I should point out that copying a boat design is not ethical. If you do want to copy a design, ask the designer. If they don't want you to, don't. The designer has the right to determine how his design is used.

If you get permission, your rights to the design only extend as far as the designer prescribed.

There are good reasons for using the tick-stick method (or any other) for getting the lines of an existing design. For example computer modeling of a design for comparison with others. However, using the lines to build your own boats without the designer's permission is not one of them.