The best way to set up this type of run is start by setting it up as you would any other resistance run, with the model in equilibrium in Rhino/Orca3D (by entering the weight/CG or the Sinkage/Trim in the CFD dialog). At the bottom of the dialog, check the box to Create Run Files Only, and then click on the Create button (instead of Run Simulation).


Then start Simerics and open the .spro file that was created by Orca3D. You will prescribe the Heave value to get the vessel out of the water and fix it at that height. Initially as the run begins the free surface will be very confused as the boat pops out of the water, so you have to let it run for a little while so that the free surface can settle out. Then you drop it into the water. You will need to check the mesh to be sure that it is set up to allow that much heave (i.e., it can morph as much as is required for your desired heave), and also check that the heave limits (min/max stops that normally keep the boat from doing anything crazy) are suitable.


  1. Check the mesh and rebuild it if necessary
    1. Click on Built Meshes in the Geometric Entities pane
    2. In Properties change the Setup Options from Template Mode to Extended Mode
    3. If you are using an incident wave (Premium version), look at the Max Heave. If you will be moving the boat up less than the Max Heave, you’re fine. Otherwise, adjust the Max Heave and click the Build Marine Mesh button at the top of the Properties pane to rebuild the mesh.
    4. If you are not using a wave (i.e., calm water) the Max Heave is ignored. Therefore to allow the mesh to morph enough, you can set the Max Pitch to 45 degrees. This does not mean that you expect the boat to pitch that much; this is only a way of modifying the mesh to allow enough morphing in the heave direction. Again, if you make this change, rebuild the mesh.

  1. Check the Maximum Displacement in the Heave module
    1. In the Model tab, click on the Translation (1 DOF) marineHeave module
    2. In the Properties pane, change the Setup Options to Extended Mode
    3. Adjust the Maximum Displacement if necessary

  1. Fix the Heave value; while still in the Properties for the Translation (1DOF) marineHeave module:
    1. Change the Motion Type to Prescribed
    2. Set the Displacement to the value required to get the vessel to the height that you want

  1. Fix the Pitch angle
    1. In the Model tab, click on the Translation (1 DOF) marinePitch module
    2. In the Properties pane, change the Setup Options to Extended Mode
    3. Set the Angle Displacement to 0
  1. Start the simulation, and watch it until the free surface settles out

  1. Once the free surface has settled out:
    1. Stop the simulation by hitting the Stop button
    2. Change the Pitch back to Force Balance – in the Translation (1DOF) marinePitch module, change from Prescribed to Force Balance
    3. Change the Heave back to Force Balance – in the Translation (1DOF) marineHeave module, change from Presribed to Force Balance
    4. You may want to save results frequently so that you can get a good animation of what happens when it drops in the water, so change the Result Saving Frequency to 5 or less (1 will save at every time step, giving the best possible animation, but of course taking more time and consuming a lot of disk space).
    5. When you restart, the Simulation Time shown will be added to the amount that has already happened. For example, if the Simulation Time is 8s and you ran for 2s before stopping the simulation to change the heave and pitch back to Force Balance, then it will run for 8 more seconds for a total of 10 seconds. If you don’t think you will need that long, you can adjust the Number of Time Steps accordingly (you cannot change the number of seconds directly)
    6. Click the Start button