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Special Interests - Surfing New York and New Jersey => Shaper's Shack: Surfboard Repair, Restoration and Shaping Tips => Topic started by: little_nasty on February 12, 2008, 03:41:57 AM

Title: Dimensions Rule of Thumb
Post by: little_nasty on February 12, 2008, 03:41:57 AM
So i'm looking for a new board, and for a little fun i decided to dig and look back at all the boards i've owned for which i have dimensions - thinking about which ones i liked most and how they rode/paddled/etc.  I have a nerdy little sheet with all these boards on it.  Anyway, turns out my favorite boards of all different lengths seem to have similar volumes.  So in the interest of sharing and maybe hearing a little bit about y'all's experiences, here's a little rule of thumb that i think works for me.

Take the length in inches x width (in.) x thickness (in.) divided by your weight in lbs (at the time you rode that board).  My favorite shortboards all seem to gravitate towards the number 20.

(Big wave guns of course a bit higher.  Funboards and 70's kinda shapes up around 30.  And longboards around 40.)

I think the 20 at my current weight corresponds to up near 2000 cu.in. (no, surfboards are not box-shaped) which is about 72lbs of buoyancy.  Anyway, just a thought i came across as i was considering new boards and maybe useful for figuring out dims for alternative shapes and whatnot.  I'd sure be curious to hear where other people's numbers come out.
Title: Re: Dimensions Rule of Thumb
Post by: SeaCliff on February 12, 2008, 07:02:47 AM
I have to sharpen the pencil and give this a shot...curious how it'll come out!
Title: Re: Dimensions Rule of Thumb
Post by: Clams on February 12, 2008, 07:36:14 AM
Whats your height and weight?
Title: Re: Dimensions Rule of Thumb
Post by: Crackie Onassis on February 12, 2008, 08:11:46 AM
Seriously,

Little Nasty, check out my twinzer. Of everyone I know, I think that you are the person who can pull the sword from the stone with this board.

It is the ideal Box-Rocket. Round tail keeps you barrelled, yet it is fast enough to outrun closeouts. The size (do the math: 6'2"L-19"W-11.5"N-14.5"T 2.38"R). So, if your biorhythms check out, you should really come by and give this board a look (maybe ride it on Thursday)?

Title: Re: Dimensions Rule of Thumb
Post by: Harry Balzsac on February 12, 2008, 09:36:33 AM
I'm so fat, when I do that calculation, I end up with a fraction.
Title: Re: Dimensions Rule of Thumb
Post by: Jake on February 12, 2008, 09:55:54 AM
i cant do math....
Title: Re: Dimensions Rule of Thumb
Post by: little_nasty on February 12, 2008, 10:29:07 AM
Seriously,

Little Nasty, check out my twinzer. Of everyone I know, I think that you are the person who can pull the sword from the stone with this board.

It is the ideal Box-Rocket. Round tail keeps you barrelled, yet it is fast enough to outrun closeouts. The size (do the math: 6'2"L-19"W-11.5"N-14.5"T 2.38"R). So, if your biorhythms check out, you should really come by and give this board a look (maybe ride it on Thursday)?



you know crackie i was seriously considering it.  In fact, that was part of the reason i went to my dimensions sheet.  Thing is that i think it's a little too thin for me, and i could probably use another inch or two.  The volume/buoyancy works out to around 67# which is actually less than my 6'1" sharpeye.  Don't get me wrong, i think i'd love love love that board on a 3-4ft ocnl 5ft day with 8-12kt offshores.  I just need a little more volume for my fat ass for the more typical NYNJ days - and i'm looking for an everyday all-rounder kinda board.

Plus, i really liked loose's firewire - i'd like to try a board that really keeps its spring for a long time (if in fact they do).
Title: Re: Dimensions Rule of Thumb
Post by: UNCLE!! on February 12, 2008, 11:22:03 AM
I'm so fat, when I do that calculation, I end up with a fraction.

oh god that was funny.

You guys are nerdz ;)
Title: Re: Dimensions Rule of Thumb
Post by: Kdropin on February 12, 2008, 12:14:59 PM
i came up with 19.34 for my firewire... love how it rides

don't know what that number means though   :-\
Title: Re: Dimensions Rule of Thumb
Post by: jammy on February 12, 2008, 07:42:51 PM
my 2 boards come in around 22. i did make some adjustments for added wetsuit weight and poly vs. epoxy. this # makes sense to me since i like a bit more volume.

another consideration is WHERE the board carries its volume. crackie's twinzer feels rather corky to me b/c its volume seems to be too far forward for my taste. its a "23" for me w/a wetsuit on so it shouldn't feel so so different but yet it does!
Title: Re: Dimensions Rule of Thumb
Post by: slow_ride on February 12, 2008, 08:09:23 PM
Seriously,

Little Nasty, check out my twinzer. Of everyone I know, I think that you are the person who can pull the sword from the stone with this board.

