Does rocker increase per board length?

Couldn't come up with a more eye catching title. Sorry.

Here is what I mean:

Sharp Eye has chosen to list the nose rocker with the dims of their stock sizes. Naturally all dimension numbers increase as the template gets larger, but so does the rocker. Is that true for all board models everywhere or is this unique to Sharp Eye? How much does rocker increase with each added inch of length? 

Hey Dubl I didn't click the link but get the gist of what you're saying.  Its not like there is a "formula" that I'm aware of anyway, for increasing rocker .x inches for every one inch increment of length.

As many others will testify, rocker is so much more than just a number in the nose and tail, even 'tho those numbers can be useful for certain things.

If you make your own boards, you can make your boards any way you want!  But sometimes with foam boards I stick pretty close to the rocker in the blank.  With wood boards I build whatever I want for that design, rocker and template are two things I like to start with, as a foundation to the rest of the design (rails, foil, bottom, etc.).

To get some ideas about the relationship of rocker to planshape, and to length, I suggest you download the US Blanks catalog, and study it.  There is just so much useful information there, because their blanks are designed by pros, and they state what kind of board is suggested for each blank, and their blanks are pretty close tolerance, meaning close to the finished shape.

True, a good shaper will have little nuances he will shape into his rocker, those are his personal secrets, but you can check the rocker of any board you own.

These are just some of my thoughts to get the conversation started, there are other board builders here with much more experience, I'm just a backyarder who enjoys making surfboards.

Hi DublAK2 -

I've seen guns with 8"-9" nose rocker and noserider longboards with less than 4" nose rocker.  I've also seen boards with less than 2" and others with as much as 5" tail rocker.  It really depends on the board's purpose.

If you are referring to a formula for scaling up rocker on one specific design, I'm sure a formula could be calculated if you knew the lengths and rockers of the various boards of that design.  As with widths, there can be a direct proportioning method which maintains the same curve or something like 1/8"of width for every 1" of length which will change the overall curve but prevent a super wide board.

Awhile back someone posted an image of superimposed diagrams from a blank catalog.  It was shocking how similar most of them were.  Many of them, regardless of length, were almost perfect matches.

I guess there must be a reason why so many blanks have the 5"(+/-) nose and 2 1/2"(+/-) tail rocker formula?


As to your title, "Does rocker increase the board lenghth?"  The answer is yes if you measure length along the bottom with a curved measuring tape.  Put more concave and you flattend the rocker and the tape and it will read shorter.  This is why I have been measuring the true lenght of the board on the deck.  Thanks to Jim Phillips for this way of thinking.

No. Potato chips and guns slash your question…

…John and Huck seem to agree with Stingray on this issue…The Masters have blanks for sale in every blank catalog…

Nose flip beats me up when I'm looking at total rocker…Surfer Steve has his own ideas. You need to have your own ideas too.


Any rocker recs for a 5'11 fish, 6'4 HPSB, and 6'9 step-up for a three board quiver at a beach break? 

what are "rocker recs"?

what exactly is it you're looking for - are you going to shape these boards yourself?  Can you post rocker shots of your favorite boards, for a reference point?


I'm not fluent in Australian but I think he's looking for recommendations.  

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He said "per board length" not "the board length" or are you just joking?  I like over-curve too for some reason.

Anyway, here's my answer to his question.  You will find that longer boards do tend to have more rocker in total since they

are longer and it just sticks out more at each end.  You will also find that some longer boards have about the same or

