RECENTLY I WAS INTERESTED IN FIGURING OUT THE ROCKER IN MY 9’5", FIRST I USED A STRAIGHT STIFF PIECE OF ALUMINUM AND HELD IT DOWN IN THE MIDDLE OF THE BOARD(AS SEEN BY OTHER SHAPERS) AND GOT MY READINGS, THEN I REMOVED THE FIN AND LAID IT ON THE FLAT FLOOR(RUG) AS IT WOULD BE IF IT WERE FLOATING IN THE WATER SO TO SPEAK, THIS GAVE ME A DIFFERENT SET OF READINGS. NOW I CAN SEE HOW THE ARC IN THE BOTTOM MIDDLE AFFECTS AN ACCURATE READING(OR DIFFERENT LONGBOARD BLANKS FOR THAT MATTER) SO HOW THE HELL CAN ANYONE HAVE ACCURACY? IF I SAY I WANT 4.5" OF TAIL ROCKER HOW CAN YOU PROVE TO THE CUSTOMER IT HAS BEEN ACHIEVED? SEEMS LIKE A THIN OR THICK NOSE WOULD AFFECT THE BALANCE OF ROCKER ALSO!!!
RECENTLY I WAS INTERESTED IN FIGURING OUT THE ROCKER IN MY 9’5", > FIRST I USED A STRAIGHT STIFF PIECE OF ALUMINUM AND HELD IT DOWN IN THE > MIDDLE OF THE BOARD(AS SEEN BY OTHER SHAPERS) AND GOT MY READINGS, THEN I > REMOVED THE FIN AND LAID IT ON THE FLAT FLOOR(RUG) AS IT WOULD BE IF IT > WERE FLOATING IN THE WATER SO TO SPEAK, THIS GAVE ME A DIFFERENT SET OF > READINGS. NOW I CAN SEE HOW THE ARC IN THE BOTTOM MIDDLE AFFECTS AN > ACCURATE READING(OR DIFFERENT LONGBOARD BLANKS FOR THAT MATTER) SO HOW THE > HELL CAN ANYONE HAVE ACCURACY? IF I SAY I WANT 4.5" OF TAIL ROCKER > HOW CAN YOU PROVE TO THE CUSTOMER IT HAS BEEN ACHIEVED? SEEMS LIKE A THIN > OR THICK NOSE WOULD AFFECT THE BALANCE OF ROCKER ALSO!!! I also watch other “experienced” shapers do the same proceedure, I just about bust a gut every time. Slide the blank forward or to the rear and the rocker reading will be different each time. People ask me all the time how much rocker a particular shape has and my answer is “I don’t know, about that much”? Changing the volume in the rails, moving the wide point, increasing thickness or any one of a jillion other things will change what the rocker is doing. After a few decades of shaping, the visual image of the rocker is indelibly etched in your minds eye. As it is shaped in you will see what the bottom will be doing as it moves over and through the water. I watch others use the flexible rocker templates to recreate a “majic” board for a customer, it is no guarantee. I have used top and bottom templates, rail templates and used a complete thickness flow measurement and had the customer tell me it doesn’t ride anything like the last board. Go figure!
Seems to me that rocker may perhaps be the most complex part of shaping a board. You have a number of variables going into it. But check out what Jim was really saying…After all is said and done it is more of a “feel” thing that any sort of measurable quantity. Are there other areas of shaping that are guided by feel?>>> I also watch other “experienced” shapers do the same proceedure, > I just about bust a gut every time. Slide the blank forward or to the rear > and the rocker reading will be different each time. People ask me all the > time how much rocker a particular shape has and my answer is “I don’t > know, about that much”? Changing the volume in the rails, moving the > wide point, increasing thickness or any one of a jillion other things will > change what the rocker is doing. After a few decades of shaping, the > visual image of the rocker is indelibly etched in your minds eye. As it is > shaped in you will see what the bottom will be doing as it moves over and > through the water. I watch others use the flexible rocker templates to > recreate a “majic” board for a customer, it is no guarantee. I > have used top and bottom templates, rail templates and used a complete > thickness flow measurement and had the customer tell me it doesn’t ride > anything like the last board. Go figure!
Seems to me that rocker may perhaps be the most complex part of shaping a > board. You have a number of variables going into it. But check out what > Jim was really saying…After all is said and done it is more of a > “feel” thing that any sort of measurable quantity.>>> Are there other areas of shaping that are guided by feel? SEEMS LIKE KNOWING SPECIFICELY WHICH LONGBOARD BLANK A RIDER LIKES THE FEEL OF, AND THE SHAPER FOLLOWING THE NATURAL CURVE THAT THE BLANK HAS ALREADY IN IT IS THE EASIEST WAY OF DECIDING THE STIFFNESS OR LOOSNESS OF A BOARD, CAUSE THE 9’1Y HAS GREAT LOW NOSE ROCKER AND THE MOST TAIL ROCKER OF THAT SIZE BUT THE 9’5S HAS MORE NOSE BUT LESS TAIL ROCKER. SO IF A HOTSHOT RIDER SAYS TOO “STIFF” THE NEXT SHAPE WITH THE SAME BLANK COULD BE ORDERED FROM CLARK +3/4"T TOO ACHIEVE A LOOSER FEEL! WHAT DO YOU THINK? CAUSE I KNOW GUYS LIKE DOBSON WANT/KNOW WHAT THEY WANT OUT OF A BOARD…DO BLANKS ALL HAVE THE SAME REPEATABILITY IN THEIR MANUFACTURED DIMENSIONS EXPECIALLY BOTTOM CURVE?
The universal method to measure rocker is holding a straightedge at the center point of the board and measuring at the nose and tail and points inbetween. This is the "Clark Foam " method. While there are flaws in every rocker measuring method, this is the easiest and most efficient so everyone’s on the same page so to speak. You can use all the straightedges, rail templates, rocker templates, etc, but you can never duplicate a board. Each blank is diffrent,each stringer will have a diffrent flex pattern, even the weather on the day the board is glassed will have a huge effect. Every board is unique, just like an original piece of art. That’s the beauty of it. Aloha
The universal method to measure rocker is holding a straightedge Do you rest it and let it level itself or do you hold onto it? at the > center point of the board and measuring at the nose and tail and points > inbetween. This is the "Clark Foam " method. How is the board resting? On board stands with the bottom up or on a flat surface resting on nose and tail. While there are > flaws in every rocker measuring method, this is the easiest and most > efficient so everyone’s on the same page so to speak. You can use all the > straightedges, rail templates, rocker templates, etc, but you can never > duplicate a board. Each blank is diffrent,each stringer will have a > diffrent flex pattern, even the weather on the day the board is glassed > will have a huge effect. Every board is unique, just like an original > piece of art. That’s the beauty of it. Aloha
You put the board on the racks bottom up. You put a mark on the stringer at midpoint. You have a mark on the straightedge at it’s midpoint. Set the straightedge on the midpoint with the centerline marks matching. Put your finger on the straightedge on the mark and hold it tight against the board. Now measure the rocker.