• If you have two surfaces joined in a station plane that coincides exactly with one of the station locations that you have defined, Orca3D will compute stations on both surfaces, so the sectional area there will be double what it should be. One case where this can happen is with a hull that has a planar, vertical transom, and the transom surface is modeled. Simply move the station location slightly forward or aft, so it doesn’t coincide with the joint between the two surfaces.
  • Incorrect sectional area data can also result from including non-wetted surfaces in your selection when you compute hydrostatics. For example, if you have modeled interior surfaces, and include them in the calculations, Orca3D will include their areas in the sectional area curve (as well as their volumes, so your displacement, and all of the other hydrostatics values will be incorrect).
  • If you have a loose absolute tolerance setting, equal to or greater than your section spacing, Orca3D will not be able to distinguish successive stations from one another, resulting in incorrect values.
  • Check to be sure that you have correctly specified whether to “Mirror About the Centerplane” when setting up your hydrostatics calculation. If you have modeled the entire hull (port and starboard halves), and you check the “Mirror About the Centerplane” box, your sectional area values (and displacement) will be double the correct values.