Boarding School: Rocker
In the second instalment of Boarding School, Cory Russell throws a curve ball at the class. That's right - rocker. The arc of a surfboard when seen in profile. What is it? And how does it effect your surfing?
As always, questions, feedback, and sly payouts are welcome in the comment box below.
When people refer to a surfboard’s rocker they are referring to the bottom curve from nose to tail along the centre of the board. The rocker is your surfboard’s engine and will determine how much speed the board will have as well as how easy you will be able to generate speed.
It wasn’t until the 1970s that shapers gave serious consideration to rocker. The Shortboard Revolution of the late 60s allowed them greater turning ability and all of a sudden surfers found themselves in hollower parts of the waves. How to make the surfboard fit those curves? Put a curve in the surfboard.
A board’s rocker can be measured by supporting it in a level position and placing a straight edge in the centre of the board (along the stringer). In doing this and you will see the intricacies of the bottom curve, including the rocker’s apex, how much nose and tail lift there is, and whether your board has a continuous rocker or a three stage rocker.
A ‘continuous rocker’ refers to a continuous bottom curve with no flat spots. A board with a continuous curve often feels more sensitive and responds to the surfer’s smallest shift in weight and pressure. These boards tend to focus on a surfer placing the majority of their weight on the front foot to control speed. A board does not need to have extreme nose and tail lift to have a continuous rocker.
A ‘three stage rocker’ refers to a bottom curve that distinguishes the nose rocker from the flatter middle rocker and the tail rocker. This type of rocker was created in an effort to maximise three important elements of surfing: speed, manoeuvrability, and forgiveness. As surfboards became smaller and more refined it became increasingly important to isolate each section of rocker to ensure the boards balance of resistance and release.
Three stage rocker
Nose rocker refers to the combination of bottom curve and overall nose lift from the centre of the board to the tip of the nose. This combination determines how the water makes first contact the surfboard. If the board has a flatter nose rocker it will make it more efficient to paddle or accelerate compared to a board has a large amount of nose rocker that can push water.
Tail rocker refers to the combination of bottom curve and tail lift from the centre of the board to the tip of the tail. This ‘combination’ of curve between the surfers feet will determine the board’s sweet spot and the tail lift will provide the speed water will release off the tail.
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A ‘flat’ rocker will possess a certain amount of down the line speed however it will provide more resistance during turns. Traditional single fins are great example of using a flat rocker for maximum speed.
An extremely curvy or ‘banana’ rocker will provide a surfer with extra sensitivity when shifting their weight around and the ability to turn tightly with little effort. The drawback is this type of rocker can lack speed in small or poor quality waves. Shane Herring rode Greg Webber bananas boards to devastating effect in Australian reef and rip bowls, yet faltered when he took them to the flatter beach breaks of France.
Greg Webber holding a modern banana rocker
There’s been renewed interest in banana rockers with Greg Webber shaping some for Kelly Slater. Unlike the 90s versions, the modern Banana has increased dimensions so they can be ridden in a wider range of waves. At the time of creating the banana rocker Shane and Kelly were riding boards around 18 inches wide and approximately 2 inches thick.
Stuart D’arcy of D’arcy Surfboards recently told me, “Banana rockered boards were a critical part of surfboard evolution and it changed the way I thought and shaped boards.”
It's unrealistic to try and isolate one aspect of a surfboard - even one as important as rocker. All designs have to be seen as part of a whole. Boards with an extreme rocker will often use a more parallel outline which provides the surfer with resistance and propels the board forward. Boards with a flatter rocker will implement a curvier outline providing the board with release ability to turn.
If the relationship between the rocker and outline is conflicting, it will make for a board that is rigid or alternatively a board that turns on the spot. I asked Jamie Byrne of JB Surfboards what he thinks about when discussing rockers and he told me, “The amount of rocker curve comes down to where you want your surfing to go and what type of waves you surf.”
In my opinion one of the most important elements of rocker is the rail rocker. This aspect of surfboard design is very difficult to measure and relies on the shaper’s ability to create a nice curve along the bottom of the rail with their eye. The apex of the board’s rail rocker is usually different to the apex of the rocker through the centre of the board. If used correctly a shaper can add or reduce the drive or resistance a surfer feels and so enhance the board’s performance.
I have read various shapers opinions regarding whether a surfer is ‘front’ foot or ‘back’ foot. This refers to the perceived area where a surfer generates his speed and does turns from – front foot or back foot?
The way a surfer uses their weight is determined by the waves, the surfer’s ability and their overall stance. If the wave is small and/or has a steep face then you tend crouch down placing more weight on your front foot to generate speed and quickly respond to changes along the wave. When a person is surfing these types of waves the board they are riding needs to have a good amount of tail lift. This allows the water to travel quickly from the surfer’s front foot and exit the tail of the board with minimum resistance. If the board does not have this type of rocker it can feel like you are towing a weight behind you.
If the wave is big and/or has a flatter face the surfer tends to stand more upright letting the natural speed of the board match the speed of the wave. In these instances a surfer will place more weight on their back foot for controlling the speed supplied by the wave and focus on turns. When a person is surfing these types of waves the board they are riding needs to have a less amount of tail lift to maximise speed. If the board does not have this type of rocker you may find yourself caught behind sections with a lack of speed in and out of top turns. In both instances the surfer will turn off their back foot unless they blow the tail (in which case they’ll shift their weight over the front foot to complete the turn).
The final consideration when it comes to rocker is a person’s stance. This is often the most difficult aspect of surfboard design as humans come in all shapes and sizes. When analysing a person’s stance or the distance between a surfer’s feet you can use the following;
First measure your inner seam (from the lowest part of your crotch, along the inside of your leg, to the floor).
Then measure the distance between your foot marks on your board.
If these measurements are the same you have a balanced stance, similar to that of an equilateral triangle in shape and places the surfer in the best possible position in relation to the surfboard’s design.
If the distance between your feet is less you have a narrow stance, similar to that of an isosceles triangle in shape. This stance restricts a surfer’s weight reduced to a small area on the board, usually positioned more toward the tail and causing it to tilt up in the nose while submerging the tail. In this scenario the person’s board may feel too responsive, unstable, and lack speed.
If, however, the distance between your feet is greater you have a wide stance, similar to that of an obtuse angled triangle in shape. This stance extends the surfer’s weight to cover a large area on the board and usually results in the person's foot positioned in front of centre. In this scenario the person’s board may feel unresponsive, rigid, and lack speed.
In both cases the best option is to contact a local shaper to discuss options and address the problem. When I contacted Alex Crews at ACSOD he told me he has been doing a lot of research and development with his models to identify which ones suit each type of surfer, "Front foot (speed generating) surfers and back foot (speed harnessing) surfers definitely like different boards."
In the future I can’t see any great changes in a surfboard’s rocker and this is because the waves a person will surf largely determines what is the best rocker for them. What we can have, however, is a greater understanding of rocker so surfers use it to their advantage rather than buying the latest model.
Nick Blair of Joistik Surfboards is very passionate about customers getting the right equipment as he sees a lot of people out in the surf unaware of how much water their board is pushing or the lack of drive and speed due to the incorrect rocker. He encourages all surfers to talk to a knowledgable shaper so they can match you to an ideal curve. Sometimes picking whether you’re back or front footed can be harder than usual so seek advice, try a bunch of different boards and see what works.
If you’re pushing water or cannot turn… you’re on the wrong rocker.
Next up, surfboard volume.
Cory Surfboards / Stretch Boards Australia