Balancing of Otterboards The Program "Balancing of the Otterboards" has been produced to allow design and adjustment of otterboards while fishing. It enables the calculation of the equilibrium position of a bottom or pelagic otterboard in specific fishing conditions.

Application

The Program is for use while fishing. It fulfills the following operations on board a fishing vessel:

• Adjusting otterboards for specific conditions of operation.
• Selecting the optimum boards for the specified conditions of operation out of a given number of otterboards.
• To make small alterations to the construction of the otterboard on board fishing vessel with maximum precision.

The Program is also useful for design and construction of new otterboards. For these purposes it provides the following functions:

• Investigation of the existing boards performance for specified fishing conditions.
• Selecting prototype for a new design.
• Calculation of the attachment points of cables and warp fixing in order to provide equilibrium position in completely new operational conditions.
• Comparison and evaluation of the existing otterboards.
  

Functions.

The Program "Balancing of Otterboards" calculates equilibrium position in a flow. Equilibrium position is determined by the angles of turn around the axes of coordinates, connected with the flow (an attack angle around the vertical axis, a trim angle around cross-axis and a heel angle around longitudinal axis). An equilibrium position is a position in which the sum of all moments of acting forces is equal to nil.

The following forces are taken into account in calculation:

• Hydrodynamic force of a board wing.
• Hydrodynamic force of stringers.
• The force applied from cables side.
• Board's weight in water.
• Resistance and support reaction of the ground.

The Program requires the following entry data:

• Geometric characteristics of a board - coordinates of the points of forces application (points of warp and cable connections, centre of gravity, centre of wing and stringers pressure), areas of wing and stringers, dimensions, weight of the board in water.
• Speed of trawling, trawl resistance, the angle between cable and a rear edge of the board.
• Medium specifications (density of water, ground, carrier qualities of ground).
• Hydrodynamic coefficients of a board wing.
• Ground - dynamic coefficients of keel.
• Geometric specifications of keel.

The Program's output data is the following:

• Attack angle of a otterboard.
• Angles of a board's turn around axes in an equilibrium position.
• Forces (board's resistance, spreading force, pressure on the ground).
• Values, specifying stability of a otterboard (i.e. ability to regain an equilibrium position).
  
  

Interfaces

The Program has a friendly interface specifically for engineers. The instructions for entering data are supplied with drawings, explaining the character of the values to enter. The Program has a context-sensitive Help, giving a detailed description of a function underway and methods of work with Program.

Image 1: Dialogue of inputting the data. Side view.

Image 2: Visualization of a board's position in space.

Download the demo version of the program (1.2MB)
Demo includes Oval otterboard only. "Open", "Save" and "Print" items are disabled.

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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© Konstantin Sokolov