Most plans sold will tell you the size of the boat or give you a scale that they have been drawn in. If you want the finished boat to be bigger or smaller than what the plan provides then a trip to Kinkos is in order.

At one time I was going to build a Russian Naptha tanker in !/48'th scale. The original plan was on a 8-1/2" by 11" sheet. The final plan turned out to be, are you ready for this....... 18 feet long, 3 feet wide, 13 inches from keel to waterline, 13" from waterline to the deck. Rough displacement was 3000 lbs at waterline.

The manager was glad to see me leave because the kid helping me kept making small adjustments to get to the final size instead of one good calculated one. Once the printing started you couldn't stop it and I refused to pay for the 8 tries that were the wrong size. Thats why you let them do it, let them eat their mistakes.