OK Im loosing sleep over this and need help.
How do you take the 5’5 Steve Lis fish for example and scale up to 6’1 ? What will the width be ?
OTION 1: I have heard the add an 1/8" in width for every inch of length added - Greg Loehr.
OPTION 2: BUT… if I want to keep the width to length proportions accurate to the little 5’5 the width would be much more.
What does the industry do ?
“the industry” doesn’t bother to scale up or down.
They just hire some template maker, usually a master shaper, tell him length, width, some more specs, and he makes the template, to be used as a master, for all future boards that particular size.
Scaling doesn’t really work, as thickness flows, wave curves, actual rocker and profile, rail thickness and shape, balance, and lots of other factors have to be just perfect before scaling comes into play.
Outline is one of the least important parts of the equation, or at least no more important than any of the above listed criterias.
Nope…still totally confused.
How wide would the 6’1 be if the 5’5 is 20 1/4 wide.
Help!
Bobsie…
Since you have Greg Loehr’s method, here is a direct proportioning method. Greg has pointed out that if you try to scale a 6’ board to 9’ using this method, you will end up with a very wide board. For close conversions, it may work for you.
Direct scale involves first converting length to inches and dividing longer length by shorter length. (73/65 = 1.123…) Now multiply your starting width by that number. (20.25 X 1.123 = 22.74")
If you use Greg’s method, multiply the length difference by 1/8. (8 X 1/8 = 1) That gives you a width of 21 1/4" for your new board.
Do the same to your nose and tail widths too. Take your pick.
That is very clear, thanks John.
BUT… which way is the right way ?
Which way would you do it ?
If you want the TRUE SCALE, it can be found by the relationship between L and W as defined by a basic ASPECT RATIO equation:
AR = L/W
this will give a TRUE SCALE (I dont know what pro shapers are using)
after solving for AR using your knowns (L1 and W1) using basic algebra you can then use AR and L2 to solve for W2.
Heres one example: you know L1 = 65",
W1 = 19" (assumed) and L2 = 73"
solve for AR: AR = L1/W1 = 65/19=3.42105
solve for W2: W2 = L2/AR = 73/3.42105 = 21.34"
Aspect ratios are very useful in every day gearhead living (its were the 40, 50, 60 dimension of car tires comes from)
good luck…
“Eyeball” is my preferred method.Just like rail bands.
Yeah CL sounds good, but your a pro with thousands under your belt…and we are just squirrels trying to get a nut…sorry couldn’t resist…lol…peace and waves…
Ok, here’s another way to look at it…
If you go with direct scale as John has worked out for ya, then nose, tail and such are gonna be easy too: multiply by 1.123 and there ya go…sort of, 'cos you’ll have to multiply the foot back from the nose and foot forward from the tail by 1.123 too. That will give you an exact scaled up outline shape. Will that work for you as a board? Good question. You won’t know unless you try it.
If you go with 1/8" per inch, you will have to kinda swing for the fences on what your nose and tail measurements are gonna be with eyeball and batten. Though I’ll note that many Lis-style fish, the successful ones, in that size range tend to run around the 21 1/4 - 21 1/2 range. See, for instance, the Mandalas and others on http://www.swaylocks.com/resources/Photo_Archive/5ft_to_5ft_11in/ - so, you have some evidence that a fishie in that width range will work.
Or, there’s Cleanlines approach - go with something that looks good, feels right. Which is taking the 'add an eighth ’ method a step further. That works if you’re good and it doesn’t if you’re not. You wind up doing some outlines with batten and scrap and eyeballing them and thinking about it.
Now, myself, if I was doing it, I’d try a few fish in that size range and see what I liked and didn’t like and what worked… and especially what didn’t… and go from there, synthesise a little. Bear in mind that a 6’1" scaled up version of a Lis fish…are you gonna be kneeboarding it like Lis or using it in a more pedestrian manner? Lots of things to consider, y’know, an exact copy or an exact scaled up copy may not be what you want anyhow.
The Right Way … there isn’t one right way, it’s not an exact science. Otherwise we’d have been replaced by software long ago.
doc…
At the risk of starting an unintended debate, I think crafting a surfboard is all a matter of balance between art and science. I don’t believe Cleanline’s comment was a stab at technerds who prefer equations and robots to shape boards, but rather an honest revelation that he uses his senses as an artist also. Sure he has crafted thousands of boards, but I doubt he evolved from beginnings as a scientist/engineer who ultimately put away the calculator.
