At the Seattle Boat Show, one of the power boat manufacturers brought in a prototype of a proposed boat.
It was made up of a series of CNC cut plywood panels, assembled into 4 (or more?) sections, cleverly keyed so that they fit together without any possibility of misalignment. As this picture shows, it was possible to walk thru the prototype and get a feel for the interior and exterior spaces. In some places there were slots machined into the plywood; thin battens were slid into them to give a feel for (for example) how close the overhead would be.
|Picture of a picture|
It really wasn't possible to get far enough away from the prototype in the show to get a good view from above, so I took a picture of one of the pictures they had on the poster session they had attached to the lower hull. As it shows, the prototype is fitted out with appliances, seats, controls, etc. These are all required to get the important 'feel'. There were even vases with flowers in the staterooms.
And if design changes are called for, it is relatively inexpensive to make them in the CAD program and CNC cut some revised plywood sheets.
When the final design of the prototype is approved, it then serves a second purpose: it becomes the foundation for the male plug from which the female mold will be pulled. Thin battens are sprung over it and it is glassed in from the outside. Finally, the plug is carefully faired and polished. The production female mold is then laid up on the plug.
Computers and computer-driven machining have really made huge differences in the boat fabrication business.