Rudders and Fins
Original material produced for Carolina Paddleboard Co. and adapted 3/26/2019 to include Outrigger Canoe rudders.
In today’s ultra-competitive world of Paddle Racing, choosing the right rudder or fin may mean the difference between a personal best with a podium finish or packing up in disappointment after a hard fought race. Selecting a fin or rudder that fits the conditions of the course and the capabilities of the rider can make a big difference in the outcome of a race where seconds count.
What to Consider When Choosing a Rudder or Fin
Before diving into the specifics of fin design, there are a few basic generalizations to consider as you are shopping for a outrigger canoe rudder or SUP fin. Depending on your skill, strength, weight and balance along with board/boat design and race conditions, you will need to make fin selections taking into account the need for stability, speed and tracking. Fin design will affect all three of these aspects heavily.
You can’t ignore the shape of the fin, but in general the more surface area on the fin the more "grab" it will provide, where grab is a combination of stability and hold if you're on a wave. Where this surface area is distributed in a rudder or fin also impacts how it will handle. With more surface area, turning may be sacrificed and the surface area will also create more drag… more drag means less speed. In a very simple sense, large fins are slower but more stable; small fins are faster but provide less stability and tracking.
But what is fast for one racer may not be the fastest fin design for another. The paddler’s skills and board design may combine to dictate a different set of fin characteristics for maximum speed. These considerations must be taken into account when choosing the right stand up paddleboard fin or when choosing the right outrigger canoe rudder.
For instance, a skilled paddler with good stroke mechanics and good balance may be able to maximize a smaller, raked fin/rudder design. But a less skilled rider using the same fin/rudder may be swimming more than paddling while fighting to stay balanced.
So let’s get into the specifics of fin and rudder design.
Outrigger Rudder & SUP Race Fin Design Elements
H= Height Height is key in determining surface area in fins. Distribution of surface area is critical in determining how well a fin tracks or holds the boat tracking in a large ocean swell. B= Base The base width is another key factor contributing to surface area and tracking. Typically a broader base tracks straighter, while a narrower base allows for more pivot. The shape of the fin tip can also contribute to ease of pivot. R= Rake The rake in a fin is one of the most critical elements dictating fin performance. The “leading edge curve” and “foil” combine for efficiency cutting through the water and reduction of drag. More upright fins will pivot (downwind fins), but may increase drag or snag sea grasses. A= Area calculated by: A= Base x Width x Height (adjustments are made to compensate for curve)
*GENERALLY SPEAKING, more surface area in a fin offers more resistance to pitch & roll. The placement of that surface area relative to the bottom of your boat/board results in varying levels of tracking &/or drag.
More area deeper in the water = tons of resistance to roll and yaw + more tracking + deeper draft (increased drag).
More area closer to the board = less resistance to roll and yaw + excellent tracking + shallower draft (less drag).
Less area and shallow draft = less tracking + less drag(fast) + less resistance to roll and yaw
Wt= Weight Fin weight is dictated by construction method. Fiberglass lay-ups are durable but heavy. Foam core + carbon construction is more expensive, but optimize strength to weight ratios.
Outrigger Canoe Rudder Selection
1. Weed Rudder
2. Stock Rudder
3. Grip Rudder
SUP Race Fin Selection
1. Bark RFD & Black Project Tiger
H= B= R= A= Wt=
These fins minimize drag, with a very shallow "height" They also don't have a ton of surface area, so won't track very straight. But those with better technique will not have a problem. These are great for races with multiple buoy turns, and short sprint style races where you're putting down maximal power and need to switch sides often anyway (so tracking isn't a huge deal). I really enjoy the Tiger in downwind conditions as well.
2. Keel Fin: H= 6.438” B= 7.0” R= 5.875” A= 44.4” Wt= 8.5 oz
The race Keel fin keeps a low profile with a highly raked leading edge and a lot of surface area packed in close to the board. By concentrating the area shallow in the water column, the Keel minimizes drag and maximizes speed. The Keel fin tracks best in flat water conditions, however more experienced paddlers can use stroke technique to compensate while capitalizing with the added speed. Due to its large surface area, it is not ideal for races with a lot of turns. Best for: flat water conditions, or intermediate/ experienced paddlers that have a good grasp of stroke technique.
3. California Downwind
H= B= R= A= Wt=
This fin provides a ton of hold and stability in larger ocean swells. When the swells aren't that big, or you need the ability for the board to release and slide down the wave, then this fin may have too much grip.