The outline quite often can be derived from a trapezoid form, a triangular form or an elliptic form. For wave and free-ride fins rather curved forms are delivering excellent results.

 

Figure 18: Outline and its basic geometric forms

Mostly the fin outline is a hybrid of the basic forms to cope with the specific demands.

Figure 19: Parameters of the outline

T             draft

Sm          mean geometric chord

Ss            tip chord

Sw          root chord

T/Sm      aspect ratio

Ss/Sw     taper ratio