Today I want to talk about the difference that fins make to your board and to your riding. Fins come in many shapes and sizes and most often you simply use whichever size comes with the board when you buy it. This fin will generally be fine for most kinds of riding however you can drastically alter the boards performance by changing the type or the size of the fins you are using.
The way to spot the effect that fins have on your riding is to simply remove the fins from the board. Try riding the board now and you’ll notice the board handles very differently. Your back leg will feel as though its constantly about to slip away from you and the board will release from the water almost effortlessly, enabling you to do surface 180’s almost without thinking.
Fins generally effect 3 areas of board performance, these are grip in the turn, ‘slide’ and upwind ability.
The area where you’ll notice the greatest difference by changing your fins is the grip in the turn. Try a hard carve turn without a fin or with a very small fin and you’ll notice that as you exit the turn and try to apply power in the new direction unless you’re very careful the board will simply “spin out,” you’ll lose all grip in the water and your back leg will fly away from you. This is because the fin is not providing the grip necessary to channel that sudden increase of power as you set off in a new direction and the board literally starts to skim across the surface of the water. Because the board will slip across the surface of the water much more easily with smaller fins, if you’re attempting to go from heel side to toe side you can do it almost effortlessly on a board with no or small fins whilst on a board with big fins you’ll generally have to jump the board out of the water and then spin it whilst your airborne.
The final area where you’ll notice differences between different sized fins is in the up-wind ability of the board. Larger fins, because they have more surface area and thus more grip in the water, generally provide greater up wind performance than a small fin. A larger fin will also produce more lift. A fin actually produces lift just like the wing of an airplane or your kite, which also improves the upwind performance and causes a huge amount of other effects which delves deep into the realm of hydro-dynamics, which is a little beyond the scope of this email, however if you do want to know more leave a comment and I’ll fill you in all on all the geeky details!