volume algorithm - avoiding the slater copycat phenomena

General Discussion
21

Lennox 76 seems to be on the money for this one.

I have been intested in this volume equation for a while but have never figured out what would be my optimum amount (lazy)!

However, recently none of my fav boards go after a two year layoff and some of them are still mint. I am the same weight, size etc , and have kept a high level of cardio fitness. The only thing that has changed is the amount of time spent surfing and my new boards are dramatiucally thicker, wider and fatter to help me out. As far as i can see most things surfboard orientated are subjective and personal. Being dependant on so many variables would appear to make it  almost impossible to pin down any hard and fast formulas,everything else will become generalisation because of this.

Although…I am ever keen to find the magic formula!

22

wasn’t there a very recent post in another thread that mentioned 1/3 of body weight to suffice for one’s custom board volume ? forgot the title but it’s also in the general discussion section

cheers,

23

http://www.diversesurf.com.au/news/news/volume.php

 an updated link to my volume information . i have been writing on my boards since 2004.

 the  average high level surfer here rides approximatly .35 litres volume per kilo of body weight! there is a lot more variables involved. this is a simple  help to see one more factor of your boards specifics!

24

 

Is that board floating? or is it just me?

25

There's references to customer's board volumes all over the Coil Ride Reports thread.. I can't imagine doing customs without a volume measurement, I'm sure feraldave feels the same way.

26

 

heya dave,

if not for your aloha spirit, we wouldn’t be learning from your valuable experience! hmm your explanation at your site basically states “… different board contruction methods will give you different flotation. For example an EPS/epoxy board can have 15-30% more flotation with the same volume and displacement… than traditional PU…”

for boards made with non-synthetic materials like HWS, how much more / less flotation would they have compared to traditional PU boards?

 

27
feraldave wrote:
http://www.diversesurf.com.au/news/news/volume.php

 an updated link to my volume information . i have been writing on my boards since 2004.

 the  average high level surfer here rides approximatly .35 litres volume per kilo of body weight!

 

0.347 or 0.35 is the same factor that I use. Let's say you may a standard 6'1" x 18 3/8" x 2 1/4" Thruster @ 26 ltrs for a 73.5 kg surfer.

You want to make him a shorter Slater concept the .35 litres per/KG is a factor that works well for maintaining volume.

For Example:

5'9" x 19" x 2 3/8" Quad @ 26 ltrs (wider tail block)

When the surfer goes between boards in his quiver he can do this with ease if his shaper is in tune to VA (volume algorithm).

Surfding

28

This algorithm idea could be interesting to test! Maybe it could be a tool to help shapers or board sales people convince people not to get boards that are “too small”. What if you start with a “base” shortboard volume then adjust it up or down according to experience, fitness level, wave type, and board type. Something like this:

Weight Volume “starting point” in litres

70k 25l

80k 28l

90k 32l

etc.

Then you adjust something like this:

Fitness level

High - subtract 3l

Average - no change

Low - add 3l

And similarly have a few adjustment factors for the variables like experience (more experience = less volume), wave type (slower waves = more volume) etc.

 

Would be interesting to see if there was a simple model like this that could be helpful.

 

Michael

29

I find for a short board I need a ratio of between 1cubic ft to 210-170lbs. A step up the ratio shifts to 1:160-135lbs. Bigger boards that that I don’t know since I don’t ever get waves like that on the east coast. There are many variables to determine which range of the ratio I would use, from rider ability to volume distribution.

30

 

That’s the same guy who surfs on little pieces of plywood.

31

Got some funny looks from the girlfriend last night when she found me on the scales in the bathroom in full winter rubber trying to get my ‘wet weight’!

Seriously though I am 65 kilos dry, and 68.8 in fully winter rubber after a shower. More difference than i thought, Dont know how this will affect my new board but was interesting none the less.

32

so 1 more litre board volume would help when your rubbered up…

33

Yes, but only if they weigh 15-30% less!

Reserve bouyancy is what is left over when the vessel/board has displaced enough liquid the support its own weight.

A board of heavier construction will have less reserve bouyancy than the same volume board in a lighter construction.

To calculate a board’s reserve bouyancy,

Reserve Bouyancy = (board volume * water density) - board weight.

So, for a 2kg alia with a volume of 2 litres in salt water,
RB=(2*1.025)-2 = 0.05kg
therefore it will barely float itself.

If you made two boards of the same design, let’s say a 9’ longboard with a volume of 100 litres, one an epoxy compsand weighing in at 5kg; the other a HWS weighing 10kg; the reserve bouyancy of the compsand would be 97.5kg and for the HWS would be 92.5kg.

The search for a formula is probably not very useful, there just too many wooly variables.
What would be of more use, is knowing the accurate volume of the boards you ride now.

34

[quote="$1"] The search for a formula is probably not very useful, there just too many wooly variables. What would be of more use, is knowing the accurate volume of the boards you ride now. [/quote]

Good post, all of it... 

 At least Diverse and Coil's customers know their volumes. I like to quantify everything I can.

35

At least Diverse and Coil's customers know their volumes.

 

Add me to the list!

