Calc - Frequently Asked Questions

• Part 1 = number of primary zones damaged, i.e. compartment standard.
• Part 2 = no of first primary zone.
• Part 3 = indicates the number of longitudinal bulkheads penetrated.
• Part 4 = indicates the number of decks penetrated.

1. The biggest one is that the model is a GDS file that came from TID Spaces.
2. You have a large amount of compartments in the view.
3. You have defined a large amount of views. Just be patient, Calc will tell you in the output window when it has finished (and even tell you how long it took in seconds to calculate it!).

1. The final state is determined using the normal deterministic procedures, with damage compartments flooded to the outside waterline. When the ship is heeled to calculate the righting lever (GZ) curve, damaged compartments are assumed to be open to the sea, and hence their contents will vary, as the ship heels.
2. The contents of damaged compartments, fully flooded at the equilibrium angle, are then used to set up stage flooding conditions, i.e. if a compartment is specified as being 20% full at stage 2, then this means 20% of the fully flooded volume.
3. When calculating the stage flooding GZ curve, the contents of damaged compartment, are assumed to remain constant, i.e. a compartment is treated as if it were intact containing a given weight of water.
4. This implies that a stage where compartents are specified to be 100% full, is NOT the same as the fully flooded condition, as in the first case, the compartments will contain a constant weight of fluid over the range of the GZ curve, whereas in the fully flooded condition, the contents will vary. Hence the GZ curves will be different for the two cases.

The problem is that you cannot embed images in an HTML document, only link to them, so when you move the main document file, the links are broken. However, the following procedure can be followed to convert the links to embedded images:

1. Open Word and read in the HTML file output from Calc.
2. Save the file as a Word document (*.doc file).
3. Select each image in turn and do the following:
   • Copy the image to the clipboard.
   • Delete the image from the document. (Don't move the cursor)
   • Use Paste/Special to embed the image as a Picture.
4. Save the document.

This process can be automated using the following Word macro: embedimages.vba

The way end and fore-poppet pressures are calculated by assuming that the net weight (weight - buoyancy) of the ship is spread in a trapezoidal type distribution over the length of contact between the sliding and fixed ways. Depending on the position of the centre of gravity this can degenerate to a triangular distribution, in which case either the fore-poppet or way-end pressure will be zero.

However, in some circumstances, the centre of gravity is beyond the length of way contact making the pressure calculation impossible. This is what is happening when the program outputs "******" for the pressure. An explanatory note is included in the report.

This is because the identifiers used for compartments, bulkheads, decks, etc. do not conform to the rules for assigning identifiers.

Calc is usually fairly relaxed about this and Compartment doesn't do any checking, but as XML is used increasingly for data transfer, it is worth while trying to adhere to the XML standard, which is as follows:

1. identifiers should be made up of letters and numbers,
2. they should always start with a letter, not a number,
3. they should not contain spaces, or other characters, such as punctuation marks, back or forward slashes, etc.
4. they must be unique within the project, i.e. a compartment must not have the same identifier as another compartment, or indeed a bulkhead.
5. the number of characters should be kept to a minimum. There used to be a limit of 8, which has now been relaxed, but formatting the output becomes difficult when long identifiers, are used.

To help guarantee that identifiers are unique within the XML file, Compartment automatically adds a prefix according to the type of object. For example, COMPARTMENT_ prefixes all compartment identifiers in the XML file. This prefix is removed by Calc when the file is read.

All this applies to identifiers: titles, names, descriptions, etc. do not have these restrictions.

Here are the steps necessary to use a Britfair section offset file directly in Calc M3:

1. Using the Project Tool, create a new project, assigning it a new folder.
2. Still using the Project Tool, select this new project as the current one and import the Britfair file.
3. Start Calc and create a new project. On the geometry input page of the dialog, you should see the Britfair file that you have imported into the project. Select this and press OK.
4. The Britfair file will be read in and the project data set to default values in the usual way. However, there is one extra step needed that is very important: select the Tankplan node and edit it. On the Compartments page you should see the Britfair compartment, however the type will "Internal" and category "Unassigned". These must be changed to "Buoyant" and "Mainhull" respectively. If this is not done, then hydrostatics will all be zero, as the program cannot find the buoyant envelope.
5. Internal compartments can be imported in a similar way using the Import Geometry... command. Note that Calc sets the compartment identifier to the name of the input file. Sections can be defined as closed loops, for compartments such as wing tanks, which are not symmetrical about the centreline.