Rudder

The rudder will be created as a separate entity using NACA aerofoil sections and then added to the design twin_skeg, which can be found in the twinskeg project.

Create a Rudder

1. Select the twinskeg project outside of Surface and create a new design name, for example, rudder.

2. Select TOOLS \ OPTIONS and the Working Coordinates page or click on the WCS icon.

3. Select Waterline and enter 0.5 in the position field:

   

4. Click on the NACA icon and enter 1123 for the type, 4 for the size and 30 points. Do not select Upper.

   

5. Now, change the working plane to waterline 9 and repeat the NACA command with a length of 5.

6. The upper section needs to be translated by 0.25 aft. Select the Translate icon and enter -0.25 in the dx field.

   

7. Create a formed patch using the two c-lines NAC and NAC1 by selecting SURFACES \ INTERPOLATED \ FORMED and selecting the smaller curve, followed by the larger curve then click the space bar to terminate the selections. This is now one side of the rudder.

8. Switch off the c-lines by clicking on the Bulb icon in the tree

9. To create the other side, select the Reflect icon. Select Y=0 and Copy & Repeat, with the value 1. Click Reflect and select the surface.

   

10. To create a single surface, select the Stitch icon. This will create a single surface of the sides of the rudder. To add the ends, select the Cover Hole icon and select the surface. Render the view.

    

11. Save this design.

12. Now open the existing design "twin_skeg". Select FILE \ IMPORT \ INSERT DM FILE and select rudder.dm. Rotate the rudder by 180 degrees about the Z axis and translate it to the correct position, dx = 2.5, dy = 6.4, dz = 0.0.

    

13. Finally the rudder "FRM", is united with the surface patch "AFT10". The complete entity is stored as "AFT10"