Wednesday, February 15, 2012

What’s Up with Bottom Rocker? By Len Barrow

Bottom rocker is one of the least understood aspect of SUP and surfboard design.  Despite this the key concepts are quite simple and understandable.  The following article will explain how various rockers function and what wave types they are meant for.

Bottom rocker is simply the curve in the bottom of your board from the tip of the nose to the tail.  This aspect of design has huge ramifications in relation to how your board will perform in various conditions.

Rocker variations, allows the board to fit in the curve of a wave or lack of curve in the wave.  If you are riding one foot gentle breakers there is no need for too much rocker or bottom curve.  In fact if you have too much bottom curve in small flat waves, your board will start to “push water” rather than flow over it and you will slow down.  In short a flat fits into a flat naturally, or a flat rocker, fits into a flat wave as the board flows over the water with the least amount of friction. That’s why the big boards at Waikiki (small flat waves) have very flat and even rockers.

If the wave is bowling or barreling in a semi-circle and large the opposite is true.  If your board has too little rocker in bowling waves the board may nose-dive, or be difficult to maneuver as it cannot fit into the curve of the wave.  That’s why when you see surfers at pipeline, where the waves are extremely hollow and curved, the expert surfers are riding highly rockered boards.  Again, a curve fits a curve.   Similarly a heavily rockered board fits a heavily curved wave.

Rocker in the Tail.

Rocker in the tail is what we call kick, tail flip or simply “tail rocker”.  Again the type of tail rocker you choose depends on the type of waves you ride.  Your tail rocker roughly begins about three feet from the tip of your tail.  A highly flipped tail rocker is usually for more advanced surfers who ride fast waves.  It allows you to lift the board (like a see saw) in to the lip line in an off the lip.  It also allows for a tighter turning radius in cutbacks and snapbacks.  In big waves high tail rocker allows surfers the extra tool of leverage to make the drop by keeping the tip of the nose out of the water hence avoiding “pearl diving” or wiping out.  High tail rocker can also help you “pump” the board down the line to generate more speed.

Low tail rockers have their advantages also.  Nose riders have natural low rocker in the tail.  This allows the tail to settle into the wave which is most advantageous for nose-rides.  If the tail rocker is too high in a flatter wave the tail may pop out if one is standing  on the nose. Nose-riders also have fairly low nose rockers which allow for easy nose rides.  Low tail and nose rockers on SUP’s allow for smooth paddling on the flats and easy entry in to small waves.

Rocker in the Nose

Rocker in the nose is what Surfers call “Entry Rocker”.  It is the point where the water makes first contact with the board if you are moving forward.  Again the type of entry rocker you have is determined by the types of waves you surf.  Big wave guns sometimes have such high entry rocker that they look silly yet it is necessary to make it down 20’ drops.  Yet too much entry rocker can cause the board to “push water” and will therefore slow you down.  Low entry rocker is for small wave boards as you can keep the speed going as the low entry rocker allows the board to move through the flats without “pushing water” in front of the board.  Instead it floats over the water and you can keep your speed up in the flat sections.  Many Fish boards have low entry rockers as they are meant to surf small waves.

Picking Your Rocker for your SUP

SUP rockers are still in developmental stages but the same rules generally apply.  If you just want to cruise around in flat water and surf small conditions low rocker in both tail and nose will suffice.  This type of rocker is called “Low Natural Rocker”.  The rocker flows almost imperceptibly through the whole board, hence it looks natural.   On the other hand if you are a “hot-dogger” who surfs bowling larger waves, lifting both the nose and tail rocker will be advantageous for you.

The above commentary are just general guidelines.  I have had board with such high nose and tail rockers that still worked well in flat waves and low rockered board that surprisingly worked well in big waves.  It must be understood that one design feature does not dictate how the board will work as a whole.  Board performance is a calculus of tail design, thickness, outline, fin set-up, bottom contours, and of course rocker.      

One of the beautiful things about surfing is that there is an infinite variety of designs that you can fool around with. You can still be a kid tinkering with your toys!  Despite this, a good understanding of rocker will allow you to pick a proper board for yourself.  Have fun.  In fact why not pull your board out and have a look at your rocker.  You may find out something new!         

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