The rocker of a surfboard is the combinations of curves that make up the shape of the board. The bottom rocker of a surfboard is often referred to as the backbone of the board. It is one of the most critical parts of how the board will perform in the water. The bottom rocker can be seen when you look at the profile of the board. If you were to lay the board down on a flat surface, finless of course, and the board touches the surface at almost all points, it would have a flat rocker. However, if the board were to touch at only one point it would be a curved rocker. Although a flatter rocker can generate more speed and drive, it is more likely to pearl (nose dive) on steep drop-ins. A board with more bottom rocker can handle the steeper drop-ins with more ease because it is shaped more to the contours of the wave. More rocker also means the board can make turns with a tighter turn radius but can’t generate as much speed. The aspects that go into the bottom rocker are the nose and tail rocker along with straight or continuously curved rocker.
The nose rocker, also known as entry rocker, of the surfboard is the amount of curve from the midpoint forward. The purpose of this rocker is to keep the board from digging into the wave. Surfboards that have little to no nose rocker will generate more speed because there is more planing surface. However, it is also likely the nose will catch, or pearl, in steeper surf. As a result, boards with little nose rocker are typically long boards, fishes, or boards for small mushy days. Boards with large amount of nose rocker are good for steep and hollow waves. This is because the board fits better with the shape of the wave. However, more rocker generates less speed because the nose flip of the board creates drag. Boards with a lot of nose rocker tend to be high performance and big wave boards.
The tail rocker of the surfboard is the amount of curve from the midpoint back. Tail rocker controls how responsive the surfboard will be. The trade off is that the more tail rocker means the less power generated. More curve in the tail will loosen up the board to make more pivot like turns. It will also help the board on steep waves because the upward lift of the tail won’t force the nose into the water as it would with a straight tail. However, because the lift in the tail reduces the amount of planing surface, the board will not have as much drive. As a result, generally, more tail rocker means more control and less tail rocker means more speed.
Bottom rocker doesn’t stop at the amount of nose and tail rocker. A surfboard can have a continuous or a staged rocker. Continuous rocker has no flat spots in the bottom of the board. Think of a banana. This makes it so that the surfer can shift his/her weight smoothly between front and back foot and surf rail to rail. A flatter rocker lengthens out the turn radius and allows for more projection out of turns, while an increased continuous rocker allows for tighter turns but has less projection out of them. A staged rocker is flattened in the middle of the board and curved in the nose and tail. This helps drive and down the line speed. It also helps catch waves earlier. Like with continuous rocker, staged rocker can be tweaked to have more or less nose flip or tail kick.
The bottom rocker of the surfboard can have any number of different curves to create the ideal board for any individual. Nose flip can be increased for steep waves or decreased for speed. Tail kick can be increased for snappier turns or decreased for more power out of turns. The rocker can also be continuous for rail to rail surf or staged for more power. All in all the bottom rocker is the board’s backbone. As a result, the type of wave the board is intended for should be well thought out before deciding the amount and type of bottom rocker.
Next we will discuss concave and how they affect different rockers in order to create different results on a wave.