I have heard both Skip Frye and Michael Hynson refer to their shaping as “functional sculpture”. Watch many skilled veteran shapers at work and you’ll notice they constantly feel, look, listen to the planer, tune their handplanes perfectly… because they are crafting and creating art.
OK, I don’t want to get too cosmic here, just trying to make a point. Granted, the late Bob Simmons is known as the father of modern design and was a “mad scientist”. But I have been told also that he was a very creative artist as well.
My point is that while some bust new tech barriers, others go down paths toward Asian factory production, and ultimately robots find a place in all of this, it is also a craft. There’s a place for one of a kind works of art created more from soul than from equations. So find your niche, go your own way, and aplaud those who go another.
Break is over, time to get back in the shop. Enjoy the ride (wherever it goes)!
I had a “round nose fish” (far from it) to template for BC surf in San Clemente. It was a 6’6", I plugged in all my measurements. got the templates to line up nicely and sawed it out. But once I started running around it with my planer, the lines from about 16" back from the nose to about 20" from the tail just refused to be removed by the planer. So, my “scaling” for this one was a bit too narrow for what would be the “natural curve” around the points.
I have a Bertlemann style temp, borrowed off a Nectar 20 years ago, that I wanted to use for bigger boards. On a piece of door skin, I marked it off for 6’4", drew in the nose to middle and tail to middle. The lines at this point looked like one side of the Infinity logo. Wanting the wide point ahead of center on this temp, I went through all of my old pre 80’s temps with forward wide spots to loft in the new curve, of course it was plumping up in the center. But to compensate for this, I pulled in the nose and tail dim’s slightly.
Robbie Keagle brought me a blank to try and dupe a Mark Richards G&S twinny from. He had pulled a crude temp off a battered old one and asked if I had something like it. I pulled out the new 6’4" and it fell right onto the lines on this temp. Sometimes it takes a lot of elbow grease to get a satisfying curve, but in the end the result will be worth the effort
OPTION 2: BUT… if I want to keep the width to length proportions accurate to the little 5’5 the width would be much more.
the man has asked a simple question focusing on accuracy and much of what I’m reading is noise… funny thing is, even with my engineering background I still prefer the eyeball/feel approach… however when a read a newbies question I prefer to answer questions directly and keep subjective opinions to a minimum…adding 1,001 opinions will only lead to more confusion. the simplest answer to the question is AR = L/W take it or leave it.
I like the technical aspect of this question.I am old school so therefore not too swift in the math-tech. area.However we have done what you are talking about using a computer(not me…a buddy of mine).He took a digital picture of the board we wanted to scale up and he somehow used the computer with an architectural program to enlarge it.At this point he took the specifics to a blueprint place and they printed a full length 1/2 template on paper.It only cost around $7bucks.I took the paper template and glued it to a door skin and cut it out.It came out real nice.Much wider that anticipated but the curve was maintained and it rode great.That was a scenario where my “eyeball” told me it was too wide but the machine was right in the end.
Every one has a different way of doing things. In my opinion it is an art with feeling and flow. No need to spaz ,everyone has an opinion…and some of it is subjective. Even “noise” is good sometimes,just because it is not yours does not mean it won’t add to the subject being discussed. I love swaylocks and there is no cut and dry answer to many questions of design…even scaling up…not always a mathematical solution to solve it all…peace and waves…
There are many good ways to do things in life Grasshopper. The search for the “right way” can be very disappointing. Figure out what is right for you and have peace with it. When you do that you will become like Frye and Hynson etc. That’s what they did. Then people will be asking you how to do it.
The method I presented gives the exact same result as the AR method IF the same original width is used. For some reason, Meecrafty substituted an “assumed” width of 19" in his demonstration. The direct proportional scaling method is the same in both techniques… It’s actually pretty simple math involving cross multiplying and dividing - you just have to set up the known dimensions and the unknown variable as a proportional ratio to get the missing number which is exactly what Meecrafty and I have both done.
Try Meecrafty’s method using the given 20.25" width originally specified and see.
There obviously is no widely accepted “right” way. Direct proportioning only works to a point. That’s why a 9’ retro fish isn’t really workable with the same proportions as a 6’ retro fish unless you want a board 33" wide.
This too is a good approach. Actually, its the one I favor.
hey beardw… either you are lost or I’m the one who is lost… Grasshopper is not in this thread, or is he?
I guess I’m the one who’s lost… what the heck just forget it…
I gave Bobsie, the one who started the thread, the nickname “grasshopper”. It comes from an old television show called “Kung Fu” staring David Caradine. He had a guru who helped him figure out the mysteries of life. The guru called him “Grasshopper”