This year's hull is created in Rhino, because it contains hydrostatic analysis and allows easy modification of hull forms.
- Draw rough deck outline
- New layer, draw rough rocker for boat hull
- New layer, create a small (<10) profiles or cross sections.
- Use Surfaces, Loft feature to create hull form.
- Check for concavity or aberrant behavior in hull.
- Use edge of hull polysurface to create transom, bow and deck polysurfaces (don't use original outlines, as the hull polysurface does NOT coincide with them)
- Use the Analyze, Mass Properties feature to view volume and hydrostatic data about the shape. (Note that some hydrostatic features assume a mass, which leads to some false statements)
- Redo steps 1-7 until it looks like a boat and doesn't sink for a given mass.
The design of the hull for an experimental autonomous sailboat is most concerned with reliability and functionality, not speed.
For a static situation, the weight of the water a boat displaces is equal to the weight of the boat. Simplifying, the volume displaced is equal to the mass of the boat divided by the density of the water in which the boat sails.
For a total mass of 32.5kg, and in salt water with density of 1025kg/m^3, the hull needs to displace 0.0317m^3 while floating. Using this simple analysis and Rhino's built in Volume function, we can predict where the waterline of the boat will be.