What if you were told that everything you know about selecting a paddle shaft just changed?  What if you were told that you need a flexible paddle shaft and a blade that is larger than you use right now. That would go against all the commonly accepted rules and pretty much everything we have been saying on this website for the last few years.  Right? Indeed.

The paddles we are using today were developed, in part, with an understanding of the history of paddle sports such as outrigger canoeing. Shapers, manufacturers, and designers took the knowledge from other paddle sports and applied them to SUP.

The problem is that SUP may be a fundamentally different sport from other paddle sports. One major difference is the length of the paddle. Whereas a relatively short paddle is used in paddle sports such as outrigger canoeing, a relatively long paddle is used in SUP. That long paddle shaft creates much bigger stresses on the shoulder and this may be one of the reasons we are seeing and hearing about more and more paddlers having orthopedic injuries related to paddling

According to Dr. Scott Shoemaker, an avid paddler and surgeon living in San Diego, what is needed is a paddle shaft that will allow  “a soft, more human interface that provides for a better transfer of energy for a longer period of time with less fatigue.” Stated another way, the stiff paddle shafts that are common in SUP have the potential to cause unnecessary injury.

Moreover, the belief that a stiff paddle shaft is the fastest paddle shaft may be erroneous. According to Shoemaker and designers at BST Nanocarbon (more on them shortly)

“a flexible paddle shaft can be designed to work as “an energy storage device” to increase speed while decreasing fatigue and injury.  At the beginning of your stroke you have the most power and the tendency to cavitate the blade through the water – which is a waste. If you loose 2 inches of distance on each stroke in a six mile race this amounts to  nearly 600 feet  (say 600 strokes per mile – 3600 stroke  so 7200 inches which is 600 feet – 200 yards or 2-3 min)”

“So the idea is that as you apply load to the blade you would rather the shaft to bend than the blade drag through the water. Then as you bring the blade towards your hip your ability for power is less and then the shaft straightens again – returning the stored energy and allowing you to snap the blade out and back to the front of your stroke.”

All flex is not created equal

Designing a paddle that could flex AND store energy in the proper manner was no easy task. A flimsy, poorly designed fiberglass paddle is not what we are talking about. The flex pattern of the shaft must be very specific in order to create a performance oriented tool.

For assistance, Dr. Shoemaker turned to BST nonocarbon ( http://www.bstnano.com ) a company that has extensive experience with carbon design in the sports and aerospace industries. When designing the new line of Aztek stand up paddles, the team used the same sophisticated computer simulations that are used in the aerospace and automotive industries. According to the manufacturer, “Computational Fluid Dynamics (CFD) software is used to simulate water flow around the paddle, and the engineers use this software to optimize paddle design by maximizing paddle power.  The lift and drag coefficients of each paddle are closely analyzed to give the paddler maximum lift at the beginning of the stroke as well as maximum power throughout the rest of the stroke.”

One of the things they learned is that the flex profile of the paddle shaft is dependent on many factors and the flex profile of each shaft must be configured to the paddler, length, blade size and type of paddling (surf, race, etc.)

As a general rule, the bottom of the shaft must remain very rigid. In this segment of the paddle, the shaft maintains its straight shape which creates the feel for the water and allows you to easily extract the blade. All of the flex is located at the top of the shaft. This allows the top to have a natural transfer of power to your body. According to Shoemaker “If you have ever paddled a large blade on a stiff shaft – this ‘cooks’ your shoulders and makes rotator cuff issues and shoulder impingement more likely. The flex prevents this from happening.”

Designing a paddle that only flexes at the top of the shaft was one of the major design hurdles but the BST engineers were able to dial in the flex profile throughout the length of the shaft while maintaining strength and lightness.

Currently, Aztek paddle shafts come in three levels of stiffness (225, 250, and 275).

Additional design features

Although the flex profile of the shaft is the number one design feature that should excite paddlers, the engineers at BST went a few steps further and created a paddle that has other potentially game changing features including:

• Easily interchangeable blades: The blade is held to the shaft with a screw. It is therefore easy to change out the blade for different uses and training and racing conditions. You may be asking (as we did) why don’t other vendors use a screw to secure the blade to the shaft. The answer is “because it is difficult to design a paddle with a screw because the screw is a point of failure and adds weight at the blade face where you do not want it.” The engineers, however, were able to design the blade and neck of the paddle such that the paddle is as strong and as light as any other so there are no issues with paddle failure or excessive weight at the level of the blade.”
• Blade design and size: If you look at the blade of the Aztek paddle there is a low profile dihedral located high on the blade face. You might be asking (as we did) how come there is no full dihedral like many of the other popular paddles on the market AND how does all of this flex and low profile dihedral affect the size of the blade we would use to paddle. The answer was at one expected and also unexpected. According to Shoemaker:

“the flex pattern of the shaft dictates that you don’t need as much of a dihedral.  The point of the dihedral is to allow for pressure to be evenly relieved off the blade so that it interacts with the water evenly and smoothly. Paddlers with less control, strength, and experience need more of this. The downside is that a big dihedral may result in a loss of power.”

The problem is that a blade face without a dihedral on a stiff shaft will overwhelm your shoulders. That is where the flexi-top shaft comes in – to humanize the energy transfer and allow for prolonged high speed paddling but still allow for a sticky blade and minimal drag through the water.

In development, we tested a number of different designs and a deep or double dihedral was a discovered to be a liability once you have flex in the shaft. The fact of the matter is that the dihedral designs that are popular on the market are designed to overcome what we feel are limitations in the shaft. Dihedrals are necessary when you have a stiff shaft but are obsolete when you have a shaft that flexes.”

As far as blade size, what you are going to find is that many paddlers will use a larger blade than they are accustomed to with the Aztek paddle. Because of the flexible shaft, the forces on the shoulder and upper body are reduced. With a stiff shaft you must depend on a smaller blade and high dihedral to ‘save your joints’ by having the blade slip through the water a bit. Instead of wasting this energy the flexitop stores it and gives it back with less slipping in the water. So you save your shoulders and go faster. Win win.”

Give that fact that at one of our editors just went through shoulder surgery we are excited at the possibility of testing a paddle designed to “humanize” the paddle experience. We are also excited about the possibility of having a paddle where we can change out the blade size for different training workouts and different shaft lengths for our different boards. We are currently testing the Aztek paddle. Our initial impressions are good. A full review will follow in a few weeks.

Aztek paddles are not sold in stores. Each paddle is custom made and you will need to use their online fitting tool to get the right paddle. Here is a link: