Without fins it’s near impossible to paddle in a straight line as the board is always trying to move sideways.
By changing your fin configuration can determine how your board performs in certain conditions.SUP FINS GUIDE
STARTING THE SPORT WITHOUT ANY KNOWLEDGE?
WHY A SINGLE CENTRE FIN?
Single fin configuration are most common at the start and are mounted in the centre tail of your SUP.
Centre fins can be removable or fixed with settings that can be either secured at a fixed point or adjustable.
Fixing a centre fin further forward should give your board more manoeuvrability and make it quicker to turn so the surfers choice.
Fixing the centre fin further back offers more stability, tracking and speed, it will make it slower in the turns – good for longer distance paddling.
Adjustable centre fins often have three adjustments with the centre fixing being the default setting offering both good stability and manoeuvrability. Without fin adjustment the fixed setting is likely to be similar.
With touring we want to go as straight as possible so the design will have a wide base and longer leading edge to the fin offering stabilization but reducing drag where possible.
In racing you’re looking for tracking and speed which is achieved with larger surface areas but not one that creates too much drag and is short enough to manoeuvre around buoys.
WHY SHOULD I USE THE SIDE FINS?
There’s many multi fin configurations on SUPs and one of the most common is the 2+1 where two equally sized sidebite fins mounted a few inches in front of the rear larger fin.
This configuration steers and compresses the water flow increasing speed. Often found on SUP's designed for surf.
All these extra fins not only increase the grip but can slow you down because of the drag that is being created, but this is very often easily overcome by using the wave to power you forward instead.
The 2+1 set up is also often seen in flat water SUPs as it allows good tracking and the front side fins resist sideway drift from crosswinds.
With this set up it’s possible to ride without a centre fin which creates a much looser board and a good idea if in shallow conditions.
WHERE DO I POSITION THE MIDDLE FIN?
The most common fin system on SUP boards is the US fin box, which is a track that is slightly longer than the fin itself.
This design allows you to customize the performance of your board via the fin placement either further toward the nose, or tail of the board.
Depending on where you position your fin, you’ll see different performance out on the water.
FURTHEST TO THE BACK:
- Perfect for long distance SUP or when you want increased straight line tracking.
IN THE MIDDLE:
- Positioning your fin In the middle of the fin slot will give you a mix of control, stability, tracking, and speed on your board.
TOWARDS THE NOSE:
- Putting the fin all the way forward in the fin slot will make your board feel more manoeuverable and make it quicker to turn. Perfect for a surf feel.
WHAT ARE THE TECHNICAL ASPECTS OF A FIN?
The fin BASE is the part of the fin closest to the board it’s nearly always the widest part of the fin offering stabilization and tracking.
The TIP design offers speed and tracking.
The LEADING EDGE of the fin can be vertical but usually swept back which is known as the RAKE. The rake affects turning and pivot and how quickly it releases water improving speed. Increased RAKE is better for releasing weeds. Some fins even have cutting LEADING EDGES for weed cutting.
The TRAILING EDGE has an effect on how a board turns and pivots, improving water release would also improve speed.
On multi fin boards, the out board fins often tilt towards the edge of the board, this is called CANT allowing the board to be more responsive on turns. An upright fin, one with NO CANT will be faster than a fin with CANT.
Apart from the tilt of a fin (CANT) the fin can be TOED IN. This is the angle relative to the centre line. Usually more TOE equates to more grip.
Fins can create lift and direction via its FOIL design. Differing FOIL shapes and thicknesses will alter directional forces.
Stiffness in a fin gives a board stability but will resist a turning motion so FLEX isn’t necessarily a bad thing as it can be suitably responsive to water conditions and FLEX over rocks and logs.
WHAT IS DRAG?
Any surface creates DRAG through friction.
The larger the fin the greater the surface DRAG ultimately effecting the speed of the paddleboard but it will guide the board in a straight line.
In Racing or touring DRAG is kept to a sensible minimum to retain speed whereas a surfer may prefer to retain DRAG to offer bite for the turns in waves.