Rocker and roll: Should your board be flat or curvaceous?
Published in Wavelength issue 217
Rocker is the term given to the curve or foil of your board from nose to tail. How the nose flip blends into the mid-section then merges into the middle section then tail kick defines the board’s behaviour greatly. Nose rocker controls how the board enters the water, if it’s flatter then it helps create drive and speed through the rest of the board. If it’s flipped, then it helps develop manoeuvrability. Tail rocker abides by the same rules too. Small wave boards, such as fish, traditionally were flatter rockered. High performance boards were always medium to high rockered, and step up boards for barrels and big wave boards high to extreme bottom curve. General rule was flat waves need flat rocker, extreme waves and extreme surfing needs extreme rocker. Why? Hydrodynamics-wise, water travels down a straight line faster than a curve purely down to surface area. So the more curve, the more surface area, the more drag and therefore the more control. Huge amounts of rocker appeared heavily in boards in the early 90’s when Slater and Machado first entered the scene. These boards were known as banana boards and sadly it was only Slater and his “new school” pro crew that could get the most out of them. However it didn’t stop the public from copying much to the detriment of surfing.
More recently the rocker has started to flatten out as boards are getting shorter. This is down to leverage on the boards as it is quicker to shift your weight longitudinally (nose to tail) to compensate to stop the nose or tail from digging in during high end manoeuvres such as airs and fin released moves. Typically boards are lowering their nose rocker but increasing their tail rocker to increase speed and drive into the board but still keep manoeuvrability. Slater and Josh Kerr’s shift of bringing small boards into big and or extreme waves is mostly down to low rocker lines which develop speed. Current trend is for rocker to be quite low our flat in the nose area, blending through smoothly into the mid section and then really increasing from the fins out to the tail. This creates speed straight from your take off and whenever your weighting up your front foot, but the tail kick creates manoeuvrability off the back foot. This rocker template seems to compliment the new short and fat 80’s templates boards.
Another very important role of the rocker is how the water is guided through all the different bottom contours that go into the board’s hull design. The rocker can make a concave deepen or flatten depending on what the shaper wishes. One key element that we shouldn’t forget is that water doesn’t only flow from nose to tail but also from rail to rail, and diagonally through turns. There are a multitude of direction changes with water flow when you’re riding a wave, even more so the more radical your surfing gets. Rocker still isn’t fully understood as there are too many factors to account for, however the best shapers seem to nail it. Whether this is down to experience through trial and error, or whether it’s something they’ve calculated is still a closely guarded secret. I’d like to think there’s still a little bit of luck involved somewhere too.