New to surfing, why do some boards have 3 fins and others have only 1?

Question

New to surfing, why do some boards have 3 fins and others have only 1?

Answer 1

Fins are designed to add stability to the ride. They function similarly as does the airfoil quality of an airplane wing. A three fin board has three different shaped fins, the angle of attack is different for the thrusters (They are the ones on the sides)., and they help hold the board into a turn. However, more fins, more surface area = more drag. More drag equals a slower moving board. That is why the fins tend to be smaller on boards with multiple fins. The total amount of surface area is what is important for drag, the shape of the fin is important for control (angle of attack). I ride  twin fin fish (board with a swallow tail), which gives me most control in short radius turns with the least drag. Its all clear to you now, right?

Think about a centerboard sailboat. The center board stops the boat from side slipping across the water. Same thing with a surf board fin. Now picture the fin as a pivot point in a turn. One big, two small, three small, four small all have different degrees of the same hydrodynamic properties.