Internal Arrangement

Our intention is now to subdivide the vessel, using decks, transverse and longitudinal bulkheads. This will ultimately lead to the creation of the spatial arrangement of the vessel by the generation of compartments. It is worth bearing in mind that compartments are defined as a notional space defined by six boundaries (top, bottom, aft, forward, port and starboard). Thus the simplest result is a box, if all boundaries are planar. The increased complexity of the internal boundaries and the fact any of the boundaries can be the external envelope (the hullform definition we have been producing) leads to complex shapes. However, it is not possible to define the most complex compartments through this method. Therefore the facility is available to build up a more complex compartment by the merging of several other base compartments.

The process of generating transverses, longitudinals and decks is very similar as they are simply planes in one of the three orthogonal planes.

We will employ the Predefined method of creation to generate an internal surface, by specifying the location and name. Initially we assume it’s bounding constraints are simply the parent envelope, (represented by the asterisk character ‘*’). We shall then edit its definition by relimiting it to other internals (now that they have been defined), hence creating a more accurate visual representation. Both the name and location can also be edited so any changes can be incorporated following design reviews as a result of say volume checks or stability assessment.

1. Open the Internal Surface Editor dialog (menu: COMPARTMENTATION \ INTERNAL SURFACES \ EDITOR...). Set the dialog mode to Create (only the Geometry and Constraints page will be displayed) and select the appropriate internal type, either Transverse, Longitudinal and Deck. In the Geometry page select the option Predefined in the Creation Method panel. Now enter into the two edit fields, Position (location) and ID (identifier) relevant values for the internal to be created.

   Note: Values entered in the Position field are in the current units, unless (fr) or (stn) appear to indicate the value is expected in frames or stations (x axis only) as defined for the appropriate axis.

2. Now switch to Constraints page and leaving the limits as ‘*’ click Apply. A simple planar bulkhead is created.

3. Repeat this process to generate all the internal bulkheads and decks.

4. Change the mode of the Internal Surface Editor dialog to Edit. This dialog can now be used to edit an internal surface, and we are going to constrain the extents of our internals with other internals. For instance make a double bottom deck run between the fore (collision) and aft peak bulkheads we have created. The list box to the right contains the internals to be considered for editing. Thus this list needs to be populated, so ensure the correct type is selected (either Transverse, Longitudinal and Deck) then either:

   • use the list’s pop-up menu to select GET to interactively pick a series of internals (click the spacebar to finish the picking of elements)

   • or alternatively select all the required elements in the Full View or Compartment View tree and drag them (while holding the Left Mouse button down) and dropping them (release the Left Mouse button) into the list.

5. When editing an internal element, it must first be selected in the list. Activate the Constraints page and the current boundaries will be shown. To set the required boundaries either:

   • interactively pick a boundary surface (by clicking the button), or

   • use the drop down list to select the relevant boundary, or

   • use the above 'drag and drop' method from the Full View or Compartment View Tree, only releasing the Mouse button over the Appropriate button and not the list box.

6. Once all the appropriate constraints are in, click the Apply button and the graphics views will update to show the change.

The other creation methods available are Interactive and Offset Shell (which is specific to longitudinal bulkheads). for further information see Internal Surface Editor.

Very quickly a simple arrangement of bounded planar internals can be generated. However greater complexity can be achieved for the internals we have created. There are limits to the definition of each internal surface which are illustrated in this table.

Table 3: 1. Showing limits to the definition of each internal surface

for further information on corrugations and stools see Corrugation Page and Stools Page respectively.