Boarding School: Rocker

Stu Nettle
Design Outline

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.

2.rocker_edited.jpg

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.

continuous.jpg
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.

staged.jpg
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.

sh06-387.jpg
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.”

10294247_10203111268356514_6131404795843967539_n.jpgIn 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.

equilateral.jpg

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.

isosceles.jpg

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.

obtuse.jpg

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 Russell
Shaper
Cory Surfboards / Stretch Boards Australia

Comments

dewhurst's picture
dewhurst's picture
dewhurst commented Tuesday, 15 Nov 2016 at 3:57pm

That's the first time Ive read about stance width compared to traiangles. A few years ago I went on an Indo boat trip with a guy from home who has a really wide stance. At home he surfs OK in gutless beachbreaks, he can throw his board and body into snap turns, but that shit doesn't fly in Indonesia. He really struggled, just didn't know how to carve through a turn. We all told him to reduce his stance but that's pretty bad advice for someone who's been surfing for years.

Wonder if a different rocker would've helped?

udo's picture
udo's picture
udo commented Tuesday, 15 Nov 2016 at 4:11pm

.

chook's picture
chook's picture
chook commented Tuesday, 15 Nov 2016 at 4:21pm

udo, this is no time to start talking about points.
by defintion, a point lacks any rocker (at least in euclidean geometry).

the-spleen_2's picture
the-spleen_2's picture
the-spleen_2 commented Tuesday, 15 Nov 2016 at 4:22pm

Webber banana boards sound good in theory but I still can't bring myself to chip in and buy one.

chook's picture
chook's picture
chook commented Tuesday, 15 Nov 2016 at 5:49pm

looking at that banana board, it doesn't seem extremely rockered. maybe holding a ruler up to the screen doesn't quite capture things.

stunet's picture
stunet's picture
stunet commented Tuesday, 15 Nov 2016 at 4:37pm

Nah, that photo doesn't quite capture it, but that said, the modern bananas have less bend than their 90s brothers.

spelled3's picture
spelled3's picture
spelled3 commented Tuesday, 15 Nov 2016 at 9:27pm

A surf shop owner in Vic once insisted to me that only longboards have a three stage rocker and that short boards have a two stage rocker. The shop is still open. He never surfs and rarely ever did. They don't make their own boards anymore.

cory's picture
cory's picture
cory commented Wednesday, 16 Nov 2016 at 6:52am

Hey Spelled3,
Shops can be the best and worst experience for shapers and customers. My motivation for doing these articles was to deliver correct information direct to the surfers and promote the benefits of a relationship with a local shaper. The experience you talk of is a worrying trend that is growing unfortunately. Thanks for the feedback everyone!

aku not me's picture
aku not me's picture
aku not me commented Wednesday, 16 Nov 2016 at 10:06am

Corey, congratulations on the idea of seam measurement and using triangles to describe stance. I havent tested the measuremnent but I like the way you can visualise the stance. Not all customers are the same but Ive found using images are the best way to convey ideas to them and it sounds like you do too.
My only concern using that would be I'd want to see how the surfer surfed first. Do they keep their feet planted or are they shuffling them around a bit? A surfer with a narrow stance can make up for some shortcomings by staying mobile on the board (John John anyone?) Although a surfer with a wide stance obviously can't.

No other bones to pick, well done for bringing something new to the table.

cory's picture
cory's picture
cory commented Wednesday, 16 Nov 2016 at 12:15pm

Hey aku not me,
You are correct... people move their feet around a surfboard the more advanced they become to get the most out of it. What I have found is there are often defined foot imprints on a board where their feet spend the majority of the time. What I have found is people often refuse to accept the measurement because the stance a person has on a surfboard is slightly more aggressive with their knees bent. Small adjustments can be made to the rocker to accommodate the various stances but in my experience people in the extreme category need to address their stance to progress.

stunet's picture
stunet's picture
stunet commented Wednesday, 16 Nov 2016 at 11:00am

I had a little reminder on the effect of rocker this morning. On Monday I picked up a new board, a step up number shaped for six foot point surf. It's 6'1" x 18 1/2 and, despite the length, it's almost identical to my standard shorty. One difference, however, is a slightly reduced rocker. I say slightly 'cos, really, it's a marginal change. You gotta pay attention to notice it.

