This is a really hard question that sounds easy. How do you tell where the rocker on a board peaks. That is where the rocker goes from highest point in the middle (or thereabouts) to a descending curve to the tail. You can’t do it by eye, because at diffrent angles it looks diffrent.
This is a really hard question that sounds easy. How do you tell where the > rocker on a board peaks. That is where the rocker goes from highest point > in the middle (or thereabouts) to a descending curve to the tail. You > can’t do it by eye, because at diffrent angles it looks diffrent. Jimmy, I must confess that I really don’t understand your question. “Highest point in the middle…” How is the board oriented? How are you looking at it. Please clearify. Maybe Jimmy’s question begs the question: “How do you measure rocker?” Anyone care to answer? Swaylock http://www.swaylocks.com/boards/boards.html
This is a really hard question that sounds easy. How do you tell where the > rocker on a board peaks. That is where the rocker goes from highest point > in the middle (or thereabouts) to a descending curve to the tail. You > can’t do it by eye, because at diffrent angles it looks diffrent. The correct way to measure rocker on a board is to lay the board upside down on some saw-horses or shaping racks. Start by measuring the board length and determining the center of the board, place a pencil mark at this point. Now you need a batton of some sort. I use a 2" wide by 1/8" thick by 8’ - 0" long aluminum flat bar that I have punch-marked in the center. Hold the flat bar on edge, over the top of the board and line up the center marks from both the flat bar and the board. The flat bar will ballance on the center point and act as a sort of level while you take your measurements. Remember to measure rocker 12" from the tail and 12" from the nose. Hope this helps.
Sorry folks! That last line should read: Remember to measure rocker at the tail and the nose using a vertical measurement. Hope this helps.
The correct way to measure rocker on a board is to lay the board upside > down on some saw-horses or shaping racks. Start by measuring the board > length and determining the center of the board, place a pencil mark at > this point. Now you need a batton of some sort. I use a 2" wide by > 1/8" thick by 8’ - 0" long aluminum flat bar that I have > punch-marked in the center. Hold the flat bar on edge, over the top of the > board and line up the center marks from both the flat bar and the board. > The flat bar will ballance on the center point and act as a sort of level > while you take your measurements. Remember to measure rocker 12" from > the tail and 12" from the nose. Hope this helps. This makes sense - but I have one problem: It seems that how the board balances on the saw horses will be directly related to where and how wide apart you put the saw horses. Won’t this will effect the way the aluminum bar lays on the midpoint and thus effectively make measurement of nose and tail rockers relative? I don’t want to reinvent the wheel here but I would think the surest way to measure rocker would be to put a shaped blank with no fins bottom side down on a flat surface, let it banance, and then measure the nose and tail rockers. Swaylock
This makes sense - but I have one problem: It seems that how the board > balances on the saw horses will be directly related to where and how wide > apart you put the saw horses. Won’t this will effect the way the aluminum > bar lays on the midpoint and thus effectively make measurement of nose and > tail rockers relative?>>> I don’t want to reinvent the wheel here but I would think the surest way > to measure rocker would be to put a shaped blank with no fins bottom side > down on a flat surface, let it banance, and then measure the nose and tail > rockers.>>> Swaylock, I totaly agree with you on that one. The method I described earlier was the method used in the video “Shaping 101” by Crossfire productions with John Carper. I have also read several books that describe the same method. As for myself, I try to put the board evenly spaced between the racks and take my measurements from there. It would be awsome to hear from someone like Rich Harbour or Rusty P. on this one. Mark.
Mark. I’m not a shaper but a surfer and filmaker. When I shot Shaping 101 with John Carper I noticed John’s racks were extremeley adjustable and accurate making it easy to obtain a perfect level for your blank. It’s also helpful to start with a level floor. Living in La Jolla in the late 80’s I saw John kick out tons of boards for Rusty. John and Dave Parmenter actually pioneered several shaping tools which are now used world wide. John also shaped for HIC before creating JC/Hawaii. I would take his advice on Shaping 101 & Glassing 101 literallly as I would if it came from Rusty or Al Merrick. Keep in the water… Carl Ackerman
Carl I hope I haven’t offended anyone by giving my $ .02 worth. I highly value John’s advice and methods, they work great for me. I also would be appreciative of any profesional shapers comments, sugestions or opinions (hint hint all you pros out there).
That’s a good question, Jimmy. The responses were good, but what I think you’re asking is where the entry rocker stops and the tail rocker starts. If you simply set the board on the ground deck up without fins and see where the board touches the ground as one of the readers suggested, you get the balance point and not a rocker reading. Try this method: Set the board either on a single shaping rack or something else about 2 or 3 inches wide. The deck should be up. Move the board around untill it balances (no fins). Take a line level (a 2 INCH long level brick masons use) and move it along the stringer. You’ll notice when the bubble is in the middle of the level you’ve found the rocker “peak” as you call it. Small wave boards usually have a spot that’s fairly flat at just behind center. Boards for larger waves should have little or no flat. If the board has concave, You’ll also want to check your rail rocker with the same method by putting the level out on the rail and moving it nose to tail. You’ll probably notice quite a diffrence between the stringer rocker and rail rocker. Small wave boards will generally have their “peak” farther back than boards for more powerful surf. This is an IMPORTANT part of design. Excellent question.
That’s a good question, Jimmy. The responses were good, but what I think > you’re asking is where the entry rocker stops and the tail rocker starts. > If you simply set the board on the ground deck up without fins and see > where the board touches the ground as one of the readers suggested, you > get the balance point and not a rocker reading. Try this method: Set the > board either on a single shaping rack or something else about 2 or 3 > inches wide. The deck should be down. Move the board around untill it > balances (no fins). Take a line level (a 2 INCH long level brick masons > use) and move it along the stringer. You’ll notice when the bubble is in > the middle of the level you’ve found the rocker “peak” as you > call it. Small wave boards usually have a spot that’s fairly flat at just > behind center. Boards for larger waves should have little or no flat. If > the board has concave, You’ll also want to check your rail rocker with the > same method by putting the level out on the rail and moving it nose to > tail. You’ll probably notice quite a diffrence between the stringer rocker > and rail rocker. Small wave boards will generally have their > “peak” farther back than boards for more powerful surf. This is > an IMPORTANT part of design. Excellent question.
Jimmy, I must confess that I really don’t understand your question. > “Highest point in the middle…” How is the board oriented? How > are you looking at it. Please clearify. Maybe Jimmy’s question begs the > question: “How do you measure rocker?” Anyone care to answer?>>> Swaylock Jimmy, I’ve been researching this topic for several weeks now. It seems to me that if you were to duplicate the rocker of the blank by setting up your racks so the measurements given in the blank catalog (provided by your blank mfg. ie…CLARK FOAM) reflect the measurements of your blank before you start shaping and making adjustments to the rocker, then you should be pretty close to the factory “rocker peak”. Mark.