The Most Underrated Paddling Technique to Gain Efficiency

A few years ago, a client and friend of mine, Zouhair Belkoura (of Pacifica Board Factory), were talking about how an experiment might be conducted to test board length in regards to efficiency and speed. Shortly thereafter, we devised a small experiment where he shaped three surfboards of the same volume but varied in length (6’, 7’, and 8’), attempting to keep the profiles as close as possible, only changing thickness and width to achieve an equal volume.

We began collecting data in early 2021 and wrapped up in Aug/Sept 2021.

The results are as you would expect, with the 8’ being the most efficient in regards to stroke rate, 7’ next best, and 6’ worst; and, in regards to average speed, the same trend emerged.

You can watch the podcast talking about this experiment here; and Zouhair’s write up here.

The Anomaly?

There is one statistic that I’d like to point out in this article and explain with a little more detail. And that is the data that emerged from my own paddling tests in the experiment. I’ve mapped them here against the average for the group to illustrate:

See anything strange?

Compare my 6’ to 7’ change vs the group average 6’ to 7’ change.

See it now?

My stroke rate didn’t change between 6’ and 7’. The groups’ differential of stroke rate from 6’ to 7’ was very linear. How did I make a 6’ board paddle with the same efficiency as a 7’ board when clearly the group average showed a 7’ board should be significantly more efficient?

At face value, this may just seem like an anomaly. But when you view my video, you may notice what I find so interesting.

The technique I use for the 6’ is vastly different than what I use for the 8’, but eerily similar to the 7’ board.

The question is, why? Why did I use the same paddling technique for the 6’ and 7’ test, but changed it for the 8’. (Watch again if you aren’t seeing the difference).

The key difference here in the technique is the first part of the stroke, right after I enter the water. Notice the extended arm and hand underwater (shallow and forward) in the 6’ and 7’ tests. Contrast that with the 8’ test, where the arm and hand dive straight into the propulsive phase of the stroke (i.e. deep and forward).

This is a conscious effort I am making because of the length of the waterline of the given surfboards.

The Bulbous Bow

Let’s take a quick side trip down shipbuilding and hydrodynamics for a moment. This topic was discussed in the Dropping In Surf Show episode Hydrodynamics, Drag, Propulsion, Lift with Mark Buetzow. 

This is what’s known as a bulbous bow - 

(1) shows the profile of the bow with a bulbous bow.

(2) shows the ship’s profile without a bulbous bow (a conventional bow).

(3) shows the wave created by the bulb (the green line). Notice how the wave begins in front of the ship’s front waterline.

(4) shows the wave created by a conventional bow (using ship’s profile without the bulb from (2)). Notice how the bow wave begins at the front waterline of the conventional bow.  

Lastly, you can see how the green wave created by the bulb cancels the blue wave created by the conventional bow (i.e. the crest and troughs offset each other - the area in the middle - above the number two in the illustration) and thus, creates (5), the new waterline.

(5) is the new waterline that the wave created by the bulb canceling the wave created by the conventional bow, thereby creating less drag on the vessel.

Bulbous bows on ships reduce their fuel consumption by an average of 15%. That is enormous, and it’s this cancellation effect that contributes to that reduction.

The Most Underrated Paddling Technique to Gain Efficiency

There are several types of drag we experience in water when paddling a surfboard and wave drag is one. This principle of lengthening the waterline outlines how we can minimize wave drag – create a longer vessel, or create a bulbous bow to our vessel to aid in canceling the wave drag created when we have a shorter waterline.

When we paddle on shortboards, we can effectively use our arm and hand to create this cancelling effect and provide increased efficiency in our stroke. As the waterline of the surfboard increases, we need to make a decision – when does this extension of the arm/bulbous bow principle stop becoming an advantage?

Let’s use an example where it is clear when not to enter and extend – a 9’6” longboard in which I am clearly out of the water.  

My arm and hand cannot possibly extend past the front waterline of this board so entering and extending would simply be slowing me down.

So what about mid-lengths?

Mid-lengths aren’t quite longboards in length and volume, and not quite shortboards (where it’s clear we should enter and extend).

This is why I constantly tell surfers that mid-lengths are technically the worst surfboards to paddle. They aren’t short enough for us to get a large impact from lengthening the vessel using our arm, but also not long enough to let the waterline extend naturally and glide.

But as you can see in the paddling test, I used the shortboard efficiency technique. That is because I have found using shortboard technique on a mid-length, when the goal is efficiency, to be superior to using longboard technique on a mid-length. However, when speed and acceleration are the goal, longboard technique prevails.

The 6’ shortboard in my test paddled just as efficient as the 7’ mid-length because I used the same lengthening technique, manipulating the waterline with my arm and hand just long enough to gain an advantage. Whereas for the 8’ board, the board's waterline clearly being longer than I can reach forward underwater, I used longboard technique and dove straight to the propulsive phase of the stroke, driving efficiency by hovering or pausing slightly between each stroke, letting the board glide naturally between each stroke.

While this principle of lengthening the vessel (either using your arm or paddling a longer board) reduces wave drag significantly, there are still two other types of drag we need to concern ourselves with when paddling. But for now, give this a try and see how it feels.

As always, feel free to reach out to set up an in-person Level 1 Private 1-on-1 course, or join the Surfing Paddling Academy online course and walk through this technique and others at your own pace.

In the meantime, I’ll see you in the water.