"I'm 195 lbs and 5'10" and in good shape with most of my weight on top. I ride a 6'6" to 6'10" for my normal shortboard and got a 5'10" fish this year. I love the ability to get into waves, the speed and maneuverability in under head-high surf, but have problems with the outside nose rail digging at times. I also have problems with steep takeoffs because of the lack of nose rocker. What aspects of the fish should I keep and what should I change?"
Rusty, who's been shaping since before the original fish was invented, fillets the question:
Ironically, the traditional/old school fish was designed for and excelled in fast hollow waves like Old Break, Big Rock, and Blacks, but it was primarily ridden as a kneeboard and ridden much shorter than your board at 4'8" to 5'2". In fact, 5'6" was considered big. Eventually more and more people actually started standing up on the bigger ones and discovered that they were fast and maneuverable (sort of) in small, mushy, running waves. If you are interested in more background, hit up Eric Huffman at: BirdSurfBlog.com
Rocker, or lack of, can be the culprit when a nose pokes on takeoff: the board isn't fitting the curve of the wave. Either the board needs to be shorter or have more curve. On your next fish, try a little more rocker in the nose and possibly the tail. A little more curve in the back half is just as important -- if the tail curve isn't fitting in the steepest part of the wave, it will lift the back end and drive the nose in.
It is important to have some balance in the curve. By that I mean the rail arc needs to flow from one end to the other. Having excessive curve at either end won't correct the whole package and abrupt changes in curve will cause drag.
Your outside rail digging is partly related to rocker and is also probably a result of the nose being too wide for certain conditions. Once again, the back half of the board may be coming into play. If the tail is very wide and the outline curve is straight (factor in low rocker), the back end of the board won't fit and/or release in a controllable manner.
Again, I am assuming your board is a traditional/old school fish. My numbers on this type of board are something like this: 5'10", 2.3" thick, width: 15.5" (nose), 20.5" (center), 16.5" (tail) and 12+" corner-to-corner on the pins. Rocker: 4.25" (nose), 1.3" (12" down from nose), 0.52" (12" up from tail) and 1.4" (tail).
My suggestion would be to pull in the nose and tail about an inch or so, leaving the middle width about the same. Pull the corners of the tail in at least an inch, maybe more. As the fish evolved, it sprouted wings. This helped to step down the width on the back end of the board and reduce the pin-to-pin distance to something on the order of 10".
Rocker: A little goes a long way. The front end could come up to approx 4.5". The back end on the older fish was low -- something on the order of two inches in the tail. Once again, an even curve would probably be a lot more user friendly in a broader range of conditions.
Thickness: The old fishes were flat, but relatively thin compared to other boards of the day. Adding thickness to a flat-rockered board becomes a little problematic, in that the deck line starts to develop a hump, or an "S-deck", and transitioning out to a clean rail line becomes more challenging. To compensate for some of the volume you have given up by pulling in the template, you can add a little thickness to the center. With a little more bottom curve, you can probably add back in some thickness in the midsection.
Fins: A lot of the old school boards have the glassed on wood keel fins. These were designed to build more drive into very short boards. As you go longer, you have more rail and can probably get away with a shorter-based fin. If you don't have removable fins, try a fin system so you can experiment with different feels for different conditions.