even less - it's whatever the shaper wants.  I have a 6'10" board that has about 2" tail rocker and about 4 31/32" (almost 5") nose rocker.  That's fairly flat and as a result the board paddles well and catches waves well and it does well in chest high surf, but not AS well in head or overhead when it's hollow - it's ok in head high just not perfect.  It might need a little more rocker for those situations or perhaps a little less outline in the nose or more aggressive rails, whatever.  But it would not be strange to have 5 1/2" or 5 3/4" nose rocker, even 6" or more if you wanted a board for the Pipeline in Hawaii.  It just depends on what you want to do with the board.  There are pipeline guns that have a lot of rocker.  If you want to surf a typical beach break on a 7' long board, you don't need 6"+ rocker.  Less than 6" would do you.  And the tail can be 2 1/2" or thereabouts.  It doesn't need to be like 3".  It's funny - you can build boards with all different kinds of rockers and rocker-flows.  You can have a continous rocker which is what I like since I think they are more swivelly.  You can have different flows.  This is why you have to be careful if you choose a hot-dog (close-tolerance) blank but you want less rocker.  Be careful.  You may wind up shaving too much tail off of the blank (why? - because your rocker-flow may be different than the blank's).  If you want flatness with a shortboard blank (not a fish blank), you may want to order a custom blank.  This will make your life much easier.  Shaving the bottom of the center of the board will help you get less rocker but be careful the rocker flow is what you want.  I'm just trying to give some wisdom here.  If given a hot-dog blank, it is easiest to shape a hot-dog board with that blank.  It takes more skill to reshape the board's rocker flow.  So a hot-dog will have a bit more than 5" in nose rocker, it could have as much as 6".  But honestly, 1" difference doesn't make the 5" one useless in head-high surf, it's just a bit more drag, that's all.  Than can have benefits as well as drawbacks.  There are trade-offs of paddle speed versus better slipping into the tube, better carving, etc…  Naively, one might think that to make a longer board from a 6'0" board, we can just let the shape stay the same - which means greater nose and tail rocker.  Maybe someone can give you feedback on that.  I have always flattened my rocker slightly since I just can't fathom having boards with huge rockers yet - since I don't surf the Pipeline.  Maybe in a future time I will have a 6'10" board with 6"+ rocker.  I just have not gotten to that board yet - but I would love to have one with that much rocker.

For my basic mushy day at the beach, 5 3/8" rocker seems to be ok for about chest to head high surf.  It gives me a little

more paddle that way.  If I rockered it more, it would paddle less well, but probably be a little faster in the tube.  So the

rocker will change depending on what day you want the board for - chest-high wind-swell, hurricane ground-swell - these boards of mine are guns and have a little more rocker - I'll have to measure my 7'2" guns - they are probably close to 6".

By the way in summary: Many longer boards are only slightly scaled up in rocker since they are not used in the same way that a short-board, step-up, or pipe gun are used.  They are survival boards and don't need the extreme carvability of a shortboard - they need to catch the wave so the surfer isn't pitched into doomsday.  Once on the wave, they will NOT be doing a backside air like Julian Wilson or Kelly Slater or some ASP pro, they will just get covered by a massive barrel and wave to their wives when they eventually come out of it alive!  Too much rocker and they might stall before getting to wave to the chicks!


Don't take me too seriously, I've only shaped one blank so far!


I'll do the HPSB but I am opting out of anything to bank on for the fish and the step-up since I don't know them well enough and I might be off by a 1/2" or so on them.  Clearly the fish could be as little as 2" or less in the tail and can be much < 5" in the nose.  Roughly, the step-up can be > 5 1/2" in the nose and > 2 1/2" in the tail, but please ask an expert for better numbers.

But typical 6'4" HPSB = 5 3/8"+ nose, 2 3/8"- tail (+ means or a little more, - means or a little less).  By the way, not

to make this complicated, but the thickness of a board CAN affect rocker choice since thicker boards can be harder to

turn - sometimes a thicker board will have a wee bit more rocker thrown into it to make it easier to turn.  How heavy you

are may affect some of these parameters a little bit.

if you hold the shape constant, you can do a straight line proportion of rocker with board length.  IOW, if you want to take a 5-6 fish up to 6-0 you can ratio the rocker with the increase in length.

I trust guys like Greg Tate and John Mellor and Huck. What seems to be missing here is a starting point.