It is the ideal Box-Rocket. Round tail keeps you barrelled, yet it is fast enough to outrun closeouts. The size (do the math: 6'2"L-19"W-11.5"N-14.5"T 2.38"R). So, if your biorhythms check out, you should really come by and give this board a look (maybe ride it on Thursday)?



you know crackie i was seriously considering it.  In fact, that was part of the reason i went to my dimensions sheet.  Thing is that i think it's a little too thin for me, and i could probably use another inch or two.  The volume/buoyancy works out to around 67# which is actually less than my 6'1" sharpeye.  Don't get me wrong, i think i'd love love love that board on a 3-4ft ocnl 5ft day with 8-12kt offshores.  I just need a little more volume for my fat ass for the more typical NYNJ days - and i'm looking for an everyday all-rounder kinda board.

Plus, i really liked loose's firewire - i'd like to try a board that really keeps its spring for a long time (if in fact they do).


you ever consider a custom shape to whatever dims your little heart desires (or whatever calculations you brain comes up with) glassed with resin X??

go down to natures shapes or shoot mike an e-mail from his web site and he'll give ya the whole run down.  the flex and durability is amazing on those boards.

Title: Re: Dimensions Rule of Thumb
Post by: little_nasty on February 12, 2008, 09:10:25 PM
that's a good suggestion.  i've been very indecisive about this new board.  i'll probably just do like i usually do and end up in a shop and get seduced by anything fast and loose.
Title: Re: Dimensions Rule of Thumb
Post by: jammy on February 13, 2008, 01:56:46 PM
whee
(http://www.susannahray.com/m10.jpg)
Title: Re: Dimensions Rule of Thumb
Post by: jscottk on February 13, 2008, 03:09:35 PM
26.52 retro egg
21.61 retro fish
and 46.73 for the hansen 50/50 hahahah
Title: Re: Dimensions Rule of Thumb
Post by: skSURF on March 02, 2008, 03:59:49 PM
I think its a little to much of an over simplification but could definitely be useful. I got an 18.7 for my favorite board which I think is a little to buoyant and a 19.2 for my second favorite which I wish had a little more float.I did some calculations somewhere for my first two boards that were insane If I can find them I'll share them. Next to doing a displacement test it's as crazy as any person with a hope of behaving normally would want to get.

Does the dead sea ever have waves. maybe then I could ride something under 6
Title: Re: Dimensions Rule of Thumb
Post by: Looseness on March 02, 2008, 05:48:16 PM
Do you add the wetsuit weight or not? There's a board of mine that rides/paddles great with a suit but can be a bit stiff and hard to set a rail off the bottom if I surf it in trunks.
Title: Re: Dimensions Rule of Thumb
Post by: Crackie Onassis on August 02, 2008, 02:20:41 PM
I can't believe that according to this equation, my 6'6" CI Black Beauty will float better than a 6'8" JC SD3
Title: Re: Dimensions Rule of Thumb
Post by: boyeee on August 02, 2008, 05:33:12 PM
my last 3 boards  (my every day board) i have had (all the same dims) came out to: 19.9963

thats good right? 
Title: Re: Dimensions Rule of Thumb
Post by: Justin-PI on April 17, 2009, 12:35:28 PM
math geeks
Title: Re: Dimensions Rule of Thumb
Post by: ez_ed on April 17, 2009, 01:34:20 PM
Checking the Firewire website I was shocked to see that the 6'2" fish had more volume than the 7'2" Alternator.
Title: Re: Dimensions Rule of Thumb
Post by: Justin-PI on April 17, 2009, 03:01:04 PM
19.4  You may be onto something here.

Hey "dad" you're off the job again. Kui is once again Justrodamus' go-to Science Officer. Sorry.
Title: Re: Dimensions Rule of Thumb
Post by: Justin-PI on April 17, 2009, 03:03:44 PM
Seriously,

Little Nasty, check out my twinzer. Of everyone I know, I think that you are the person who can pull the sword from the stone with this board.

It is the ideal Box-Rocket. Round tail keeps you barrelled, yet it is fast enough to outrun closeouts. The size (do the math: 6'2"L-19"W-11.5"N-14.5"T 2.38"R). So, if your biorhythms check out, you should really come by and give this board a look (maybe ride it on Thursday)?



you know crackie i was seriously considering it.  In fact, that was part of the reason i went to my dimensions sheet.  Thing is that i think it's a little too thin for me, and i could probably use another inch or two.  The volume/buoyancy works out to around 67# which is actually less than my 6'1" sharpeye.  Don't get me wrong, i think i'd love love love that board on a 3-4ft ocnl 5ft day with 8-12kt offshores.  I just need a little more volume for my fat ass for the more typical NYNJ days - and i'm looking for an everyday all-rounder kinda board.

