PIAS Manual  2023
Program for the Integral Approach of Shipdesign
Grainmom: calculation of grain heeling moments according to the IMO Grain Code
This module enables you to calculate the actual grain heeling moments according to the requirements of IMO Grain Code, or according to the requirements of the Dutch Shipping Inspectorate.

Grainmom module

After choosing this option, in the list of compartments, you can click through to a compartment to make further settings for calculating grain moment tables, in the menu displayed below. The definition of the compartment has to comply with the requirements that are listed in Definition of compartments

Define void space and longitudinal girder of this grain compartment:


Coordinates of longitudinal girders of compartment: "Name Compartment"
Void space Half breadth Height Subcompartment
0.100 -4.500 9.000 PS part
0.500 4.500 9.000 mid part
1.000 - - SB part

The function of this input screen is to define one or more longitudinal girders per subcompartment. Only the girders at the topside of the subcompartment have to be defined. If no girders are present, this is marked by a dash (-).

  • Void space: height of the void space above the grain (acc. to Chapter VI, Section I A.a of the IMO Grain Code).
  • Half breadth: half breadth of the girder from centreline (SB positive, PS negative).
  • Height: height of the underside of the girder from baseline.
  • Subcompartment: name of the subcompartment as defined at the module from Layout.

When defining a longitudinal girder the [Girder] option can be used to toggle the presence of a longitudinal girder.

Define volume interval for calculations

The tables are calculated at the volume interval defined here.

Calculate volume & COGs of graincompartment

This option calculates the table of volumes and centres of gravity, without heeling angles (see figure underneath).

Table of hold volume and COG's according to IMO Grain code

If the compartment for the grain calculation has been defined including a curved sounding pipe (see Layout), then the output table will also contain a column with the ullage. The ullage is calculated from the top of the defined curved sounding pipe. The top of the sounding pipe will normally be the top of the coaming in case of a grain compartment.

Calculate volume & grain moments grain compartment

This option calculates the table of grain heeling moments at the prescribed heeling angle (see figure underneath). There is a special option if the calculations are submitted to the Dutch Shipping Inspectorate.

Table of heeling grain moments according to IMO Grain code

Configuration for drawing of cross-sections of grain compartment

At the next 2 options a cross-section is drawn on paper. The position of the cross-section to be drawn is defined at this option.

Print cross section graincompartment including void space

Draws the grain level including void spaces, at zero angle, see the figure below.

Graincompartment 1

Print cross section graincompartment including grainlevel

Draws the grain level with the heeling angle as prescribed by the regulations, see the example below.

Graincompartment 2

Create datafiles for (graphical) loading of grain in Loading and LOCOPIAS

To load grain graphically, it is required to define the geometry of the holds and bulkheads and possible positions. In Layout, make sure you have defined a compartment 1 metre long with the outline of the straight section in the grain hold. If there are also non-parallel sections, you need to define these as a separate compartment. This can be done from the aft/fore of the hold to where it runs parallel again. In the compartment list, you can set the tank to No so it is not counted twice.

General information for (graphical) grain in Loading

This menu allows the user to define the following grain hold specifications:

  • Weight group number grain bulkheads: Here the number of the weight group the grain bulkheads fall under must be entered.
  • Weight group number grain holds: Here, the number of the weight group the grain holds fall under must be entered.
  • Default tank top height: The default height of the bottom of the hold must be entered here, i.e. the height of the tank top underneath.
  • Default coaming height: The default height of the top of the coaming must be entered here.

Define movable bulkheads

Movable grain bulkheads are specified here. Each grain bulkhead can be given its own name and weight.

Define grain bulkhead positions

Here the user can define all possible positions of the grain bulkheads, both of movable bulkheads and static bulkheads. For each position, the following must be entered:

  • Bulkhead type: Choice of static aft, static fore or movable. In the case of a static bulkhead, only 1 number (rear or front respectively) needs to be entered.
  • Position name: The name of the position.
  • Rear: The rear of the position in metres.
  • Front: The front of the position in metres.
  • Bottom: The bottom of the position in metres.
  • Top: The top of the position in metres.
  • Breadth: The breadth of the position in metres.
  • VCG: The VCG of the movable grain bulkhead above the base in this position.
  • LCG: The LCG of the movable grain bulkhead from the All in this position.
  • TCG: The TCG of the moveable grain bulkhead from the CL in this position.

Define ''basis'' grain holds

To define grain holds, they must be available as compartments in Layout. For the part, or parts of the hold that have a simple rectangular cubic cross-section, define a rectangular compartment (hold/metre) in Layout and select this compartment here, where you set the ''variable'' column to ''yes'' and set the length to 1 metre. This compartment is then used for all rectangular cuboid parts of the hold, for which no other compartments are set. If the hold, or parts of it, is not rectangular cuboid, then this part of the hold must be defined separately in layout. Add these compartments in this menu, and specify the aft and forward boundary of the positions between which this grain hold is to be used.

  • Variable: A variable compartment (''yes'') is used between all defined positions of the grain hold, for which no other (non-rectangular cubic) hold is defined. It is then usual to define a compartment of the parallel part (hold/metre) with a length of 1 metre. The length of this defined compartment should be specified in the column ''length''. (typically 1 metre). A non-variable part ('no') of the hold, is used between the positions specified.
  • Name: Here the user can select the relevant grain hold from the compartment list by name.
  • Length: If 'yes' is selected for variable, the length of the selected compartment should be specified here.
  • Name bulkhead aft: Here the user can select the name of the respective grain bulkhead position from the list as defined under Define grain bulkhead positions which selects the rear of the hold.
  • Name bulkhead fore: Here the user can select the name of the relevant grain bulkhead position from the list as defined at Define grain bulkhead positions which selects the front of the hold.
  • Pos. aft: This is automatically filled in after selecting a position in the column ''blkh. Name aft''.
  • Pos. fore: This is automatically filled in after selecting a position in the column ''blkh. name fore''.
  • Start record: This is the line number in the grain moments table, where the table of moments for this particular part of the grain hold begins. This is useful if you want to edit or view the grain moments table manually.
  • Contour points: A ''0'' means that no contour has been created. If a contour has been defined, the number of defined points is displayed here. You can click through on this column. You will then get an input menu, in which contour points can be defined. This contour is only used in the graphical interface to display the grain space in the side view.

Defining holds excluded for loading of grain

It may happen that a part of the hold arises between two grain shot positions where it is not desired to load grain with the graphical grain module. These parts can be specified here by specifying a rear and front position.

Generate tables of grainholds

Select this option to (re)calculate the grain moment tables based on the data entered for the data file for the graphical grain module.

Edit grainhold tables

Once the tables have been calculated with the above option, you can view them here and manually adjust them if necessary.

Definition of compartments

A compartment which is going to be used to compute grain heeling moments will be defined by one or more subcompartments, which have to comply to the following definition requirements:

  • The subcompartments have to be defined from portside to startboard.
  • No negative subcompartments are allowed.
  • The vertical line through a longitudinal girder has to be a boundary of a subcompartment.
Appendix 1
Appendix 1
Appendix 1