Even though it's made for bigger waves I took it out in clean three foot surf this morning and was surprised at how stiff it was. That's OK, I'm sure it'll go fine in the waves it's meant for, but it's a reminder of how tiny changes can have big effects.

leckiep's picture
leckiep's picture
leckiep commented Wednesday, 16 Nov 2016 at 11:31am

Hey Stunet - Do you use the same fins and fin systems in both boards?

stunet's picture
stunet's picture
stunet commented Wednesday, 16 Nov 2016 at 11:55am

Yeah, took the fins out of the shorty and whacked 'em into this board. It's a quad, FCS H2s on the front, and in the rear a set of fins Allan Byrne made years ago that I found in my shed. It's odd combo, no doubt, but was working unreal in the shorty.

sharkman's picture
sharkman's picture
sharkman commented Wednesday, 16 Nov 2016 at 11:41am

if the board is a step up , the fins would be further apart , therefore stiffer and not the rocker?

x

stunet's picture
stunet's picture
stunet commented Wednesday, 16 Nov 2016 at 11:50am

They're only marginally further apart. Eighth of an inch maybe? Board is only two inches longer than usual so all the changes are very minor. The lower rocker the most noticeable (even though subtle).

sharkman's picture
sharkman's picture
sharkman commented Wednesday, 16 Nov 2016 at 12:00pm

moving a fin 1/8th of an inch or is it 1/4 , can be the difference between a board being too loose or stiff , is the rocker lower in the front , or tail or both?

x

stunet's picture
stunet's picture
stunet commented Wednesday, 16 Nov 2016 at 12:08pm

Yeah, no doubt but I know the feeling of this design inside out. It's my fifth version of the same board only this time two inches longer. Lower rocker is more noticeable forward but still reduced in tail.

sharkman's picture
sharkman's picture
sharkman commented Wednesday, 16 Nov 2016 at 11:07am

so you have different rockers for different types of surfers , do you also narrow or widen surfboards , because of a persons build or style?

If yes what are the different groups that you have indentified ,and what rockers suit , say , a 6 0 guy who is 70KG's , and a 5 10 guy who is 90KG's?

x

cory's picture
cory's picture
cory commented Wednesday, 16 Nov 2016 at 12:19pm

Hey Maurice,
There is definitely a shortage of ergonomic information when it comes to surfers and their equipment. The point you make is very true and as you know a shaper has the rail thickness as well as the width to play with when designing a board or making a custom order.

What are your experiences and data do you have to share?

Gary G's picture
Gary G's picture
Gary G commented Wednesday, 16 Nov 2016 at 12:11pm

Y'all want to be schooled on the use of rocker?

Gary's got you covered: https://www.youtube.com/watch?v=wPURJNqL8U4

I’ve created a monster. Cause nobody wants to ride faceys no more, they want Gary; I’m chopped liver.

But if ya want Gary this is what I’ll give ya: a little creatine kiss from a hard licker

Gary G's picture
Gary G's picture
Gary G commented Wednesday, 16 Nov 2016 at 12:23pm

Also, Gary can't really relate to those stance diagrams as they don't represent his chiselled torso: could you please include one that depicts an upside down triangle hovering over a surfboard?

I’ve created a monster. Cause nobody wants to ride faceys no more, they want Gary; I’m chopped liver.

But if ya want Gary this is what I’ll give ya: a little creatine kiss from a hard licker

Pecka's picture
Pecka's picture
Pecka commented Wednesday, 16 Nov 2016 at 3:52pm

I don't totally buy into the whole back footed surfer v front footed surfer thing. At least when it is used to classify someone overall as being back footed or front footed. It comes down to the type of waves on the day. Good waves will often result in someone surfing more back footed when in crappy surf that same person may otherwise surf more front footed to generate speed. The point about rail rocker is a good one. Have a look at some of Maurice Cole's insane deep concave boards. They have a flat rocker in the middle yet lots of rocker curve along the rail line. Looking at rocker is not just about nose to tail, but stringer to rail as well. Just to make things even more complicated than they already are.

Doublems111's picture
Doublems111's picture
Doublems111 commented Wednesday, 3 Apr 2019 at 10:05am

Been reading a lot about tail rockers as I have a predicament. Bought a new board for "beach break" conditions. It super fast which is great but sooo hard to turn. I changed to FCS reactors to to hopefully help loosen her up.... Any further advise, I'm thinking next would be making a conscious effort to move my back foot further back. I was hoping to have a slightly more skatey feel, quad maybe? Racing is all good and well but you end up just doing close out floaters or cutbacks, no off the bottom/off the top or snaps... HELP:)

udo's picture
udo's picture
udo commented Wednesday, 3 Apr 2019 at 10:35am

What Size board ?
Small size C-drive fins up front Reactor for rear fin.
Thats if you can get hold of C-drives...they still seem to be unobtainable...

Doublems111's picture
Doublems111's picture
Doublems111 commented Wednesday, 3 Apr 2019 at 10:40am

It's a 6'2 x 20 1/4, I'm 6'3. So shorter stubbier swallow tail/quite wide. So you think quad will help loosen her up? I't definitely fast enough, just want to leverage that speed into something. Smaller fins even?