Checking for errors in the compartment definition

It is quite possible in complex arrangements to find that an incorrect boundary has inadvertently been selected, resulting in double accounting of volume in the vessel. The sectional area curve (SAC) provides a very useful way of checking this.

1. Open the Sectional Area Curve dialog (menu: COMPARTMENTATION \ SECTIONAL AREA CURVE...). Enter a Draft so the value is above the top of the vessel and leave the trim as 0.

2. In the Envelopes list box select an envelope and the Compartments list box will now display all the compartments associated with that envelope.

3. Select all the compartments that represent the internal volume (not any which have simply been generated to construct a merged compartment). This is usually those marked for release as Calculation Geometry, so selecting the Calculation Geometry option will automatically do this.

4. Click Generate, to display the two curves, one the envelope’s (or hullform’s) and the other the selected compartments. If you have fully defined all the internal spaces then these two curves will be coincident. If the compartments curve extends above the envelope’s at any point this means some compartments include the same volume and thus there is an error in the definition and you need to investigate this. If the compartments curve dips below the envelope’s at any point, then some volume within the envelope is undefined by a compartment. This may be expected as you have decided they are not needed for consideration when assessing loading or damage stability.

Figure 3:6. Compartment SAC extending beyond Envelope SAC.