36

Alright, welcome to the movement!

It's an important ''dimension'', just like length and width and thickness. Like I've said when this came up before, it's a great tool to have when working across a guy's quiver, and it lets you see how much personal preference there is in static bouyancy. Some people like to float, others like to swim...

37

few variables to consider which may make whatever maths stuff you come up with useless IMO...firstly diff surfers like a different amount of volume, some like more so it floats well, others hate volume and want to have a sensitive and thinner board, also to consider is materials, different foams have different floatation qualites, different glassig and the amount of resin sanded also makes a difference to overall wieght which therefore affects the floatation so then the volume may be incorrect...I find that discussing with the surfers and finding out what they like with volume is the best way, then use your knowledge and experience to create what the have requested ( or require which is sometimes the same, sometimes not )....fitness also comes into it , just because an 80kg surfer is suited to a 2 9/16" shorty, does that mean his unfit chain smoking, asthmatic mate who also weighs 80kg's needs the same volum ? I think not....theories are great but there are way too many variables for anything accurate....imho

38

I think not....theories are great but there are way too many variables for anything accurate....imho

Pridemore: Your right from your perspetive.

Math is a tool like anything else.

Shaping is both an Art and a Science.

The Art is how you use that Science.

VA is only another tool. (Volume Algorithm)

Think of it as a starting point and once you have the VA for a given surfer you can use the value as a factor to build his quiver. A surfer who is serious about surfing should have at least 6 boards. Knowing the VA of the Surfer is valuable in meeting his requirements for his quiver.

Each surfer has his on VA.

A 27 year old surfer 70KG who surfs 2x everyday and does the tour may have a value somewhere between:

25 - 26 Ltrs/Cubic Meters

A 23 year old surfer 60KG who surfs 2x everyday and training for the tour may have a value between:

22 - 24 Ltrs/Cubic Meter

A 13 year old surf team ripper: 19 Ltrs/Cubic Meters

A heavey Pot Smoker who surfs only when the waves are good and watches a lot of Tele and eats junk food and doesn't train would be on a totally differnt board anyway: 27 - 30 Ltrs/Cubic Meters and maybe he's on a fish or a tuby?

Fittness and seriousness does play an important role in all this. The beauty of the Math is that Math doesn't lie.

VA is like DNA (For Ilustration). Every surfer will have his on VA and as a board builder you can use it as a tool to adjust the desired volume. Otherwise your just building random boards and trying to get close in meeting the customers needs. Kind of like playing "Black Jack"! Math Formula's will help you to solve many problems and make your designs that much better.

Sure you can do it all on intuition?

Just like making bread: You don't just throw some Flour, Water and Yeast together at random and expect to have good tasting bread? No you measure each ingredient. The Art comes from knowing how much yeast to add based on: {time; temperature; fermentation}. How about "Altitude"? Its not random!

The VA value is by no means meant to be used as one size fits all. It's up to you to formulate what works for the surfer? 

After a while you will be able to peg a VA value on a surfer after a bit of background. So math becomes organic as you calibrate your mind to use it to your benefit in your given craft!

The usefulness is when you build a standard Thruster at:

6'1" x 18 3/8" x 2 14" = 26.1 Ltrs/Cubic Meter for a good surfer

5'9" x 19" x 2 3/8" = 26.1 Lrs/Cubic Meter for the same surfer (Maybe I change the fin set-up to a quad?) Slater's Approch to reduction. I have been doing this a lot lately for many good surfers.

Within the HPSB range this is a great tool. Now when you get into larger boards these values are a bit different.

You don't have to use the VA factor. It's just a another tool. Use the tools you want?

Surfding 

 

 

39

Very helpfull post surfding.

I am trying to get a starting point for my shaper to work on a new quiver and all of your posts have been really helpful. Feral daves info on his site was really helpful too.Thanks.

According to feral daves formula  were I a pro, surfing d- bah in my 5mm winter wetsuit, boots and gloves ,despite being very hot, my body weight would require a board of approximately 24 litres. My general surfing conditions are much weaker than this and I am no pro. I have however surfed since i was a kid and despite a couple of years off due to injury most of what I learnt over the years is still in there somewhere.

I do not really fit into the pot smoker category above and have a well above average level of fitness.  I guess a good starting point for myself may be about 26/26.5 litres.

All this info is great, though  i am concerned about the transition to non computer shaped boards based on these numbers. My shaper is very experienced but stuggles to get into his email account! I am thinking rail shape more than anything? For example, a six foot board whose plan shape and dimensions remain set will surely suffer reasonable fluctuations in volume due to rail shape, whilst this is very obvious to most of you, how do you quantify this? Could i possibly figure this out in a shaping program then discuss with my shaper how this translates? I have heard that acu shaper is available on a free demo, is this any good?

40

If Your Shaper is Very good :ie experianced. and of age where email accounts are not often used then just discuss your board with him. he will make you a great board. the Volume knowledge is the most use for the shape uneducated & the stock off the shelf buyer who does not get to talk to his shaper. i Believe any thing i can teach my customers helps me make better boards for them everytime as they understand more and learn to communicate about it!