…So…Mr DublAK2,Do you own a surfboard that you can measure? Flip the board over and put a straight edge on it. We know you own a computer. What's stopping you from downloading a blank catalog? Read the shapers comments…you will learn.

For a fish you need to buy a US Blanks 6'2 or 6'10 fish blank. Work it from there. It's amazing how much information is in a Blank Catalog…

and one more thing… 1/16 of an inch will get lost during the glassing process…so if you go with a computer design thats cool,but sooner or later the board gets glassed and 1/16" can get lost with one pass of the sander, or a heavy hot coat…Stingray.


I agree with Greg's comments about keeping the shape constant.  No problem there.  And stingray's comments about

starting with a good fish blank so you don't struggle with the shaping too much.  I think it would be a good exercise to

take a 5'11" shortboard or fish and scale it up by keeping the shape constant and see how the board surfs.  I have this

on my todo list.


By the way, my nose and tail rockers for the HPSB above were given in terms of the blank itself, not the glassed board so please

understand that the glassed board will be slightly different due to the thickness (as stingray mentions).  I know

that a lot of shaping programs and boards are sized by the final board - and this makes sense when you really think

about how a board will behave in the ocean.  The glass DOES affect it's shape somewhat.  I just don't worry

about this since I can tolerate 1/16" difference in my boards since I'm a beginner at shaping, and it only makes a

small difference in how it will behave.  But most boards ARE sized down to the 1/16", like a typical Dane Reynolds board

might be 2 7/16" for a chest-high+ day (like 2.5' @ 12s or whatever) - but I would bet that there are shapers who could do even a little better than that if they tried really hard.  There may be machines who can top this too.  I haven't yet seen any stringer dimensions that are described in 1/32" - perhaps others have seen this?  I'll have to visit some shops.

Nope, not trying to shape. Just want to learn.

<p>I just measured a Ryan Sakal 7&#39;2&quot; pintail Pipeline-style gun.&nbsp; It measures 7&#39;2&quot; x 18 1/2&quot; x 2 1/2&quot; and it has</p><p>5 5/8&quot; nose rocker and 2 1/4&quot; tail rocker.&nbsp; The pic shows how I measured the rockers.&nbsp; Note that if I were to move</p><p>the rocker-stick a little forwards I might get a wee bit less in the nose and a wee bit more in the tail and vice-versa.</p><p>I usually just try to center the board on the highest point of curvature that I can find, and I balance the board as best</p><p>I can on it&#39;s centerline (which I&#39;ve drawn on the rocker-stick).&nbsp; I just have to choose some point and go from there - that&#39;s</p><p>how rockers are measured.&nbsp; If you have any questions about how to measure rocker - I&#39;m not an expert - there ARE experts</p><p>on this forum.&nbsp; I would like to be that man soon though as it will be easier for me to do these jobs.</p><p>But now we can scale these rockers down to a 6&#39;9&quot; board.&nbsp; I surf this 7&#39;2&quot; board in hurricane surf and in California</p><p>on a waist-chest day or larger.&nbsp; It&#39;s fun because I can do head-dips on it at Manhattan Beach even though it&#39;s not really</p><p>a thick-enough board for my 192 lb. body.&nbsp; But it&#39;s ok to surf this board.&nbsp; I would love to have a slightly floatier gun.

Folks, I honestly did something a bit WRONG when I measured the rocker - I did not use a level substrate and I did not have a level board.  The board is level with the

ground which is on a hill’s downslope so I would guess that the 0 rocker point  would be more properly back a smidgen.  So it may have slightly more than 5 5/8"

of nose rocker and slightly less than 2 1/4" tail rocker.  I just didn’t think first.  SO USE A FLAT  SURFACE horizontal to the earth if possible and put a small level

on your rocker stick if possible.  It’s also possible that the rocker is close - hard to tell but my guess is that the rocker stick should be a smidge to the right in my photo.


