Changing your fins = Performance
The best SUP boards on the market have removable fin configurations that allow you flexibility to install a variety of fins specific to your use, which can change from day to day. There are 3 aspects to a fins dynamics they are : Template (shape) Foil (cross section) Flex (responsiveness). Changing these aspects will depend on what you use the fins for .
Race/ Touring fins
Fins for flat Water, downwind and Ocean touring change quite dramatically in shape.
In brief Flat water fins have a swept back appearance and highly efficient foil to maximise glide.
Downwind fins are usually more upright in appearance allowing for pivoting turns to help you catch the next glide on a swell.
Ocean fins are more like your typical surfing fins but with more rake and tip volume allowing for great stability and efficiency.
Changing your fins can make a big difference in the way your boards feel under your feet. Larger fins with more base width are used for bigger surf or when more hold and drive is required. Smaller fins give the board more of a loose feel with increased speed when surfing.Some board fin setups i.e. Quads (4) Thrusters(3) allow you to mix fins so that you can have a larger set in the front fin boxes giving you drive, and a smaller set in the rear boxes meaning the board will be loose off the top of the wave for turning.