Stab.exe

(Hydrostatic stability program)

Command line options Creating input files Installing Stab.exe Error Messages Release Notes

Stab.exe is a hydrostatic stability program that will allow you to calculate some basics of the hydrostatic stability of a ship.

The mass details and the ship's geometry and stored in the input files.

When started the program first adds up all the masses to calculate the centre of gravity of the ship. Then the geometry is read in and the ship is put through different angles of heel (from 0 to 180 degrees)

For each angle a correction for trim is made via some iterations if needed.

The results of the calculation are:

Arm of stability
Wet surface
Trim angle

When using the graphic option the results are visible during the calculation.

It is assumed that the user of this program has basic knowledge of theoretical shipbuilding, especially with regard to hydrostatic stability and the Simpson rule

Disclaimer, important restrictions: This program may not be used for commercial purposes. The author can not be held responsible for any damage as a result from the programs output.

Command line options

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D:\usr\BIN>stab4
Stability program by Chris van Gorp. Version 4.0
file D:\USR\BIN\STAB4.EXE
link date is 19 12 2001 22:18:50
=====================
Disclaimer, important restrictions: This program may not be used for commercial purposes.
The author can not be held responsible for any damage as a result from the programs output.
=====================
Missing arguments ...
stab project-file [output] [G] [S]
where [output] = output file for results
G = graphics screen, and S = save screens

Example:

stab4 barge results.txt G

Whenever you hit a key other then the Enter-key the program will pause. Pressing the Enter-key will resume the program.

Argument	Purpose
project-file	This is the name of the mass- and cross-section file. See also filenames
[output]	Optional argument as denoted by the [] . This is the name of the output file. All results will be written to this file. If you do not specify the filename the results are written to standard output (the screen).
[G]	Optional argument as denoted by the [] . This is the graphics option. If you specify 'G' as an argument the results will be shown in graphs on the screen.
[S]	Optional argument as denoted by the [] . This is the screen save option. Do not use this option.

Creating input files

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Filenames

To program expects the mass file and the cross-section file to have the same name.

For example: if you are working on a barge, your mass- , cross-section- and simpson integration file are named respectively barge.mas , barge.spt and barge.smp.

The filenames of the cross-section geometry files must correspond with the filenames as entered in the cross-sectionfile.

Coordinates and Axis

Stab.exe assumes

the positive X-axis running from stern to stem (from aft to front of ship)

the positive Y-axis running from centre-line to portside (left of ship)

the positive Z-axis running from bottom to top

Where you place the origin is up to you.

The mass file.

every known mass item of the ship should be entered in the mass file

Name: project name, extension : .mas

File description:

line	Example	Meaning
dx dy dz	0.0 0.0 0.0	Correction in X, Y and Z axis to bring origin of masses to origin of cross-sections. Most times the values are 0.0 for X, 0.0 for Y and 0.0 for Z axis
mass mx my mz description text	200.0 0.00 0.00 0.00 weight of barge	this line, and all other to the end of the mass file, describe the masses that make the ship. Think of hull, engines, winches, mast(s), deckhouses, oil- and watertanks, ballast tanks, sails, persons etcetera.
idem
idem
idem

The cross section file

this file contains a list of filenames that hold the cross-sections

there can be 25 cross-sections maximum

Name: project name, extension : .spt

File description:

line	Example	Meaning
cross-section-number filename longitudinal offset (X-axis)	1 barge_1 -10.0	this line, and all other to the end of the mass file, describe the position of cross sections of the ship
idem	2 barge_1 0.00
idem	3 barge_1 10.0

The Simpson integration file

this file holds the Simpson rule for every 3 consequent cross-sections the ship.
For equi-distant cross-section the 141 rule can be used.
Because your cross-sections are rarely equi-distant, I introduced the 142 rule that deals with non equi-distant cross sections

Name: project name, extension : .smp

File description: (as example the file barge.smp is used)

line	Example	Meaning
Simpson-factor cross-section1 cross-section2 cross-section3	142 1 2 3	this line, and all other to the end of the file, describe the Simpson factor and related cross-sections.
idem
idem
idem

The cross section geometry file

this file holds the geometry of 1 cross-section of the ship.
Important: Stab.exe assumes that the geometry of cross-section is symmetric (so both the portside as well as the starboard part are identical)

Name: see the cross-sections-file extension : .txt

File description: (as example the file barge_1.txt is used)

line	Example	Meaning
y-coordinate z-coordinate	0.00 -1.00	this line, and all other to the end of the file, describe the geometry or shape of the specific cross section.
idem	5.00 -1.00
idem	5.00 1.00
idem	0.00 1.00