Hi -

Mark some points at the center point and 12", 24" from each end on the bottom of the board.

The straight edge is placed so it touches at the center of the board.  By looking closely and rocking the stick up and down, you can determine where it touches the board at the midpoint.

If the straight edge isn't long enough to reach the ends of the board, 'shim' it at some point to maintain it's position and slide it to where it does reach the ends.  Measure at your predetermined points.

A 'rocker stick' is surefire but there are cheaper (admittedly less accurate) ways to skin the cat.


Blank catalogs hold a lot of info.

As a hand-shaper, they are my bible.

I have a collection.

Clark,Bennet,US Blanks,WNC,Walker, and so on.

Study them.

Lots or answers there.


I did not click the link because of the SurferSteve nonsense I've delt with before.

…Tonight I clicked the link and it took me to Sharpe Eye Surfboards. Great boards if you are small and you rip. Not so good if you need to lose a few and are over 40…Looks like computer numbers…and that's fine…but One number for rocker is only good for the guy running the numbers…or the machine…

I'm backyard and over 50. Surf 2-3 times a week. My go to blanks are the USB 7'7A and the USB 6'10"A. The Blank catalog has the numbers. Rocker is very important…spliting hairs is a waste of time. I can kill 1/16" with a wrong twist of the sanding screen…1/32 is hard to see with my glasses on…how wide is your pencil tip?        Any question about rocker is a good question.


The above pic should have been labelled:

Ryan Sakal 7’2" x 18.5" x 2.5" x 5 5/8"N x 2 1/4"T simple rocker measurement.

And I meant to say, “See duh bro Barry Snyder’s comments for more on rocker measurement”.

My editing didn’t go well, sorry.

Keep in mind that you really just need to pick a reference point and stick to it.  If using the computer, try to use the computer’s exact point of 0 rocker.  Sometimes

we don’t have this luxury - perhaps the blank isn’t even shaped enough yet.  Just stick with a point.  But there is a point where the board stops going out and starts

going back in.  In my pic of the board on it’s deck, it’s the highest point on the board.  We just have to find it somehow - in my case, my rocker-stick has a centerline

that is pretty much the center of gravity so we can play a game of see-saw as someone else mentioned in this thread but be careful that your board is the same

mass on each side of centerline - not always a good assumption - so what to do?  Don’t use a KD Spruce or Douglas Fir stick - get one that’s hyper-moderne somehow.

How?  I don’t know - See someone like Barry Snyder until I come up with a better stick!  Maybe use a graphite stick or plastic or aluminum or some other metal.  Woods

are not as reliably uniform in density.  We need uniformity in density or we need a good eye to see the point of 0 rocker or both!  I guess you can use your surfboard

to find the center of gravity just by balancing it while measuring the rocker and then mark the board for future use!  Or put the piece of wood on some thin edge and mark it

before trying it with your board.  So wood is ok - just be careful to find the center-of-gravity sooner OR later.  But be wary that wood is kind of a dynamic beast - it’s

moisture content could change in a funny non-uniform way or something.  Just beware of these things.  Your eye is almost as good as the center-of gravity.  Try

to use a real nice flat table under your board - this is not always easy for people - you may have to build it!   The 0 of rocker is not really a unique point - if you put

your board on it’s belly it may not lie right on the 0 of rocker.  Likewise on it’s back, if it’s on an incline, you will get a different 0 of rocker depending on the incline.  So

it’s kind of complicated.  Just relax and pick a point that looks pretty good and stick with it.  Now your nose and tail rockers are forever in a give and take - whatever

the nose gives, the tail takes and vice-versa.  But you shouldn’t really care because it’s the same board either way!  So we could have a board sitting on it’s nose and it

would have 5" of tail rocker but that would be ok since the 0 of rocker is on the board’s nose (not near the center) - after all, it’s the same f-in’ board.  So relax and pick your best point, and be careful of rocker flow - is this a hot-dog board, a small-wave board, and do you care which?