Plus, i really liked loose's firewire - i'd like to try a board that really keeps its spring for a long time (if in fact they do).


you ever consider a custom shape to whatever dims your little heart desires (or whatever calculations you brain comes up with) glassed with resin X??

go down to natures shapes or shoot mike an e-mail from his web site and he'll give ya the whole run down.  the flex and durability is amazing on those boards.



stop the presses! You can order surfboards, CUSTOM MADE to your specs? Get out of town. Next thing you know you'll be able to pick your colors or which side the leash plug goes on. Silly talk.
Title: Re: Dimensions Rule of Thumb
Post by: sir_schadenfreude on May 20, 2009, 06:42:37 PM
Seems interesting, but surfboards are not boxes, so I'm not sure how accurately you can compare the volume of two different shapes based on a LxWxT calculation.  A fish is going to have a lot more volume than a pointy thruster with the same measurements--same goes for a long board and a gun.  Still an interesting relationship, though.
Title: Re: Dimensions Rule of Thumb
Post by: little_nasty on May 24, 2009, 07:39:25 PM
Seems interesting, but surfboards are not boxes, so I'm not sure how accurately you can compare the volume of two different shapes based on a LxWxT calculation.  A fish is going to have a lot more volume than a pointy thruster with the same measurements--same goes for a long board and a gun.  Still an interesting relationship, though.


as mentioned, it's been duly noted that boards are not boxes and come in different shapes.  In fact though, i used the equation for an ellipsoid which is 4/3*pi*L*W*H/(2^3) then figured buoyancy as around 62.3lbs/cu.ft.  So actually i think it's pretty close given that ellispoidal volume is linear in those dimensions same as rectangle and then you just have to adjust for constants and your weight and then a little common sense for the shape.  But as a rule of thumb, i know that a "25" is going to be quite a bit more "floaty" than a "22" and that an "18" might bog a bit in mushy waves for a guy like me.
Title: Re: Dimensions Rule of Thumb
Post by: jamie on June 04, 2009, 11:38:41 AM
Me: ~200 lbs
My boards:
Daily Driver: 6'4"x19 7/8 x 2 5/8 squash==== 19.82
Step Up: 6'6"x19 1/2 x 2 5/8 roundpin=====19.96
"Reverse Mullet" Fish/Squash Hybrid that I just shaped for small waves: 6'1"x21x2 5/8====20.12


Looks like you are onto something...
Title: Re: Dimensions Rule of Thumb
Post by: ya_bloody_wanka on September 04, 2009, 02:20:49 PM
this is cool i weigh 150lbs and i did a few of my favorite boards (between 5'6-5'11) and one i got coming and they are all between 17-19. i guess if your wondering if a board will work based on dims you can figure out what range of numbers work for you which should mean those dims should work
Title: Re: Dimensions Rule of Thumb
Post by: skSURF on September 08, 2009, 01:52:28 PM
this is cool i weigh 150lbs and i did a few of my favorite boards (between 5'6-5'11) and one i got coming and they are all between 17-19. i guess if your wondering if a board will work based on dims you can figure out what range of numbers work for you which should mean those dims should work
Based on the overall shape of the board you can add or subtract from the target number too. Fish +1.5 MinniGun -1.5
Title: Re: Dimensions Rule of Thumb
Post by: sandorka3 on April 06, 2011, 07:38:06 AM
interesting information!!! thank you!!!
Title: Re: Dimensions Rule of Thumb
Post by: adamlesper on January 04, 2013, 11:01:00 PM
Interesting thoughts although my recent boards came out in the 28-30 range as I have asked my shaper to add volume + i'm only 145lbs.  My new board is 6'4 x 20.5 x 2.875 and it comes out to 30 when I apply your equation.  I havent ridden it yet but am anxious to see if it is too much board. 


How much weight does a 5/4 winter suit with a hood, boots n gloves add when wet? 
Title: Re: Dimensions Rule of Thumb
Post by: BltByKrmn on March 01, 2013, 01:15:57 PM
Call me a nerd, but I put this together.  It's every board I've spent a serious amount of time on.


I'm 6'1" 170-175lbs and an average surfer. Fitness fluctuates greatly depending on season, my paddle strength right now will be no where near what it will be come late summer into the fall which effects the notes section quite a bit.


Looking at this, I really should be on boards that are 31 for EPS/Epoxy and 32 Poly if I want to maximize the time out actually surfing vs paddling.  But then of course it will be early September when I'm in boardshorts wishing I was on aboard that was a little smaller.  ;)


(http://i243.photobucket.com/albums/ff74/toc1616/surf.jpg)
Title: Re: Dimensions Rule of Thumb
Post by: Smith St. Surfer on March 10, 2013, 02:32:12 PM
Was reading this issue of Surfer's Journal last week http://www.surfersjournal.com/issues/21-6 (http://www.surfersjournal.com/issues/21-6)


Had a really insightful article up front about what they're doing with CAD design and Volume as the new most important factor in board design.  The unit of measurement all agreed on is "the liter".  Rusty and others are working on perfect formulas taking into account body weight (more with our winter wetsuits) to devise what the perfect Liter amount should be in a custom design.


Don't hang out in shapers shack so this might have been covered before. New to me.  Found it fascinating.  Next custom job I get I'm making sure this is taken into account.