Can A Paddle Make A Difference?

Let’s cut to the chase. Yes.

There’s a simple logic to this. If your paddle is lighter you’ll do less work lifting it out of the water and swinging it back to the front of the board (recovery). If the blade is more efficient because of the hydrodynamic design and structure, then that efficiency will be applied to every stroke. But how much value does this improvement represent? Is it worth the extra hundred or so dollars for an ultralight racing paddle. And if you’re a surfer, or you’re chasing swells doing downwinders, does any of this matter at all?

Let’s talk about the racing and cruising aspects first, then we’ll get to surfing and downwinding. To quantify the benefits we’ll have to dig into some numbers. It’s really not that hard, but there will be math...

After the BOP distance race–my Ke Nalu paddle made it ten percent easier

Weight
Let’s look at the simplest element–what the paddle weighs. A typical paddler in a race paddling with good technique is paddling about 45 to 50 strokes per minute and traveling 10 to 14 feet per stroke. Let’s go for the low end and call it ten. That means to travel one mile we need to stroke 528 times (5280 feet per mile/10 feet per stroke = 528 strokes). At 45 strokes per minute that mile takes us 11.7 minutes, which means we’re doing 5.12 MPH. You’re not going to win the BOP Elite race at that rate, but you won’t be last.

45 strokes per minute *10 feet per stroke = 450 feet per minute, 5280/450 = 11.7 minutes

That means in every hour you are lifting your paddle two feet out of the water (assuming you have a 17″ paddle plus some shaft to lift) and you clear the water by a couple of inches) 2700 times each hour. Then you are accelerating it to three times your board speed (15 MPH) and then decelerating it to push it into the water. So assuming your paddle is on the ordinary end of the weight scale (two pounds) how much of the power you’re using is consumed just lifting the paddle and getting it back to the front of the board?

A little aside here. Doesn’t this make it kind of obvious why a Tahitian or disciplined Hawaiian stroke beats the pants off a natural sweep stroke that travels back as far as you like? Not only are you concentrating your efforts on the part of the stroke where the paddle is vertical and your muscles are in the best position to apply power, but you’re also lifting the paddle half as high and recovering it for less than half the distance. Obvious.

I’ve tried several ways to calculate the power used to lift the paddle and accelerate it (I ignored deceleration). The power required to lift a two pound paddle is about 5 watts, the power to accelerate it is about 37 watts. I came up with slightly different answers but they center around 40 watts. A fit athlete with optimal equipment can generate about 250 watts continuously (about 1/3 of a horsepower, one horsepower = 746 watts), but a Stand Up Paddleboard is hardly optimal. As a SWAG (stupid, wild ass guess) I’d estimate the power available as half of that or 125 watts available for propulsion and I’m assuming that a paddler uses all of that in a race. That makes paddle lifting and recovery for a heavy paddle about 24% of the total work load. Forty watts is probably high, but I think propulsion horsepower for an intermediate paddler is more like 1/10 of a horsepower = 74 watts, so our errors probably cancel each other a bit if we’re looking at percentages of the total, and those are the numbers I keep getting, so lets live with it.

Recovery work load percent = (recovery load/(recovery load + propulsion load)) X 100

Our assumption of the amount of power used to move a SUP is based on the amount of power we think is available and the kind of speed that elite paddlers typically attain in flatwater races of known length. As a crosscheck I researched formulas for power necessary to propel displacement and semidisplacement hulls near hullspeed. Using Gerr’s formula for power required we get about .2 horsepower at 5 MPH for a 14 foot SUP with a combined weight of board and rider of 200 pounds. One horsepower is 746 watts, so that’s 149 watts–we’re in the right ballpark.

Gerr’s formula: HP = lwl / ((2.3 – SL Ratio)*8.11)^3

Reduce the paddle weight to the racing paddles generally available (550 grams/1.2 pounds) and it’s 24 watts and 16 percent.

Use a Ke Nalu paddle at 450 grams/.99 pounds and it’s 19.8 watts and 13.6 percent.

In other words you can save about 10 percent (24 percent – 13.6 percent) of the energy you’d use by getting a light paddle. Gotta tell you, at the end of a 15 mile race saving 10 percent of the energy makes a HUGE difference.

Now let’s look at paddle efficiency. Here the numbers are simpler but the degree of faith required is greater. Here’s the faith part–we think our paddles are five percent more efficient in the stroke. The leap of faith is not too great when you look at the underwater videos of blade turbulence and our Paddle Pod graphs of wobble, flutter and vibration. Couple that to an offset angle and face curve designed to optimize efficient strokes and five percent seems pretty easy to believe. It’s just a guess, but when did that ever stop us.

This five percent gets subtracted from the power used to propel the board. Lets’ start with 125 watts needed to go 5 mph.

For a Ke Nalu paddle thats 118 watts (five percent less) plus 19.8 watts for recovery = 137.75 watts
For a typical racing paddle it’s 125 watts plus 24 watts for recovery = 149 watts
For a heavy paddle its 125 plus 40 watts = 165.

The Ke Nalu paddle only needs 83 percent of the energy of a heavy paddle to attain the same speed. The cool part is that it really does feel like that. I’ve always used the thumbnail notion in car and motorcycle racing that drivers can feel a ten percent change. I’m told that designers use the same number in bicycle design–that anything less than a ten percent difference will show up in the results but not be experienced by the rider. Our Ke Nalu paddles really do feel “efficient”, that is they are noticeably stronger in the catch, stable in the water, and faster in recovery than other paddles. Seventeen percent accounts for a noticeable feel.

So, yeah, this is all theoretical and some of it is probably wrong. The proof is in the paddling. But at least we have an idea of the potential for improvement from just a better paddle. Add better paddling technique to that same mix and you’re even further ahead. All this theorizing connects very well with real life experience. The first time you use a high-performance, light weight paddle it is a real revelation. It’s not out of the question to see a five to ten percent improvement in your race times.

What about Surfing and Downwinding?
There’s no math here, just an assertion. The most important two things you need from a paddle in surfing and downwinding is catch and recovery speed. Catch is how you accelerate your board and get into the wave or swell, recovery speed lets you get the blade back into position for that second or third pull you need to make that big wave.

Ke Nalu paddles are built from first principles to optimize catch. When you see a paddle with a 10-12% offset and a flat blade you KNOW it’s not made to maximize catch, it’s made to make it easier to get it out of the water when you pull it too far. When you first push the blade into the water virtually NONE of the surface area is perpendicular to the direction of pull. Now look at the cross section of the Ke Nalu blade. The curve of the blade and the resulting mitigation of offset means 60 percent of the blade area is near vertical when you first start to pull. In the first ten inches of the stroke 92 percent of the blade is within 3 degrees of vertical.

THAT’s how you optimize catch. Pull it past your feet and it sucks out loud–you’re shoveling water. Don’t do that. This paddle isn’t for beginners.