and hydrodynnamic resistanceis calculated.
- Flexible Kite. (tarpaulin sheet). The hydrodynamic lifting force and hydrodynnamic resistance is
calculated.
- Hard Kites of the HiPlan (Ãèïëàí) type (plastic). The hydrodynamic lifting force and hydrodynnamic
resistance is calculated.
- Spherical Bobbins. The weight force, hydrodynnamic resistance and ground friction force is calculated.
- Groundrope spacers. The weight force and hydrodynnamic resistance calculates here.
- Chains. The weight force is calculated.
- Cables. The weight force is calculated.
The Program calculates following total forces:
- Headline lifting force.
- Weight force in the water (ground pressure) of footrope or groundrope.
- Headline hydrodynamic resistance.
- Footrope or groundrope resistance (hydrodynamic and friction force).
- Total rigging resistance.
The Program generates the detailed log of the calculation.
Screen 1. Working with lines.
Screen 2. Entering data of ground's central section rigging units.
Upload Demo version of the program rig_demo.exe (250Kb).
CAD/CAM Laboratory, Commercial Fisheries Dpt.
of Kaliningrad State Technical University for Fisheries.
Russia, 236000 Kaliningrad , Sovietsky procpect 1,
Phone +7(0112)463818. BBS/Fax +7(0112)465487,
FIDONet 2:478/3 Fishwar BBS.
E-mail: sokolov@fishwar.koenig.su
Konstantin Sokolov
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